| 00:01 | alright, I think we're going There we are. Alright, so |
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| 00:12 | we are, one more day, many days till the end of |
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| 00:17 | No one is keeping track three more . See these are the important things |
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| 00:24 | I was a long time ago I high school um forward grad school and |
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| 00:30 | were counting down and I taught math down by prime numbers, so you |
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| 00:36 | every day would come in the vice that we're looking at us funny because |
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| 00:39 | wear like a different tie or something what's going on today, Oh |
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| 00:43 | nothing just counting down the days. what we're gonna do is we're going |
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| 00:48 | look at the parts of the I we're going to kind of dive down |
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| 00:52 | little bit deeper, so we're gonna with the rods and the cones, |
|
| 00:55 | gonna see some complexity stuff that may may not be important. I'll point |
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| 00:59 | like this is important, this is important, you know, that sort |
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| 01:02 | thing. And then what we're gonna is we're gonna look at the mechanisms |
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| 01:06 | allow us to actually turn light energy an action potential, which is called |
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| 01:12 | transaction. Um and it's it's basically a g protein coupled receptor pathway. |
|
| 01:18 | was the first one discovered. So kind of interesting in that sense but |
|
| 01:22 | literally going to be doing some some which are kind of I think are |
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| 01:27 | of interesting, so hopefully we'll get all that and then what we'll do |
|
| 01:30 | we'll jump into the ear and look the structures of the year and how |
|
| 01:33 | ear hears? And I think we that when we're talking about the |
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| 01:37 | ear does two things. It plays role in hearing, also plays a |
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| 01:40 | in equilibrium or balance right. And we're gonna get hopefully get through the |
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| 01:45 | part. And so our starting point is where we left off, we |
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| 01:48 | talking about the rods and the And so remember we said the retina |
|
| 01:52 | multiple layers of cells. And so we're just gonna do is we're gonna |
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| 01:55 | of look through a couple of these and we kind of tend to focus |
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| 01:59 | on the rods and cones because these the photo receptors use the ones that |
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| 02:03 | receive that light energy and convert that energy into a graded potential that then |
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| 02:09 | transmitted through the bipolar cells and ultimately the ganglion cells to be submitted up |
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| 02:14 | the visual cortex so that you're perceiving light energy. And so we have |
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| 02:19 | two different types of cells Roger because they look like rods cones, |
|
| 02:22 | name because they look like cones. what they do is they respond to |
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| 02:27 | wavelengths of light and allow us to within that particular spectrum. Now you |
|
| 02:35 | see here, we got kind of compare contrast thing. And so you |
|
| 02:38 | , we have Rogers only one type rod cones and humans, there are |
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| 02:42 | types of other species that may have , like chickens have four. You |
|
| 02:47 | , So it's just different. And , what do they do? |
|
| 02:50 | the rod is primarily responsible for night . Alright. It's the one that |
|
| 02:54 | you to see kind of in the notice, kind of in the dark |
|
| 02:58 | you can't really see in the Whereas the cones, they play a |
|
| 03:02 | in color vision. So it's really of daytime vision in terms of where |
|
| 03:07 | located. Well, the outer you can see outer segment is simply |
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| 03:11 | series of folds that then turns into kind of elongated structure. And within |
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| 03:17 | are these kind of membrane bound They look like pancakes stacked on top |
|
| 03:21 | each other. And so where we're to be looking in terms of the |
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| 03:25 | transaction pathways occurring within those pancakes, in the cones, this is actually |
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| 03:30 | membrane folded on itself over and over over again. So structurally they're |
|
| 03:35 | Um Which is why they come up their unique appearances. Um In terms |
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| 03:41 | where they're located, if we take retina, remember we said we have |
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| 03:45 | round structure if we flatten that out think of it as kind of a |
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| 03:48 | eye that kind of expands outward towards edges, we're gonna see the rods |
|
| 03:54 | located on the edges on the whereas the cones are gonna be located |
|
| 03:58 | what is called the central uh phobia , which is basically the center of |
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| 04:02 | bull's eye. And you can see terms of numbers, the number of |
|
| 04:07 | heavily outnumber the number of cones by significant margin. But that doesn't |
|
| 04:12 | It's just that you're covering a greater and we're going to see kind of |
|
| 04:15 | picture in that of that in just moment. So as I said, |
|
| 04:19 | rods are primarily night vision, so where there's dim light. What that |
|
| 04:23 | is is that the reason that you're to see in dim light is because |
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| 04:28 | has a high degree of sensitivity towards . And so you can send a |
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| 04:34 | at a single rod cell and stimulate rod cell to fire. All |
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| 04:38 | And so you perceive even minimal but because they are so sensitive, |
|
| 04:45 | you overstimulate them, they stop All right. And so in |
|
| 04:50 | the cone cells, they're very they very low sensitivity. It takes more |
|
| 04:55 | energy to stimulate them. And so you get a lot of photons that's |
|
| 05:01 | they turn on. And so all a sudden now you kind of see |
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| 05:03 | , when it's dim my roger kind working and then what happens, it |
|
| 05:07 | too bright. And then the rods working and the cones kind of take |
|
| 05:11 | . Alright, so that's kind of that works. And so the other |
|
| 05:15 | of that is the acuity All And this is going to have to |
|
| 05:18 | with the degrees of concentration. All . And so what we're going to |
|
| 05:22 | is because they're so highly concentrated, cones, we have a high degree |
|
| 05:27 | acuity. Whereas the rod to kind spread out, they cover larger visual |
|
| 05:33 | that you get kind of a blurrier . Alright. In other words they're |
|
| 05:37 | quite as acute now they'll use the I tend to use and we're going |
|
| 05:41 | see a little bit later and if not tech savvy, I apologize but |
|
| 05:46 | the easiest one you can think about . You know? So back when |
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| 05:50 | was growing up, you had basically standard definition like 480 p. |
|
| 05:57 | I see people looking at me like ? And then high def came out |
|
| 06:00 | couple of years back about 20 years when I was 7 20 p or |
|
| 06:04 | 80 P. All right. And now you're starting to see the four |
|
| 06:08 | TVs and what those represent are the of pixels over a certain area. |
|
| 06:13 | right. So if I have a that is oh I don't know, |
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| 06:16 | inches tall. It's saying there's 480 from top to bottom. Whereas with |
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| 06:21 | 7 20 it's 720 pixels. If 10 80 that's 1000 and 80. |
|
| 06:26 | four K is 4000 and so and forth. So what you're doing is |
|
| 06:30 | getting smaller and smaller and smaller So that gives you greater acuity, |
|
| 06:36 | put it this way, which would rather do watch a movie on an |
|
| 06:39 | television or would you like to watch movie on a brand new spanking four |
|
| 06:42 | tv? The four K. It's realistic, right? You can tell |
|
| 06:49 | that's on an old tv. It's yeah, that looks kind of like |
|
| 06:53 | . Alright, so that's that acuity that's what we were kind of talking |
|
| 06:57 | on Tuesday when I told you kind look at that piece of paper or |
|
| 07:01 | that that thing that your you know your laptop or whatever and look right |
|
| 07:06 | forward, you can see it's very clear, but if you don't |
|
| 07:08 | your vision you can see it's kind blurry out here. Alright, that's |
|
| 07:12 | example of acuity, it's like you tell there's stuff there but it's not |
|
| 07:16 | clear. So what do you do you turn your eyes to kind of |
|
| 07:19 | and see what's going on. The thing that I want to point out |
|
| 07:24 | again, has to deal with the portion is the convergence. Alright, |
|
| 07:30 | convergence recall is the number of cells are attached to the next level of |
|
| 07:36 | . Alright, so I have given example previously, it's like you can |
|
| 07:41 | and I'm gonna use this number for , there might be 100 rods and |
|
| 07:45 | the 100 rods, there might be bipolar cells and for 10 bipolar |
|
| 07:50 | there might be one ganglion cell not making up numbers but it's it's |
|
| 07:54 | of an easy thing to do. you go A factor of 10 |
|
| 07:58 | So that would be an example of degree of convergence. Going from lots |
|
| 08:01 | cells to like one cell with Part of the region of high acuity |
|
| 08:06 | because you have low degrees of So you might have one cone to |
|
| 08:12 | bipolar to one ganglion cell. So means your field. If a ganglion |
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| 08:18 | represents your visual receptive field, you what your brain perceives light coming |
|
| 08:24 | Then for a cone, the light field is very very small. Whereas |
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| 08:29 | the rods it's actually rather large because ganglion are receiving information from so many |
|
| 08:34 | cells. That's again that security. we're gonna see this hopefully in just |
|
| 08:38 | minute. But this is kind of overview so you can do this. |
|
| 08:41 | simple compare and contrast. What does one do? What does that one |
|
| 08:46 | ? And so here is looking at retina. Alright, this is what |
|
| 08:50 | optometrist does when he shines or her shines that light in your eyes. |
|
| 08:55 | is what they see in the back your eye. Alright. We said |
|
| 08:58 | goes in but it doesn't come out it's getting absorbed by that uh that |
|
| 09:02 | or not really, that pigmented layer epithelium. And so you can see |
|
| 09:07 | this uh is you know, there's down here is kind of representing where |
|
