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BIOL 2301 Human Anatomy & Physiology I - 2301_lecture17_1025
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00:05 Alright, good, good morning, ? There we are kicking.
00:12 today, what we're gonna do is gonna look at the glial cells then
00:15 gonna jump into um some kind of of what the nervous system or nervous
00:21 is, like uh the arrangements of , all that fun stuff. And
00:27 we're gonna kind of lay the groundwork work in the peripheral nervous system and
00:31 what we'll deal with on Thursdays, nervous system now. Yeah, it
00:36 performing system. All right. So what we're looking at here is we
00:41 just kind of continuing on like where left off we were saying,
00:44 there's basically two groups of cells to types. We've we've kind of dealt
00:49 the neurons already previously. And what gonna do is we're gonna try to
00:54 away from there and just kind of , what are the other cells?
00:56 are the supporting cells and then we're come back and deal with what neurons
01:00 doing. All right, So, supporting cells are Kind of like all
01:04 players. I mean, I think may have used this analogy before.
01:07 you think of a football team, team has made aside on a football
01:11 is made up of 11 players. quarterback is kind of usually the one
01:15 kind of does look quarterback. How how cool. And then we kind
01:19 ignore the other 10 players. And the support cells, the glial cells
01:24 like the other 10 players on the team, everyone. Oohs and Ahhs
01:27 the neurons, but it wasn't for support cells, the neurons couldn't do
01:31 they do. So they provide all types of support for these cells or
01:37 these neurons. And we collectively refer them as the neuro glia. Which
01:41 a weird way of saying it. look at, you want to say
01:43 glia, it's neuro glia because we're . And uh the other thing is
01:49 cell. Alright, so when you that word you can think glue,
01:54 that's probably the best way to they , when they first discovered it,
01:57 didn't know what the purpose of these were. And it's like, well
01:59 holds everything together. And so glial , the glue that holds the nervous
02:04 together. So there are different types that's what I'm looking for. Uh
02:10 are different types. The this little kind of shows it to for
02:14 there are four types that are found the central nervous system and two that
02:19 found in the peripheral nervous system. two that are in the peripheral nervous
02:22 are very similar to two of the that are in the central nervous
02:25 So we're kind of lumping, we're lump them together while we're discussing but
02:29 should know or distinguish where they come . All right, so the neuro
02:34 are typically much smaller than neurons. right. And they are capable of
02:40 . So their job is to kind do the things to help create the
02:47 that the neurons are responsible for So, if you don't have
02:51 you don't really get neuronal function. right. Now, these don't transmit
02:56 single signals. All right. They talk to other selves including themselves and
03:01 neurons and vice versa. But they're using electrical signaling to do so.
03:07 , there's that value. Why I use the football team. Is they
03:10 outnumber neurons almost 10-1. So, you look at nervous tissue, you're
03:15 looking at glial cells with some neurons of embedded in there. Alright,
03:21 , like I said, there's four . We'll see them astrocytes. I'm
03:24 gonna go in the order here. . Epidermal cells which we've already talked
03:28 the micro glia. Notice how we that again. It's not micro
03:32 It's weird for me micro glia, ? It's like when you say
03:37 you don't say auto mobile or It's just you put weird except accents
03:43 different parts of it. And the group is yellow gender site.
03:46 the alleged gender site and the Schwann are very, very similar to each
03:50 . Um And then the satellite cell the astrocytes are very similar to each
03:55 . So, that's kind of how can kind of associate them and you
03:59 see astro sites astro for star satellites that's how I remember how they're
04:06 All right. So, what we're is we're gonna kind of walk through
04:11 different cells. All right. So order to understand the site, we
04:16 to first understand that where they come . They come from a group of
04:19 stem cells called ali progenitor cells. these cells do is they're capable of
04:28 into a whole bunch of different types cells including neurons. So they are
04:32 stem cell that can kind of go . And what they do is they're
04:35 of found all throughout the central nervous and they are aware of what's going
04:40 around them because at their tips they what are called growth cones. And
04:44 gonna see this a little bit more when we're talking about neurons and how
04:47 move around. And so what they is when they kind of are receiving
04:53 and they will differentiate divide and move go to where they need to
05:00 Now when you have a damaged area gonna see all the sights kind of
05:06 and kind of fill that out. see that also with astrocytes. But
05:10 idea here is I'm filling up You don't want empty space where damage
05:15 occurred. So the first real glial that we want to talk about where
05:22 this OPC can kind of turn into yellow underside. When we talked about
05:26 Ellen this is the kind of cell talking about and you can see none
05:29 the pictures are gonna be great to demonstrate the many connections. So that's
05:33 name is Allah go many Hydro means and side to sell and so here
05:39 the cell you can see this is cell body and it has all the
05:43 going out and these extensions find the axons of neurons and they wrap
05:48 around and they create those myelin sheets the central nervous system so that is
05:53 primary function alright, they can myelin up to at least 50 axons and
05:59 more. They also play a role blocking the ability of a neuron uh
06:08 from dividing. So they actually send signals to inhibit growth and activity of
06:13 neurons. And um basically they can tell the neuron what to do.
06:19 very often when we when we look these things you just kind of thinking
06:22 alright there Myelin and they just sit and they do nothing other than just
06:25 there and create them island but they , they actually play an important role
06:29 communicating with the neurons and it's telling supporting neuronal function is kind of the
06:35 that you can think about that. the key thing here is when you
06:38 all good inter site Myelin central nervous here, we're jumping in the peripheral
06:45 system. Looking at the Schwann Cell Cell does the same thing, it
06:49 those my own sheets in the peripheral system, it just does so differently
06:53 of those Myelin sheets are are a Schwann cell. So what they do
06:59 they start off as an immature cell when they come across that axon,
07:05 they do is they wrap themselves around times around that cell, flat themselves
07:10 and create that myelin sheath. All . Um When a neuron becomes damage
07:18 along the length of the axon, will happen is that axon will
07:21 And then these cells they go through transformation and they stay where they
07:28 And what they do is they release to help that axon be regenerated along
07:33 same path. But because neuronal regeneration fairly slow, it's not always
07:39 So it's really if you have a small distance to go then you can
07:42 . But if it's like a long it doesn't work so well because the
07:46 connective tissue will fill that area. they play a role in helping damage
07:52 send their axons to the right places just that. So the astra
08:00 this is the most abundant uh cell the nervous system. It just won
08:05 american league. Oh wait that's the . The astro's sites are star
08:11 that's where their name comes from. right, so they just looked and
08:15 look these things are shaped like What you can think about is you
08:18 think of them as being like the that kind of creates the environment of
08:22 tissue. This is trying to show here, it's like here's this astra
08:26 , you can see it has all extensions and they're connecting themselves to different
08:30 in order for those different things can arranged where they know to be.
08:34 you can see here, we saw it was associated with the blood
08:38 The capillaries helped create the blood brain , right? We're seeing here that
08:43 are holding the neuron in position. seeing that it's basically holding the synapse
08:49 place and maintaining the synapse. So two cells are communicating with each
08:54 They pick up materials from the blood transported into the blood. Extra cellular
09:00 the brain. Extra cellular fluid. it provides the nutrients that those cells
09:05 , It releases signals, It controls environment by ensuring that there is the
09:09 ion concentrations between the blood and the the cf. So this is a
09:15 that plays an important role of creating environment of the nervous system.
