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BIOL 2301 Human Anatomy & Physiology I - 2301_lecture16_1026
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00:02 Oh. Mhm. All right, all we are going to get started
00:11 . Uh We're jumping around a lot , I mean it's it's like we're
00:15 everywhere. So today what we're gonna is we're gonna start with the glial
00:18 and just kind of go through what do, then we're gonna look at
00:23 networking and how the nervous system actually itself, and again this is very
00:28 . Um If you find any of stuff interesting, remember for example the
00:33 of nervous system, developmental biology is the place you want to go and
00:38 a little bit more. Um So gonna do that, then we're going
00:41 look at not only the networks, gonna then move onto reflexes, and
00:44 we'll get to the macro levels and start digging into the spinal cord and
00:49 from there next week or sorry, thursday we're gonna continue with the spinal
00:53 and kind of move outwards. So just kind of like kind of wrapping
00:58 organizational stuff in the nervous system before really kind of dive deeper into the
01:03 in its argument and structurally what it like. And so when we
01:08 do you guys have a good I'm sorry, I mean I should
01:12 started that. Did you have a weekend? Uh Did anyone stick around
01:16 the did anyone go to the game then get rained out and then did
01:19 stick did you stick around? No didn't. Yes, okay, so
01:24 you didn't know the game on saturday delayed and it was delayed five
01:29 Yeah. And then this is the part for those of you who care
01:33 game took forever. It was like four hour game started eight like ended
01:37 midnight and it went into overtime. mean, you could tell it was
01:42 to go into overtime because our players their players really kind of run around
01:45 this, they bump into each other that was a tackle. That was
01:50 was it was one of those uh of those games. All right.
01:55 , but it was I'm glad. you do know tomorrow it's gonna start
02:00 and we have a cold front. . Just making sure because none of
02:04 guys ever check the weather. I this. Right, Okay. So
02:10 that we've gotten there and we've had social time now let's start dealing with
02:14 cells. And remember on thursday what did is we kind of introduced the
02:18 of the pyramid sell as kind of neuron of the nervous system. And
02:22 not the only type. There are and tons of neurons. It's very
02:25 system. But for our purposes we really need to know that. We're
02:28 kind of saying, look, we neurons and then we have these support
02:31 that are glial cells. All So we have up here, they're
02:35 smaller in nature. We typically called cells glia means glue. And then
02:41 you'll hear the term sometimes using neuro . You don't you don't say neuron
02:47 , it's neuro glia and it's again cells of the nervous system. All
02:51 . So what we're gonna do is just gonna kind of go through
02:53 And some of these we've already all right, we've already talked about
02:57 to a little bit, right? they're typically smaller. They are capable
03:02 dividing. Whereas neurons do not write you're born with your neurons more or
03:06 , you're stuck with what you Right? So these are capable of
03:10 mitosis and multiplying as needed. They transmit nerve signals directly. I mean
03:17 really just serve as a functional or . L all right now. Typically
03:22 use glial cells and neurons in the typically uses like a football team.
03:28 know, you know, who is important player on the football team,
03:32 , right? We always think the , he's not the most important
03:35 I mean, there's been movies made this stuff like I mean the blind
03:39 who is the most important player on football team, the left guard
03:43 or the left tackle. You if you watch the blind side,
03:46 learn that. But the truth is that we focus on their own because
03:49 the one that has an important role sending signals and regulating and monitoring the
03:56 really kind of created the responses that body does, right? It's the
04:00 cell of the body. The glial on the other hand, support those
04:06 . And so typically what we say there like the rest of the football
04:10 . What makes the quarterback look good a good front line and what makes
04:13 quarterback look good our receivers that actually footballs and what makes the quarterback good
04:18 when he hands off the ball to running back that then bust through a
04:22 that actually opened a hole for So even though we taught quarterback quarterback
04:27 that quarterback would be terrible if he have his support around him. All
04:33 . There's no I in team, we used to say, All right
04:36 , why is football team is analogy one I like sports and two is
04:40 it's 10-1. And this is where turn to all the people who watch
04:44 . How many people are on a on a football team? 11.
04:48 you have 10. Support one All right. And that's why we
04:52 that. Now half of the mass the brain, half the volume of
04:55 nervous system is made up of glial . So it really shows you they're
05:00 right? There's lots of them and make up almost half the math.
05:05 are six types for that. We're to see in the central nervous system
05:08 that are focused in the peripheral nervous and I've got them listed out
05:11 but we're just going to go through um before we hit the alexander
05:16 right. What we are going to about is where they come from.