| 09:11 | are. So the blue dots represent , the green dots represent cones. |
|
| 09:16 | if you use this graph, you see out on the periphery, it's |
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| 09:19 | rods and then all of a sudden , it drops right down and in |
|
| 09:23 | very center of the eye, there's and lots of cones and then moving |
|
| 09:27 | out through the retina. You see and lots of rods again. So |
|
| 09:30 | like lots of rods and then nothing lots of rods. Again, if |
|
| 09:34 | go cones, very few cones and of a sudden lots of cones and |
|
| 09:37 | no cones or very few cones. that frame of reference though, is |
|
| 09:43 | the back of this. I And you can see the back region if |
|
| 09:46 | shining light directly in the back of eye, what you're doing is you |
|
| 09:49 | that large bullseye, you guys play . I mean if I'm saying bull's |
|
| 09:53 | , you know what that is, . You know, with the bulls |
|
| 09:56 | , there's a single bulls eye. then there's another smaller dot. That |
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| 10:00 | dot is called the trying to see plays darts here because you're at the |
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| 10:07 | where you need to be learning how play darts. All right. I |
|
| 10:11 | , that's that's what college is all , right? Going to the |
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| 10:14 | go into the pubs, learning how play darts. We don't drink at |
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| 10:16 | pubs. We just played darts. single bullseye double bull's eye. There's |
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| 10:22 | big circle, smaller circle. More for the smaller circle. Okay, |
|
| 10:27 | . See we know you're just not along with my game this morning. |
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| 10:31 | right. So the bigger circle is the Macula Lutetia. Alright, So |
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| 10:36 | basically where light goes and hits. , so that's where your light's |
|
| 10:42 | But the center of the macula Lucia the phobia centrales. That is where |
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| 10:47 | highest concentration of cones are located. when you think of the focal point |
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| 10:52 | the eye, that's the phobia centralist this region called the macula Lutetia. |
|
| 10:58 | , you can also see if you in the back, you'll see this |
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| 11:01 | where blood vessels and all the nerve are entering into the eye. And |
|
| 11:06 | this is all the axons of the cells, there's no need to put |
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| 11:12 | uh photo receptor cells or bipolar, not room for it. This is |
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| 11:17 | optic disc. And because there's no photo receptor cells, it's also your |
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| 11:23 | spot. And so it's a little spot in your eye where no light |
|
| 11:27 | actually hitting. And so what your does, it actually fills in the |
|
| 11:31 | for you. It's a really, small thing. I don't know if |
|
| 11:34 | when I was in third grade, taught us this optical illusion where it |
|
| 11:37 | like you draw a dot. And an X. On a piece of |
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| 11:41 | and you stare at the X. then you move the people, you |
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| 11:43 | the paper back and forth and you watch the dot disappear as it passes |
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| 11:48 | where the optic nerve is located. optic disc. All right now notice |
|
| 11:53 | is gonna be on the medial side the eye. And then so again |
|
| 11:57 | pointed out here with the periphery that's here on the edges. This is |
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| 12:00 | you're gonna see. Mostly rods. mean there aren't any cones, but |
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| 12:04 | are mostly rods there. So I this, we're going to come back |
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| 12:12 | in terms of how the rods and cones work. We refer to con |
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| 12:16 | vision as faux topic we refer to as uh rod dependent vision as sco |
|
| 12:24 | . Alright, so faux topic. easy way I remember this photo |
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| 12:27 | photographs color. All right. And you're an R. T. Purchase |
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| 12:32 | black and white, I'm sorry. just messed everything up. But really |
|
| 12:36 | this basically says is look my vision dependent upon how much light is |
|
| 12:40 | Alright, when it is dark and is very little light, my roger |
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| 12:44 | be stimulated because very little light is to stimulate that. And so that's |
|
| 12:48 | be the first level, that's the stuff that gets turned on. So |
|
| 12:51 | now depending on scope topic. Vision about when you wake up in the |
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| 12:54 | of the night. You don't turn the light, you're just going to |
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| 12:56 | bathroom or whatever and you're moving around room and you can see objects in |
|
| 13:00 | room, right? You can see pile of laundry in the corner. |
|
| 13:05 | think it's a pile of laundry because , you remember that's where you put |
|
| 13:07 | laundry, It might be a you're not quite sure, but you're |
|
| 13:11 | going to turn on the lights to out because we know that's the |
|
| 13:13 | you don't turn on the lights to out, right? But you can |
|
| 13:17 | of see the general shape, you see the dresser, there's enough light |
|
| 13:21 | through from outside that you can probably around the room, but you can't |
|
| 13:26 | the details of what's in that So that's an example of sco topic |
|
| 13:31 | , you turn on the lights now have enough photons that your your rods |
|
| 13:36 | oversaturated. So they basically stopped working now your vision is now dependent upon |
|
| 13:42 | or skills beyond cones. Now you discern colors, you can discern shape |
|
| 13:48 | right in the dark. It's really to discern color. It's kind of |
|
| 13:52 | dark or it's not dark, So that's the idea. Now, |
|
| 13:58 | adapt very, very quickly. think about when you go outside after |
|
| 14:03 | to a matinee. Have you ever to a matinee? You know what |
|
| 14:08 | is, that's a show during the in texas. If you go to |
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| 14:12 | matinee, it's dark in the you open the door, What |
|
| 14:16 | You're blinded, right? And everything bright, It's like white and you're |
|
| 14:21 | , okay, I can't see Right, But you still managed to |
|
| 14:26 | to your car because you do All right. Maybe you cover up |
|
| 14:30 | little bit here. The reason you're to see quite a bit quicker after |
|
| 14:35 | blinded by the light is because those are re stimulated because it got |
|
| 14:41 | just like your rods do. But reset all the mechanisms inside very, |
|
| 14:47 | quickly. It takes about 2-3 minutes reset a cone rods on the other |
|
| 14:53 | , Adapt very slowly. If you them too much light, it takes |
|
| 14:55 | about 10 minutes to adapt. Think going from a bright space to a |
|
| 14:59 | space and how long it takes for eyes to adjust to the dark |
|
| 15:03 | Yeah, you can see the shapes stuff, but it's your now you're |
|
| 15:06 | kind of working on those cones and cones are going, I can't see |
|
| 15:10 | . And it takes about 10, minutes for you to kind of really |
|
| 15:13 | able to see well. And the is it takes about 30 minutes before |
|
| 15:17 | rods are actually ready. There was great show on. Mr what is |
|
| 15:22 | ? Mystery buster? Mystery mythbusters. they asked the question, this is |
|
| 15:28 | a fun one. Why did pirates patches? Alright. You think |
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| 15:33 | because it looks cool, right? guys aren't interested in pirates, are |
|
| 15:39 | ? Mhm. Alright, why do wear patches? Well, maybe they |
|
| 15:43 | their eyes knocked out? No, the, the theory behind this, |
|
| 15:46 | from the artistic and how it looks is that the pirates had to be |
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| 15:51 | on deck where it was sunny and when they had to go and fight |
|
| 15:57 | , right, it would be dark it's very hard to see. So |
|
| 16:00 | you're fighting someone who's already dark adapted your light adapted, you're going to |
|
| 16:04 | the loser. So what they did they put a patch over there, |
|
| 16:08 | gotta do it like this so that are light adapted in one eye, |
|
| 16:11 | adapted in the other. And so they went downstairs you just lift up |
|
| 16:15 | patch and now you can see just myth buster said, is this |
|
| 16:23 | They tried it and guess what? , so maybe I think it had |
|
| 16:30 | to do with that, It looks . Alright, bipolar cells are weird |
|
| 16:37 | hard and we're gonna use one example a bipolar cells. These are there |
|
| 16:41 | multiple types of bipolar cells. But in essence what a bipolar cell |
|
| 16:47 | , is a cell that's downstream of photo receptor cell and its job is |
|
| 16:53 | turn on or turn off the ganglion downstream. So notice it's either going |
|
| 16:58 | be an on cell or an off . Alright, so what they do |
|
| 17:02 | usually you'll have a photo receptor cell you'll have to bipolar cells associated with |
|
| 17:06 | one that's gonna be the only one gonna be off. I'll give you |
|
| 17:09 | example. You don't need to know , but there's like the blue versus |
|
| 17:12 | . So some cones will be sell some will be yellow cells. |
|
| 17:17 | so they're basically turning, if blue hits it, it's gonna it's gonna |
|
| 17:21 | one photo one bipolar cell. If hits that particular cone, then it's |
|
| 17:26 | be the the other bipolar cell. really what this does is that it |
|
| 17:31 | for your brain to understand contrast much than it would than if the information |
|
| 17:37 | up here and it started processing. what we're doing here is we're really |
|
| 17:40 | of processing information and stimulating pathways That information never even leaves the |
|
| 17:49 | All right. And so they kind served as a point. So this |
|
| 17:52 | what this is trying to show you . Here's our cone and says one |
|
| 17:55 | here is off center, one is center. So when light hits this |
|
| 18:00 | , this receptive field and light hits receptive field in the center. So |
|
| 18:05 | this cone happens to be in the then it's going to turn it |
|
| 18:08 | But if the light is not hitting , then that's going to turn |
|
| 18:11 | And so you get a different So basically what you're doing is you're |
|
| 18:15 | here, I got out side by , one is in the center, |
|
| 18:18 | is not. If this one gets , this one definitely um sends a |
|
| 18:24 | . This one definitely does not and creates this greater contrast between dark and |
|
| 18:31 | . Again, I'm pointing this stuff over here, light out here, |
|
| 18:35 | over there. The reason your eyes perceive the difference is because right now |
|
| 18:40 | getting their bipolar cells going, oh more light out here than there is |
|
| 18:45 | here. So if I'm looking at receptive field in the center of that |
|
| 18:49 | field is saying it's more dark. I'm turning the off centers on and |
|
| 18:55 | turning off centers or the on centers . It's kind of how it |
|
| 19:00 | But when you think bipolar cell, is what you need to think downstream |
|
| 19:04 | the photo receptor upstream of the ganglion modifying signal. Okay, we're going |
|
