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00:04 | okay today is going to be interesting we got a lot of ground to |
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00:10 | catch up with the protection of the . Then we're gonna jump into the |
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00:14 | system itself. We're gonna start looking structure, We're going to focus on |
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00:18 | spinal cord. All right. So in anatomy class, what you'll do |
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00:22 | you'll do the brain first and go the spinal cord, then go to |
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00:25 | peripheral nervous system. For some your book does, it kind of |
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00:28 | , it goes to the spinal cord , then it does the spinal nerves |
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00:32 | it goes back to the brain, it does the cranial nerves. It's |
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00:35 | kind of wonky. But I think easier just to follow the book and |
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00:39 | jump around in the book. So kind of where we're gonna go |
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00:42 | And our starting point here is gonna the blood brain barrier. As I |
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00:47 | , we were saying, there's different in the brain. Started with the |
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00:52 | that we moved to the meninges from meninges. We talked about the cerebral |
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00:56 | fluid. Now we're down to this tiny structure. This weird thing, |
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01:00 | is called the blood brain barrier. it's gonna be abbreviated BBB uh in |
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01:05 | and there are different parts of the that have these kind of unique environments |
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01:09 | are kind of separated and really what have here Is a structure that is |
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01:16 | from uh the glial cells and the that are actually found in the |
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01:22 | Now, I know we've never talked blood vessels. So, I've just |
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01:26 | to give you like a 32nd understanding blood vessels, arteries move blood from |
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01:32 | heart to whatever the organs are, , move blood from wherever the organs |
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01:37 | back towards the heart. The place blood exchanges in that organ is called |
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01:42 | capillary. The capillary is a leaky . Alright. It's like taking your |
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01:48 | putting them together with your fingers slightly separated and like scooping up water, |
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01:53 | would kind of drip through. All right. So imagine taking marbles |
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01:58 | then doing the same thing with water so the water would drip through. |
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02:01 | the marbles would stay in your Right, Okay, so that's how |
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02:05 | work through. About oh I don't , 95% of your body then we |
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02:10 | the blood brain barrier. Blood brain . Like taking those same fingers |
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02:14 | And having them separated. But instead separating it, what the what the |
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02:17 | cells the astro sites do is they um let's go ahead and put a |
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02:21 | bit of superglue between your fingers so your fingers are now glued together and |
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02:25 | can't sneak through. And so when scoop up water, water stuck. |
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02:28 | the only way the water is going be getting out is it actually goes |
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02:32 | your hand. Alright. And this a process called Transito sis when you |
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02:36 | through a cell. Transito sis If you go between cells, it's |
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02:42 | . Oh sis. Alright. So you see that word or hear me |
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02:45 | that word? Or see it on picture? That's what it means. |
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02:48 | right now, the reason we have is because your brain is really |
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02:53 | Would you agree your brain is really ? I mean, we have to |
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02:56 | at all the protections. We we have the skull, we have |
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02:58 | meninges, We have the cerebral spinal . We are protecting that brain from |
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03:01 | sorts of physical damage. So here blood brain barrier is there again to |
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03:07 | as a barrier between the stuff that's in your blood. That could then |
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03:11 | transferred to that tissue and causing Let's think of a fun thing that |
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03:17 | put in our bodies that causes our to kind of go conquer for a |
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03:22 | bit right. Can you think of ? Hmm. I saw lips say |
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03:29 | , drugs. Well, alcohol, , alcohol is our favorite thing. |
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03:35 | sorry. Different generation. So, , when I was college, that's |
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03:40 | it was all about. Remember I to school in New Orleans. |
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03:42 | I was just like, how can go out every night and have fun |
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03:45 | . All right, alcohol is one those things can actually penetrate through the |
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03:49 | brain barrier. We'll see why in a moment. But you can see |
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03:53 | adding one small chemical, right, it can affect the brain imagine of |
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04:00 | the different types of chemicals. Because we've already talked about like ions, |
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04:06 | ? And how were carefully regulating where are. Imagine how if we change |
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04:12 | imbalances, what would happen to your ? So this barrier serves as both |
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04:18 | anatomical barrier because it's physical and it's physiological barrier determines what goes in and |
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04:25 | comes out of the brain tissue. right. Any sorts of changes that |
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04:32 | do to the brain or two, fluid, that extra cellular fluid in |
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04:35 | brain can cause disastrous effects. So that in mind, let's kind of |
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04:41 | and see what the anatomical restrictions And then we look at physiological |
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04:48 | These are the structures. Alright, I've already mentioned that we have tight |
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04:52 | that instead of there being uh spaces the capillaries. So, so here |
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04:58 | your capillary, it's the red So you can see where the capillaries |
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05:02 | separated. Instead of that being a junction where things could sneak through that |
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05:07 | a tight junction. This is being primarily by the astrocytes. Astrocytes being |
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05:12 | glial cell, that's the purple cell you see right here. So the |
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05:16 | come along and wrap themselves around the and say, hey capillaries, we |
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05:20 | you to tighten up those junctions. nothing come through. And that's what |
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05:24 | is you seal those tight junctions and we also have these other cells. |
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05:29 | parasites, not parasites, parasites The next to sell. And they're |
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05:35 | as well and their job is to of have this conversation with all the |
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05:41 | cells to kind of determine what's going . So if I have something that's |
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05:45 | the blood that I want out here the extra cellular fluid near my |
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05:49 | it first has to pass through the . If there happens to be a |
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05:53 | there, it has to go through parasite parasite and then it has to |
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05:57 | through the astra site, that means one of those structures has to have |
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06:02 | right receptor, right or the right or the right carrier molecule to allow |
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06:07 | to happen. Right? So you see it's like getting your I. |
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06:11 | . checked every 10 ft as you're down a pathway. All right. |
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06:16 | so not only do we have we also have a basement membrane that |
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06:20 | in between the capillaries and the astro . And so that kind of serves |
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06:24 | a screen door. So even if you can sneak through the capillary, |
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06:29 | it's too big, it's not even near the astrocytes in terms of physiological |
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06:36 | . This goes back to what we a little bit earlier about water soluble |
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06:40 | and lipid soluble substances. Alright, I'm water soluble, I want to |
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06:44 | wherever there's a watery environment. So that means that demands that I |
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06:49 | some sort of carrier molecule passing So I have to have the right |
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06:55 | there to be able to move it cell to cell to cell for that |
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06:59 | sis if I'm water. Remember we water kind of breaks the rules. |
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07:03 | can kind of go where it wants go because it's small. So it |
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07:06 | actually diffuse through the layer. But has to follow the rules of |
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07:11 | right? So if there's less water the brain and more water in the |
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07:14 | , water will flow towards the But naturally there should be balance between |
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07:20 | two. So there should be no specific flow one way or the |
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07:24 | Alright. And then lastly, if lipid soluble you don't want to be |
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07:28 | a watery environment, you want to wherever there's fat. Right? And |
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07:32 | plasma membrane. So what's gonna happen that lipid soluble substance is gonna find |
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07:36 | way through those cells just fine because basically jumping from plasma membrane to plasma |
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07:43 | . The plasma membrane moving just wherever need to go down their concentration |
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07:52 | This is just not working. Oh is. Okay. All right. |
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08:00 | , what we have here is we a way to control what's going in |
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08:04 | what's going out of the brain. . We can determine what's near |
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08:08 | Now. The blood brain barrier is to be found around the blood vessels |
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08:13 | the cerebrum. All right. I we don't know the three women is |
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08:15 | gonna learn more about this a little later. All right. So as |
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08:21 | said this is what we're making is selective transport mechanism. Or elect a |
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08:26 | transport process to move things in and the blood brain barrier at the |
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08:30 | Oid plexus is just gonna be there the epithelial cells and the idea here |
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08:35 | remember the cord plexus. What are doing? We're making cerebral spinal fluid |
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08:40 | we want to be able to pull much more easily from the blood. |
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08:44 | the structure of the core Oid plexus a little bit different. But it |
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08:48 | a barrier. It's still there so anything can come in. It's just |
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08:53 | as dense. And then lastly there parts of your brain that have no |
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08:58 | brain barrier. Alright. And so places are where you want to actually |
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09:03 | into contact with the blood so you see what's going on. One structure |
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09:07 | the hypothalamus. We'll get to where structures are in the next unit. |
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09:12 | the hypothalamus is, its job is determine which hormones need to be released |
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09:17 | you usually dependent upon some sort of coming from the another um structure. |
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09:23 | a hormone as well. So you to be able to have easy exchange |
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09:26 | those environments. Penal glands. The thing. Um I mentioned the court |
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09:32 | . It has to have a certain of permeability but then we also have |
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09:36 | centers. All right. Why the center. The most likely way that |
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09:46 | poisoned yourself by putting something in your . All right. We are creatures |
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09:53 | put weird things into our bodies solely eating things. All right. That's |
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09:59 | we explore our environment. That plant good. I will eat that. |
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10:04 | frog looks tasty. I will lick , whatever. All right. |
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10:09 | the natural way, the most likely to get something that's dangerous to your |
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10:13 | is likely that you've ingested it. once you've ingested it, that toxin |
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10:18 | into your blood and then it circulates your vomit center is kind of looking |
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10:22 | those toxins and says, oh, a toxin. Hmm. I wonder |
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10:26 | it got in the body. Probably something. We threw it away we |
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10:30 | and throw up. Isn't that So, if you get bit by |
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10:34 | rattlesnake and injects you with the You know the one the first thing |
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10:38 | do besides the profuse sweating you vomit your brain says, well, I |
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10:45 | ate something. Didn't follow the 5 rule. Yeah. So anyway, |
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10:52 | that's the blood brain barrier. And kind of just shows you a little |
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10:55 | more clearly so you can see, ? So here's that simple diffusion. |
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10:58 | talking really, really small molecules. talking like water, oxygen. You |
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11:03 | , the gasses. Some lipa. drugs can actually pass through. If |
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11:07 | look at this chart, it even ethanol. It's able to buy pass |
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11:11 | the tight junctions. Just fine because very, very small molecules and they're |
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11:16 | dependent upon any of those much more rules, we have some molecules that |
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11:24 | to have the receptor. So, that trans psychosis I was referred |
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11:28 | That's the receptor mediated transport. the idea is if I have the |
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11:31 | receptor, I combined it, I across and move it into the into |
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11:36 | fluid so that the next cell can it up and so on. And |
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11:40 | , some cells or some molecules will specific carriers that are available. These |
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11:45 | the easy ones to think about, amino acids, for example, |
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11:48 | for example, are things that the would want. So, you're already |
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11:53 | have those carriers available so that you just pluck that stuff from the blood |
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11:58 | you need it. All right. if you don't have the right |
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12:02 | if you don't have the right if you're not that Itsy bitsy teeny |