09:21 it's not just there holding things what's interesting, this is another tissue
09:28 plays an important role in creating scar in the brain. I think I
09:32 this class about a student who had up after a lecture like this and
09:36 , oh I got hit in the with an ax when I was a
09:39 . Right, and it was so you can imagine you damage those
09:44 and you now have this big giant in that tissue, right? So
09:49 happens? Well, astrocytes multiply and and they fill up the space and
09:55 act like fibroblasts and create that that to fill up that gap. And
10:02 that portion of that brain where he damage no longer had neurons that were
10:08 , it was just astrocytes. So can think of access scar tissue.
10:14 it also talks to other glial cells the elegant gender sites and tells them
10:18 to do. So it's an important astrocytes. I think the next one
10:24 have here. No, I don't I'm uh let me see.
10:29 I'm just gonna say it here. don't have a slide for it.
10:31 the satellite cell is similar to the site in the peripheral nervous system.
10:39 specifically found around the cell bodies not the length. So we're gonna see
10:44 primarily in ganglia. And what they is they help separate out the
10:48 provide nutrients to all the things that do. They just do it in
10:53 peripheral nervous system. Epidermal cells we've kind of talked about. We may
10:59 have picked up on when we're talking when we're talking about the creation of
11:02 cerebral spinal fluid. That's what epidermal are responsible for. And so here
11:06 are, we're looking inside one of ventricles and you can see here are
11:11 epidermal cells that look like this, can kind of see there sicilia.
11:15 what they do is they produce the spinal fluid. They pick up materials
11:20 the extra cellular fluid that has been by the capillaries in the core oid
11:26 . And then they take that fluid other nutrients and they push it into
11:30 create the cerebral spinal fluid. All , so, that's their primary
11:37 Cerebral spinal fluid. The microbes are weird ones. They're they're the most
11:43 . These are the ones where a of people are spending a lot of
11:45 doing research right now, we're gonna to keep it simple but understand that
11:51 role in the nervous tissue is much more complex than what we're looking
11:55 here. All right. So, can think of them as primarily as
12:01 . So when damage occurs in the tissue, they're kind of sitting around
12:06 nothing just like in your skin. have a bunch of resident macrophages just
12:10 of going, I don't know what do. But when something causes damage
12:15 the skin, those macrophages become alert awake and they start alerting the immune
12:20 because of the blood brain barrier, do not have access to the immune
12:24 , like you do everywhere else in body. So, these micro glia
12:30 as that immune response. So when occurs they become active and those macrophage
12:36 activity is there to start picking up dealing with that damaged tissue.
12:43 They are not only capable of dealing damaged tissue, but they can also
12:47 pathogens. And so for the most they're they're not really all that active
12:53 . But when things show up in nervous system that shouldn't be there,
12:58 when they become awake and active. . So they recognize pathogens, they
13:03 act as antigen presenting cells to activate immune immune insights. They can also
13:09 inflammation. Now you don't need to this down, but just so you
13:13 , it appears that these types of also serve as neural stem cells.
13:18 play an important role in regulating how body responds to trauma or your brain
13:25 to trauma. There's all these really things that they do um And we're
13:32 like tip of the iceberg type stuff terms of this stuff. Um Anyway
13:39 I went to a talk where they how they migrated stuff during development when
13:43 trying to you know, make grow brain and stuff. And so it's
13:47 interesting how they kind of move and the things that they do. So
13:55 is kind of the big picture of your brain does. Alright. And
13:59 like this part of the lecture because using our brains to listen and we're
14:04 about our brains, thinking about the , right? So it's a very
14:09 concept, right? That's that's its . Alright. So what we're doing
14:14 is we're receiving and processing both external stimuli all the time. That sensory
14:20 . Right now you look around the , the room is bright, the
14:24 is moderate in terms of its humidity is decent. These are all
14:30 that you're now aware of because I said that alright, but your brain
14:34 monitoring that all the time. You're , oh I'm just kind of
14:37 You know, that's when you kind realize that you perceive but your brain
14:41 always paying attention and stuff. What's on outside you if you're thirsty
14:46 you need to go to the all that fun stuff your brain is
14:51 you or is monitoring what's going on your body and alerting you to those
14:56 facts. Right? So that perception you becoming consciously aware of the things
15:03 the brain is actually monitoring. The other thing that it does that
15:08 can integrate information and what that You can store memories. For
15:12 you can act on actions or you can ignore stuff. So like
15:17 now some of you are falling asleep the very very kind tones of my
15:22 . Right? It was early when woke up this morning. It was
15:26 , kind of cold and right now smooth velvety voice, it's like time
15:34 sleep. All right. That's an of ignoring me. I don't
15:37 That's actually probably taking in the stimuli say uh comfort, safety going to
15:42 now? All right. But the is that you're taking in information from
15:48 surrounding environment from here and you're responding that stimuli. Alright. You can
15:54 send signals throughout your body. So basically gonna be promoting what what we're
16:00 to be doing to that in response stimuli. So you can stimulate
16:04 That can be you can think in of movement, stimulate glands. You
16:07 something that's like like oh I don't , fresh brownies and what is that
16:13 make you want to do? Right? That's your I want my
16:17 , right? Um Other cells in body are responding. We're not gonna
16:22 the endocrine system in this uh in half of a Mp. But in
16:27 . And P. Two. If come back, we're gonna talk about
16:29 endocrine system and all the fun things your hormones are doing and what they
16:34 . All right. So that's another . Conscious awareness I think therefore I
16:41 . Right. That's good. Or a day card. But we're aware
16:44 who we are and our surroundings and what we're doing right now right?
16:50 conscious awareness. You're perceiving the world you, perception is just your awareness
16:57 that stimuli and I just want to something out. This is a question
17:01 like to ask and it's just kind a fun one. Uh Not test
17:04 . Is the world around us The world that we that we are
17:09 of. Is it reality? Yes no, No. Alright. It's
17:14 we perceive. We have receptors that us to perceive very specific things about
17:20 world around us. But let's just a real simple thing for me to
17:23 it. There are radio waves that cannot detect. Right? Can you
17:29 x rays? Can you detect radio ? No, they're on the same
17:35 Or if you look at radio electromagnetic , there's this broad spectrum from you
17:42 gamma rays on through radio waves through that stuff and you can only detect
17:47 very itsy bitsy teeny tiny sliver of radiation. We call that the visual
17:53 right? Those are the colors. what allows our eyes to see.
17:56 we got all this other stuff going . Some snakes for example can detect
18:01 the infrared range. All right. they perceive a world that's slightly different
18:07 ours. Bees for example can detect the ultraviolet range. We can't we
18:16 to have machines that do that. how they find their food source.
18:19 looking at the reflections of UV light the absorption of UV light in in
18:25 . The way we look at the like oh how pretty when a bee
18:27 at a flower, it's like big arrows pointing to say this is where
18:30 food's at. You know? So is just an example what we perceive
18:36 simply a function of the receptors that have to allow us to experience the
18:41 around us. But there's so much we have no idea what's going on
18:46 we don't have the receptors. so reality is much much bigger than
18:51 we perceive which is both kind of and kind of scary because what can
18:56 perceive that's going on around this? knows? Guess we'll find out
19:03 All right, can you guys understand words I'm talking about? Yeah.