| 19:11 | see at least this example a couple times to help you understand, we |
|
| 19:17 | about receptive fields, receptive fields simply remember when we talked about touches the |
|
| 19:21 | in which a neuron is receiving input a from a receptor. Alright, |
|
| 19:27 | we have receptive fields in the we said that cones have very, |
|
| 19:32 | small receptive fields, we have rods have very large receptive fields and this |
|
| 19:36 | trying to show you what that looks . So the ganglion cell. |
|
| 19:41 | so remember we have the photo We have the bipolar and then we |
|
| 19:44 | the ganglion cells. The ganglion cell the receptive field. Because what we're |
|
| 19:51 | about is the number of cells that converging on that ganglion cell. And |
|
| 19:56 | in the Phobia Centrales where we have , we have very few or we |
|
| 20:03 | very or very little convergence. So kind of a 1-1 to 1 is |
|
| 20:08 | example that's being shown. Alright. if you look on the periphery you |
|
| 20:12 | have a gangling sale, but there'll lots of cells affiliated with that. |
|
| 20:16 | right. And so it's basically telling the area in which I'm going to |
|
| 20:21 | light. So if light stimulates over , I still stimulate the gangling |
|
| 20:25 | Light stimulates over there. I can stimulate that one ganglion cell and I |
|
| 20:30 | have a lot of acuity when that . I don't know where the light |
|
| 20:33 | . It's some place within this But if I have only a |
|
| 20:37 | then when light hits that one, stimulating. So I know exactly where |
|
| 20:41 | light is coming from. I have high degree of acuity and that's why |
|
| 20:45 | use that, why we use an like this. Your eyes are not |
|
| 20:51 | . All right, But you kind get the sense this would be an |
|
| 20:56 | where you have high convergence. You see the stuff in that picture, |
|
| 21:02 | ? I mean, you can perceive that is back there. What is |
|
| 21:06 | come out right? Does it look a mountain? I mean No, |
|
| 21:12 | it's kind of fuzzy. You can it's very blocky, right? But |
|
| 21:16 | brain looks at that and says okay that kind of that blocky image type |
|
| 21:21 | over there. Yeah, that's kind a mountain. It's kind of like |
|
| 21:24 | you look at your peripheral vision, you focus forward and kind of look |
|
| 21:27 | here you can see there's stuff out , it's kind of fuzzy, I |
|
| 21:31 | what that is that looks like a over there. It has kind of |
|
| 21:34 | the the shape of what I expect be a person to be and how |
|
| 21:38 | I know I can go and look Oh yeah, that's definitely a |
|
| 21:41 | Alright, so your brain is taking shapes and stuff and saying this is |
|
| 21:45 | I think it should look like. on the periphery that's just fine. |
|
| 21:52 | is at 4K. Look at the , the number of pixels just say |
|
| 21:57 | there to there is A significantly it's about 10-fold greater than pixels from |
|
| 22:03 | to there and you get much much sharpness. So in areas of high |
|
| 22:10 | right, you're going to have greater . Alright, sorry, hi convergence |
|
| 22:15 | lots of things you're gonna have lower . So this is an example over |
|
| 22:19 | of high convergence over here. This lo convergence. So you're going to |
|
| 22:24 | much much, much greater degrees of . All right. And again, |
|
| 22:31 | just correlating directly to the receptive Small receptive fields, great yield high |
|
| 22:39 | , large receptive fields leave yield low . And typically those fields are out |
|
| 22:47 | on the periphery. Here we are , looking at the bipolar cells. |
|
| 22:56 | right. And what we're doing here we're kind of looking at that center |
|
| 23:00 | surround. So, what this So, down here, this is |
|
| 23:04 | ganglion cell right here. These are cells. And so these three cells |
|
| 23:10 | the receptive field of this ganglion Now, we have two ganglion cells |
|
| 23:14 | here and they both have the state field. Okay, that's kind of |
|
| 23:20 | . Right? They have the same field. Well, why does that |
|
| 23:23 | ? Well, they're receptive fields One is an on center, one |
|
| 23:26 | an off center. So what it is that when this ganglion ganglion cell |
|
| 23:32 | stimulated, that means light is hitting portion of the receptive field when it's |
|
| 23:37 | center, this cell is going to stimulated. And what it's saying is |
|
| 23:41 | is hitting on the outside of that field. And so this is that |
|
| 23:45 | thing that I was talking about. when light hits the center, it |
|
| 23:49 | you a sense that there's more light the center of the receptive field. |
|
| 23:52 | it makes it brighter if it's not the center is hitting the outside, |
|
| 23:57 | the outside should be brighter. The is darker. Now, I want |
|
| 24:01 | to think about a three dimensional object light height hitting it? Think of |
|
| 24:04 | apple. Right? You get the . You have that little bit of |
|
| 24:07 | shine. Actually, there's a great right here. If you look at |
|
| 24:10 | , the shiny bottle, I mean see how the light hits that and |
|
| 24:14 | kind of comes out at you and can kind of see the three dimensional |
|
| 24:17 | as a result of the light hitting bottle. Does the metal bottle? |
|
| 24:22 | . Alright, That's because more light hitting the center of the object for |
|
| 24:27 | receptive field. And so it gives a sense that this is popping out |
|
| 24:31 | you. Whereas if it was concave would be absorbing in the middle, |
|
| 24:35 | of like what we see over All right. And so it gives |
|
| 24:39 | a sense of the center is darker that's why you get that dark |
|
| 24:43 | You get that contrast. And this just a way for the brain to |
|
| 24:46 | the contrast better before it ever gets . All right. So, we |
|
| 24:52 | these fields that are basically working against other ones. A positive field. |
|
| 24:56 | is a negative field. And this is just saying on off as |
|
| 24:59 | , you know, is it light the center or is it not? |
|
| 25:02 | I told you there's many different And this is just one of |
|
| 25:07 | Okay, but what do we have photo receptor cells? What does photo |
|
| 25:13 | cells do receives light converts it into to a greater potential. That goes |
|
| 25:21 | a bipolar cell, which modifies a . And then that is going to |
|
| 25:26 | a ganglion cell. It sends a up to the brain. All |
|
| 25:31 | That's what you guys need to know now. All right. But it's |
|
| 25:34 | complex. What's going on along the . That's less of what you need |
|
| 25:38 | know. Just know. It's So, what I want to do |
|
| 25:43 | is I want to transition I want move down into the molecules what's actually |
|
| 25:48 | on in these rods. And these , we're gonna use the rod as |
|
| 25:51 | example. The same thing is happening the cone. It's just differently |
|
| 25:56 | Remember we said in the rod, have these little tiny pancake structures. |
|
| 26:00 | , these uh little tiny um uh is what they're referred to as. |
|
| 26:07 | , membrane bound disks now embedded in disks in the rod embedded in the |
|
| 26:14 | of the cone. Is our structure the photo pigment photo pigment is what |
|
| 26:21 | the light energy and converts the light ultimately into a signal. So, |
|
| 26:26 | just basically is there to absorb life different types. And so, really |
|
| 26:30 | we have here is we have two to it. We have a g |
|
| 26:33 | coupled receptor. That's what the green is. It's called option. And |
|
| 26:37 | upon where you are, you have types of options. So like in |
|
| 26:40 | rod you have rod options. See it is right there, rob Dobson |
|
| 26:44 | the cones. It's called Photo ops . So just option is good enough |
|
| 26:49 | us. Alright, so that's the that's a g protein coupled receptor now |
|
| 26:55 | learned and hopefully you haven't flushed from brains what G protein coupled receptors do |
|
| 27:01 | there are part of a signal transaction . A molecule comes along binds to |
|
| 27:06 | receptor activates a receptor and then something downstream. Do you guys remember |
|
| 27:11 | Okay, so what that tells us if this is the G protein coupled |
|
| 27:15 | it needs to have some sort of and it does the ligand is this |
|
| 27:22 | kill right here is retinol. if you go and look at a |
|
| 27:25 | of vitamin A, you'll see it's long chain with these little tiny rings |
|
| 27:29 | the ends. And if you clip right now, if you get a |
|
| 27:31 | and a retinol so that's with the retinol. Alright, now retinol is |
|
| 27:38 | pre bound to our G protein coupled . All right, so this is |
|
| 27:44 | weird case where I have a receptor already has its ligand attached to |
|
| 27:51 | So if I'm bound to my my leg is bound to the receptor |
|
| 27:54 | would usually tell you what's what are doing with the receptors that on or |
|
| 27:59 | . It's on. Okay, so kind of the first thing that's kind |
|
| 28:03 | weird. Now, the other thing want to point out, do not |
|
| 28:06 | these numbers. All right. I want you to see, do you |
|
| 28:09 | that there there's overlap? You guys the overlap. Do you see that |
|
| 28:13 | different? They have different peaks. . And what this represents is the |
|
| 28:20 | in which light energy can be traveling stimulate those different types of receptors. |
|
| 28:25 | you've learned at some point in your that you have these three cones and |
|
| 28:28 | have names. There's the red the blue cone and the green |
|
| 28:31 | All right. Those are terrible The reason they're called that is because |
|
| 28:36 | this peak value right here. All . Those peak values tell you kind |
|
| 28:41 | what wavelength of light you're kind of at visible light, but that's not |
|
| 28:45 | these actually work. All right, overlap here is the other thing I |
|
| 28:50 | to really kind of highlight here. at the rod. The rod overlaps |
|
| 28:54 | everything. So this is the light by. I'm just gonna make up |
|
| 28:57 | word gray light. I mean if is a No, there's no such |
|
| 29:01 | as gray light. Right? So stimulated by the save wavelengths of light |
|
| 29:06 | your cones are stimulated by the difference is that it doesn't give you the |
|
| 29:12 | of color. Alright. It's basically what we said. Very little bit |
|
| 29:16 | energy activates the rod. Too much basically over stimulates it so it can't |
|
| 29:21 | anything. So what this is basically is that at low levels of light |
|
| 29:27 | stimulating the same way you stimulate these so you're able to see but you |
|
| 29:32 | really perceive color. I think I to this. Yeah. So this |
|
| 29:37 | what color perception really is. You learned your Roy G biv? |
|
| 29:42 | okay. How many colors are Really? If you had to guess |
|
| 29:47 | do not say eight. We're That's Roy Jeep at seven. |
|
| 29:52 | How many thousands? She? You wouldn't want to go higher or |
|
| 29:58 | . Higher. How many? How ? I heard a number infinite. |
|
| 30:05 | probably way too many. Well, gonna do this. You're probably |
|
| 30:10 | There's probably an infinite number of All right, but I'm going to |
|
| 30:15 | the harder question. How many colors the human eye perceive a small portion |
|
| 30:24 | infinite? Yeah, you're correct, correct. How many? It's in |
|
| 30:34 | millions. That's absolutely correct. It's the millions. All right. |
|
| 30:39 | how many colors can you name The are like seven Roy G biv, |
|
| 30:45 | ? You you can probably go to 40. You don't think so. |
|
| 30:49 | think higher or lower? Well, right, ladies, I want you |
|
| 30:53 | name five colors of blue. Go . Navy. See another one. |
|
| 31:03 | blue. I heard another one, , turquoise and teal. All |
|
| 31:10 | Some of the guys are standing on are blue. How do you guys |
|
| 31:14 | cornflower? Some some layers are like , I do. Yeah. You |
|
| 31:19 | . So here here's the fun Alright, I'm gonna ask the guys |
|
| 31:24 | what color is this red ladies, color is that? Scarlett? |
|
| 31:35 | my point is is that we can lots of colors. I want to |