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12:06 | molecule. If you're not lipa you're not getting in. And usually |
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12:10 | is the place where I tell the about the P for the week |
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12:14 | But I'm not gonna do it If want to find out about it, |
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12:16 | listen to an old lecture. Don't enough time for that story. All |
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12:23 | now, here's where we're going to in for the first time into some |
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12:27 | anatomy. So, sorry. All . What we're gonna first do is |
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12:33 | gonna look at the blood vessels of brain. Alright. And if you |
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12:37 | at the brain, what we've done we've taken the brain and we're looking |
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12:40 | it from the bottom side. this is the inferior view. Here |
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12:44 | your spinal cord coming out and towards . All right. It's really hard |
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12:48 | do in three dimensions. When you're at a two dimensional structure. And |
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12:52 | you can see is I've kind of a line here, this green line |
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12:55 | represents the separation of the anterior portion the brain and the posterior portion of |
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13:00 | brain. Alright. And what we is that we have these kind of |
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13:05 | circulations that serve each half. There's three circulations that we're going to look |
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13:09 | . But I just kind of want separate out in those two. And |
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13:13 | circulation is And here in this post is served by this unique connection in |
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13:18 | brain called the Circle of Willis. basically, what is a series of |
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13:22 | that form a circle so that if include one of those vessels, there |
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13:27 | a way for blood to find its around to the vessels on either |
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13:32 | It's kind of cool. Can we a time out real quick? only |
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13:36 | 80% of us have circle of Willis we talk like this is an absolute |
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13:41 | not an absolute But just presume we have it. Okay. So I |
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13:47 | 80%. Don't sorry, Don't 80% us do have that circle of |
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13:53 | So, it's just very strange. portion. Alright, So, what |
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13:58 | gonna do is we're gonna name some and and looking at this, you |
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14:01 | see how they've again overloaded the And we're just gonna focus in on |
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14:05 | of them. All right. you've heard of your carotid artery, |
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14:09 | ? If I strangle you, I'm to compress the carded artery, it |
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14:12 | up through the neck and then it up into the brain. This, |
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14:15 | here represents that point where it's now up with the brain. And what |
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14:19 | does is it actually divides into three . All right. It joins into |
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14:26 | we've got this branch right here, middle cerebral, right? We also |
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14:31 | the anterior cerebral. So, those are kind of the important ones. |
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14:34 | we have some other branches as All right. And we're gonna be |
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14:38 | to this is that part of that of Willis, The communicating artery to |
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14:42 | sure that the blood is actually going in that circle to be able to |
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14:46 | blood towards towards the posterior sides. , when you think of the internal |
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14:52 | , what they're doing is they're supplying to the anterior portion of the brain |
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14:58 | that anterior cerebral. So, there's one branch and that middle cerebral the |
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15:04 | branch. So it's dealing with the part of the brain Anterior and middle |
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15:09 | are the two big ones. When talk about the middle or sorry, |
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15:12 | posterior segment, what we're gonna be is we're gonna be looking at the |
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15:17 | arteries. There's a pair of They come together and they fuse they |
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15:21 | this basil or artery and then that artery then supplies not only the |
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15:27 | but the little tiny brain in the called the cerebellum plus mother's structures. |
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15:32 | right. So we say as you see here is that basal artery makes |
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15:35 | the base. Alright? And it an artery called the anterior inferior sarah |
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15:42 | . So, I want you to that this is an adjective sarah Beller |
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15:46 | cerebral. Very very similar. But refers to the cerebrum. One refers |
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15:51 | the cerebellum. Cerebrum is your big . Cerebellum. Is your little |
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15:56 | literally. That's what it means. right. They're not big brain. |
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16:00 | brain, but that's when you look them, you're like, oh |
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16:03 | okay, this would be your This big thing in the back is |
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16:07 | cerebral so anterior inferior. So when hear that, what do you what |
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16:13 | you think of when you hear anterior in front and below? Right. |
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16:19 | that's what it means. So, just shows you where it's going with |
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16:22 | to the cerebellum. All right. forms what are called the ponte een |
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16:29 | . All right. The Ponty means right there. They intervale or |
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16:34 | Innovate. They vascular rise the We don't know the ponds is |
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16:39 | But you can see where the name from, Fontaine refers to ponds. |
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16:46 | also have the superior serra bela Alright, So the superior serra bela |
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16:52 | have lost them here. Okay, right there. Alright? And again |
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16:56 | goes over the top of that The one that I didn't highlight here |
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17:03 | I should is the posterior cerebral So here it is, right |
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17:07 | And so that's gonna be providing blood the post airport of the cerebrum. |
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17:15 | , so the ones that I highlighted really kind of the important ones. |
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17:18 | , what you don't see on here you, whenever you see a drawing |
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17:22 | blood vessels, red is usually going be an artery. Blue will be |
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17:26 | vein. So you notice there's no in here. So they're not showing |
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17:29 | . But the blood returning from your arrives via or leaves via the internal |
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17:37 | . Alright. And how we get the internal jugular is through these dural |
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17:41 | and this combination of other sinuses joining to form these structures here. I've |
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17:47 | everything away so that you can see the brain. So this is the |
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17:53 | . That little tiny thing down there the cerebellum. This is the brain |
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17:57 | and this bulgy part right there is ponds. Alright. So the Pontiac |
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18:02 | would be right there. But it kind of shows you it's like where |
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18:05 | this blood go? And so when talking about the anterior cerebral artery, |
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18:11 | really dealing with the frontal lobe and top part of the brain. We're |
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18:16 | about the middle cerebral artery, which that big one that goes on. |
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18:19 | basically the bulk of the middle of brain. And we were talking about |
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18:22 | posterior sara Bella or cerebral arteries. been seeing cerebellum, cerebral cerebral cerebral |
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18:28 | artery. It's going to be the here, part of your brain. |
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18:32 | , you can kind of see there's organization to how the blood vessels |
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18:36 | And fortunately the nomenclature kind of goes it. And as we mentioned, |
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18:44 | our circle of Willis, right, whole structure right there. And what |
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18:49 | does is ensures that there's an overlap flow of blood to the front and |
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18:54 | the back of the brain. This an important structure. We want to |
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18:57 | sure that nothing blocks the blood so the tissue stays well or alive. |
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19:04 | , what we have this little tiny right there. So, remember this |
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19:07 | the anterior cerebral there's anterior cerebral coming . So you can see part of |
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19:13 | forms that circle of Willis. Is communicating artery in there? All |
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19:18 | So, basically you have two separate that are coming together but it's like |
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19:22 | , no, no. We're gonna ahead and put another little bypass right |
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19:25 | to make sure that blood can go that circle shouldn't need to. All |
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19:31 | . And then here's the baseler Right. And where's that basal artery |
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19:35 | from? It comes from the vertebral and then there's a bunch of spinal |
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19:41 | as well that we're not really going focus on. All right. |
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19:47 | those are blood vessels that you've got know. This is kind of the |
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19:50 | list. Know them. All May .1 of these and say, |
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19:55 | is it so far? You guys me? All right now, we're |
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20:04 | move into the spinal cord. But we do that, let's kind of |
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20:08 | sure we understand which types of cells we're working with. We've been talking |
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20:11 | neurons. Remember the neurons are the cells, they're the quarterbacks there. |
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20:15 | excitable cells that the nervous system We've looked at the multipolar neurons as |
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20:21 | example of neurons communicating. But in central nervous system, the primary neuron |
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20:27 | called a pyramidal cell. Can you me why you think it's called a |
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20:30 | self because of its shape? That's . And you can see it. |
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20:35 | mean, it's it's it's almost stupid I asked the question. All |
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20:41 | It is a type of multipolar But notice that the axon doesn't really |
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20:47 | out quite so clearly. Right. because it's in the small networks. |
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20:51 | so it doesn't need to send a , very long axon, very far |
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20:55 | . It's really just talking to a cell. That would be like right |
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20:59 | here. Okay, so that's kind why it has this unique shape. |
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21:04 | . But it plays a major role you understanding it. I want you |
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21:12 | think about the pyramidal cell. Your cells are processing the idea of the |
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21:18 | cell cognition. Understanding okay, thinking is the best part your brain |
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21:27 | Thinking about. Thinking alright, you're the idea of processing information. Mm |
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21:37 | . Deep thoughts. The rest of cells. These supporting cells are a |
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21:44 | bit smaller. They're not quite as to us but they're very important. |
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21:49 | you didn't have them, the neurons do their things. So what we're |
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21:53 | about now, these supporting cells are glial cells are what we call neuro |
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21:57 | And there are six different types of for that are in the central nervous |
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22:02 | to that are the peripheral nervous We've already talked or mentioned them a |
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22:06 | bit as we've been going along. now these neurons are capable of |
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22:12 | They're the ones that multiply and divide needed even into adulthood and beyond. |
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22:18 | do not transmit nerve cells and they outnumber the number of neurons almost |
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22:24 | So they make up about half the of the brain and about half the |
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22:28 | of the entire nervous system. So everywhere. They're all over the |
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22:32 | They're just much much smaller than the themselves and when I use examples like |
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22:36 | the neurons a quarterback the reason I them a quarterback. Because if you |
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22:39 | anything about football, football teams are up on each side of how many |
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22:45 | Come on guys. Thank you. is what we're looking for. So |
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22:50 | means we have 10 players in one . Right? So this is the |
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22:56 | of the football team, quarterback doesn't good. If he doesn't have a |
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23:00 | quarterback can't throw a pass that can caught if there's no receiver. |
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23:06 | So that's why use as an example the six types, you can see |
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23:11 | broken them down here. So here the central nervous system. We have |
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23:14 | handymen cells. We mentioned them. talked about the L. A. |
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23:17 | sites. We mentioned the astro sites never mentioned micro glia micro glia. |
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23:22 | you want to call it that if was hard, but micro glia, |
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23:26 | ? And then we've talked about Schwann . We haven't ever mentioned satellite |
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23:30 | So these are the peripheral, those the central nervous system. They all |
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23:36 | off life from the oligarch. Dendrite cell. All right, in |
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23:42 | these are the cells that give rise other types of cells. They're all |
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23:46 | the central nervous system. What they is they kind of sit around and |
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23:50 | they sense their environment. They have little tiny growth cones, which is |
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23:54 | fancy word for saying an extension that receptors and it detects chemical messages and |
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23:59 | chemical messages tell them where to And so in this case you can |
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24:03 | what we've done is we've formed an contender site that all good inter site |
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24:07 | located to where it needs to And it sent out its extensions to |
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24:10 | around the cell to create those Myelin in this little cartoon. All |
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24:18 | So where we have damaged areas? are things that can come in and |
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24:22 | . Alright. So they're kind of progenitor cells of a bunch of different |
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24:25 | of cells in the brain. We've talked about the tender side. I |