19:08 we all have language. Right? of you are bilingual, some of
19:11 are trilingual, some of you are more lingual right? The idea is
19:16 we communicate by using a common common and that common sound we've all agreed
19:23 mean things. And so that's This idea of reasoning if I do
19:28 , this is what's gonna happen to if I do that, that's what's
19:30 happen to me. What should I ? I will do this over
19:34 That would be an example of reasoning ? Your ability to remember. I
19:38 you to all picture um Oh I know what you did this friday this
19:45 friday. Can you picture something you this last friday? I know it
19:49 like four days ago right? But you picture that? I mean I
19:53 say can you picture your first How about that? Can you picture
19:56 first crush? Yeah, but that's memory we can pull stuff like that
20:03 some better than others. Alright, . All right. These are our
20:09 . These are the things that how respond to stimuli at a kind of
20:16 of this role level. And so this is gonna be controlled in the
20:20 system by different aspects of the nervous . And we could spend an entire
20:24 . In fact, if you're interested stuff you can go take the neurophysiology
20:28 where they do talk about this to detail. But this is where we're
20:31 gonna leave. We're just gonna say brain, your central nervous system does
20:35 whole bunch of stuff and allows us understand what we can about the world
20:40 us. And it actually does things even I'm not gonna say it tricks
20:43 , but it fills in the right? For things that we don't
20:48 understand. So you guys watch cartoons your kids, right? Maybe like
20:53 , did you watch cartoons? Do guys remember like those shows where they
20:56 the anthropomorphic whatever it is. I I just if you don't know anthropomorphic
21:01 it means human like right? So if they have a toaster and they
21:06 the toaster into like they put a on the toaster because you have the
21:10 down thing and that's like its nose you have the line. All you
21:12 do is give it eyes and now got an anthropomorphized toaster. Alright,
21:17 brave little toaster that you there's also Brave little steam engine. They're all
21:21 by Disney. Yeah, there were were like three of them.
21:25 So why don't we look at these ? So this makes it all
21:28 That didn't work for you? Think every single Disney movie Pixar movie that's
21:32 come out, Right? I what was the one with Zootopia?
21:38 ? All the, all the all animals do animals walk on their hind
21:43 and talk and use cell phones and crimes. Something they can do a
21:50 bit, but they don't write. what we've done is all we gotta
21:53 is create a couple little characteristics in brain says, oh, I'm going
21:59 suspend my disbelief for a little bit I'm just going to enjoy the little
22:03 that's going on here, even though know that giraffes don't play volleyball naked
22:09 hippopotamus is as an example, Maybe do and we just haven't seen it
22:19 now, the process of creating nervous called neurogenesis. And it's it's a
22:25 , very complex process. But what want to show you is that the
22:29 that it does, so changes over . That's what the next couple of
22:33 are so very early on the way the brain is developed is that we
22:38 these glial cells and the neurons are . So you can see here,
22:42 a early form neuron, that's what is supposed to be and it says
22:46 it does. It finds a glial and uses that glial cells travel to
22:49 it needs to go. And so can see it finds its like,
22:52 , now I'm gonna work my way and I'm working outward. This is
22:55 is referred to as radio migration. the brain grows in this direction as
23:00 create these different layers. All And the way that the neurons nowhere
23:05 go is because the surrounding cells are out factors signals to tell them where
23:11 go. All right. But once become adults, you've established already the
23:16 layers of the brain. And so happens is is that if you need
23:19 move a neuron, what you typically is you move within the layer that
23:24 found and this is what is referred as tangential migration. Alright, So
23:30 idea is I'm not going up up down through layers. I'm going to
23:34 by side in the same layer. right. Now again, this is
23:39 be reliant on signals that are being by the surrounding cells and telling them
23:44 to go. And I think this of shows you this process a little
23:48 better. So this is an example how this is done. So how
23:52 nowhere to go. It's through a of chemo taxes. We can actually
23:57 this in the lab. You put neuron in addition you can add chemicals
24:00 you can make the neuron grow and following the chemical. It's really kind
24:06 cool. You can also do it lasers and I don't know why that
24:09 . But you know it does. can just basically say, here do
24:13 and the neuron follows. So this a process when you're doing with chemicals
24:18 chemo taxes. Now, chemo tax a generic term that just says following
24:22 chemical. So for example, when have an infection and you have immunity
24:27 that are certain the blood, there's to be signals released by the tissue
24:31 has that infection or that damage to . And those chemicals attract the immune
24:37 into that tissue. That's chemo Alright. So when chemicals are used
24:41 attract a cell someplace, chemo Alright. So typically what it
24:48 you're gonna be using a growth hormone responsible uh to uh move the neuron
24:56 the way that you want. So of the chemicals are gonna be
24:58 hey you come this way, others saying don't come this way. So
25:02 basically kind of guiding traffic and what acting portion of the neuron is,
25:07 called a growth code. And so is what this is trying to
25:10 So you can imagine here this is dendrite that's kind of expanding outward and
25:14 to find out where it goes. it shows you, so we're
25:17 really close up, you can see little red things here are basically showing
25:21 the those growth cards. This idea like, I'm reaching out and I'm
25:24 to find where the chemical is. kind of like if you've ever watched
25:28 week, it's like watching a shark a trail of blood. It's like
25:32 a drop of blood, there's something the water and I'm just gonna keep
25:35 to find where that goes. And they're trying to figure out how and
25:39 to go. So, that would the growth boom. Alright,
25:42 what we're doing is we're following to place other places maybe sending signals saying
25:47 come here, and then the one basically that drives you in a specific
25:52 . So you get all sorts of and cause a neuron to branch and
25:56 can cause it to become more sensitive that there's a greater interaction between
26:02 There's all sorts of different types of that ultimate result in a change in
26:08 nervous tissue. And what we refer this as is we refer to this
26:12 neural plasticity. And what this really means is that your brains are not
26:17 formed. All right. In other , once you create your brain,
26:21 not like it's done, done Everything you can do is already
26:26 What this means is that your brain constantly changing. And what I wanna
26:30 is I want to just focus down very, very bottom at these little
26:34 and stuff. And what each of dots represents is a neuron All
26:38 And so over here on the left saying, look, when you were
26:41 you were born and your brain was , that's where we got neurogenesis.
26:44 so we created this network of neurons we can see that there are two
26:49 that are in this network that aren't to the other one. Is that
26:53 ? Six? The other six Alright, but we can see that
26:57 of the neurons are connected in some of strange pattern. Now the pattern
27:00 matter. This is just for the of understanding this. All right.
27:05 what happens is is that throughout life going to experience different things right?
27:11 right now, you're learning something new , you're learning about neurogenesis and right
27:17 your brain is trying to figure out do I do with this. And
27:21 what you're doing is you're exciting neurons what you're doing is you're disrupting their
27:26 interactions between a certain group of neurons your brain. And that's what the
27:31 picture is trying to show you is , look, they're rearranging themselves in
27:36 a way that they can create a network. And as you continue to
27:41 this stuff and continue to to work this. Is this new information will
27:47 a new pattern in this little cluster that's what you're saying. So,
27:52 uh new arrangements are gonna be Old arrangements are gonna break down and
27:59 you're gonna end up finally is a structure, a new relationship and notice
28:05 neurons that were there haven't disappeared. just no longer a part of the
28:10 network. The network has changed. this is what neural plasticity is.