|
| 31:38 | you. All right. Everything You see your Roy G biv up |
|
| 31:41 | What color is her shirt is Is it up there? What about |
|
| 31:48 | sweatshirt for hoodie? What color is ? It's pink. Alright, we're |
|
| 31:53 | go with the guy answer pink. we see pink up in the color |
|
| 31:59 | . Huh? All right. What is showing you is the wavelengths that |
|
| 32:06 | can break out the colors as But can saturate colors with white and other |
|
| 32:11 | and with black and other combinations to different degrees of these different colors. |
|
| 32:17 | you've ever played with Photoshop or any of thing where you can manipulate |
|
| 32:21 | you'll know that you can hit about million colors. Right? And the |
|
| 32:26 | because of the way these cones actually . Notice what I said, we |
|
| 32:30 | them red, green and blue, their real names are the STM and |
|
| 32:33 | L cone And it refers to the of light that they're being stimulated |
|
| 32:37 | And what it shows you is if look at this, if this is |
|
| 32:39 | percentage of stimulation. All right, you can stimulate something 0%. Up |
|
| 32:45 | 100%. Can't overstimulated above 100. under stimulate below zero. Right? |
|
| 32:50 | that's a nice simple range 0 to . I can have say, for |
|
| 32:55 | , I'm gonna use the green the green cone, Which is named |
|
| 32:59 | here's the range of green stimulates Look at that. I am not |
|
| 33:03 | maximally stimulated. I'm stimulated somewhere around . So when you think of a |
|
| 33:10 | , what it is is not the of a single cone, but a |
|
| 33:15 | of all three cones in the So again, let's go here and |
|
| 33:19 | can see I'm barely stimulating the I am sort of stimulating around 50% |
|
| 33:26 | the red cone and I'm stimulating the cone about 75%. So my brain |
|
| 33:31 | perceiving that color right there. so green, the perception of green |
|
| 33:37 | a result of the degree of stimulation each of these cones and simultaneous stimulation |
|
| 33:45 | all three of those cones, This why we're able to see millions of |
|
| 33:50 | , right? Because it's whatever that happens to be alright now, |
|
| 33:56 | if you've gone and played with Photoshop you're like adjusting your C. |
|
| 33:59 | M. K, which is really colors. Or if you're adjusting your |
|
| 34:03 | and you're like, you know, goes up a dot that goes down |
|
| 34:06 | dot what you're doing is the same that this is doing right, that |
|
| 34:11 | eyes are doing when, when light it at a particular wavelength. It's |
|
| 34:14 | at this wavelength I'm gonna stimulate the by this much, I'm gonna stimulate |
|
| 34:17 | green by this much. Or I'm gonna stimulate the green cone, |
|
| 34:21 | red cone and the and the blue . Or the SML cones at these |
|
| 34:25 | different percentages. And so now you're orange, if that makes sense? |
|
| 34:31 | , I always ask this color or color. Always ask this question to |
|
| 34:36 | . So, it's just something you want to put a star by is |
|
| 34:39 | is color perception? Is it perception a single cone? Or the perception |
|
| 34:43 | stimulation of all the cones? Something those lines. So make sure you |
|
| 34:48 | that? All right. The scary . Not scary at all. |
|
| 34:55 | this again. Uh This is a machine. Right, basically asked the |
|
| 35:00 | of All right, if I stimulate , how do I get the whole |
|
| 35:04 | to create an action potential. And we said, this is photo trans |
|
| 35:09 | . Alright, so, we're gonna photo pigment and you can see this |
|
| 35:12 | the picture from your textbook. And I've color coded it to match |
|
| 35:16 | you see over here. So, pigment is the green thing. Uh |
|
| 35:20 | have translucent, which is a G . Alright, so this is translucent |
|
| 35:25 | . Alright, we have a photo race PDE is how it usually |
|
| 35:30 | So as PDE right there, we a channel which is a unique |
|
| 35:35 | It's stimulated to open when it's bound the cyclic GMP. So it's called |
|
| 35:40 | cyclic nucleotide gated channel. So the happens to be GMP. So it's |
|
| 35:46 | GMP. Alright, so these are things Oh and then we also have |
|
| 35:50 | late cyclist up here. Guan. cyclist is what makes cyclic GMP. |
|
| 35:55 | . So in essence what we're just at. And when you're looking at |
|
| 35:59 | picture, you're going to be asking question, what do all of these |
|
| 36:01 | do when there is light energy or there is not light energy. All |
|
| 36:06 | . And so I'm gonna use this because I started when I started teaching |
|
| 36:10 | class. This is the picture I . I've color coded it to |
|
| 36:14 | To match that. I'm sorry. the wrong direction. Come on. |
|
| 36:18 | thing. Yeah. To match this that you can kind of go |
|
| 36:22 | But it's it's basically the same I even put the same color. |
|
| 36:25 | is just remind you what we're just at. Alright, so what I |
|
| 36:29 | to do first is I want to at this with regard to the |
|
| 36:34 | All right, so imagine no Alright. No. Like what's going |
|
| 36:38 | ? Well, we have one late over here, One late cyclist takes |
|
| 36:43 | nucleotide GTP. Alright. And what gonna do is it's gonna cleave off |
|
| 36:48 | two last phosphates. And it makes cyclical molecule. And we said this |
|
| 36:52 | GMP is what binds to this channel causes it to open up. And |
|
| 36:58 | that channel opens up sodium comes into cell and when sodium rushes into the |
|
| 37:02 | , what do we call that? polarization? So in the dark your |
|
| 37:09 | are d polarized and typically when we d polarized, what that means is |
|
| 37:13 | cell is activated. Okay. So we have here is we have a |
|
| 37:18 | that is being turned on in the . Now can you see in the |
|
| 37:25 | you don't perceive light in the dark very definition. But what we have |
|
| 37:30 | is a cell that's already turned on active. All right. And so |
|
| 37:35 | it's doing is that when you de , that's gonna spread throughout the whole |
|
| 37:40 | and it's going to cause the release neurotransmitter, the neurotransmitter happens to be |
|
| 37:46 | . And so what is doing is it's not being stimulated, it's telling |
|
| 37:50 | bipolar cell downstream is I'm not being . Do not send a signal up |
|
| 37:54 | the brain. And so you perceive how very backwards. That's not how |
|
| 38:03 | would design it was No, of I wasn't in charge of creating the |
|
| 38:11 | . Now if you have sodium coming the cell eventually you're going to fill |
|
| 38:15 | the cell of sodium and it's gonna working. So you need to have |
|
| 38:18 | way to remove sodium and so we something that's called the dark current. |
|
| 38:22 | the dark current is basically taking an sodium potassium pump. And as sodium |
|
| 38:27 | in you pump it back out. so what you do is you create |
|
| 38:29 | natural flo of course potassium is going . You want to also create a |
|
| 38:34 | for potassium to leave and so potassium . So to ensure that the system |
|
| 38:39 | working, you have a dark circuit a dark current. Alright, so |
|
| 38:45 | the dark there's mechanisms in place to sure that the current keeps happening if |
|
| 38:51 | is coming in, you want to it out so that sodium can keep |
|
| 38:55 | in. So now we have light comes along and stimulates the photo |
|
| 39:09 | Now we said the photo pigment has parts to it, it has the |
|
| 39:12 | protein coupled receptor part, that's the molecule, it has the uh the |
|
| 39:17 | that's already there, that's called retinol exists in two states. The state |
|
| 39:22 | you find it in in the dark it stimulated is the cis transformation. |
|
| 39:29 | you can see the little picture right . You can see the little tail |
|
| 39:31 | it. So if my hand portion kind of the ring of the retinal |
|
| 39:36 | , my finger represents the tail. would be the cis confirmation, |
|
| 39:41 | And what's gonna happen is light comes and plays with that little joint and |
|
| 39:47 | that sis turn into trance. so what I'm doing here is I'm |
|
| 39:54 | the shape of the molecule and you at the very beginning of the semester |
|
| 39:57 | I change the shape of molecules, happens. Okay, now this molecule |
|
| 40:03 | to be inside that particular option, is a specific size. If I |
|
| 40:11 | inside there like this and I change shape, what am I going to |
|
| 40:14 | to the shape of option do you ? What do you think you're gonna |
|
| 40:23 | shape? And when you change the of molecules, something happens. |
|
| 40:30 | So changing the shape of red and change the shape of options, change |
|
| 40:33 | shape of option option does something In other words, I've activated the |
|
| 40:38 | protein coupled receptors now. Really? you very much. Here we |
|
| 40:50 | Double check. Alright, so this just trying to show you here's the |
|
| 40:54 | confirmation. You can see there there's 11, that's the 11 carbon. |
|
| 40:58 | happens is you change the shape of the trans shape? So the tail |
|
| 41:01 | big. What happens is when the gets big, it no longer likes |
|
| 41:04 | shape, it changes the shape of option molecule. So now what you've |
|
| 41:08 | is you've activated opposite opposite is now of turning on the pathway that's downstream |
|
| 41:16 | protein coupled coupled receptors are called G coupled receptor because they're coupled to it's |
|
| 41:22 | a trick question. What is G proteins thank you very much. |
|
| 41:27 | all there in the name. So gonna happen is you've now activated That |
|
| 41:33 | retinol is no use anymore. So want to get rid of it and |
|
| 41:36 | reorganize it. So you're gonna send on its way. It's gonna go |
|
| 41:39 | to the pigmented epithelium and that pigmented that absorbs light is gonna say I'm |
|
| 41:44 | twist you back into the right shape I'm gonna send you back in a |
|
| 41:46 | of minutes. All right. But other thing because the opposition has changed |
|
| 41:52 | . What that does is it changes relationship to the G protein when you |
|
| 41:58 | a G protein coupled receptor. Remember there to turn on or activate the |
|
| 42:02 | protein. The G protein is normally by GDP. And what that does |
|
| 42:07 | that confirmation all change here causes a in the shape there. That says |
|
| 42:11 | don't need you anymore. Go G. D. P. I |
|
| 42:13 | something new. I want GTP so kicked the GDP out of the place |
|
| 42:18 | comes in GTP has energy and it I want to be activated. And |
|
| 42:22 | that's what you're doing is you're activating . That's the name of this particular |
|
| 42:27 | protein it's called transducer because when they discovered it they're like oh look we're |
|
| 42:32 | light energy from light into this signal then they discovered 40,000 others good on |
|
| 42:41 | . So we just call them G now. So transducers becomes activated. |
|
| 42:47 | right now notice we haven't done any yet. We're just doing step by |
|
| 42:50 | . We go to the next go to the next step. |
|
| 42:56 | The G protein remember has two parts it is the alpha subunit, beta |
|
| 43:00 | subunits. We're focusing on the alpha here because it's bound up to |
|
| 43:04 | T. P. It has energy it's saying I've got to go turn |
|
| 43:07 | on and when the thing that it's to turn on is this molecule called |
|
| 43:11 | dia strays Now there's lots of different diess traces in the body. They |
|
| 43:15 | do kind of slightly different things. it says it's a phosphor restoration of |
|
| 43:18 | it's doing is it breaks phosphate Right? Fossa di ester bonds that's |
|
| 43:26 | its name. So what you do when the G protein comes along and |
|
| 43:29 | foster diaspora. Foster diaspora says I'm for these diaspora bonds. Where can |
|
| 43:33 | find one? It says oh look have them right here on cyclic |
|
| 43:37 | So it's targeted cyclic GMP. The of cyclic GMP we said is to |
|
| 43:42 | keep this channel open and I've got thing over here constantly making cyclic |
|
| 43:46 | And so it's able to bind this . But if I start chewing up |