05:19 this is the alexander site progenitor cell is a mouthful and basically what it
05:24 , this is a cell that gives to the alexander sites. It can
05:28 give rise to neurons and astrocytes. , depends on what sort of signal
05:32 receives, but typically what we're talking is how do we get along good
05:35 your sight? All right, So are all good inter site progenitor cells
05:39 all throughout the cns. What they is they sense their surroundings when they
05:43 their signaling through these little points which called growth cones? We're going to
05:49 a picture of one at the at molecular level really at the microscopic
05:54 so we can see what a growth kind of looks like. And so
05:57 they do is when they're stimulated, they do is to divide and
06:00 So here it is, it's trying show you, oh look, I've
06:02 signaled growing and I'm differentiating into an go dangerous site and now I'm in
06:08 of the danger site and so what do is they go to these damaged
06:11 to serve their role. So what the knowledge of danger site, do
06:16 we talked about my Ellen and the site is the cell that is responsible
06:21 by eliminating neurons in the nervous in central nervous system. All right.
06:26 the peripheral nervous system, we have different type of cell which is called
06:29 neural homicide or the Schwann cell. right. So, we'll get to
06:33 in just a second. All So, while ago tender site we'll
06:36 go means mini den dro is And so, what we have is
06:41 have a cell with many branches. so here you can see here is
06:44 cell body. You can see the going up. And this is
06:48 the artist has just kind of made four here to make life easy.
06:51 you can imagine it's got uh You , 10 maybe a dozen of these
06:56 . And it's reaching out to all different neurons that are traveling near
07:00 And it takes it's a cytoplasm and plasma membrane and it wraps around creating
07:07 myelin sheath. All right. And this is and there it is.
07:12 said a dozen. It's up to axons that it can come across.
07:16 50 different cells. All right. , one of the things that it
07:21 , it release a signal that basically the neuron don't regenerate. Alright,
07:27 , it produces these growth inhibiting proton proteins to ensure that the neurons that
07:33 have is what you get. All . So, that's one of the
07:36 that it does. And it also other different types of factors that play
07:42 role in neuronal function that we're not to go into. So, the
07:46 takeaway from this is that Allah God Ender sites are responsible for producing those
07:51 sheets. Remember what is my own you guys? Remember it insulates it
07:57 what purpose? Exactly? Uh that's what I hear when you more
08:05 one person talks. Right, and that's fine. The idea here is
08:08 it speeds up transmission of a neural , right? By creating an area
08:13 insulated. So you're jumping over the areas. All right, The neural
08:19 site or Schwann cell is this is to the alexander site, but it's
08:24 the peripheral nervous system. Alright, here, what we have is we
08:27 individual cells. So here you can the side of plasma, you can
08:30 how it's wrapped itself multiple times, that cytoplasm out into the the soma
08:39 of this neural homicide. And so what you now have is you have
08:43 and layers and layers of fat which as insulation. So, each of
08:47 myelin sheets are one of these neural . All right, now I have
08:54 that one of its roles that it an important role in regeneration of
08:59 All right. So, in the nervous system we want to be able
09:03 regenerate damaged neurons. Now, we're going to take a cell, a
09:08 that's died and replace it. What talking about if we take a cell
09:13 nick the axon so that that axon damaged. What's going to happen is
09:17 going to degrade the end away from selma if I'm the body. And
09:22 what we do is we re grow portion of the axon. All right
09:28 this is a really slow process and needs assistance and this is kind of
09:32 the alexander site are. Sorry, neural inside is for is to release
09:35 factors to help guide where that I'm supposed to go all right.
09:40 against a complex process. I think might talk about it later, but
09:45 not going to promise that I All right. Not necessarily in this
09:49 this class. The Astra sites are in the World Series tonight.
09:55 Yeah, I know. Let's not it. I mean I mean that's
10:01 the key thing is I'm like the Astros jinx ever. So, if
10:04 even think about the Astros they So, I'm not I'm not Astrocytes
10:10 cells are not a baseball team. do you think they're called astrocytes?