28:15 the rearrangement of the interactions between the to support whatever it is that you
28:21 , whatever is a new skill, new idea, a new memory and
28:24 trauma that that's forcing you to recall or to be alert about something.
28:30 if you got bit by a are you gonna want to be around
28:32 anymore? No, it's not your , it's someone else's dog. You're
28:38 down the street and you're like, , I like dogs. And dog
28:40 up and bite you in the You're gonna you're gonna be thinking about
28:43 every time a dog comes up, are you gonna be thinking? Is
28:46 dog gonna bite my face? You think that probably right? And that's
28:53 function of an experience that would change that you're dealing with this new reality
28:58 this idea that when I see what I do and that would be
29:01 going on? So your brain is doing this, it's constantly undergoing
29:12 All right, And that's what neural is now, what this means for
29:23 and for you to understand this is neurons are well integrated. They're not
29:28 lying around and and it's not just , one idea comes in, one
29:33 goes out right? Or one activity out instead. What we have is
29:38 have these groups of neurons that are pools or their circuits. And what
29:42 doing is they're there to do the making based upon the input,
29:47 So they're undergoing the change. And that change occurs, if you keep
29:53 whatever it is, like if it's skill or if it's a memory or
29:56 , then that pattern of excitation will in that neuronal circuit or pool.
30:02 so that is what causes the the response afterwards. Now, there's
30:08 movie um you may not have seen because it's it's actually kind of
30:12 But when I first started teaching, was Jim Carrey and kate winslet I
30:16 is the Sunshine spotted Mine. I never remember the title because like,
30:19 like a 10 word title. It's but it's a it's a it's a
30:24 basically about kate winslet and Jim Carey dating and then they had this horrible
30:30 and she didn't want to remember that was dating Jim Carey. Well,
30:37 could blame her? I'm sorry. just it's a funny joke.
30:42 So there's a company in this in particular world that allows you to to
30:47 memories and the way that they make make it make it happen is like
30:53 neuron holds a memory, right? not how that works. So the
30:57 is that they're going in and they're deleting the memory from neuron to neuron
31:01 neuron. And the whole story is the memory trying to find a way
31:05 preserve itself and to be remembered, ? So that they can remember that
31:10 were happy times, It wasn't a thing. That's not how this works
31:14 memory. And there they've done some , really interesting things, They've done
31:18 in rats, they've done these in and in essence what they can do
31:21 you can see that a an idea an experience results in a series of
31:28 activity, right? So what you see as you might see like say
31:31 neurons, we're gonna make this So neuron fires and neuron b fires
31:34 neuron c fires. Alright, so you do the activity, you see
31:39 abc abc and so now if you stimulate abc that activity is what's going
31:46 happen as a result of that. for example they would take rats and
31:50 put them in this little maze because what we do to rats right?
31:54 how we tortured them and this was figure eight mais. So you had
31:56 maze go around this way in the and it came back this way and
31:59 the middle where the two circles meet that figure eight, there was a
32:04 and they trained the rats get the runs in the wheel a certain number
32:08 time and hops off and when it off it knows that it has to
32:12 around the circle, jump back on wheel and then it has to run
32:16 other circle and then of course they a whole bunch of electrodes in the
32:20 brain so they can watch what's going . So you can imagine it's kind
32:23 weird seeing either an antenna or basically bunch of wires attached something but they
32:27 watch the activity and they can see that rat is doing is like as
32:32 learning it, this is the pattern creates and you can watch that neuronal
32:38 and they see before the rat would a decision what it needed to the
32:42 , what that pattern would would appear them on the monitors before the rat
32:48 actually do it. So they could see the rat thinking about what needed
32:51 be done before the next activity. . Huh? Alright. Well it's
32:56 who cares did this in humans All right now again, it's a
33:01 bit different. We don't drill holes humans brains and stick a bunch of
33:04 and see what we do instead. we do is we do a big
33:08 skull caps with a whole bunch of attached to the top and what they
33:12 is they took a bunch of epileptic because those are the people that you
33:15 work with because they're available. And they made them watch a whole bunch
33:20 cartoons and clips from movies and stuff that. And then after, so
33:25 recorded the brain activity, see what were watching while they're watching it.
33:29 again you see the pattern as they're and processing and then afterwards they ask
33:33 questions and before they answered you would a repeat of the exact same
33:39 So it's the pattern in the That is important. That is what
33:45 memory is, that is what causes to do the action. Right?
33:51 it's the pool that becomes important. these neurons can either be localized in
33:55 case that means that they're confined to specific area. So when we start
33:59 at the different regions of the central system, this is what this
34:03 That's what we're referring to. That's localized activity that we were able to
34:08 or identify. But we also will that some of these things, some
34:12 these pools are actually distributed across multiple or different regions of the central nervous
34:18 . When we look at visual we'll say, oh yeah, it
34:21 back here in the occipital lobe, 80% of your brain is responsible visual
34:26 . So you can see this is of a distributed type of circuitry Even
34:32 we say it's back here localized it's lot more how these circuits are
34:40 They can be very very limited into you're going to put into it.
34:44 for example if you wanted to know smell of something you want, the
34:48 from what structure your nose. Do want to have input from your eye
34:54 tell you what it smells like? , So you have limited input,
34:58 don't need all the sensory input coming and telling you everything you need to
35:02 about something. All you need to is a little bit so circuits are
35:07 specific as to what they receive and the information that's going out is going
35:12 be very specific as well. it's gonna be fairly limited or
35:18 Lastly these systems can be either simple complex and what this means and I
35:23 that's what the next slide is. , is that their structure can be
35:28 , really, really easy to We're gonna we're gonna primarily deal with
35:32 simple ones today but understand that there these we have these complex activities which
35:39 to complex circuitry and I think this kind of demonstrates this bet.
35:44 so this would be an example of simple certificate. Can you, is
35:47 easy to understand right here, neuron turns on two and right look at
35:53 complex one, neuron one turns on to which turns on neuron one downstream
36:00 the soma. So, what we here is a circuit that once we
36:04 it on, if we activate this , this would keep generating a
36:10 Right, repetitive. So whatever is here would constantly receiving a signal.
36:15 there's that branch doesn't mean I'm only one way, I'm going both
36:20 Alright, so branching is just simply you go down both paths at the
36:27 rate. So, simple circuits, cell with another cell. Notice what
36:33 have here, uncommon in the central system. They're common. More and
36:39 nervous system. We'll see that in second. But yes, but you're
36:51 to see some more complex than just one complex multiple connections. These are
36:56 ones that are more common. So here's two examples of these complex
37:03 . We have a converging circuit and circuit. So picture matches, converging
37:11 . What you can see here here have a single neuron. It's not
37:14 input from one neuron. It's getting from multiple neurons. Three neurons.