|
| 43:50 | GMP, I no longer have the to open the gate. If I |
|
| 43:55 | have the key to open the what's going to happen to the |
|
| 43:58 | It's going to close. So phosphor hates his job is to chew up |
|
| 44:03 | GMP basically cleaved that bond. So you just have regular GMP. That |
|
| 44:09 | doesn't recognize that channel. So you cyclic GMP when you lose cyclic |
|
| 44:15 | the next step is of course, the channel closes when the channel |
|
| 44:19 | sodium can't come in. If sodium come in, you are no longer |
|
| 44:24 | polarizing the cell. If you're no de polarizing the cell, then that |
|
| 44:30 | polarization becomes hyper polarization. This is weird use of that term. The |
|
| 44:35 | polarized cell now has less sodium. no no deep polarization or there's hyper |
|
| 44:42 | . Five hyper polarization have no signal cause release of inhibitory neurotransmitter. If |
|
| 44:49 | not releasing inhibitory neurotransmitter, I am longer inhibiting the bipolar cell. If |
|
| 44:55 | no longer inhibiting the bipolar cell by cell begins to fire and that signal |
|
| 45:03 | received by the ganglion cell and the cells send it off to the brain |
|
| 45:08 | says guess what? At this point where light hit. So I stimulate |
|
| 45:18 | photo receptor cell which causes the loss inhibition for my brain to perceive life |
|
| 45:27 | than what I would expect it to . But I'm not in charge of |
|
| 45:31 | these things. All right. So is kind of a way that you |
|
| 45:36 | put it up. So I walked all those steps and you're sitting there |
|
| 45:38 | , man, that's a lot of . No, it's really just step |
|
| 45:40 | goes to step B step B goes step, see it's just a Goldberg |
|
| 45:44 | machine. Just start at the beginning work your way through. But you |
|
| 45:47 | kind of say okay, what's going in the dark versus what's going on |
|
| 45:50 | light And you can just say all , in the dark. I had |
|
| 45:53 | retinal. The channels were open. membranes d polarized. That means I'm |
|
| 45:57 | neurotransmitter. It happens to be its inhibitory. I put green because |
|
| 46:02 | stimulating this cell. And when I'm the cell and really I'm stimulating it |
|
| 46:07 | to fire basically, you're not allowed fire. So, the bipolar cell |
|
| 46:12 | not doing anything. All right. over here, in the light, |
|
| 46:16 | light causes that retinol to change shape it changes shape, that cascade of |
|
| 46:21 | that we just describe from transducer and of PDE to the destruction of cyclic |
|
| 46:27 | causes the sodium channels to close. means this membrane hyper polarizes. Which |
|
| 46:33 | I'm no longer releasing neurotransmitters. If don't release the neurotransmitter, there's nothing |
|
| 46:39 | the cell. So the bipolar cell active and starts sending a signal and |
|
| 46:44 | why your brain perceives light. That's a nutshell, everything we just |
|
| 46:51 | it's right here. So, we've talked about this. So, I |
|
| 47:03 | I decided to repeat it. So adaptation is simply adapting to the amount |
|
| 47:09 | light in the dark. The rods going to be activated first and then |
|
| 47:14 | light levels rise, they become oversaturated over activated. So they stop |
|
| 47:19 | In essence. They're basically they can't anything other than bright at that |
|
| 47:24 | And so they get downplayed. And now the cones take over and that's |
|
| 47:28 | you start dealing with the faux topic . All right, that's that light |
|
| 47:38 | . This is one of those slides again you're gonna be tempted to go |
|
| 47:42 | and try to see this. This is a representation of a much more |
|
| 47:48 | process and I don't even want you learn what all these things are. |
|
| 47:53 | is what I want you to know this. All right. In the |
|
| 47:56 | cycle we said the cis retinal turns trans retinal. Trans rational is kicked |
|
| 48:00 | and sent away to go get rico . This is the recon jiggering. |
|
| 48:06 | , so what it basically says is light comes along, I'm going to |
|
| 48:10 | the shape of the retinol. Once that trans retinol, what I do |
|
| 48:15 | I kick it out to the pigmented , a whole bunch of stuff happens |
|
| 48:19 | that it gets back to its original and now once it's back to the |
|
| 48:22 | cyst shape, I'm going to escort very carefully and insert it back into |
|
| 48:26 | option molecule so that it can perceive receive light energy again and go through |
|
| 48:31 | whole process all over again. All . I mentioned it takes longer for |
|
| 48:37 | to adapt it. About 10 minutes a rod to adapt. Whereas for |
|
| 48:42 | it takes about three minutes now. is that? Well the cones aren't |
|
| 48:48 | dependent upon these pigmented epithelial cells. also have the same sort of system |
|
| 48:56 | them so they can reset themselves. right. But the idea is |
|
| 49:03 | All right. You don't need to all this stuff. The simple thing |
|
| 49:06 | is you have to record jigger the in order for you to see it |
|
| 49:11 | . Alright. Use it. It to be fixed so light hits the |
|
| 49:27 | . It stimulates the photo receptor Photo receptor cells are going to act |
|
| 49:31 | the bipolar cells, bipolar cells act the ganglion cells. The ganglion cells |
|
| 49:37 | the signals or produce that action potential then travels up to the visual |
|
| 49:43 | But there's a process. So the nerve is simply the uh all the |
|
| 49:51 | of all those ganglion cells leaving the . Alright, so that nerve represents |
|
| 49:58 | the receptive fields going forward. They crisscross and so fibers are going |
|
| 50:03 | go to both the left and the hemisphere. Alright. First place they're |
|
| 50:08 | to go. Is there going to thalamus? Remember we said in the |
|
| 50:12 | we have the lateral genic Hewlett That's the first place information goes from |
|
| 50:17 | And then from there it's then sent to the primary visual Cortex which we |
|
| 50:22 | v. one. This slow down slide. I don't want you to |
|
| 50:29 | again. All right. What I you to see here is that when |
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| 50:32 | look at those layers you can see six layers. Remember we talked about |
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| 50:37 | the cortex always has six layers. is an example of that. And |
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| 50:41 | I want you to see here is you have different groups of cells in |
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| 50:46 | locations. So for example you have magnets, cellular cellular cells. |
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| 50:50 | They play a role in high Alright. Try and even see if |
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| 50:54 | even show here. So it's the , they're showing you down here. |
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| 50:59 | , parvo cellular cells deal with spatial and colors. I love the names |
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| 51:04 | the areas where you're processing. Conor blobs. I thought there was a |
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| 51:11 | that it was organized. When I started looking at this stuff, I |
|
| 51:14 | looking at stuff and I was like I don't get it. You don't |
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| 51:17 | to get it either. It's all . All right. But the idea |
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| 51:20 | that information is broken apart spatial Understanding the distance between objects is broken |
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| 51:29 | from color which is broken apart from which is broken apart from movement and |
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| 51:35 | these different things are being processed at levels within the cortex and then they're |
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| 51:41 | to other areas. Remember what I . Visual Processing takes place in a |
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| 51:46 | of different parts of the brain. focus on b. one not a |
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| 51:51 | that you need to know. I want to show you the complexity. |
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| 51:55 | you have V. One, here's . Two, there's V. |
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| 51:58 | V three A. Here's V. over there. Down along the |
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| 52:02 | there's V five and you can see basically information is being sent to a |
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| 52:07 | bunch of different areas. You can just as an example. V three |
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| 52:10 | processing motion, right? So when perceive motion, think about motion. |
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| 52:16 | see if somebody moving that's easy. think about a video game. Why |
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| 52:21 | it look like on a video The person is moving correctly. |
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| 52:26 | Is because they can mimic But you in terms of the number of sprites |
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| 52:32 | they use in some cases what movement like in your brain fills in the |
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| 52:37 | and says oh that's what the movement like. All right, so the |
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| 52:43 | cortex is vast because we are visual , we are dependent on vision to |
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| 52:52 | our environments. All right, we're . Our eyes are on the front |
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| 52:57 | our heads and on the sides looking danger. Right? We hunt by |
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| 53:03 | and whether that means going to taco and hunting where they're going out into |
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| 53:07 | bush and hunting you're hunting. I that's all we have. Yes. |
|
| 53:14 | , so I'm gonna stop there for second. I know we talked about |
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| 53:17 | confusing things. So this is your to say wait a second. I |
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| 53:20 | understand this and I know that no is going to raise your hand because |
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| 53:23 | all a bunch of do it, it. Uh huh. Yeah. |
|
| 53:31 | . Yeah. Yeah. Yes. to. All right. So, |
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| 53:35 | questions of visual cascade. Alright, just gonna focus in on their |
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| 53:43 | Okay, But you can walk through think of each of those slides as |
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| 53:47 | the next step. All right. I want to do this because I |
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| 53:50 | this is easy to remember in the . The cell is already active, |
|
| 53:55 | ? Because what you have is your cyclic GMP. That's what Guadalupe cyclist |
|
| 54:00 | . It produces cyclic GMP, cyclic . What it wants to do is |
|
| 54:04 | wants to bind to that receptor that that receptor. It opens the channel |
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| 54:09 | channel then allows sodium to come So you have lots and lots of |
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| 54:13 | inside the cell causes deep polarization. polarization results in release the neurotransmitter release |
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| 54:18 | neurotransmitter causes the bipolar cell not to stimulated. Alright, it's an inhibitory |
|
| 54:26 | . It's like pressing on the All right. So when the light |