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24:31 | want to go any much further. than to say When you see these |
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24:34 | , they can't draw how widely spread do. I mean they can myelin |
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24:39 | up to 50 axons. So they that. You can understand why they're |
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24:43 | all ago. It's like all these that go from it and they can |
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24:47 | of wrap around all a bunch of cells. All right. They also |
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24:51 | tell neurons stop growing, stop doing you're supposed to do. They basically |
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24:55 | and say I'm in charge. All . We've talked about the neural insight |
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25:03 | the Schwann cell again it's producing Myelin . This is a kind of better |
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25:07 | at it. So here's that ax this is a cell and you can |
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25:10 | what it had done wrapped itself around times. This is central nervous |
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25:15 | This is peripheral nervous system. So can see now, here's my my |
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25:19 | chief, my own chief, my chief. Each of those represent a |
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25:22 | cell. All right. Where they're , also determines how if we damage |
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25:31 | cell where that damage neuron will actually again. They actually kind of serve |
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25:36 | a path to say, this is you were grow back this way if |
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25:40 | capable of growing, but it only for a short period of time. |
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25:44 | , ma'am. Which yeah. Why they divide? Because you have cells |
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25:59 | it not to? That's right. that sense, the neurons stopped doing |
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26:05 | we would expect to sell to do other cells are telling it don't do |
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26:10 | . Right? So that's kind of of the thing is there's a lot |
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26:14 | stuff in biology. I'm just this just an aside, there's a lot |
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26:17 | chicken and egg stuff that it's like learned something that I find out why |
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26:21 | does it. And you're like, , well, that wasn't quite clear |
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26:25 | first time and it's just gonna happen all of I mean, especially when |
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26:29 | get into these classes where you're starting dive down into the alphabet soup of |
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26:34 | . You know, it's just like yeah, I'm still right. For |
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26:44 | is correct. So what will Yeah, go ahead. No, |
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26:47 | , go ahead. They can repair . Right? So, the reason |
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26:54 | don't see a lot of repair in cns is because the cells remember we |
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26:57 | those pyramidal cells and we go back they're not very big, right? |
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27:02 | only have these very very small extensions the peripheral nervous system. Typically ourselves |
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27:07 | these long multipolar cells. So we these long axons that travel far |
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27:12 | If I chop my ax on I've done no damage to the cell |
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27:16 | , where all the cellular machinery If I do damage here is a |
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27:22 | chance, I've actually done damage to cell itself. So, that's why |
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27:26 | there's less of a chance of All right. So, and we |
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27:31 | talk about I think your book actually about repair. But at one point |
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27:35 | just decided like this really isn't that to know how it creates the the |
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27:41 | . It's just astrocytes named for right? No, no. It's |
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27:53 | because its star shaped the star Alright, Most abundant glial cells in |
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28:00 | nervous system. These are like the tissue. This is kind of the |
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28:06 | that holds everything together, functionally it establishes the physical structure of the |
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28:11 | . So it is scaffolding onto which neurons are actually built. So, |
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28:16 | can see right here in this little , here's my astro side. It's |
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28:20 | the capillary where it should go. telling the neurons where it should be |
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28:24 | it's holding everything into place that's its . Alright? It also controls the |
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28:31 | environment. Remember what we did? had a whole bunch of astrocytes creating |
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28:36 | barrier blood brain barrier. So what doing in the first place is |
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28:40 | I will determine what gets into this here. Alright. I'm telling the |
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28:45 | what to do and then I'm going be the ultimate arbitrator, ultimately one |
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28:50 | deciding what's getting in and what's getting . Because in order to get from |
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28:54 | , you have to pass through that and pass into this cell and then |
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28:58 | cell decides when it's gonna let something into the extra cellular fluid it stores |
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29:03 | glycogen. Glycogen can be broken down glucose. It provides the glucose and |
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29:09 | lactate to these neurons to allow them be functioned be functional. Excuse |
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29:15 | All right. So, very, vital role as a cell that controls |
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29:22 | extra cellular fluid in the environment surrounding astro site. This is another important |
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29:28 | right here. It actually serves at site of the synapse to help maintain |
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29:34 | synapse. So, we look at synapse and go, okay, here's |
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29:37 | pre synaptic cell. Here's the post cell and then stuff happens in between |
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29:42 | . But that synapse is actually held place because astro sites are surrounding |
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29:48 | We talked about a little bit about do we stop you know, activity |
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29:51 | the synapse and we had that You know, if you went back |
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29:55 | looked at it and I was like , sometimes there's these astrocytes that take |
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29:58 | the neurotransmitter. There you go. what it's doing. Alright. It |
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30:04 | to repair the damage that you see nerve cells. Alright. So if |
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30:11 | are damaged, they can actually multiply fill in that space and act as |
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30:15 | tissue and last thing they can do they can stimulate other cells to |
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30:21 | So for example, they tell the good danger sites where to go and |
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30:25 | to do. So astro sites are important? This is this is just |
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30:29 | short list. Astra sites are really important cells. They just don't |
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30:34 | that sexy job of sending signals. no. Astro site neurons can't do |
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30:42 | they want to do or or what designed to do. Epidermal cells we |
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30:49 | produced cerebral spinal fluid. You can here the cilia on it and if |
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30:52 | look closely you can see kind of little hairs there, so remember what |
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30:56 | are they're found or localized within the . The cord plexus is where the |
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31:01 | vessel gets really, really close to surface of the ventricle. So what |
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31:04 | doing is these epidermal cells are actually fluid and materials from the blood and |
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31:11 | that cerebral spinal fluid that then fills ventricle and then it says, |
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31:15 | you move that way I'm gonna make so that's the easiest way to think |
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31:20 | these micro glia, there's nothing we about these things that are useful at |
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31:28 | point. Every time we turn around see a new paper or something new |
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31:33 | them. Alright. We're gonna go what the textbook says. Alright, |
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31:38 | it just makes our life easy About 10 to 15. 10 to |
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31:43 | of the central nervous system is made of these micro glia. Now they're |
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31:48 | microgreens. Micro small glia, small cells, that's what they are. |
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31:52 | just the small ones. And what do is they just kind of sit |
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31:56 | and do nothing for most of the and it appears that they're related to |
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32:01 | monos. Aight all right, That is a modest site. And |
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32:04 | know you haven't learned this stuff. mon a site is an immature macrophage |
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32:09 | a macrophage is a cell that chews and destroys foreign material. Alright, |
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32:15 | learned a little bit about that. it just kind of sits around and |
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32:19 | pretty much nothing, it just kind releases growth factors and says, |
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32:22 | what's going on? Make sure everything functioning right? But when they become |
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32:26 | , if damage happens to the brain that converts that mona's site like selling |
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32:31 | the macrophage and it migrates to where damaged tissue is and begins to focus |
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|
32:35 | ties it. Lot of research done uh the word stroke, stuck in |
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32:45 | head and that's not what a concussion , what I was looking for. |
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32:48 | lot of concussion research has shown that you get a concussion, you activate |
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32:53 | cells like crazy. They start migrating over the place. It's wild. |
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32:57 | . So, the way you can of this is that you can think |
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33:00 | it as an immune defense cell. . So, it's able to find |
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33:04 | wrong things in your brain. So something leaks into your brain and it's |
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33:08 | supposed to be there, this is cell that's there to fight it. |
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33:12 | right. It also helps to prevent in terms of the immune response. |
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33:16 | that's where we're going to leave But there's a lot of evidence that |
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33:20 | may actually serve as a neural stem . There's a lot of evidence that |
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33:25 | a lot of other interesting things. so maybe in 10 years you're going |
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33:30 | find out that this is the most cell in the brain. It would |
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33:36 | into new neurons. So, the that I've been telling you is that |
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33:43 | nervous system doesn't repair itself. We're go ahead and say it doesn't repair |
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33:47 | . Just just trust me on that . Okay. But it might it's |
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33:52 | a lot of evidence that keeps pointing direction, but we're keeping it |
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33:57 | We're not changing. We're not we're going to go with what the paper |
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34:00 | three weeks ago, right? We're trust what the textbook says and let |
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34:04 | science work itself out and it's actually not true. It's not from three |
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34:07 | ago, it's been around for about or four years. So now we |
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34:13 | the population of the cells. All . We got our neurons which are |
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34:18 | pyramidal cells, but they're not just cells. We've got four different |
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|
34:21 | So, I didn't even talk about cells. What's the satellite cell? |
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34:25 | cell is like an astro site except in the periphery. That's how important |
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34:29 | is. I just don't even have slide for it. Okay. We've |
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34:36 | about the glial cells. All And when you think about the nervous |
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34:40 | , what what is the nervous What is its job? It receives |
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34:44 | . It processes information. And then transmits a response to the information that |
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34:50 | just received and processed? Does that of makes sense? In other |
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34:55 | if I'm outside and I touched something , I detect that hot. I |
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35:03 | that signal and say, the thing touching is hot. It's probably causing |
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35:07 | . My brain then sends a signal back down and says, alright, |
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35:10 | go ahead and just move that And that is what we're talking |
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35:14 | It's receiving the signal processing what that means. And then how do I |
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35:20 | to the signal that's ultimately what the system is responsible for. All |
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35:27 | It can store information in a right? It can ignore information. |
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35:34 | fact, much of the input, of the sensory input that you receive |
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35:38 | a regular basis is completely ignored. ? If it doesn't have a direct |
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35:43 | on your behavior, right? This your brain goes, let's not worry |
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35:46 | that right now. Right. And this stuff is occurring at the level |
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35:51 | the neuron. Right? So, going to kind of talk broadly, |
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|
35:55 | remember that we're dealing with how neurons talking to each other through that chemical |
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|
36:01 | . All right, They send that ultimately onto the muscles. That's |
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|
36:06 | glands, for secretion and other cells tell them what to do. But |
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|
36:12 | isn't all that it does. You here and thinking about the brain and |
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36:16 | about yourself is consciousness? You are aware, Your brain, your nervous |
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36:22 | is responsible for that. It is for your perception of the world around |
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|
36:29 | . Alright. That's dependent upon the of sensory input that you're getting. |
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36:34 | responsible for language, for you being to understand these sounds that I'm making |
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36:40 | have They have meaning to you, . For reasoning. Should I eat |
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36:46 | oreo that I dropped on the It's only been there for three |
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36:51 | You know, memory. Think about , I don't know think about the |
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36:56 | person you had a crush on. you picture him when I when I |
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37:01 | that all of a sudden your brain back there. See that's memory and |
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37:05 | evoked some sort of response to write some sort of emotion, whether |
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37:10 | was good or bad. Right? all in the nervous system. All |
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37:18 | . So when we're looking at this , we're going to kind of point |