37:19 right. And so, what we here is we're getting information from multiple
37:24 . And so we're not uh we're the signal into a single circuit or
37:31 single cell to get a single All right, So it comes down
37:37 a common circuit is what we're looking . So lots of information. So
37:42 about salivation for a moment. All , And this is why salivation,
37:48 ? Is dependent upon a whole bunch different things for example, it's dependent
37:53 gustatory stimulation. If I take chocolate put it in my mouth. Am
37:58 gonna salivate? Yeah. There are there that detect the presence of the
38:04 molecule on the planet. No one's agree with me on that. Uh
38:09 agree? Okay. I like Get chocolate. It's not an actual
38:13 but but there's lots of molecules in . There's sugar in there.
38:20 Right? And so that's that's an . All right. We're gonna have
38:26 again. Think about that browning. . We're gonna find out a little
38:29 later that the gustatory system in the system are closely aligned to one
38:34 So when things smell good when I that brownie and I smell it,
38:40 mouth just gets like all excited, does my brain, right? And
38:44 when it goes in my mouth, only am I smelling and tasting
38:47 Oh yeah, that's like and then also tactile. Think about that brownie
38:51 in your mouth, right? That And yeah, so there's tactile
38:57 Have you ever noticed that food that look good? Doesn't necessarily taste
39:01 Yeah. Right. I mean it always but you know often like oatmeal
39:07 you look at it like it's not taste good, right? The only
39:10 that rescues it is close your eyes just taste the cinnamon? It's like
39:15 this is okay. Right, Because that's part of the input? Gray
39:20 just doesn't look edible. All That would be an example.
39:25 Diverging circuits on the other hand is we're amplifying stuff. Alright. So
39:29 taking input. And what we're doing we're seeing a lot of different systems
39:33 to know this. And so we're to send the signal outward.
39:36 It's fanning out becoming larger. Um example I'm using here is like um
39:43 . So walking isn't simply one Walking is multiple muscles. It's lots
39:48 balance, lots of equilibrium. And the idea of like, oh,
39:51 want to get from here to there be a simple input, but the
39:55 is this muscle, that muscle, muscle, that muscle, that muscle
39:59 muscle to allow me to get to I need to go. All
40:07 So, these are a little bit more complex. And again, remember
40:10 of those branches represent a signal that's simultaneously. So here the rhythm,
40:15 is a parallel ostriches, that rhythm circuit. So think of something that
40:20 do that's rhythmic. Think what's something you do that's rhythmic walking is
40:25 Something else where you think something There's a lot of them. I
40:30 , I'm not like trying to look a single one, Humming.
40:35 Could be, but it's it's not repetitive thing. So breathing is a
40:40 one. You know that it's not something you think about, right?
40:44 mm hmm. How about chewing that heartbeat is actually independent of the nervous
40:52 . But it's a good idea, ? There is regulation that we can
40:57 , but the heart actually does its beating, right? So chewing dribbling
41:03 basketball, riding a bike, you , walking as she said, you
41:08 , all of these are examples of right now. If you've ever watched
41:12 walk, you know, uh it's obvious in a four legged animal,
41:17 you can see it in two legged too, when you walk and watch
41:20 arms what they do and you'll start that the opposite start swinging,
41:25 My arm over here matches this I'm over here. And so it's
41:30 of like this now you guys probably see it because you're on your phone
41:34 the time. Right? Yeah, gonna make fun of you guys as
41:42 as you guys have phones. It's it's sad. All right.
41:47 so that rhythm that we create when moving when my arms are swinging,
41:51 legs are going is a function of types of circuits. And you can
41:55 of see here we have more than . And what we're doing is we're
41:58 back over and over again. So the signal is getting bigger and bigger
42:02 bigger and bigger and bigger. And something causes it stop. And then
42:05 big big big big big and stops this is really obvious in breathing,
42:10 ? I mean when I'm inhaling the contracts and then it relaxes. That's
42:16 the stop signal. The muscle And when I breathe in I'm contracting
42:22 muscle and then something causes the muscle and then I'm exhaling. All
42:27 so that's that is an example that generating rhythms generating. Alright, what
42:35 using here is something called a central generating circuit and that's that thing that
42:40 the up, up, up, , up, up and then
42:43 The last one here is a parallel discharge. These are typically what we
42:47 are what are used in higher order , you know, like decision
42:51 planning that sort of stuff. And way that I can best describe this
42:56 that the neuron here is being affected just by one neuron. But what
43:01 doing is we're creating multiple signals that at different times in that receiving
43:07 So you can see here this cell directly acting on this but it's also
43:11 on these cells of different links. the signal gets to these cells at
43:16 different time, then it gets here then this cell here affects that
43:21 And so if you're following the what you're gonna see is like one
43:24 fires, then the next cell fires the next cell and in the next
43:28 in the next cell. So that cell is getting barraged. Like up
43:32 up up up up. So it's long response or a long stimulation in
43:38 cell so that you get a larger . So that's a pattern that you're
43:46 in order to create a unique neuronal . That's why it's higher order thinking
43:57 memories that were kind of describing from movie. Now your circuits are started
44:06 early on during fetal development and you of start making those manipulations to it
44:11 the early stages of your life neonatal . Alright? But this is that
44:17 I was talking about. So you as you're doing thing, you're going
44:20 create new interactions. You'll tear down ones and build new ones. All
44:26 . And so that's what allows us do the unique things that we do
44:32 we sit here and I say, know pedagogic li you know, I'm
44:36 big words you know in order to first, you expose yourself once and
44:41 you expose yourself the next time and you expose yourself another time. And
44:44 you do practice, which is how class is designed, right? You
44:48 , you come to class, you your notes and then you do homework
44:53 , right? Those are all geared making your brain reorganize itself and creating
45:01 neuronal patterns. You can't be exposed something once and have it really change
45:09 your brain works. There are examples that happens trauma is one of those
45:13 and that's not the best way to , right? Would you like me
45:16 come in here and smack you every I give you a new idea,
45:20 or have your neighbor everyone hit the to your left clock, right?
45:24 know. It's like, okay, time I get hit, you
45:27 this is something I have to learn it's not gonna be away. So
45:30 idea here is by redesigning our we're going to hold on to
45:37 create new skills or or become better skills that we've been exposed to.
45:43 other words, practice makes perfect. this last little thing is you're not
45:50 with what you are as a You know, you've heard the statement
45:54 teach an old dog new tricks, ? When my mom comes over and
45:58 , I can't figure out my it's like, no, you're just
46:03 . Alright. Certainly you can write I can do it and as old
46:08 I am, I can figure out stuff. Certainly you can write when
46:13 young, that's part of life. is new, new, new,
46:17 , new, so you're, you're a constant change of or nervous tissue
46:23 adulthood. You've seen a lot and you get lazy, right? But
46:28 all capable of change. I think last two years basically demonstrated that pretty
46:32 , didn't it? Not necessarily good . Sometimes. All right. So
46:40 circuits will be able to regulate complex . It's not simple equal,
46:44 complex equals complex. You're gonna use as needed. So, whatever works
46:50 . And what we're trying to do very often is we're gonna see reflexes
46:54 a response to these particular neuronal And so our shift here is gonna
47:02 two reflexes. Now reflexes are this I'm just going to say the definition
47:08 that you get in your brain. a rapid pre program involuntary reaction.