10:16 star shaped. That's the key I like to come to class and
10:19 their name the Astros because they're discovered Houston. That's not true. All
10:24 . So they're they're star shaped, the they're the most abundant and really
10:28 , the connective tissue of the brain the best way to think about
10:31 They are responsible for establishing the physical of the central nervous system. All
10:38 . So they're scaffolding in essence. they do is they basically arrange where
10:43 goes and they create the spatial relationships the neurons and the capillaries and all
10:48 other cells in there. So they of like do this, you're
10:52 okay, I'm gonna hold this over and you keep that and they're basically
10:55 everything in their proper position. All . The other thing that they do
11:02 that they play a role in repairing to the nervous tissue. So,
11:06 you damage nervous tissue where the cells die, they actually multiply and fill
11:12 space where the neuron was. So kind of creek or they kind of
11:15 as scar tissue. All right. play a role which we've seen already
11:20 role between exchanges between the nervous tissue the capillaries. They form that blood
11:24 barrier. Um They help control the environment. So, I kind of
11:29 to show you right here, you see here is a neuron and there's
11:32 synapse right there between the two neurons you can see the astra site is
11:36 of wrapped around kind of like a and kind of they're holding those that
11:40 in opposition at the two cells in to one another. But it also
11:45 as a way to remove materials or provide nutrients for the astra sites or
11:51 for the neurons. It plays this role in ensuring that there's a proper
11:55 balance of material in the brain. right. So it's not just ion
12:00 all sorts of fun stuff. glucose is a big one. Materials
12:04 are moved from the blood have to first through the astra sites. And
12:07 astra sites decide when the neurons get sugar. Okay, so they're
12:14 they play a major role. All . So they also talked to the
12:18 and decides to help tell them when do what they need to do.
12:21 , they are major player in regulating this is the key thing they regulate
12:26 structure the environment of the central nervous . Okay, very, very
12:34 Epidermal cells we've already talked about We said this is the cell that
12:38 the cerebral spinal fluid. Alright. so here you can see uh they're
12:43 remember in the core oid plexus and ventricles they have cilia. And so
12:47 they do is they take materials from surrounding interstitial fluid which comes from the
12:53 . There's no blood brain barrier They pick up those nutrients and pass
12:57 in and that's the cerebral spinal So this is where it is.
13:00 the silly are there to beat that spinal fluid forward. All right.
13:05 , um you can see down here that this is the layer of our
13:10 Imo cells. And then you'd say there's a basement membrane there and there's
13:14 sites on which they were embedded or on top of. All right.
13:21 See what else. Oh yes. Glia again, it looks like micro
13:26 . But you pronounce it Micro All right. I don't know.
13:30 some british guy did it first and why we do it that way.
13:33 right now, this makes up a portion of 10 to 15% of the
13:39 nervous system and micro glia for the part behave like macrophages. Alright,
13:46 uh their resident macrophages that related to sites in general. So that means
13:51 they are going to behave as those chewing or pathogen finding cells. So
13:57 basically act as part of immune All right now, ideally you're never
14:02 to use them. All right, you have the blood brain barrier.
14:05 have all this protection stuff. tissue damage can occur and things can't
14:10 their way in the nervous system. so that's their role is to basically
14:14 as an immune defense cells. All ? So, in the resting state
14:17 promote brain cell survival. But in active state they become mobile. They
14:22 to sites of injury and they remove tissue foreign substances. Either of those
14:27 things or what's going to happen. , so, damaged neurons, infectious
14:32 basically they serve and we don't talk immunology here in a P.
14:38 You'll get your full dose of But they're what are called antigen presenting
14:43 . They find what is bad in body. And then they present that
14:47 your immune system and say this is I found. Okay, So,
14:51 kill that. Go find it and kill it. All right. And
14:55 play a role in preventing inflammation If you don't know, is the
15:00 sign of bad things happening in your . All right? So, when
15:05 run your finger like that in a minutes, you'll see a little red
15:07 inflamed. That's a sign of bad have just happened there. Just
15:12 My arm. All right. those are the different types of
15:18 There's one cell we didn't mention in . That's the satellite cell and really
15:22 cell is akin to the astra It's basically the astra side of the
15:26 nervous system. But we haven't really a lot about the satellite cells.
15:30 , we don't really talk about it that much. It's just they're they're
15:34 and around cell bodies in the peripheral system is good enough. Okay.
15:39 , ma'am. Uh micro glia. , It's okay. You're always allowed
15:49 butcher names in this class. All . If you're up here teaching
15:52 then you're only mostly allowed to butcher . Yeah. Are they like like
15:58 buy something or they send out. typically what they do is when when
16:04 actually recognize the pathogen is what you're . So, remember they're going to
16:07 for the most part of the quiet they're just kind of hanging out sending
16:09 signals to keep the brain tissue All right. But let's say you
16:14 head trauma, some sort you someone whacks on the head with a
16:17 bat. All right. All So you're going to have some trauma
16:21 there that's going to cause damage to tissue. So that damage tissue sends
16:26 a signal that says I'm actually And if you actually kill off cells
16:30 what's going to happen is it starts cells start breaking down. And so
16:33 you have particles that shouldn't be in brain when the material is detected.