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37:21 | the areas where different things are actually . All right. But I want |
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37:25 | to understand that like when you talk a memory, a memory is not |
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37:28 | stored inside a neuron, a memory the way that a neural network, |
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37:35 | bunch of cells talking to each other in a specific sequence in a specific |
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37:41 | . And so all we gotta do just cause a repeat of that sequence |
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37:45 | your brain takes that signal and basically this is what it means. |
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37:52 | your brain is formed during embryo while an embryo and then it continues develop |
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37:59 | . There's a lot of research that that your brain is almost completely rewired |
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38:06 | during puberty. So basically during your , so remember all those horrible fits |
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38:12 | you had and how everyone made you and nothing was ever fair and |
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38:17 | blah blah. You know, all stuff that's your brain rewiring itself to |
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38:22 | a mature brain so that you can a functional in the world today. |
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38:26 | . And what does functional mean? not gonna go there were just basically |
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38:31 | feed yourself and reproduce. How's Okay. The brain uses different ways |
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38:37 | organize itself during development. Alright, very early on we call this development |
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38:44 | neuro brain, right genesis beginning. during early neurogenesis when you're an |
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|
38:51 | we use this type of this um called radio migration. And hear what |
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38:58 | is is if you look at the , you'll see that there's these different |
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39:01 | . All right. And we're not spend a lot of time talking about |
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39:04 | layers in the in the gray matter it gets confusing and it's and it's |
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39:07 | and and and truthfully for our purposes not really that important. But the |
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39:12 | is that I hear I've got a the green stuff represents glial cells. |
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39:16 | what that neuron does is it migrates layer to layer to layer, usually |
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39:22 | finding a glial cell and then migrating the length of that glial cell using |
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39:26 | chemicals that that glial cell is signaling it to tell it where to |
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|
39:30 | Right? So that's what radio migration . But once you become an |
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|
39:35 | you're going to use something that's a bit different. Alright, so that |
|
|
39:39 | , those changes that take that take , say during puberty are going to |
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|
39:44 | something a little bit different called tangential . And here what you do is |
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39:49 | move within the layer that you're in you move back and forth. Unless |
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39:54 | signal tells you to shift that layer then you move again back and forth |
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39:58 | that's kind of what this is trying demonstrate to you. So what's happening |
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40:02 | is that the way your brain is and changed differs depending upon where you |
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40:09 | in your development. So early on using radio and then later on using |
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40:17 | . All right. But neurogenesis is process of organizing our brain. So |
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40:22 | becomes functional now. Neurogenesis we said dependent upon some signals. Right? |
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40:29 | said. The glial cells here are signals out and then what causes it |
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40:33 | move from layer to layer is a of signals that are telling those cells |
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40:38 | to go. And this process of a chemical signal is called chemo |
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|
40:45 | It is not only done in the is done all over the place. |
|
|
40:48 | right. Chemo taxes is simply using signal that's usually chemical chemo. And |
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|
40:55 | that chemical trail. If you've watched shark week, you've watched the shows |
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|
41:00 | they're talking about a little bit of in the water and the shark sits |
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|
41:03 | and can follow the trail of That is a form of chemo taxes |
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|
41:08 | a macro stage. Right? That's you're doing here is you're taking that |
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|
41:12 | chemical and there's more chemical here. gonna keep following the trail of chemical |
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41:16 | there is more. I'm gonna just going following it until I find the |
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|
41:19 | of the chemical the portion of the that does this is that growth |
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|
41:26 | All right. That's what that fancy is. So, it's basically you |
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|
41:28 | imagine I've got these extensions and other corns and there's these that's what these |
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41:32 | represent. Those little red things. this is the cell as it's stretching |
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41:37 | out and then it has portions of cytoplasm kind of sticking off with little |
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41:42 | on the end, looking for where chemical is coming from and it just |
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41:45 | of follows it along. It can all these really kind of unique |
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41:51 | It can cause branching, right? can cause sensitivity to other cues. |
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41:56 | example, things that repel the acts away or can say this is the |
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42:00 | you need to go. And ultimately happens is we end up creating this |
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42:05 | of cells that are interconnected or they're other cells. And then what we |
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42:13 | do now is based upon where these are. We can make modifications to |
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42:18 | network through a process called neural You've probably heard the phrase can't cheat |
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|
42:24 | teach an old dog new tricks, ? You heard that? I can't |
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|
42:29 | that. That's that's too complicated. not true. Your brains are |
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|
42:36 | not barbie plastic, malleable and And in fact, that's how your |
|
|
42:42 | actually learns and stores information. All . So, what I want you |
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|
42:48 | do is don't focus on this. want you to focus here. So |
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|
42:51 | right? Here represents how your brain a bunch of cells. So each |
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42:54 | those dots represents sell each line represents connection between those cells. So this |
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|
43:00 | is talking to that sell that sell sell on. That cell. The |
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|
43:03 | is talking to those two cells and on and so on. And so |
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|
43:06 | . These two cells are all lonely sad because they're not part of the |
|
|
43:10 | . All right. But what happens you create an experience, right? |
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|
43:14 | little baby, You stick keys in mouth metal tasting right? And so |
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|
43:19 | happens is is that through this process neurogenesis, through this process of chemo |
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|
43:25 | and extending you're going to start creating connections. And so you can see |
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|
43:31 | cell has started creating a connection This cell has started creating connection |
|
|
43:35 | so on and so forth. That's the dotted lines represent. So, |
|
|
43:38 | cells that were initially not part of network are becoming part of the |
|
|
43:42 | As your brain is trying to you know, these interactions. You |
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|
43:48 | , whatever it happens to me and just have keys in your mouth. |
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|
43:50 | don't know. But what will happen as you continue doing whatever that activity |
|
|
43:57 | and start reinforcing it through practice is going to strengthen certain interactions. |
|
|
44:06 | And so the signaling between the cells going to increase in certain areas and |
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|
44:11 | in other areas. And so what up happening is over time you reorganize |
|
|
44:16 | network so that there's this new interaction this is what represents whatever that new |
|
|
44:22 | that you just learned now again, is just cartoon stuff. And the |
|
|
44:26 | here is you start off with something this and you end up with something |
|
|
44:30 | this and that's simply through experience and that our brain changes. All |
|
|
44:38 | How many guys know how to How many 10 years ago? You |
|
|
44:42 | know how to drive? Well, of you should be like, I |
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|
44:46 | know I mean yeah, you played theft auto, but that ain't |
|
|
44:50 | That's that's that's just fun, Right? You learned how to |
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|
44:56 | You sat through the boring lectures, watch the videos of the trains running |
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|
45:00 | people and cars, right? I kids going through drivers at right |
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|
45:06 | I'm doing the parent teaching ones. it's gonna be a lot of |
|
|
45:11 | But the idea is that, you , this is what your brain was |
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|
45:15 | before you drove right in that area learned how to drive. And then |
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|
45:19 | you became more proficient at it Now can weave through cars on the highway |
|
|
45:24 | 80 mph, right? Yeah, too hot. So, so the |
|
|
45:34 | here is don't think of a connection so much of a if I do |
|
|
45:39 | connection, then X will happen. the network is going to create those |
|
|
45:44 | . It's kind of like saying I'm to five friends. You're not you're |
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|
45:50 | to as many connections as needed in to perform whatever the function is, |
|
|
45:56 | ? So if you need to have friends to run for political office, |
|
|
46:00 | gonna find 1000 friends, right? will be strong friends. Some will |
|
|
46:04 | weak friends, right? If you need five friends to walk with you |
|
|
46:09 | the aisle, you're going to figure how to do that as well. |
|
|
46:12 | ? So each of those networks that creating are gonna be unique for whatever |
|
|
46:15 | task is, it needs to be and it's gonna, you're basically what |
|
|
46:19 | gonna see here in just a second that the clusters of cells are all |
|
|
46:24 | be associated with one another because they're involved in whatever that activity is. |
|
|
46:28 | right? And so if you think a baby, then this is kind |
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|
46:32 | a way you can think about it in that first year of life, |
|
|
46:35 | them learning how to do stuff and their brain to start developing these |
|
|
46:41 | I mean, they they do things you stick out your finger and they |
|
|
46:45 | it right? And then they're you know, they're like amazed. |
|
|
46:49 | what they're doing is they're training their . If I reach for something and |
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46:53 | it, then I'm actually touching something that's training the brain to believe this |
|
|
46:58 | what happens when I reach out. know, or when they grab the |
|
|
47:01 | and start looking, it's like, , this is what something tastes |
|
|
47:04 | I'm gonna explore my environment through right? And when you smile at |
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|
47:09 | and they respond back, you you smile at them, they smile |
|
|
47:12 | you and you smile back and it's oh when I do this, this |
|
|
47:16 | the response I get. And so building up that activity by reorganizing the |
|
|
47:22 | and how they interact with one right? And that's kind of |
|
|
47:28 | again, that's like the kindergarten I mean I'm not saying you got |
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|
47:31 | kindergarten, it's just like this is the baseline understanding of the nervousness if |
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47:35 | really want to understand the nervous if at some point you have time |
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47:38 | take the neural path or the neurophysiology doctors burke's teaches. It's a great |
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47:43 | to learn this stuff in more All right, so this is kind |
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47:48 | like, what I was just trying say is like, you know, |
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47:51 | we're gonna do is we're gonna do and integration. So we're learning information |
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47:56 | the neurons already grouped together in these patterns. Alright. And what we |
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48:01 | is we call these things pools. it's a neuronal pool or neuronal |
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48:06 | All right. So if you hear words, just think lots of neurons |
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48:09 | alright. And typically they're going to a functional group as a whole. |
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48:14 | basically they all kind of are able process the same type of information. |
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48:19 | you're doing is you're trying to figure which ones are gonna work together and |
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48:21 | what they do is they then send information off to the next group of |
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48:24 | of cells that then do something and on. All right. So if |
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48:29 | thinking about the neurons, they're either to be very very localized. So |
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48:32 | you've got all these neurons in a place and this is gonna make a |
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48:35 | of sense when we start going through rebrand and saying this is where X |
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48:38 | processed. Like this is the visual . Okay, so that means specific |
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48:44 | of vision is processed in this All right. But you might also |
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48:49 | that the neurons are going to be throughout the cns. So it's not |
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48:53 | that one location. That information is there. And then it's moved to |
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48:57 | different location. Again, I use here because in the brain while the |
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49:03 | visual cortex is the occipital lobe, you're gonna see is there's a |
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49:07 | So that's called V one. That's the abbreviation visual one. There's a |
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49:11 | two and V three, V V five, V six, A |
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49:14 | seven, V eight, V nine V 10, V 11. And |
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49:17 | a Bs and CS from any of things and I think it goes all |
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49:19 | way up to like 17 or We'll never have to learn any of |
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49:23 | . Alright, but the idea is in order for me to look at |
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49:26 | and understand what it is. It to go through all of these different |
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49:29 | of processing before your brain can Oh, lollipop. Right. What |
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49:39 | is being sent to And where that is going to be sent from is |
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49:43 | to be restricted. Right? I'm going to send visual information to an |
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49:48 | that's responsible for processing spell. It make sense. Right? So, |
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49:53 | that information comes from is from the , right. I'm not gonna send |
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49:57 | from the back of my knee to eyes or to the visual cortex saying |
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50:01 | you did you see that? Because there's no there's no input from |
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50:06 | area. All right. So we're where the information comes and goes. |
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50:11 | then those uh circuits can be either simple or they can be very very |
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50:16 | . And what we do is we them down into four basic types. |
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50:19 | I want to show you what simple complex looks like before we go into |
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50:23 | of the four different types. All . Again, that rule that we |
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50:29 | about, the synaptic delay, those apply. So the more complex the |
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50:35 | , the more synaptic delay you the longer it takes to process |