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| 54:31 | along, what it's gonna do is going to stimulate the change in the |
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| 54:35 | of that retinal molecule. Alright, photo pigment is opposite and retinol. |
|
| 54:39 | , if I change the shape of retinol, that means I change the |
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| 54:42 | of the option if I change the of the option the G. Protein |
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| 54:46 | which the G protein coupled receptor is changes shape and when it changes shape |
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| 54:52 | it does, it kicks out a energy particle GDP and replaces it with |
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| 54:58 | unused one. So now has energy so it can go do stuff. |
|
| 55:03 | . So that's what this is And saying, look I'm kicking out |
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| 55:06 | old and replacing it with the unused now I'm gonna take that. I'm |
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| 55:10 | use that unused portion or really that plus this active portion. And what |
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| 55:17 | gonna do is I'm gonna stimulate the molecule down the road. And that's |
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| 55:21 | called phosphor dia stories. All And again, the chemistry background would |
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| 55:27 | you to go phosphate ester bonds. what the case. It's It's an |
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| 55:30 | that breaks that. Alright. But not there. It's okay. |
|
| 55:35 | What it does it takes cyclic Right? We're making lots of |
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| 55:39 | And what we're gonna do is we're break that little bond. That's a |
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| 55:43 | bond like this. We're gonna break . So, there's only one |
|
| 55:47 | So basically what I've done is I the shape of this molecule into that |
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| 55:51 | . So once I change the shape now has a different function. It's |
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| 55:55 | capable of binding this. So if can't bind this this can't open if |
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| 56:01 | can't open. sodium can't come If sodium can't come in I can't |
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| 56:06 | polarize if I can't be polarized, can't block the stimulation of bipolar |
|
| 56:11 | So simply by removing the cyclic Right? Breaking that bond. That's |
|
| 56:17 | that does. What it does is creates this cascade of events that ultimately |
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| 56:21 | in no neurotransmitter being released, no being released. The bipolar cell will |
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| 56:28 | de polarize on its own and then sends a signal to the Was that |
|
| 56:35 | ? I know I was talking over but was that helpful in understanding. |
|
| 56:44 | , and that's what all these little are. Yes, sir. Is |
|
| 56:50 | no independent? So, you can when you have intense intense light. |
|
| 56:57 | , the intensity of light represents primarily number of photons that are being |
|
| 57:03 | Right? So the brighter it is what that means is there's more |
|
| 57:07 | That's not always true because we remember we said, there's amplitude as well |
|
| 57:10 | that's going into something entirely different. right. But if you have lots |
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| 57:14 | light receptors, that means you have recycle these faster. So just think |
|
| 57:19 | bright light. The first thing that is if I have too much |
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| 57:22 | my my pupils are going to constrict let less light in so I can |
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| 57:28 | or regulate. But let's say I keep shining in bright light. Then |
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| 57:31 | happens is is I start over using uh photo pigment. So it's you |
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| 57:39 | the photo pigment has to go through whole recycling thing. And like in |
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| 57:42 | cone it takes about three minutes to a single molecule. So if you |
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| 57:48 | using too many of those up what you start perceiving is white |
|
| 57:53 | Right? So if if basically if have overstimulated my eyes, everything just |
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| 57:58 | bright and white, that's kind of it looks like. Well, that's |
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| 58:02 | brain perceives. So that kind of the question. Yeah. Anyone |
|
| 58:08 | Yes, sir. Where? so rods and cones. This is |
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| 58:16 | rod in the cone. Alright, that's kind of the shape right |
|
| 58:19 | See there's and there's the uh the bound disk, that's what that's supposed |
|
| 58:23 | represent. Alright, So, I my art's terrible, but that's that's |
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| 58:27 | this is. Is So when you of the rod and cone, they're |
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| 58:30 | ones that are doing this pathway. the rod in the corner of the |
|
| 58:34 | that are upstream. Let me I had a better. Yeah, |
|
| 58:45 | guess that's going to work. All . So, what this is showing |
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| 58:49 | this is your rod. Now, could be a cone. I could |
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| 58:52 | this and say let's do the exact thing in a cone. Alright, |
|
| 58:55 | here's your bipolar cell. So, you're talking about photo transaction, you're |
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| 59:00 | this is what occurs in a rod a comb. All right. And |
|
| 59:05 | because of that stimulation of the right the cone that you're able to then |
|
| 59:09 | the cells downstream. Okay. Another . Yeah. Yes. I wouldn't |
|
| 59:33 | , so remember what we're saying here when I when I convert cyclic GMP |
|
| 59:37 | GMP, I'm no longer able to the channel so it's not GMP closing |
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| 59:43 | channel. It's the loss of the to keep the door open. Imagine |
|
| 59:48 | a door jamb, cyclic GMP is door jamb. If I kicked the |
|
| 59:51 | jam out of the way, the slams shut, I have to put |
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| 59:54 | cyclic GMP back into place. And really the bounce between visual visual |
|
| 60:00 | The idea of light versus dark is is the photo pigment hitting here. |
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| 60:05 | the photo pigments hitting here or sorry light's hitting the photons hitting the photo |
|
| 60:10 | then I'm chewing up cycling GNP faster I can make it. If photons |
|
| 60:15 | not hitting then I'm making cycle GMP than I'm chewing it up. So |
|
| 60:19 | kind of the balance that you're playing is how much cycling GMP I have |
|
| 60:24 | correlates with how much sodium is able come in more cyclic GMP more sodium |
|
| 60:30 | cyclic GMP. Less sodium. That of makes sense. Yeah, I |
|
| 60:36 | it's first time going through it. see this every day then it's like |
|
| 60:41 | . All right. But that's that's of the idea here is you're you're |
|
| 60:46 | a system and trying to keep balance the two. I think I'll quickly |
|
| 60:51 | eyes are responding to I mean you your move your you know, your |
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| 60:55 | of vision across the room and think quickly you can discern color and shape |
|
| 61:00 | stuff like that. So it's being to change and respond to all that |
|
| 61:06 | that's coming in very, very That makes sense. Was there another |
|
| 61:13 | over here? Want to learn about here is a little bit easier. |
|
| 61:20 | right. Don't know why that point there. All right. So remember |
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| 61:28 | said the ear it was a problem hearing equilibrium when we think of the |
|
| 61:31 | . We think of this portion out . There's actually three parts of the |
|
| 61:35 | . We have the external ear. ear is basically your oracle or peanuts |
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| 61:41 | it's called as well as the ear , which is called the external acoustic |
|
| 61:45 | auditory medias Medias is just a word means tube or tunnel. Alright then |
|
| 61:50 | have the middle ear. Middle ear the space between the tim panic membrane |
|
| 61:57 | what is called the round window and oval window basically this is where the |
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| 62:01 | are that allow for light or the . Excuse me. Sound waves to |
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| 62:06 | transmitted between the outside of your body the actual sound detecting devices which is |
|
| 62:13 | in the inner ear. Now the ear has two parts to it. |
|
| 62:17 | are is the cochlear and vestibular Alright. So this is a fluid |
|
| 62:22 | structure. You're gonna see it over over again. Right here. It's |
|
| 62:26 | this this all this stuff right So the cochlea is the thing that |
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| 62:31 | like a snail shell snail shell. . It's the one that actually converts |
|
| 62:36 | waves into nerve impulses or the structures it. Do. And then the |
|
| 62:40 | apparatus is all this weird looking stuff there, basically, it's responsible for |
|
| 62:45 | our position of our head space. basically it's responsible for equilibrium. All |
|
| 62:51 | , So just going through the structures quick, the oracle, that's your |
|
| 62:56 | you would call your ear. So it's the skin flap in the |
|
| 62:59 | underneath. It has this really weird and that weird shape is what allows |
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| 63:03 | to direct sound to the next which is the external acoustic mediastore |
|
| 63:09 | Meet us. You might call it canal. And so basically sound waves |
|
| 63:12 | going to travel down to that to tim panic membrane, which will vibrate |
|
| 63:16 | the same frequency and intensity as the waves traveling to it. And so |
|
| 63:22 | the acoustic auditory um and the acoustic us, you have fine hair. |
|
| 63:26 | have sarah Municipal guns. So that's earwax, that's what they produce. |
|
| 63:30 | there to protect the meet us. so basically collects airborne particles, |
|
| 63:35 | all sorts of horrible nasty things. the media's itself is there to direct |
|
| 63:40 | to that tIM panic membrane when you into the middle ear. All |
|
| 63:47 | What you're gonna see is a couple first. I'm just gonna point out |
|
| 63:49 | station or auditory tube. This is opens up to the nasopharynx. Nasopharynx |
|
| 63:54 | nasal cavity pharynx, his throat. it's the point where those two things |
|
| 63:59 | . And so when you need to your ears, what you're really doing |
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| 64:01 | you're trying to collaborate the pressure in middle ear to the external environment. |
|
| 64:05 | the easy thing. All we gotta though, right? And basically what |
|
| 64:09 | doing, you're opening up that tube of spreading it and allowing air to |
|
| 64:13 | back and forth freely through that. right now, the reason we want |
|
| 64:18 | do that is if you've ever noticed the pressure gets high and then things |
|
| 64:22 | of sound a little muffled. It's same way if anyone here play drums |
|
| 64:27 | . So when you bang on the and you put your hand on the |
|