16:39 the signal of the materials detected by micro glia. That's when they begin
16:43 become active, they move or migrate the area of damage. They begin
16:48 that material. And then if you have blood leaking into the system,
16:52 when you can be a managing presenting and actually say this is what I
16:57 . And so that's what he So, I'll start working to actually
17:00 down and break down that material and stuff really what that's really about the
17:04 immune system. So, we don't talk about it right now. But
17:09 a good question. It's a fair to ask, you know. Thank
17:13 . All right. So what does nervous system do if you take physiology
17:19 you'll learn a little bit more about . But this is kind of the
17:22 list of all the different things first , and this is the key
17:25 It receives information processes it and comes at a plan in order to respond
17:31 it. So the idea is I'm sensory input alright? At any given
17:36 I'm seeing smelling tasting, touching all of stuff and this is going on
17:41 . Like right now, as I out, you'll notice that the room
17:44 actually kind of bright as opposed to . Right? And you know this
17:47 you got who got up here before sun came up, just a couple
17:52 us. All right, so you up and it was dark,
17:55 And you perceive the darkness and then sun got bright and it rose up
17:59 all of a sudden how you perceive . But you don't think about it
18:02 light all day long. Write your does though. Alright. So that
18:06 your input alright, you smell things if you cross the street every now
18:10 then you'll smell that sewer, it's the worst nastiest smelling su I don't
18:15 what happens. All right, But smell but for the rest of the
18:19 , you're probably like walking around, don't notice smells until they really kick
18:22 like when you smell good barbecue, know, we're like when the food
18:26 start cooking, you know, you're I think I'm hungry now,
18:31 That's that sensory input And so what's here is that input goes in through
18:36 in our body goes to the central system and the central nervous system decides
18:41 to do with that information. Much it gets discarded. Like this is
18:46 , right? Which is why you perceive right now that the room is
18:49 until I tell you that it's like just know that you can see
18:52 right? So that's part of its . And then the response to that
18:57 input, How do I respond to smell? How do I respond to
19:00 touch? How do I respond to sound? All right. So what
19:06 refer to this as is we refer as integration. Alright, so one
19:09 that we can do is we can things as memory. Some things we
19:12 do we can act on. So someone is honking at you right,
19:16 know to look up from your phone stare at them with like, can't
19:21 see them walking, which is what to me twice this morning, literally
19:25 this morning driving in green light. start going there's a student walking across
19:30 street, he starts walking across the when he's against the red right
19:34 It's like did you wait for the too? Yeah, twice low down
19:42 near Holmen and then up here, mean it was just our Sorry,
19:49 turned into a really, really mean in the car. All right.
19:54 you can do is you can ignore . Right? Information goes in an
19:58 information goes out. All right. you want an example of that.
20:03 want to give you an example how of you before I said this,
20:07 that you're actually wearing clothes right Now you can feel the clothes on
20:12 body, can't you? Now that thinking about it? But for most
20:16 your day, you don't even notice you're wearing clothes, right? You
20:19 know when the clothes fall off or the clothes get on. Right.
20:25 me, you'd notice when the clothes off. All right. So,
20:29 is occurring when we talk about this and what we're talking about is a
20:34 and the neurons that it's in contact deciding what the processing is, how
20:40 respond to that information. Now, other thing that it does is it's
20:45 to send that information for. That's response portion. Right? I'm going
20:49 come up with a plan in order that response. So, what I'm
20:53 do is I'm sending signals from the nervous system beyond So, we're controlling
20:58 sort of tissue. Typically when we're about motor neurons. What we're talking
21:02 is we're talking about things that control , glands or any other cell in
21:06 body. So, typically you're gonna muscles and glands. But there's other
21:10 that the central nervous system does. , generates consciousness. This is called
21:15 awareness. I think therefore I am right. You all recognize that you're
21:21 this room. Okay. Uh perception your senses, right? I smell
21:26 . I taste this. I think I'm hearing this. Whatever plays a
21:32 in language. All right. The that we make are forms of
21:38 Right? That's language. Another thing it does play a role in reasoning
21:44 would have fun with the reasoning. say you're starving, Right? I
21:49 , we're going to pull George All right. Some people know what
21:53 talking about here. George Costanza. was a character in Seinfeld. He's
21:56 a party and he's in the kitchen this party. On top of the
22:01 can. In the kitchen is a new piece of cake sitting on the
22:05 hasn't been touched. And he looks that he thinks what a waste.