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50:39 | Okay, so this is simple versus . This is just a generic, |
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50:44 | versus complex. Alright. We got , basically. What you see here |
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50:49 | one neuron talking to another neuron. common in the peripheral nervous system. |
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50:54 | very common in the central nervous All right. You'll see this neuron |
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50:59 | to that neuron which talks to that peripheral nervous system often what you mostly |
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51:04 | in the central nervous system are these things. And this is just an |
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51:08 | of a complex. You can see got this talking to this cell, |
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51:11 | then this cell talks to the next , but it also talks back to |
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51:14 | cell that talk to it in the place, that's complex, Right? |
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51:18 | what that means is you now have circuit that's kind of reverberating on |
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51:24 | Yeah, like there's like a physical , so in this case what it |
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51:33 | , it's you can think of it I'm not gonna do a good job |
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51:37 | this because I don't know computers that . But it's like how computers process |
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51:41 | . It's there's like binary responses. something or don't do something excite or |
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51:48 | , Right? And so if you imagine a network of cells where it's |
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51:51 | , okay, my job is to the next cell to become excited. |
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51:54 | next cell in the in that chain say releases a hormone or a |
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51:59 | then whatever stimulates me, tells tells me to tell the next cell |
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52:04 | to do next converge back on the cell. And so what you're doing |
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52:08 | you're creating a pattern of response so at the very end, whatever you're |
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52:13 | to get done gets done. what you're doing, like when you're |
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52:20 | is you're actually creating that pattern. . So, remember what I said |
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52:24 | that when you're dealing with uh thinking memory, it's not stored inside a |
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52:31 | , What you're doing is you're creating neurons to fire at a certain |
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52:35 | They might be inhibiting other neurons, might be turning on other neurons. |
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52:38 | so, what you're doing is you're a pattern that's generated when you stimulate |
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52:42 | network. Again, if you can you can recreate that pattern, you're |
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52:46 | to pull up whatever the memory is whatever the idea is. And so |
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52:50 | studying is is generating the pattern. So that it then remains in long |
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52:57 | , right? In other words, storing up the pattern itself. I |
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53:01 | it's very, very I don't know the word I want to use here |
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53:07 | strange, like, what to Alright, so, this is kind |
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53:18 | cool. And you're making me go a tangent, we'll go down the |
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53:21 | and we'll pause for a break. right. So, like I |
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53:25 | it's about the pattern initial study that done to demonstrate that this was true |
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53:30 | they took a bunch of rats and put them in a maze because that's |
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53:33 | we like to do. All And what they did was they put |
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53:36 | in the brains of the rats and were looking at a specific neural |
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53:40 | Alright. So, they were able hone it down to just like a |
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53:43 | area. And what they did is trained the rats to run, it |
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53:47 | amazing, it was like a figure . Alright, So basically it's a |
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53:51 | , you know? So they had a middle track and in that middle |
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53:55 | they had a wheel. And what did is they train the rats to |
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53:58 | around, get to the wheel, on the wheel, jump off, |
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54:01 | go around, create that figure jump on the wheel again and do |
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54:04 | and then come back again and repeat process, right? So there's your |
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54:08 | , right? And what they did they could actually see the pattern being |
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54:12 | in the neurons while they were training rats. Alright. And then what |
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54:16 | did is they kept those those same stuck in their brains, which is |
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54:20 | a horrible way to run around, ? Because you've got wires and you |
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54:23 | the wires with you. But they the pattern as the rats ran and |
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54:29 | rats would actually create the pattern before got to the wheel, you're |
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54:35 | and it's like, okay, this the pattern they get when they get |
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54:37 | the wheel and they would see that rats would think about the wheel just |
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54:40 | they got to it, right? they were thinking this is what I |
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54:43 | to do next. So the idea that the pattern was stored, but |
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54:47 | could also see when the rat would a mistake before the rat made the |
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54:51 | . So if it wasn't going to through the wheel and said it was |
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54:54 | run straight or run past the they say, okay, the pattern |
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54:58 | changed and so I can't see So to answer your question, what |
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55:04 | you trying to do when you study you're trying to generate or create that |
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55:08 | right now? Does this only current the same month that they came out |
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55:12 | that paper? This isn't like There was a study done in humans |
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55:16 | the same sort of thing, but in the brain made a run around |
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55:21 | what they did is they made them videos, right? And it was |
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55:26 | that they would see watch over and again. Very small clips. And |
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55:30 | they were trying to do is trying see what sort of patterns would be |
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55:33 | . And again, they haven't watched over and over again. And then |
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55:37 | they had to interview them and again the electrodes in their brains and they |
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55:40 | see the pattern that was being generated they're watching the videos. And then |
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55:43 | they interviewed him, asked him questions , they could see the pattern being |
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55:46 | in the brain that matched the right or the wrong answer. Right? |
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55:52 | it was the correct answer. The would would be wrong. Yeah. |
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56:01 | . Well, so both of them two or more right. But it's |
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56:04 | how come, I mean how structured is and we're gonna walk through some |
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56:10 | these in just a sec. And so I mean the two easiest |
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56:14 | are the converging and diverging circuits. you ever wondered why you take physics |
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56:18 | get into some of these graduate programs health? It's because you've got to |
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56:22 | what these words mean. I mean that's what it is, is do |
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56:25 | know what these words mean? So just we'll do these and then we'll |
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56:29 | the other ones and we'll take a . All right. So converging circuits |
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56:34 | pretty simple. This is something that you guys can can see. |
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56:37 | I mean here we got a bunch inputs acting on a single cell and |
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56:44 | single cell then is acting on something . So what you're doing is you're |
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56:48 | a lot of different types of information you're consolidating that information into some sort |
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56:54 | response. Right? So an example salivation, right? Think about sitting |
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57:01 | at a barbecue joint. We all barbecue. Yeah, like it. |
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57:05 | right. So you go into a joint, what do you do? |
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57:07 | don't see the food first? You it and all of a sudden your |
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57:11 | just go right and then you look and you're like there's there's the, |
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57:16 | know, it's a proper barbecue So you're actually just walking and picking |
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57:19 | your barbecue and you see the thing want to eat and it's just |
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57:22 | oh man, I can't wait to my fingers on that and then you |
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57:25 | sit at the table and then you touch it and then you put it |
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57:28 | your mouth and it's just like to for, right? So every sense |
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57:32 | your body is like going winter winter dinner, that's what those are, |
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57:38 | would be like the gustatory. That there is the visual that right over |
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57:43 | is the sense of smell, The old factory and all this stuff |
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57:47 | converging on those salivary glands say get to eat and it's gonna start causing |
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57:54 | to salivate, right? That would an example of converging. It's a |
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57:58 | example, but it's an example nonetheless , in a diverging circuit, what |
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58:04 | have is you have an input that goes to different sources or two different |
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58:10 | . Alright? And so the example like to you here is think about |
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58:13 | , alright, walking is simply the of lifting up my leg, putting |
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58:17 | weight forward and preventing myself from right? So walking is not |
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58:23 | what is swimming? Not drowning It's keeping my body above the water |
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58:31 | , but I'm still getting motion But when I walk it's not just |
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58:35 | lifting up and dropping my leg, also maintaining balance, right, It's |
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58:40 | ensuring that posture takes place. So are muscle groups that are involved in |
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58:46 | that I don't even think about because I think about walking I think about |
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58:49 | and dropping my legs over and over , right? But there are muscles |
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58:53 | my toes, there's muscles in my , there's muscles in my belly, |
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58:57 | muscles all over that allow me to that thing. So the signal might |
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59:02 | time to walk, right? That's that is. And then it's convert |
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59:06 | it's diverging to the different parts of body and those different systems to tell |
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59:12 | time, what do we do? then those cells downstream? Say |
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59:16 | I'm going to tell this cell to excited, I'm gonna tell that muscle |
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59:19 | there to relax, I'm gonna do this. And so all those signals |
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59:22 | going all over the place to allow to create that one simple step |
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59:29 | We got the weird ones. All . The weird ones are the reverberating |
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59:35 | or the rhythm generating circuit, and parallel after discharge circuit. Alright, |
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59:40 | here in the rhythm circuit, you see we're starting off with one |
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59:44 | we're just putting two in this to our lives easier, but you can |
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59:47 | what I have is I have a . So this cell is talking not |
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59:51 | this one but two. That Alright, this cell is talking to |
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59:54 | cell as well, but it's actually , it's actually activating along the axon |
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59:59 | then this cell is actually river to , reverberating back to the original cell |
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60:05 | it's actually stimulating the cell, which also stimulate that cell. So what |
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60:08 | doing is you are creating an activity gets bigger and bigger and bigger and |
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60:13 | and bigger and bigger until something comes from the outside and says stop |
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60:18 | Think about breathing. Right? When inhale, does your inhalation continue on |
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60:25 | , right? It goes and then stops and then your muscle relaxes and |
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60:31 | when you inhale again and you just that pattern over and over and over |
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60:38 | over again. It's because you have series of cells that are reverberating to |
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60:43 | that big, big big, big and then something comes along and says |
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60:46 | all the signals and it all goes and then you relax and then let's |
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60:50 | it. And that signals which then and signals and signals get big, |
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60:54 | , big, big big again and along says kill it all and then |
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60:57 | relax again. All right, this these when you see these kind of |
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61:02 | that's a central pattern generator, It uses these types of circuits. |
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61:07 | one. Think of any sort of activity that you have is walking rhythmic |
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61:15 | right, Here's a fun one but pizza govern your mouth. Just |
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61:24 | can't stop, right, get tired one side, what you do, |
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61:28 | it over to the other side keep , right rhythm, rhythmic pattern |
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61:33 | parallel after discharge is one of those of weird circuits where the responsive cell |
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61:41 | then the cartoonist here tried to do and it's not an easy thing to |
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61:45 | . The response to sell isn't just a burst response or a series of |
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61:50 | or you know like a growing Like you see here instead this cell |
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61:54 | going to receive multiple inputs in So you can imagine like here that |
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62:01 | cell, you know, is probably of the first one that's gonna be |
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62:04 | to send a signal. But over we've got synaptic delay, synaptic |
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62:07 | synaptic delay. This cell is shorter that one. So this one probably |
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62:11 | the second signal. That's probably the signal. This will be the fourth |
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62:15 | . So this cell is receiving a like this. It's like Yeah there |
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62:21 | four there. Okay, so that is a series of 1234. And |
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62:28 | this signal is not just one it's gonna be many responses but through |