| 64:29 | side, it makes a less vibrant . It's kind of a thud. |
|
| 64:34 | ? That's what happens when that tim membrane can't vibrate if you put pressure |
|
| 64:38 | it greater than the pressure on the side. It doesn't vibrate quite as |
|
| 64:42 | . And so that's when sounds kind muffled. So that's what we |
|
| 64:46 | Right, You've been on an you go up to altitude was |
|
| 64:50 | yeah, I can tell I can the pressure things are sounding a little |
|
| 64:54 | more muffled on saturday. Do that well. Oh and advice if you |
|
| 65:01 | frequently and there are usually kids on right? Always carry dumdums, |
|
| 65:09 | dums, those little tiny lollipops. cheap and you can give them to |
|
| 65:14 | kid and their parents will be grateful they will suck on that. And |
|
| 65:18 | sucking action also pops ears which is makes kids cry on airplanes. Well |
|
| 65:24 | whole bunch of other stuff anyway in tim panic cavity um we have the |
|
| 65:30 | in the round window which we'll get in a little bit here we have |
|
| 65:34 | tim panic membrane which is where you're be receiving sound waves. The tim |
|
| 65:38 | membrane is associated with three bones. malice, the Incas and the stay |
|
| 65:42 | . These are called the obstacles malice the hammer. The Incas is the |
|
| 65:46 | the anvil, the staples is the . Those are what the names |
|
| 65:50 | And they're based on their shapes Alright. And what they do is |
|
| 65:55 | serve as amplifiers and they're going to amplifying the vibrations that are received at |
|
| 66:01 | tim panic membrane. To to the membrane which is the oval window. |
|
| 66:07 | . Round windows over here and we're get to that in just a |
|
| 66:10 | So sound wave travels through causes Tim panic membrane. Tim panic membrane |
|
| 66:15 | it vibrates, causes the movement of malice in the Incas then stay peas |
|
| 66:19 | moves back and forth at the same or same as the tim panic |
|
| 66:24 | But you've amplified the the size of wave. Alright, So wavelength is |
|
| 66:31 | , we're going to see on the slide I think. All right. |
|
| 66:34 | , have you ever been to a ? They've all been a concert, |
|
| 66:37 | . Music is really, really loud when they first start playing the |
|
| 66:40 | you're like ah it's too loud. after a couple of seconds you're |
|
| 66:43 | not so bad, Right? And reason for that is because we have |
|
| 66:48 | within these structures, the tensor tympani this temper the tensor stampede ius. |
|
| 66:54 | what they do is they wrap around bones. And so if you create |
|
| 66:57 | much vibration, those bones, they and they reduce the amount of amplification |
|
| 67:03 | that allows our ears to adjust so we don't damage the inner ear. |
|
| 67:09 | not perfect, but they're helpful. right, going to the inner |
|
| 67:19 | Alright, We have bony structure with nous structure. Alright? So what |
|
| 67:25 | you have if you take a look this thing is you're gonna see there's |
|
| 67:28 | parts and there's member nous parts and gonna go and see a picture in |
|
| 67:32 | here, I gotta make sure what we got going on. All |
|
| 67:36 | Um Well, we'll see these. the bony has three basic structures and |
|
| 67:41 | is what you're seeing out here. have the cochlear we have this region |
|
| 67:45 | that's called the vestibule. The not the vestibular, the vestibule. |
|
| 67:49 | then you have these rings, those called the semicircular canals. When you |
|
| 67:54 | through them. What you're gonna see you're gonna see these memory nous regions |
|
| 67:59 | the actual structures are that are able have the receptors that detect movement of |
|
| 68:06 | within the membrane, this labyrinth. the bone kind of sits on the |
|
| 68:10 | . They're still fluid there. But they have these little other regions inside |
|
| 68:14 | have membrane that have fluid inside And what you're looking at is you're |
|
| 68:18 | at the movement of the fluid inside membrane, this labyrinth and you're gonna |
|
| 68:21 | texting that movement. So what the do where the visual course, sorry |
|
| 68:29 | the eyes are responsible for taking light and turning it into action potentials. |
|
| 68:34 | ears while you're dealing with sound energy sound energy is a form of |
|
| 68:39 | You're really looking at movement. So are mechanical receptors that we're looking |
|
| 68:45 | Alright. And so within the bonus and the cochlear we have the cochlear |
|
| 68:51 | . We're gonna be looking at the organ. The vestibule contains these two |
|
| 68:55 | of you trichomoniasis actual which play a in balance. The semicircular canals have |
|
| 68:59 | semicircular ducts which also play a role this balance or equilibrium. Come on |
|
| 69:08 | , we are. Alright when we at light, we said it was |
|
| 69:12 | radiation. It had this really weird wavelength sounds a little bit easier to |
|
| 69:17 | . It's kind of like a rope have these periods within the wavelength where |
|
| 69:22 | you're doing is when sound travels, you're doing is you're pushing molecules, |
|
| 69:26 | molecules are compressing and bouncing off each and then spreading apart. So we |
|
| 69:31 | is compression and rare faction and that's by that wave. So you can |
|
| 69:37 | here here's the compression. Here's the rare faction over and over and over |
|
| 69:41 | . Just repeated. So again you a wavelength. That's your pitch. |
|
| 69:47 | ? When you see wavelength think frequency in hertz pitch high notes versus low |
|
| 69:53 | . Alright, high notes are when wavelengths are close together. Low notes |
|
| 69:56 | when the wavelengths are far apart. right, intensity again deals with desk |
|
| 70:02 | , its amplitude. That's loudness. , when I yell high decibels, |
|
| 70:11 | ? That's the amplitude. Alright, I can pay imagine I could hit |
|
| 70:15 | high C. I can't hit a seat. But imagine if I could |
|
| 70:19 | could do a soft high C. I could do a loud high |
|
| 70:24 | All right. Same pitch different All right. So what I wanna |
|
| 70:34 | is I want to focus here on cochlear. All right, So here's |
|
| 70:38 | coakley. It looks like a snail shell. So hard to say |
|
| 70:43 | Alright. So we're just looking at thing and what we've done is we've |
|
| 70:46 | through that and so what you're looking is you're looking at one of those |
|
| 70:50 | and you can see there's 123 different regions in here. So you can |
|
| 70:54 | the bony part. And why you three regions is because you have a |
|
| 70:58 | part as well. So here's bony it's kind of lined by this or |
|
| 71:03 | have in it this membrane. And this right here is that cochlear duct |
|
| 71:07 | you're going to have the structure that detects sound. Alright now, down |
|
| 71:13 | in this picture, what we've done we've taken that Coakley and we've unwound |
|
| 71:17 | . All right. And so what can see is that we really have |
|
| 71:21 | right there represents that. And it's tube that goes up and around. |
|
| 71:25 | goes all the way to the top then it turns on itself and then |
|
| 71:28 | all the way back down. So is going up. This is coming |
|
| 71:31 | down, right? And in between two tubes. That is that cochlear |
|
| 71:37 | . That's what this is. All . And so if you look here's |
|
| 71:40 | stay peas, there's your oval window there. There's the round window. |
|
| 71:46 | ? And so this part of the going up is called the scallop to |
|
| 71:51 | or the vestibular duct. All when it turns on itself, that's |
|
| 71:55 | helical trauma. And then when it back down the other direction, it's |
|
| 71:59 | the scallop timpani or the tim ducked. So vestibular duct, tim |
|
| 72:04 | , ducked. And sitting in between the cochlear duct or the scallop |
|
| 72:10 | Alright, so the membrane that separates out. This is called the vestibular |
|
| 72:19 | . This is called the basil er . So the frame of reference because |
|
| 72:23 | have this structure right here where we're be texting sound. The basil er |
|
| 72:28 | represents the floor of the cochlear And you can see within that structure |
|
| 72:33 | is where we have what is called organ of corti. The organ of |
|
| 72:36 | is the sound detecting device. again, same pictures are now focusing |
|
| 72:47 | on the organ of corti. It's called the spiral organ. Alright, |
|
| 72:51 | here we are. You can see have nerve fibers. Those nerve fibers |
|
| 72:56 | associated with receptor cells. These receptor are called hair cells. They're called |
|
| 73:01 | cells. Because when you look at , they got these little tiny cilia |
|
| 73:04 | up on top of them like this looks like a little tiny hairs. |
|
| 73:07 | right overlying the hair cells is another . It's a really stiff membrane kind |
|
| 73:16 | gelatinous in nature. And so what have is you have three rows of |
|
| 73:21 | cells and those are actually in The little hairs are actually embedded in |
|
| 73:27 | territorial membrane. And then you have solo hair cell called the inner hair |
|
| 73:32 | cell sitting over here to the side it's not embedded. All right. |
|
| 73:37 | then you have other cells that we're going to bother with. And so |
|
| 73:40 | neurons that are associated those receptor cells and they converge and they form what |
|
| 73:47 | called the spiral ganglion. And then spiral ganglion basically is going to afford |
|
| 73:51 | cochlear nerve. And then you have from the vestibular apparatus, the spiral |
|
| 73:57 | , the semi circular canals that's going form the vestibular nerve of the |
|
| 74:03 | Cochlear nerve got that one. Remember from last unit vestibular cochlear. So |
|
| 74:13 | it is, looking a little bit at the hair cells. There's your |
|
| 74:16 | outer hair cells. You're one inner cell. Your inner ear is not |
|
| 74:20 | with yellow. That was probably somebody LSU coloring that. And so if |
|
| 74:25 | have this is the row of cells actually detect sound. These three over |
|
| 74:32 | . Are there to modulate sound to how you're perceiving sound? So again |
|
| 74:39 | or modulating information before it ever gets the brain. So what is actually |
|
| 74:46 | on when you hear a sound that looking structure. Look at I |
|
| 74:58 | look at the ear, it's like . See how weird looking it |
|
| 75:02 | If you look at an ear long , you're just gonna be like |
|
| 75:04 | that is the weirdest looking. It like a dried apricot. All |
|
| 75:09 | But that shape direct sound in a particular way towards the oracle. So |
|
| 75:17 | wavelength and the intensity is what And it's going to bounce off the |
|
| 75:22 | portions of your little little dried it's going to bounce in and go |
|
| 75:28 | that oracle and it's going to hit tim panic membrane and it's going to |
|
| 75:32 | a tim panic membrane to vibrate. what all this stuff says up |
|
| 75:36 | Alright, that tim panic begins to . It's going to cause the malice |
|
| 75:40 | move, it's going to cause the to move the state piece to |
|
| 75:43 | But in the process what you're doing you're amplifying the movement right? Remember |
|
| 75:49 | the amplitude, that's the loudness. the reason you're doing that is because |
|
| 75:53 | you're moving on the other side of stay peas is a membrane called the |
|
| 75:57 | window, right? That oval window , just like the other one does |
|
| 76:02 | frequency. It does so more And the reason it needs to be |
|
| 76:05 | vigorous is because on the other side that window is what is fluid not |
|
| 76:09 | ? I was about to say It's fluid. Alright. Is it |
|
| 76:13 | to move air fluid? What do think? Yeah. Right. Because |
|
| 76:21 | are further apart so I'm amplifying so I can move that fluid and what |
|
| 76:27 | doing is you're moving that fluid at specific frequency. Alright. So when |
|
| 76:32 | hearing sound and I know we hear frequencies very very quickly. But you |
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| 76:37 | imagine just a single frequency, what doing is if it's at C note |