22:10 so he grabs the cake and starts it? Someone recognized that that was
22:14 cake on the top and it was gross. Right. But did he
22:18 correctly? Would you walking into a at a party seeing a piece of
22:26 on a plate that hadn't been not even touching the trash just sitting
22:30 the top. Would you be willing eat that some people like Yeah,
22:35 . People watch like that. What if you were starving? All
22:40 . Yeah. I mean, let's it, we've already talked about the
22:43 second rule. You're willing to eat off the floor. Yeah. 55
22:48 rule. I like that. Yeah. Like I said, you
22:52 I'm going to blow on it and going to be fine. That's the
22:57 part. It's making decisions based upon perception of your environment. We have
23:04 and emotion as well. Um These different things that your body or your
23:11 is responsible for and again in it can be all sorts of different
23:14 . This is controlled as we're going see through the limbic system. And
23:19 for example, I can actually let just show you attach I'm gonna attach
23:23 and emotion together. Alright, presumably loves her grandmother. I'm just gonna
23:28 that I know that's not gonna always true, you know? And we
23:32 our grandmother because she always cooked us best food. Right? All
23:35 So, I want you to picture food that she made for you,
23:40 ? That that special thing that she does. Can you picture it that
23:44 you happy? Yeah, that's a , right? And emotion put them
23:52 . Here's another fun one. All . This one's a little bit more
23:56 . You ready for a tragedy? one's an easy one. Think of
23:59 first crush. All right. Can picture the perfume cologne or soap that
24:09 used. Can you picture the smell any memory? No, can't
24:16 To this day. I can still the perfume my girlfriend wore in high
24:22 ralph Lauren Lauren. Yeah, I That's and And the fact is
24:30 I smell it, that's who I who I remember. All right.
24:34 just an example. All right. so to get what kind of emotions
24:37 we're not going to go there. it's an example of memory,
24:44 And emotion coming together now, very on your brain. Remember I said
24:50 start off basically as a tube. , so your brain starts off as
24:54 tube as well and the process of the structure of the brain and where
24:58 neurons go and where the astra sites glial cells all the rest of glial
25:03 go is dependent upon the type of that's taking place. Now, what
25:07 looking at specifically here is we're looking how do neurons get to where they
25:11 to go, Right because they don't kind of form they have to kind
25:14 travel or migrate to where they need go during your state as an
25:20 it's going to use a process called migration. And so what we're doing
25:24 is we're growing outwards. So where you think radio think of like
25:29 Right? So like this, this is the center point you're moving
25:33 like that. And so what you here is basically you'll have glial cells
25:39 are already arranged. What they'll do that neuron will find a glial cell
25:45 use based on the trophic factors, materials that those glial cells are
25:50 We'll use that to migrate to where need to go. And this is
25:54 actually forms the different layers of the system. All right. And I
25:59 think we're going to spend a lot time talking about the different layers because
26:01 very, very complex. And it's beyond what we need to know
26:05 the class. But there's multiple for example, in the gray matter
26:10 you become an adult, there's still growth that can take place and it
26:15 place through a process called tanden tangential . So, here, instead of
26:20 outward, what you do is you , you know, along a layer
26:26 essence. Alright, So, you're going to have astrocytes and other
26:31 are gonna be releasing these signals. , this is kind of just showing
26:34 it's like, okay, I might able to migrate up a level.