47:15 . That's gonna occur in muscles. can occur in gland and it occurs
47:18 a very specific stimulus. I've been the doctor's office when they did
47:23 Need your reflex. Have you never that? You can do it to
47:27 . It's really easy. Alright, do it over here. Alright,
47:32 , what you wanna do is fall the table. Right? See there's
47:38 can see it just It just wants die. All right, you have
47:41 ligament right here. All you gotta is just slap across it and I'm
47:44 try to do this without falling off table. All right. You got
47:47 karate chop it. Right, you , missed it there. I can
47:57 to not do it. Right? can't stop it. It's just,
48:02 always happens. Alright, So, is an involuntary response. That is
48:08 key thing. All right. What looking at this one is called the
48:12 reflects, Alright, babies when they're , know how to feed themselves.
48:18 do not need to teach them and , hey, you need to latch
48:21 this. Alright. Whether it be nipple on a bottle or a nipple
48:24 a person, nope, they're trying show you all they gotta do is
48:28 stimulation right here and what do they ? And they turn their head and
48:32 start feeding. They know how to it. This is a natural
48:36 So what is the stimulus? It's the sensory input. Right. Rapid
48:42 you don't need a lot of neurons to make this happen. So,
48:45 are really, really, really simple . Pre programmed. It's gonna happen
48:49 single solitary time and lastly involuntary, cannot suppress it and you don't need
48:56 effort to make it happen. All , those are going into nursing,
49:01 get to learn all about some really fun different reflexes that you're gonna
49:05 . The Bobinski reflex on babies, grab their foot, you rub across
49:08 foot, you get their foot little toes and basically it's demonstrating neuronal
49:15 There's all sorts of fun ones. , so their basic reflexes and their
49:20 reflexes. A basic reflexes. One your um that's unlearned. So this
49:24 be an example of a basic That's a basic reflex, right?
49:29 built in responses, they naturally you do not need to teach
49:35 Alright then we have what are called reflexes. A conditioned reflex is a
49:40 that's acquired after practice and learning now one that you can think of most
49:44 is the Pavlovian reflex. Right? good old Pavlov. Pavlov had a
49:50 . And what do you do? rang the bell and then he fed
49:52 dog, right? Rang the fed the dog, ringing the bell
49:55 the dog, rang the bell. feed the dog. The dog do
50:00 bit Pavlov like, where's my No, he he salivated.
50:05 because bell equals food. Right? I know you're conditioned, right?
50:13 am, Yes. Your condition, condition you all the time. Not
50:17 personally, but just generally speaking. , you're in the car, the
50:21 turns yellow, you're approaching this light it turns yellow. What do you
50:25 speed up? Right? Your I'm not gonna be stuck at the
50:30 . Yellow means I'm gonna have to stuck at the light. So I
50:33 up Now some of your rule followers you go, oh, yellow light
50:37 I slow down and you slow But when you see yellow, you
50:43 , right, That's an example of throughout high school, you heard the
50:49 the bell, What do you do it's at the end of class,
50:52 do you do pack up my get up, go and then you
50:56 the warning bell, what do you ? Run to your class? Get
50:59 your seat conditioned. Alright, we conditioned to do things in response to
51:10 stimuli. Alright, that would be example. Now, this is one
51:15 the most important images you'll see in nervous when we talk about the nervous
51:21 , not because I'm like, oh got to know everybody, but you're
51:23 see the same this same pattern like times. So when you see this
51:28 like I learned this once I've learned whole bunch of different things, All
51:32 , and what you can see in picture is we were looking at both
51:36 and peripheral nervous system. Alright, here, that's spinal cord, central
51:42 system over here, peripheral nervous all right, and what we're doing
51:46 we're looking specifically at the reflex you'll see later why this is going
51:50 be important and understanding, you the structure of the relationship between the
51:55 and central nervous system. When it to the formation of the spinal
51:59 you'll see it again in another area I can't remember what it is on
52:02 of my head. But anyway, here we are, this is your
52:05 and you can see what have we to the skin. We stuck a
52:10 in our bodies, our pen, know? And you know, I
52:15 like to make fun of it, gonna look, it's an electrical nail
52:17 there's lightning bolts coming from it, just means there's pain, right?
52:21 you stick a needle in your is it for fun? Or does
52:25 hurt? Like heck hurts? like ! Okay. Alright, so what
52:30 have in this is there's five parts reflex arc. So this is like
52:35 most basic way that the nervous system . All right. You have a
52:41 . The receptor responds to whatever the is. All right. So you
52:46 specific receptors for very specific things and going to learn about those different types
52:51 receptors later. Alright, that's today's today. So, the receptor recognizes
52:56 the stimulus is. In this particular , we're looking at damage.
53:01 And so this particular receptor recognizes mechanical . That receptor will then send a
53:10 into the central nervous system. This is referred to as the different
53:15 Now I'm gonna put a big emphasis the different right? But it's really
53:21 . Different but a fair, it easy to remember and when you say
53:25 different with a little bit of that twang, they sound a lot
53:28 Alright, so it's a different all . A fair and pathways in and
53:34 sends a signal into the central nervous in the central nervous system, this
53:38 where we're going to process information and what we refer to as the area
53:43 processing. So in this particular case has a single neuron between the in
53:47 the out. That single neuron is to as an interneuron because it's in
53:52 And this pattern right here where the is is the integration center that neuron
53:59 responsible for saying when I get poked this particular location, I need to
54:04 send a signal outward to respond to poking the red line. Here is
54:12 other pathway. This is part Remember part one receptor, part
54:16 A different pathway. Part three Integration where I'm processing the response for the
54:23 is being sent via the different pathway then downstream of the different pathway.
54:28 thing that does the response is what referred to as the effect er It
54:32 the effect. So the terminology shouldn't too weird, right? Integration processing
54:42 . And so here the effect er this particular case is a muscle.
54:47 I get stabbed, like if I on a tack, what do I
54:50 to do? I want to lift my foot, right? And I
54:55 have to think about it. let's just pretend that's fire. For
55:00 moment. I put my hand over hot or touch a hot stove.
55:03 have to go like a cartoon and , I smell something burning. No
55:08 do you feel the heat? You it away and then you start thinking
55:13 it. That's when you say oh not while it's happening, it's
55:19 Okay, so this is a very simple pathway, it doesn't require any
55:24 of thought it's occurring simply at the of the spinal cord. So this
55:29 an example of the basic reflex, doesn't travel to the brain for
55:34 And here when I say processing. mean, to elicit a response to
55:40 that stimulus again it can go up and then you're thinking about stuff and
55:46 know, there might be an emotional if you get stuck by a needle
55:49 their emotional response, Right? I , so reflexes can be pretty
56:01 I mean, so this is an of what we are looking at is
56:04 uh when we're looking at that knee reflex, that's a mono synaptic.
56:08 when you hear the word mono what do you think of one
56:12 So does it have an interneuron? . Alright, there's only a single
56:18 . So here we have the This is a stretch receptor.