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| 76:42 | the 10 panic memory, that C is being transferred to the oval window |
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| 76:47 | the frequency of that C note is move that water at the same |
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| 76:52 | None of the pictures that do this this justice. But remember we're talking |
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| 76:56 | is a wavelength. If you are short wavelength, what's going to happen |
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| 76:59 | that that wave is going to travel and then down and going to stimulate |
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| 77:04 | along the vestibular membrane near the oval . If it's a deep note, |
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| 77:10 | that wave is going to be much longer and it's going to travel further |
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| 77:15 | before it stimulates the vestibular membrane, not going to sit there and |
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| 77:18 | I'm going to travel until boom, gonna hit some point. It's basically |
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| 77:22 | wavelength determining how far it's going to . Right? So the longer the |
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| 77:27 | , the further it travels, the the wavelength, the shorter it travels |
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| 77:31 | the vestibular membrane. Now remember the membranes, the roof of the cochlear |
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| 77:37 | inside the cochlear duct because it is fluid filled chamber, there's fluid |
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| 77:41 | And if I push on a fluid chamber, I'm moving fluid and what's |
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| 77:44 | going to do, that fluid has go someplace. And so what it's |
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| 77:49 | to do is it's going to displace basal layer membrane at the same |
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| 77:54 | So, for example, if I , let's see what do they |
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| 77:58 | They don't show it here. So say I am stimulating the vestibular membrane |
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| 78:02 | . The fluid underneath is going to pressed on and it's gonna displace the |
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| 78:09 | membrane just underneath it. All So, if I have a short |
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| 78:14 | , it's going to go here and and it's going to push down. |
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| 78:18 | , eventually that sound, that wave a form of energy and so, |
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| 78:22 | needs to be dissipated in one we're not getting to the sound. |
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| 78:25 | just want to get rid of the . And so that wave will then |
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| 78:28 | through and then eventually go to that window in the round window just kind |
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| 78:31 | bulges out, absorbs the energy and it goes away. You ever seen |
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| 78:35 | stress dolls where you like squeeze them their eyes, Right? That's kind |
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| 78:39 | what it's doing. It's like I'm a force and so the energy is |
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| 78:43 | at the round window. But what want to do is what happened with |
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| 78:47 | energy as it passes through the cochlear . All right, Well, when |
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| 78:52 | passes through the cochlear duct, what doing is you're moving that fluid here's |
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| 79:01 | vestibular membrane. Here's the base layer in between. Is that sectorial |
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| 79:06 | And that that hard won the one doesn't move. And if I'm moving |
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| 79:10 | this, the fluid is rolling through that particular location and it's gonna roll |
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| 79:20 | and move and vibrate those hair The fluid is going to cause the |
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| 79:26 | cells to vibrate back and forth? so those hair cells are detecting the |
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| 79:32 | of the fluid inside the cochlear duct that particular location. When I'm detecting |
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| 79:38 | sound, what I'm really detecting is and so basically what you're doing, |
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| 79:43 | just saying at this point I expect frequency. So if I stimulate this |
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| 79:48 | , this is the frequency I'm And so your brain goes, I've |
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| 79:51 | been I've been told that I have this frequency. So this is kind |
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| 79:58 | showing you how that movement occurs, ? So the tech tutorial membrane basically |
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| 80:02 | more or less stays straight. And when the fluid comes down, that |
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| 80:08 | remembering is going to go up and . And so basically what you're doing |
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| 80:10 | you're bending hair cells back and forth the fluid flows right over it. |
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| 80:16 | is referring to that pressure wave that all the way around. So that |
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| 80:20 | center signal as a result of the in the shape here because those hair |
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| 80:24 | are waving back and forth. That's I detect sound. So this is |
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| 80:30 | closer look at what's kinda going So, here's your hair cell, |
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| 80:34 | can see the stereo cilia, the one is called the Tennessee liam. |
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| 80:38 | so what you're asking the question is I've been towards the Tennessee liam, |
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| 80:41 | happens when I've been away from the liam, what happens? So the |
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| 80:45 | is if the Tennessee liam is being or if you're bending the hair cells |
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| 80:49 | the the cilia towards the penicillium that's lead to deep polarization, so activation |
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| 80:56 | then if I move away that's going reduce the number of you know, |
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| 81:00 | potassium moving in. So what happens you basically are sending no signal, |
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| 81:04 | hyper polarizing. So what you're doing you're trying to bend the hair cells |
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| 81:10 | a particular frequency to detect it. frequency where am I stimulating along that |
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| 81:17 | membrane? All right amplitude is how movement do I see? Nice. |
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| 81:29 | a loud noise causes lots of Right? So the more vigorous shake |
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| 81:35 | left perceived the sound that's more action at that particular location. How we |
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| 81:42 | ? I see you guys getting I'm really I've got two slides |
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| 81:45 | You want to finish them now. want me to wait until tomorrow |
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| 81:49 | Its I mean this gets it out the way. Alright, so again |
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| 81:52 | with regard to the auditory pathway the comes in, it's what you're gonna |
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| 81:57 | is you're trying to get up to uh to the temporal lobe and so |
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| 82:03 | first spot is gonna be the cochlear found in the medulla, you basically |
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| 82:07 | , you have the superior and the Oliveria nuclei they play a role in |
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| 82:12 | you respond to loud sounds as reflexes directional sound and then you go to |
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| 82:18 | medial nucleus of the thalamus which basically send that information up to the temporal |
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| 82:24 | . And remember the temporal lobe is in the same way as the length |
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| 82:28 | that base layer membrane. So high are going to be one side of |
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| 82:31 | temporal lobe, low notes are on other side. So those nerves know |
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| 82:34 | where they're going and that's why your perceives the right sound. The last |
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| 82:39 | I damn. I didn't have Alright, I'm done, I'll just |
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| 82:43 | too I think nope, I had there. Alright, so this is |
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| 82:47 | trying to show you how the the is shaped. So you can see |
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| 82:52 | different sounds are gonna ricochet in different . And so it kind of gives |
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| 82:55 | a perception of where the sound is from because of that specific uh way |
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| 83:01 | it enters into the ear. There go. And then lastly in terms |
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| 83:05 | how does your brain know where it's from, It's because the information is |
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| 83:08 | to both years and they arrive at times and the way that it rides |
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| 83:14 | at your brain tells you from the it goes. So you can know |
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| 83:19 | it's coming in terms of height because the shape of the ears and you |
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| 83:23 | know which side it's coming from because when it arrives on one side or |
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| 83:27 | other and there's actually because of the low notes and high notes are treated |
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| 83:34 | differently. But basically the easy thing remember right is direction is based on |
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| 83:41 | timing that arrives at each year. , we're done. We can we've |
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| 83:46 | up, equilibrium is easy. Easy . You're late. And I got |
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| 83:54 | recorded, |
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