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62:34 | same pathway. So you get this I dis elongated response in this |
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62:42 | Now I said here it's probably involved higher order thinking. So in these |
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62:46 | networks they're all interconnected with each Like so and so you can imagine |
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62:51 | happening is you can now create right? So this may be going |
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62:56 | a big response after 1234. And maybe it's going through some sort of |
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63:01 | circuit that keeps this thing going all the place. And it's repeating that |
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63:06 | that ultimately becomes an idea or a . Thank you. The Middle |
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63:22 | No, remember. Yeah, it to go remember. Because when we're |
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63:27 | with the synapse, those two cells almost touching. You have a |
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63:32 | Did you ever play the I'm not you game with them? Always. |
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63:36 | . You know, you know what game is? Right? You can't |
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63:39 | mad at me. I'm not touching . It's like this stuff. I'm |
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63:41 | touching you. You can't be Don't be mad at me. You |
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63:45 | get mad. Right? That's what's what neurons are doing. They're playing |
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63:48 | I'm not touching you game right So close that the only interaction they |
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63:53 | is by those chemicals and those chemicals they float away, they get |
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63:57 | So you can't skip over a you have to go through the neuron |
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64:00 | that chemical signaling. Right? So well let's use this one right here |
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64:06 | you can see one there's another here's another cell. So you can't |
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64:09 | go, oh I'm gonna jump over cell because whatever chemical that synapse releases |
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64:15 | never get to that cell. And talking. That could be millimeters, |
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64:20 | ? It won't be able to reach . It has to have that |
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64:24 | that connection between them and what the can't really do is show you how |
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64:28 | that that uh that dendrite is to um tele Andrea they're literally right there |
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64:35 | to each other. Yeah. So happens if you kill this? What |
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64:45 | if that neuron is damaged or dies some, what would happen? So |
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64:52 | would lose this connection? Right, now this cell isn't responsive in |
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64:57 | in this pathway. So this cell here, which is using all three |
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65:02 | really all four pathways would then amplify it's signaling through the others. And |
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65:08 | that original pattern that you're trying to , which would be the 1234 is |
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65:12 | gonna be a 123. But how you make it do what you needed |
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65:16 | do? So you might lose the , right? You might have have |
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65:21 | reorganize how you think think about a , right. If you've known somebody |
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65:27 | had a stroke, they have a time in the same sorts of movements |
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65:31 | they were doing previously. Right? they go to a physical therapist and |
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65:36 | an occupational therapist and the occupational physical retrain how to do simple movements or |
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65:43 | complex movements in the case of an right? And what you're doing is |
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65:48 | going through that process of of really neural plasticity and saying that network that |
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65:55 | formally had no longer exists. We to find a new way for you |
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66:01 | learn this pattern of activity. That's job. All right. I guess |
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66:09 | is the last one because we'll get the spinal circuits. So, |
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66:12 | as I said, the circuits themselves gonna be developed very early on during |
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66:18 | and neonatal growth. And then they're be maintained through that plastic stick. |
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66:23 | plastic nature of the nervous system. , So we're going to reinforce, |
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66:27 | going to break down, we're going make new things. So, these |
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66:31 | are what we are doing to create networks. Right? So everything that |
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66:37 | do is gonna be dependent upon how create those networks and whether or not |
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66:44 | maintained. All right, simple circuits regulate complex behaviors. And what they're |
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66:52 | do is they're gonna produce what we to as reflexes. We're gonna pause |
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66:56 | reflexes and we're gonna come back and with the reflexes. Uh man, |
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67:00 | just kept going there, so take a like a five minute break, |
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67:04 | guess. And then we'll come back try to finish out here. All |
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67:20 | , we're gonna move on. We're talk about reflexes. Um and try |
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67:24 | get through this as like I quick as I can, we're gonna |
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67:27 | from reflexes, spinal cord spinal nerves they kind of all kind of blend |
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67:32 | because when we learn about the most of our reflexes are occurring at |
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67:38 | level of spinal cord. That's not true, but most All right. |
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67:42 | what are the reflex? A reflex definition is a rapid, pre |
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67:46 | right. Involuntary reaction in a muscle gland or to some sort of |
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67:51 | So stimulus is anything sensory input that's to initiate the reflex. Rapid means |
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67:56 | not gonna have a lot of neurons . When we say pre programmed, |
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68:00 | gonna get the same response every time all done this one. Right? |
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68:04 | knee jerk reflex, you go to doctor, put your leg on the |
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68:06 | of the table and you can sit and wax at the at the |
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68:09 | Your leg just jerks right? You do anything about it like you don't |
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68:13 | a choice. It's involuntary meaning you not have a conscious intent to let |
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68:19 | happen. This right here is an of another type. Alright, this |
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68:23 | here would be the suckling reflex. ? You can't see it because it's |
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68:26 | a moving picture. But if you a newborn and put your finger at |
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68:30 | mouth, it will turn its head that finger as if it were a |
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68:34 | so that it would begin suckling. , It knows anything right around |
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68:38 | I'm supposed to latch onto. And that's what it's doing. So the |
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68:43 | cord is primarily responsible for the integration many of these basic reflexes. There |
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68:48 | different types. We have what is basic or what are called conditioned |
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68:52 | Basic reflexes are the ones that are in responses. You are not taught |
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68:57 | . They just happen when you look a baby and smile at the |
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69:01 | The baby naturally smiles back. That a natural reflex of basic reflex. |
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69:05 | is pre programmed to say, I look cute and smile back at you |
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69:09 | you smile at me. Alright. programmed to do that a condition reflects |
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69:14 | what you practice and learn. Think all those years of going to school |
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69:18 | when that bell rings at the end class, what does that mean? |
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69:21 | up my stuff, Get up and , right. If you hear the |
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69:24 | in the middle of the class, begin doing and go, wait a |
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69:27 | . It doesn't seem right. Here's example of a conditioned reflex. You're |
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69:31 | along, you see a yellow What do you do speed up? |
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69:37 | , You've been conditioned. I'm not for that red light. It's gonna |
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69:41 | four seconds. I can get through light right now. You also know |
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69:45 | Pavlov and his dog and so that's that's the classic example of the conditioned |
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69:50 | . Alright. Um This picture is the one most important picture that you're |
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69:55 | see in this unit. Not because the reflex, but it's gonna repeat |
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69:59 | over and over again. All It's a good way to understand. |
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70:03 | only the reflex arc, but also difference between the periphery and the central |
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70:07 | system. Um And how it all together. So, you'll see this |
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70:11 | over and over again. So just of go okay I'm gonna I'm gonna |
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70:16 | this. All right. So the arc is real simple. Alright, |
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70:19 | five parts to it. There's the where the receptor is. Alright, |
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70:24 | this is where the stimulus is detected this particular case. We have a |
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70:28 | . I always say it's an electric because they put lightning bolts right? |
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70:31 | that nail has been penetrated and it's touching some sort of touch receptor. |
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70:36 | right. And then that signal that's by that interaction, then it's going |
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70:41 | travel along what is called the a pathway. Alright, I'm gonna put |
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70:46 | strong accent on the a a ferret if I did a nice texas |
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70:51 | we just call it an affront and sounds a lot like different. |
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70:56 | So it's an a different and then gonna process in what is referred to |
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71:02 | the integration center. All right, the third step. This is processing |
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71:08 | . I've just been jammed or stabbed nail. What do I do? |
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71:13 | , response is when I feel pain this place I move my hand |
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71:16 | Okay well let's tell that area to the hand away. And so you |
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71:23 | the signal down the different pathway to structure that does the job of |
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71:29 | which we call it the effect. it causes the effect. So receptor |
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71:36 | a ferret into the integration center Integration processes or integrates information. Then we |
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71:43 | the signal down the different pathway, out pathway to the effect which causes |
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71:48 | effect. All right. And each these represent where an action potential is |
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71:54 | . Now reflexes could be mono mono means one and then synaptic means |
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72:04 | . How many synapses? One mono here. 1, 2. So |
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72:10 | becomes poly synaptic. Don't let the scare you. Okay so this is |
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72:17 | most simple type of reflex that stretch . The knee jerk reflex is an |
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72:23 | of a mono synaptic. There is neuron between the different neuron and the |
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72:30 | a different different right So I stimulate received that there's a receptor sends a |
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72:36 | . It just goes right on to next neuron and causes the effect. |
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72:40 | is still an integration center. Where when that where that synapses but it's |
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72:45 | is a very very simple reflex. , no other input is being there |
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72:50 | modify polish synaptic. We will typically within their at least one interneuron. |
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72:57 | is an in between neuron. It so in the name. Alright so |
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73:01 | again I'm being an idiot. In lab I put my hand over a |
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73:05 | burner. Don't do that. It and then what's happening? I feel |
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73:09 | heat goes in. I process information move your hand away there goes to |
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73:14 | effect. Er I move my hand from the heat. This synapse while |
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73:20 | seeing here is being very very may actually cause other or there may |
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73:25 | be collaterals that go to other places you burn yourself? What is one |
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73:28 | the things that you usually say? only way you can do that is |
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73:33 | a signal is sent up to the nervous system to the brain, |
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73:36 | So that interneuron allows you to send up. There's also other places where |
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73:42 | may need to send information. So I contract this muscle I need to |
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73:46 | that muscle. So, what we're seeing in here is all the other |
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73:50 | that are taking place here for me move my hand away, because all |
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73:54 | concerned about right now is how do move the hand away? So policy |
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73:58 | have multiple neurons that are integrated into pathway to allow other things to |
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74:08 | Some reflexes are called autonomic reflexes, are called somatic. If it's dealing |
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74:14 | your organs. So think about your grumbling when you smell good food, |
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74:20 | ? That would be something that's affecting organs. It's affecting through the autonomic |
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74:25 | system. We keep using this word and over again, even though we |
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74:28 | talked about it yet. All So that is the autonomic when we're |
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74:33 | about somatic. You're dealing primarily with . Alright, so like again, |
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74:38 | I step on a tack and look foot, that would be a somatic |
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74:42 | , Right? If I like I if I smell food, my stomach |
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74:47 | grumbling, whatever that's autonomic, please confuse autonomic with automatic. All right |
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75:00 | , as I said, we're going move into the spinal cord, we're |
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75:05 | finish up with the spinal nerves. , spinal cord exits via the base |
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75:11 | the skull. Alright, So what going to see is we're going to |
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75:15 | we have the brain, the we have the midbrain and from that |
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75:18 | brain that keeps going down in that of spinal cord, it's encased by |
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75:23 | vertebral column. Remember when we looked the vertebrae we had that um framing |
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75:30 | so we were able to create a through which the spinal cord travels. |
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75:35 | protected by the bones of the It's protected by meninges, all three |