56:22 we bang that ligament that causes the to stretch muscles that I want to
56:26 stretched and so it pulls back and causes your leg to kick. All
56:31 ? So that whole process is the is detected and tells the muscle,
56:37 hey hey hey no no no. this information goes in and information comes
56:41 notice it's not confined to the It has to go to the nervous
56:45 here to elicit the response muscles don't unless they're stimulated through the nervous
56:51 So that's an example of mono synaptic there's one synapse what we just looked
56:57 on the previous page is an example policy synaptic these are a little bit
57:01 complex. So, you can see there's one there's two synapses anything greater
57:05 mono. One is poly, It's more than one. So here
57:13 , we're gonna catch your hand on . You can see what am I
57:16 ? Hey fire bad. Move your away. And so that's causing the
57:21 effect in that case is the muscle cause the hand to move away.
57:25 other input can come in from other when you're dealing with polly synaptic.
57:29 very often what you'll see is you'll mono Synaptics that branch and become policy
57:35 in other areas. So, this a real, real simple model
57:38 look, I'm just focusing on this . And so that's true that one
57:42 is mono synaptic. But for every muscle that is contracting, what do
57:46 have to do? I have to a antagonist muscle, Right? And
57:53 not being shown in this picture, it? So, you can see
57:57 there are other factors that we're not looking at. We're just trying to
58:01 it down and just kind of look what is what is mono versus
58:06 We also have different types of reactions are gonna be referring to the autonomic
58:10 system versus the somatic system. So automatic autonomic reflex is one that affects
58:16 organs. All right. This is again subconsciously, I have no control
58:22 it, right? But for um we'll just use the heart,
58:28 ? You see someone you like, very attracted to them and they
58:31 hey, how you doing? What's your heart gonna do? Right?
58:38 you can you control that? Usually when you try to control your
58:42 turns red so you have no you're gonna give it away.
58:47 Sorry. It's just the way the works, right? So it's gonna
58:52 . That would be an example of . Autonomic does not mean automatic.
58:57 confuse it to autonomic means it does on its own. Alright.
59:03 on the other hand, is affecting . So, for example, that
59:07 jerk response, right? When I that, that's affecting a muscle,
59:12 still involuntary. I can't control It's just gonna happen. But it's
59:17 something that is a voluntary structure. muscle I control. It's just in
59:25 reflex. I can't control it. makes sense. I can't control my
59:31 ever. Alright. That's autonomic and responding to the stimuli. Give it
59:38 ? And whatever that stimuli happens to being chased by a bear falling asleep
59:44 a lecture, Heart rate goes Heart rate goes down so far.
59:53 good. Now, what we're gonna is we're gonna shift gears. All
59:59 ? And we're moving into the spinal . Now, Most textbooks, when
60:04 introduced the nervous system, they go the brain and they work their way
60:08 to the spinal cord for some this textbook goes backwards. I don't
60:12 why they chose to do it this . I don't think it's wrong.
60:15 just different. Alright. So we're start with the spinal cord and as
60:20 progress to the last couple of that's when we'll deal with the with
60:24 brain and its structures. So spinal exits out through the base of the
60:32 . What's the name of the whole Ayman magnus, the Alright, it
60:38 enclosed by the bone of the vertebral . So, here's an example of
60:44 , you can see there it's right the center, there is your spinal
60:48 . All right. Just like the and the structures inside the inside the
60:54 . It's gonna be protected by that fully encased in bone. It is
61:00 by those meninges. And it has spinal fluid just like we saw.
61:04 there's a subarachnoid space. So all things are in place surrounding the spinal
61:10 . All right now, what we're do is we're gonna divide it up
61:13 like we divide the vertebrae, we're have a cervical region, A lumbar
61:17 . Student order cervical thoracic lumbar, um regions that we're gonna use to
61:25 mark the individual spinal nerves and the nerves are the are the points that
61:31 exiting out through these for amina uh go off into their different areas.
61:39 right. So each of those represent little things that look like centipede legs
61:45 the beginnings of the spinal nerves. . And that would be peripheral nervous
61:49 . So when you hear the word , peripheral nervous system, right.
61:54 don't have nerves in the central nervous . When we looked at the the
62:01 looking at the brain, we said have gray and white matter. And
62:06 we're gonna be looking here again. and white matter. All right?
62:10 depending upon where you're located, you're to see that the shape of the
62:13 cord changes here. This we're trying look at a more round area.
62:16 you'll see for the most part it's of more oval and there's gonna be
62:20 that are gonna be more oval than . All right. So it's kind
62:23 flattened here, both on the posterior on the anterior side. We can
62:28 there's two grooves on the anterior It's referred to as the anterior or
62:33 dorsal medial sulcus. It basically divides left from the right and on the
62:38 side, ventral or anterior medial So focus on the post airier fisher
62:44 the anterior um Different areas are gonna doing different things and we'll see why
62:52 just a moment. But you can generally speaking, here's your central canal
62:56 we refer to and then surrounding that the gray matter and then surrounding the
63:02 matter is the white matter. this stuff is representing the white
63:11 So what does white matter? All ? Remember we said when we were
63:15 about white matter. White matter represents And then when you're talking about the
63:21 , what it represents, Myelin ated . Yeah, mine and excellence.
63:29 what do you think the white matter the spinal cord is my eliminated
63:35 Alright. And what they are is representing fibers that are moving to the
63:43 and we're really not to the but to a specific area of the
63:46 cord before fibers are gonna exit out the periphery and up to the higher
63:53 of the brain. All right. , what we refer to these as
63:57 refer to them as tracks? All . So all this white matter represents
64:02 going up and down. So if going up we refer to them as
64:06 sending. That means they're going from spinal cord to the higher portions of
64:10 brain. It could be the brain , it could be the brain itself
64:14 be even the cerebellum, right? they're traveling down there coming from those
64:20 areas and typically what those tracks represent fibers coming from the same location to
64:27 at the same location. Alright, they're going up to some location where
64:33 coming down from that location to that area. Now we refer to the
64:38 areas of white matter as funicular because fun Niculescu funicula sauce and their name
64:47 where they're located. So over here on the dorsal side or the posterior
64:52 . So we refer to this as posterior dorsal fin, Nicholas and we're
64:57 basically divided in half funicular as plural singular. So this would be the
65:04 or dorsal over here, on the that's lateral. Over here, in
65:07 middle, on the bottom side, anterior ventral funicula. So it just
65:12 you locate and so you can just that circus in that fisher and you
65:17 each half is a mirror image of other. The gray on the other
65:26 is shaped kind of like a I think I used that before,
65:31 . And it has the different regions the butterfly are referred to as
65:39 And again, they're named on their . So up here, that would
65:43 the dorsal or posterior horn. Over on the side. This doesn't do
65:47 real good job of it, but would be the lateral horns. Sometimes
65:50 see it kind of sticking out over . That'd be the lateral and down
65:53 on the bottom. That would be anterior or posterior horn. And what's
65:59 about this is that there is organization it. They each of these regions
66:04 a type of fiber that's coming into area. And what is gray
66:10 Gray matter is where what portion of cell neuron is located, The cell
66:16 , right? So this is where is taking place. So when we're
66:20 about these reflexes notice when we let just go back a couple slides
66:25 Alright, when we're looking at these , look at where where these fibers
66:29 located, right there in the gray . And so these dot portions represent
66:36 bodies. So when we're processing information the level of the cell of the
66:43 cord, we're doing it in that matter. Come on, white
66:50 gray matter. Alright. So there a functional organization doing this is what
66:54 color coding is gonna represent over All right. So, you can
66:59 the different areas without the color sitting here and what they're trying to
67:02 They're trying to show you sell bodies this side. Alright, So,
67:08 the dorsal horn, what we have we have a different fibers coming in
67:14 there is a cell body of that fiber. It's going to be located
67:18 the ganglia. It's called the dorsal ganglia is part of the peripheral nervous
67:22 . We will get to it on but you see that fiber continues in
67:27 it terminates here inside the dorsal So information entering into the spinal cord
67:36 going to terminate on cell bodies located the dorsal horn. So sensory input
67:43 cell bodies of inter neurons processing that uh that sensory input are located in
67:50 dorsal horn. Now they go to areas. So you can see here
67:56 color coding is like look information that stays up high information that's visceral comes
68:01 little bit lower, clear to the horn. But as long as you
68:05 right now that dorsal horn equals interneuron sensory input, not producing sensory
68:12 receiving sensory input. You're in good . Now the inter neurons are going
68:18 process information and they serve to send to the different fiber and that fiber
68:26 goes on to the starts the letter . What causes the effect. So
68:34 called an effect. Er Alright so neuron that leaves is going to be
68:43 in both the lateral and the anterior . The lateral horn is reserved for
68:55 information. So let's say food enters stomach. It that signal that recognizes
69:03 stretch of the stomach is gonna send signal via the sensory neuron and it's
69:08 come in and it's gonna arrive in dorsal horn. The interneuron is going
69:13 send a signal to the autonomic fiber is going to be located in the
69:19 horn. And that signal is then down to a structure in the stomach
69:23 tell you that's what's going on. lateral equals autonomic different right Different fibers
69:33 leaving. That leaves just one option for the interior horn, anterior horn
69:41 somatic. I step on a What do I want to do with
69:47 foot, lift it fiber that goes the muscle to cause me to lift
69:53 foot is gonna be a somatic in , right? It's a muscle.
69:57 what am I gonna do? I'm find the cell body of that different
70:02 in the anterior horn. So posterior horn inter neurons receiving sensory lateral
70:12 different fibers for the autonomic nervous posterior horn cell bodies of different fibers
70:20 the somatic system. And that's it's organization. So that is that
70:32 I mean when I say it Yes, but do you think that's
70:35 hard thing to understand? Three different , three different types of cells?
70:40 . It's not like there's 30 cells . Yeah. Yes. So ventral
70:49 anterior. Right is going to be and it's gonna be somatic. If
70:56 the all the inter neurons are located the dorsal horn. Where the where
71:01 cell bodies. I mentioned it. the cell bodies of all the different
71:04 located right over here in that Okay. We'll deal with that on
71:14 . Alright. Yeah, lateral horn is gonna be different, right?
71:22 not somatic. It is autonomic. right. So, say it
71:29 dorsal horn, inter neurons receiving sensory , lateral horns. It's gonna receive
71:38 signal from the interneuron but it's sending signal. So the cell bodies are
71:43 different fibers for the autonomic system. autonomic, different anterior or ventral horn
71:51 information from the neurons. But sending . So the cell bodies are different
71:58 somatic. So somatic, different Now. There's nothing here that you
72:07 seen already. we're just reiterating some . Alright so meninges, their continuous
72:13 the meninges that we saw in the . So that means all three of
72:16 are still there. The dura This is the unique thing is
72:21 Not double layered like we saw in cranium. Um It's going to provide
72:26 and it's just gonna extend between. you can see here this is trying
72:30 show you where the dura matter is . All right. The Durham matter
72:36 all the spinal cord and keeps going . In fact it extends beyond the
72:40 of the spinal cord and keeps going further and further down to about the
72:44 to S. Two. Alright. still have CSF in the subarachnoid space
72:50 you can kind of see here see little tiny lines right there trying to
72:55 them. Can you see them in little cartoon? Those are called lenticular
72:58 ligaments and what they do is hold spinal cord in place. So are
73:04 bendy? I mean mostly bendy and of us are stiffer than other.
73:08 are we bendy? Yeah I can this, I can do that,
73:11 can do that. So our spinal allows us to move or our vertebrae
73:16 us to move in that way. our spinal cord has to be has
73:20 be moveable as well. But we to stay in the center of that
73:26 structure and so these structures the lenticular ligaments hold them in place. So
73:32 as we move it maintains the position the spinal cord so it doesn't get
73:42 . Our last little slide here. more anatomy. All right. So
73:46 you can see the spinal cord that removed the vertebrae out of the way
73:51 color coded it. So you can the different regions you can see here
73:55 spinal nerves and spinal nerves are named where they exit between the introverted.
74:00 mina right? For a singular form plural. And so you can see
74:05 see one. How many server Cold bones do we have? We
74:10 seven. So we start above and go down. So we see
74:14 Then we see 12 4 thoracic here five and then down below. You
74:21 see there's five spinal nerves for the region. So the nerves are named
74:25 where they exit. Alright. One through S. Eight.
74:30 One through T. 12. One through L. Five.
74:34 One through S. Five. If you look at the spinal cord
74:40 this doesn't do a good job of it. But we'll see it in
74:42 couple of pictures a little bit There's a region here and there is
74:46 region in here where the spinal cord fat. Not real fat. But
74:51 like if it's like this and it of expands out like that big and
74:54 get small again these are called the . And they represent the point where
74:59 nerves are going to be leaving to nerves to the lower limbs and the
75:05 limbs. Would it make sense that be more fibers leaving in those particular
75:09 to innovate your arms and legs relative your abdomen? Yeah. So that's
75:14 you have the enlargement, you grow than your spinal cord does. In
75:21 words, your body grew faster than spinal cord did. So your spinal
75:24 is a lot shorter than your And so as a result, your
75:28 cord ends somewhere around L. One . Two. This is why when
75:33 do um um Now I'm blanking on name again. Uh the epidurals
75:41 When we're doing we go about where . four is because it's below of
75:46 the spinal cord should be. We want to poke the spinal cord with
75:49 needle do we would be damaging. . What we want to do is
75:52 want to get into that pocket where just nerves. And so what you
75:56 see here, here's a whole bunch nerves traveling down. Now notice the
75:59 cord in here, but the nerves traveling down that area where the nerves
76:03 traveling down, looks like a bunch horses. Hair like in the tail
76:08 a horse. So they named it the kata Aquafina horses but that's what
76:15 name is, right? So all stuff reference is that wanna now the
76:21 tip of the spinal cord right where that's located, It's called the
76:25 medical arts. That's just the very of the of the spinal cord.
76:30 lastly we have a um basically it's ligament that comes all the way down
76:38 attached itself right down to the base the vertebrae. We refer to that
76:45 the film. Terminally, basically it's fiber that basically says spinal cord,
76:50 gonna keep you tight so that when move and stuff the spinal cord doesn't
76:55 flop around. So we have the it ligaments that are holding it on
76:58 side, the film terminology, that's it down at the bottom and that
77:02 that spinal cord in position. So we come back, what we're gonna
77:06 is we're gonna dive into the peripheral system and we're going to start looking
77:11 how the spinal nerves are organized. questions you're just like, get me
77:17 of here, it's a lot of . Alright guys, have a great
77:21 , I'll see you on
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