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75:40 | . It's protected by cerebral spinal So just like the other structures that |
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75:45 | when we said protect the central nervous . We weren't excluding the spinal |
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75:52 | When we talked about the vertebrae, talked about there being different vertebrae, |
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75:55 | had cervical, we had thoracic, had lumbar, we had sacral and |
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75:59 | had cox ideal. Alright, the cord is divided along those lines based |
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76:05 | where the spinal nerves are located. right, so the spinal nerves are |
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76:09 | exit out through and in between the at these different locations and so where |
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76:15 | spinal nerves are, you can see kind of look like the little tiny |
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76:18 | legs here. They're basically you can , okay, the first group, |
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76:23 | many would there be? Seven would cervical then, thoracic would be 12 |
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76:30 | five, so and so and so . Right. So those nerves are |
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76:34 | to be named spinal nerve number or , one cervical to cervical three. |
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76:38 | and so forth. Just like we when we learned the vertebrae. |
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76:43 | The thing is, we're not there . So that's the spinal cord. |
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76:50 | we take a slice through the spinal , we can see its organization. |
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76:54 | right now, this is not a picture of it. But you can |
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76:58 | this side right here, the dorsal the ventral or the post here in |
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77:01 | anterior sides are a little bit So you can kind of it's a |
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77:05 | bit more squished. You can see there's some grooves, right? So |
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77:10 | the dorsal side we have the dorsal media or posterior medial. Focus on |
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77:17 | anterior ventral side. We have the medial fissure. So this is a |
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77:23 | . It goes deep. The sulcus kind of goes down a little bit |
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77:27 | right, depending on where you make slice of the spinal cord, you're |
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77:32 | to see different shapes to it, it's going to have that same generic |
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77:36 | . All right. The idea of a little bit flat and a little |
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77:39 | elongate, but in areas in different , you're going to see different |
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77:45 | The gray matter is going to be central. The white matter is located |
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77:50 | and there's that central canal that I . That. Is that tube that |
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77:56 | off with the ventricles. So what white matter? Do you remember? |
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78:02 | does white matter? Axons? It's basically pathways. So basically how |
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78:09 | sending signals. And so if we at the white matter here, you |
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78:13 | imagine what we have is we have bunch of axons moving towards you and |
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78:16 | from you. Alright, in and of the out of the screen. |
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78:20 | so there's basically three columns here that call funicular. Alright. That's the |
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78:26 | we use instead of calling it a . It's a funicular. Just pick |
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78:30 | half if you like the left That's great. If you like the |
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78:33 | half, that's fine because it's the and the right is how we kind |
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78:36 | divide things. But what we have up here at the dorsal side or |
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78:41 | posterior side. We call it the or posterior. For Nicholas over here |
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78:46 | the lateral ridiculous. And then down is the ventral or anterior funicula so |
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78:53 | follows all the patterns that we've learned ? Very, very simple. All |
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78:57 | . And these tracks are gonna be or bundles of fibers that are traveling |
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79:04 | with similar origins and or similar All right. I'll elaborate on that |
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79:12 | about two slides. I want to to the gray matter. All |
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79:16 | When you draw gray matter, make life easy draw a nice simple |
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79:19 | So, here's what you do is go, All right. There is |
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79:24 | spinal cord. All right. Here's weird looking butterfly. The gray matter |
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79:32 | divided up in what are called Alright, So, you can see |
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79:38 | have one horn to horn. Three . Right up there. Not so |
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79:42 | to see the horns, but they're still there. Okay, This horn |
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79:49 | the dorsal horn. This horn is lateral horn. This horn is the |
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79:56 | or anterior. This is all post . You can use either term. |
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80:00 | tend to stick with dorsal, dorsal or ventral. All right. |
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80:06 | each of these and you can see gray matter. There's your central |
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80:10 | Gray matter uh covers that central What I wanna do is I just |
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80:19 | to point out what these are. gray matter consists of what type. |
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80:24 | what what is gray matter? Generally , if white matter is axons, |
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80:29 | matter is cell bodies. All So, here what we have are |
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80:35 | cell bodies of sensory neurons. Sorry, that I take that |
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80:43 | Strike that from the record, erase from your brains totally incorrect. Somebody's |
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80:50 | sensory neurons are located way out What we have here are the cell |
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80:59 | of inter neurons. All right. inter neurons are receiving information from sensory |
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81:09 | . So, the information that comes is coming in from that direction. |
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81:16 | , so these are inter neurons. is where the sensory information is deposited |
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81:23 | the central nervous system. In the cord. In the lateral horn. |
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81:30 | going to have the cell bodies of that are motor neurons. In other |
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81:37 | , they leave and they go out a muscle or gland. But these |
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81:43 | the lateral our autonomic if their autonomic means they're going primarily to the smooth |
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81:51 | of the viscera cardiac muscle. Or going to the glands. Their autonomic |
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81:57 | nature. All right. You can't their basically the involuntary muscle. Down |
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82:05 | . In the ventral. What you are the motor neurons of the somatic |
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82:13 | . So they're the ones that deal muscle. Okay, so sensory input |
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82:18 | in via the dorsal horn terminates on neurons in the dorsal horn. Those |
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82:26 | neurons will terminate into the lateral or horns. The lateral horns. Autonomic |
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82:34 | , ventral horn somatic neurons. And are motor. Okay. Century motor |
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82:46 | . It means these are out. , now, we're talking about protections |
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83:07 | by the brown protected by the meninges . All three are there. The |
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83:10 | is that the dura is a single . Instead of two layers, we're |
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83:15 | to see that there's a small space the door and the bone filled with |
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83:19 | . That's called the epidural space epi the dura. Right? We will |
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83:26 | that the meninges extend beyond the length the spinal cord. The spinal cord |
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83:31 | goes to L. two. Your grow faster than your spinal cord |
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83:36 | So your spinal cord shorter than your length. All right. So here's |
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83:40 | spinal cord. Your this so the go down, they cover the spinal |
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83:44 | and they keep traveling down all the to S. two. That's sacred |
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83:50 | . All right, you still have and then sitting over here on the |
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83:58 | . Those little tiny lines are what called articulate ligaments and they kind of |
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84:02 | the entire length down. And that your spinal cord from flopping around while |
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84:06 | move, basically holds it tight to to the structure so that the spinal |
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84:11 | sits in place. So while you still bend and move and stuff like |
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84:16 | , it doesn't bounce around. That's lenticular ligament. This picture here Does |
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84:23 | good job of showing what that spinal does. So here's L. |
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84:29 | That's about where the spinal cord And then you can see that spinal |
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84:36 | continue down and keep leaving along the . There's the line right here that |
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84:43 | you that dura. Look at how dura keeps going past the end of |
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84:47 | spinal cord continues on down all the down. You can see the spinal |
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84:53 | are exiting out where those vertebrae are and they just go by the same |
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85:00 | . The end of the spinal card is called the Conus Miguel Arroz because |
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85:05 | a comb, right? And then spinal nerves keep going down and the |
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85:10 | cords look like a bunch of horse hanging off the back of a |
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85:14 | So it's called the kata Aquafina but see how clever we name things |
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85:23 | what they look like. All There are 31 pairs of spinal cord |
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85:27 | spinal nerves. The exit out via inter vertebral foramen enter between the vertebrae |
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85:36 | . All right. You'll see two . You'll see an enlargement here and |
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85:41 | see an enlargement. It's right up . Okay. That enlargement just represents |
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85:47 | fibers from the limbs from the appendices up. And so it creates a |
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85:55 | of a broader or fatter area. , if you're looking at the spinal |
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86:00 | , you know without all this gunk , what you see of course I |
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86:04 | it out. It looked kind of this like that. And so you |
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86:12 | imagine that there's more fibers coming in the arms would be and more fibers |
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86:18 | the legs would be. That makes . Here we are. Again, |
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86:28 | to the structure. You're gonna see great majesty looks more like a |
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86:36 | What's that called dorsal horn. That that one very good. Alright. |
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86:49 | fibers that are leaving the ventral Alright. So remember those are motor |
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86:55 | and it's the outdoor. And what gonna form is what is called the |
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87:00 | , sorry, it's called the ventral . Alright. On the other |
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87:05 | you have fibers coming in, And that fiber coming in Or those |
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87:11 | those are axons bundled together. It's called the dorsal root. The |
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87:17 | root and eventual route converge and form spinal nerve. So, this, |
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87:22 | ? Here would be the spinal There's your ventral route. There's your |
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87:26 | root. Here's your spinal cord. right. That big fat thing. |
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87:32 | ganglion, What do we say? is having them? Cell bodies. |
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87:40 | ? That's all right. This is we why we play this game. |
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87:44 | right. So, when we are at those fibers, those sensory input |
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87:50 | have to do it over here. it smaller. What we have here |
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87:57 | we have a series of sensory fibers in like so, terminating on those |
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88:03 | neurons. Right? Sorry about the . I'm just gonna make a |
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88:07 | right? So, this is that neurons. So, their cell bodies |
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88:11 | located in that ganglion. All So, the sensory fibers, cell |
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88:18 | in the dorsal root, gangland. , we're going to learn not a |
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88:22 | , but a cadence to help us patterns. We're going to start with |
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88:25 | spinal cord spinal cord. The fibers are coming in and going out are |
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88:31 | in or going out via the Now, the truth is there's actually |
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88:34 | a smaller structure because the roots are little bit thick. So there's little |
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88:38 | structures that are called root. Let's you go spinal cord to root. |
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88:41 | root. Let's to root, convergent form the nerve so far with |
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88:49 | . Let's do it again. Start here at the spinal cord fibers going |
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88:54 | , fibers coming in via the Let's root. Let's are basically the |
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88:57 | tiny versions of the roots. The come together form the nerve spinal |
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89:05 | There's route. Let's root. Let's the root roots come together. There's |
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89:09 | routes come together for me nerve spinal . Alright, spinal nerve contains fibers |
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89:20 | in and going out, right? like a highway. There's not one |
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89:23 | , it's two ways right there all individually. So there's no mixed |
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89:28 | And what you're gonna do for a , you have this very fat, |
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89:32 | short nerve that nerve splits into three . Alright, these branches are called |
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89:42 | ramos. For single. Remy plural Raymond. We have a dorsal |
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89:50 | eventual ramus. Where do you think dorsal ramus is On the back |
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89:54 | Where do you think the venture one front side and then we have this |
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89:57 | one called the Remy communications right? gonna ignore this one as part of |
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90:03 | autonomic nervous system. We will come to it. Alright, so right |
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90:08 | we're not gonna worry about it. can see it sits off over here |
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90:10 | the side. Okay, and we're to deal with that in the next |
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90:15 | . Because if we spend a lot time talking about it, you'll get |
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90:19 | . I want to focus on the to the dorsal and the ventral and |
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90:23 | then I don't even really want to about the dorsal all that much. |
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90:26 | dorsal is simple. All right. , you start off over here, |
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90:29 | the spinal cord, spinal cord goes route. Let's root. Let's too |
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90:34 | . Roots to nerve nerve splits. dorsal ramus, muscles of the |
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90:41 | sensory input of the back. That's simple. Right? So dorsal, |
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90:49 | . That's easy. The ventral ramus the one that is interesting. |
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90:56 | It deals with all the primary nerves your body when you think of a |
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91:01 | other than the ones in the That's where they come from. Is |
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91:05 | the ventral ramus. All right. what they're gonna do is we're going |
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91:09 | see some really kind of weird interaction these Raymond. Where am I communications |
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91:15 | part of the autonomic nervous system. they're they're part of the three |
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91:18 | So, again, we got the cord spinal cord goes to route let's |
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91:21 | . Let's two routes, routes to nerve splits into the dorsal ventral Remy |
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91:27 | well as Remy communications dorsal deals with back muscle and skin. What is |
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91:32 | skin for? Is that sensory or or sensory motor? Century. I |
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91:39 | spider crawling up my back. There's be sensory nerves in my back that |
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91:43 | , hey, time to start doing thing. Right? muscles flexing. |
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91:51 | , So just remember sensory means, motor means affecting. All right, |
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92:00 | venture Ramos is going to branch off a kind of a weird way Now |
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92:08 | we get into this weird way, I want you to see is the |
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92:12 | of your body. Alright. These nerves which go into these different Remy |
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92:19 | going to be organized topographically so that you go into the spinal cord, |
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92:25 | thing that's furthest down from your body going to be more immediately located and |
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92:31 | you move up they're going to move laterally. Think about how you get |
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92:37 | the highway right? When you get the highway, Here's a really good |
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92:42 | right down here at the 288-59 right? You get down to those |
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92:46 | lanes, let's say you're in the far right lane, right on 2 |
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|
92:53 | . Well really it's 59 so you're have lanes that disappear after 2 88 |
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92:59 | down to two lanes, you go that horrible crawl, you know, |
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93:01 | know which one I'm talking about. goes like three miles an hour and |
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93:05 | cursing every big truck on the highway all the slow people who are sitting |
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93:09 | their phones right, Because that turn this All right, but if you're |
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93:12 | that left or that total right what's gonna happen is is that that |
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93:16 | lane doesn't stay a right lane much , does it? Another lane will |
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93:20 | and join you. Now you're in middle lane. You travel a little |
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|
93:23 | further past Louisiana, Two more lanes in and now you're five lanes, |
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93:27 | basically one lane from the left, , and you travel a bit further |
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93:32 | in front of lakewood. And now have like six lanes right? And |
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93:37 | you get over back to 6 10 it like shrinks back down to three |
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93:41 | right? And so what I'm trying show you here is like these fibers |
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93:46 | being pushed because more fibers are coming and they're maintaining their position inside the |
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93:53 | cord, right? These are not that just kind of go wherever. |
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93:57 | just jam them in there. There's organization to it, which makes it |
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94:03 | to understand this material as we move when we start looking at the white |
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|
94:06 | in its organization. All right. that's just kind of what it's showing |
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94:11 | is that there are nerves that are , that go more medial and as |
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94:14 | go up, they stay uh they on the lateral side. Also, |
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94:22 | nerds are named for where they're That also means the body is divided |
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94:29 | where those nerves go and go to where they come from. And so |
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94:33 | we have is there's an actual We call the derma tone, where |
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94:37 | sensory information is found and we call the Maya tome where that spinal nerve |
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|
94:42 | and innovates a muscle, Right? again, it's easily mapped. I |
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94:48 | for example that um a nerve traveling L. one is going to represent |
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94:54 | area. It's never gonna represent this . So if you have that like |
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94:58 | tingle or you lose sensation in a of your body, they know, |
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95:05 | know physician with the order. You know. Oh that would be The |
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|
95:10 | that's innovated by c. 5 All right, so there's a map |
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|
95:16 | you can actually create to your body's of cool that ramus. So this |
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95:23 | what you see here. See little . Those are the ramus is that's |
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95:27 | ventral ramus or the anterior ramus. . In this case the cervical |
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|
95:35 | So you can see C12 Yada Yada . So over in here we have |
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|
95:40 | spinal cord, spinal cords are going have fibers that go in and come |
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95:45 | via the route. Let's root. form roots. Don't do the |
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95:51 | You're gonna lose it. Alright, cord cord to its roots. It's |
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|
95:56 | roots. Roots to nerve nerve splits form ramos dorsal, ventral, rami |
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|
96:04 | dorsal for the back skin and muscle ramus is where we're focused and this |
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|
96:09 | what it does. It looks like in Houston. I was just going |
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96:16 | . Now, the purpose of a . And I'm just showing you this |
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|
96:20 | . There's an easier way to learn . The purpose of the plexus is |
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|
96:23 | ensure that a nerve or information going and from a location can get there |
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|
96:30 | say between here and your home there's massive accident on your normal route. |
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|
96:38 | there another way to get to your ? Yeah. You're not stuck on |
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|
96:42 | . Right thank goodness. Right now not an efficient route. Probably a |
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|
96:49 | you don't prefer but there is a and that's kind of what these plexus |
|
|
96:54 | . Are there not entirely like that you're not gonna get the full |
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96:58 | But basically information coming out of the can then be sent down. It's |
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97:04 | know one track or another. And you end up with is you may |
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97:07 | larger nerves by combining different Remy to the name nerves of the body. |
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97:16 | for example information from your forum will two different Remy to send information up |
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97:23 | the spinal cord. Right? So ensures that if damage occurs. Say |
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97:30 | At least I got information going through . three. That makes sense. |
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97:35 | there's multiple pathways to the same place form these larger structures like. |
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97:45 | Oh it looks like this and you to first dissect it out and figure |
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97:49 | out and play with it right? that's in essence how they identified all |
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97:54 | . All right. Yeah. Well they're all yellow and beige and very |
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98:00 | but its position what they're innovating and they what what they what sort of |
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98:06 | is detective when you stimulate them. right now, I'm showing you this |
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98:12 | because your book uses these pictures. . Which kind of looks like the |
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98:19 | maps from new york, you So if you don't know how to |
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98:22 | a subway map, you might be little screwed. But you know, |
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98:26 | think these are easier to understand Trying to look at a picture like |
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98:29 | and go, oh all right. it's it's easier of course if you |
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98:35 | a cadaver and you're able to tease things out because you'll know what you're |
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98:38 | for and where they go where they from. But I want to understand |
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98:42 | this is not one fiber. Each these represents hundreds if not thousands of |
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98:47 | traveling in the same direction. And gonna be divergence as you move further |
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98:52 | further down because you're gonna be innovating different parts, right? You're not |
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98:56 | sending one nerve fiber down to innovate the skin on the back of your |
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99:00 | . There's gonna be multiple nerves in , right? And they're converging together |
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99:04 | a larger nerve structure which then converges other stuff to form a larger nerve |
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99:09 | and so on and so on and on. All right. So we're |
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99:14 | be looking at these plexus. There's of them that you need to |
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99:18 | Okay, there's some sub plex is we don't ever focus on. But |
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99:21 | are the four major ones. What's is that those ventral Remy in the |
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99:28 | region don't use plexus. Is and reason is because we're gonna form what |
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99:33 | called the intercostal nerves enter means in costal ribs. In between the rib |
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99:42 | . See it's you see how easy is. If you if you take |
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99:46 | the magic and the mystique it becomes little bit easier. Alright. And |
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99:52 | the thoracic nerves are the intercostal There's a portion of T. One |
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99:58 | that is going to form part of brachial plexus. And we're not gonna |
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100:01 | not gonna sit there. And which does is formed by which things? |
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100:04 | don't do that. I'm not gonna you. C. Two and |
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100:07 | Three form what? That's that's not to be the case here. All |
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100:11 | . But here you can see the me basically look you can come out |
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100:16 | ? So there's one you can't see dorsal I mean, I guess right |
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100:20 | there is the dorsal. Alright. there's a split. This remains the |
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100:25 | my communications and that interior ramos just coming around and that is an intercostal |
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100:32 | . So what do those innovate? the upper ones, right up in |
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100:38 | , the tickle points, right? up here in the upper cavity then |
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100:44 | work your way down. That's gonna the anterior chest and you work your |
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100:47 | down. That's finally down into the . Alright. And really it's again |
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100:52 | and the skin, That's what you're with When you deal with the |
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100:58 | these four plexus is The Easiest one a cervical plexus. Alright. The |
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101:04 | plexus are just gonna be c. through c. five and a little |
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101:07 | of T. one. All They're going to create the nerves that |
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101:12 | with the superficial neck. What does mean near the surface? Alright. |
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101:18 | we're gonna talk about the muscles. its muscles of the hyoid, the |
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101:23 | at the surface of the neck and the lower portions of the head. |
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101:29 | are the muscles you need or not muscles these are the nerves you need |
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101:33 | know. So, I've divided it or your book is divided up into |
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101:37 | parts. The cutaneous branch and the branch. Cutaneous meal deals with the |
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101:43 | . So what they're talking about here sensory input. So cutaneous is sensory |
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101:50 | deals with muscles and movement. so here you can see them. |
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101:56 | just gonna point them out just on on the map. I'm not gonna |
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101:59 | you a picture of a plexus. just gonna ask you for if I |
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102:03 | you anything, it's like here's the plexus, What does the occipital nerve |
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102:08 | ? Well it innovates the occipital Where's your occipital scalp. There you |
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102:14 | . That are magic. A regular oracles, your ears. So skin |
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102:23 | the external auditory meters. So that's hole through your ear. That's your |
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102:29 | canal, cervical, the anterior portion your neck. So that would be |
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102:34 | post ear portion. So my anterior be right up here. Sucre, |
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102:41 | , vehicular, above the clavicle the skin of the shoulder. Do |
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102:46 | see how this is? Pretty All right. Now again, you're |
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102:50 | some point you're going to take a of anatomy where it's gonna be a |
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102:53 | more difficult than this. But right , this is where we want to |
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102:57 | muscular branch. We're dealing with the nerve. So, I'm just trying |
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103:00 | show you where they where they So, it's, you know, |
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103:03 | occipital cervical. I'm not going to it out for you, but when |
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103:06 | talking about the muscular branch, here's muscular nerve. They're super close |
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103:10 | They misspelled it. And then the nerve. All right, muscular |
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103:14 | that's the muscles of your throat. , right in there. Right. |
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103:20 | then the frantic nerve innovates the What allows you to regulate your |
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103:28 | Alright. Important nerve to know How we doing on time? Is |
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103:33 | time? Damn it. Well, least we got We only have three |
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103:37 | . Yes, I got a lot . We're gonna finish tomorrow. I |
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103:44 | it. All right. You guys have fun at the lab. |
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103:50 | I slowed down down there at the there. That was the problem. |
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103:57 | do not do |
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