26:37 then I'm moving within that level to wherever I need to go. All
26:42 . So, when we're building and the structures of the central nervous
26:48 we're using one of these two pathways upon when that process is taking
26:55 I promised you a picture of a cone and this is a picture of
26:58 growth cone. All right. And , what you're looking at here,
27:02 green and the red represent those side skeletal elements. So, we're talking
27:09 filaments. So we're talking micro filaments , which is the red. The
27:12 would be uh the intermediate filaments uh they're trying to show here. All
27:18 . And so the way that these move. So, if you went
27:21 to these and say, how did get from here to here to
27:23 an upward what I'm doing is I'm a chemical signal. Alright. We
27:28 them Trophic factors and Trophic just simply a regulating factor regulating molecule. The
27:36 of using those type of chemicals is chemo taxes. All right. And
27:42 , what's happening is you can imagine the ends of those neurons, just
27:45 we saw on the ends of that of that Allah go dinner site progenitor
27:51 . You have these little growth And what they're doing is they're expanding
27:56 and just kind of feeling there around their environment. And if one of
27:59 little tiny growth cones comes into contact a chemical, it's going to respond
28:05 one of two ways. If it's attractive chemical, it's going to move
28:08 it. If it's a repulsive it's going to move away from
28:11 All right. And so what happens the neuron moves and migrates towards the
28:16 and gets repulsed by these negative factors it gets sent to where it needs
28:21 go. All right. So, other thing that these factors can do
28:25 create branching or can create altered sensitivity whatnot. But in essence what you're
28:30 is you're placing that neuron exactly where needs to be in order to act
28:35 a specific neuronal pool. What's in rental pool? What's a bunch of
28:41 acting together? And so you can of think of it like this?
28:44 right. So, our brains are static. They are not structures that
28:48 formed and then that's the way they for the rest of time. They're
28:53 we refer to as being plastic. so, the process of how the
28:57 arranges itself and functions is called neural . So, remember, chemicals interactions
29:04 chemical interactions can lead to where the need to go. And then once
29:08 interacting, then how they're interacting is to change how the network works.
29:13 , what I want you to do I want to focus here on these
29:15 pictures. All right. Because I looking down here, rather than looking
29:19 over here makes more sense. over in this first thing right
29:23 where it says neurogenesis, what I you to imagine is that these circles
29:27 have lines attaching to them are neurons interacting with other neurons in a
29:33 All right. So, as part neurogenesis, the neurons are going to
29:37 formed into a network. All So, it's just like you and
29:40 bunch of your friends. Alright. then what happens is that other neurons
29:45 going to be introduced, these are new friends. All right. And
29:50 what ends up happening is is that the course of these people are these
29:54 being introduced into this network, these are going to be formed between the
29:59 that are already there and the cells have been introduced. And that's what
30:03 next step shows. It's showing you formation of these new synapses.
30:08 what's gonna be happening is is that we learn and as we do activities
30:15 etcetera etcetera, that's going to reinforce interactions and it's going to remove other
30:22 of interactions. Again, think about network of your friends, right?
30:27 you first came to the university, had a group of friends that you
30:30 met right away and they were you're best buddies, right? I
30:35 my first year of college on that floor. It's like this is the
30:39 of people I'm going to hang out by the by the mid semester all
30:44 a sudden now I've shed some of people because I didn't get along with
30:48 or like one of my two of friends were in the school of
30:51 So you never saw them. And so all they did was
30:55 They actually lived in the rooms where did the architecture. They took sleeping
31:00 and slept up there. Alright. those people kind of moved out of
31:04 network. And then because I was out with all the students in Biology
31:10 though was a policy major. We're about this earlier. Alright. I
31:14 new friends and I started interacting with even more. Right? And then
31:18 met a girl. And so what when you meet a girl you're now
31:22 with all her friends? Right. what you're doing is you're creating these
31:26 , right? And you're strengthening some and you're losing others. And so
31:31 what's gonna be happening as you experience in your life, as you practice
31:36 you learn pianos. You learn to a bike as you learn how to
31:40 a basketball and shoot a three right? As you learn how to
31:44 Houston traffic As you study your And P. And completely ignore your
31:49 class. Mm. All right. going to build and grow different
31:53 So what ends up happening is as strengthen those relationships but at the same
31:59 there's gonna be other synapses that are be weakened. And so what ends
32:02 happening is you create a network of that are responsible for the the responses
32:12 you're learning or for the activity or it is. And that's what's going
32:17 throughout life is you're creating new networks reinforce the activity that you just
32:24 Alright. For those of you who piano from memory, right? You
32:28 have to look at the at the . There's a piece that you learned
32:31 and over and over again. And you start that what's going to happen
32:34 that network is basically saying these are steps A. B C.
32:38 And you just do it because it's just something that's occurring within that
32:44 Yes, ma'am. Yes. Mhm. So, does that seem
32:52 it's So the question is is it new neurons or or how what is
32:58 new connection? So, remember during , what we're doing is we're putting
33:03 near one another. All right. , the way you can think of
33:05 like this as if I'm a neuron the two of you are neurons
33:09 What can I do? Right. have an interaction like this with both
33:12 you. All. All right. let's say whatever the activity is,
33:16 a greater interaction here in a smaller here. What may end up happening
33:20 I send more signals this way and signals this way. Or what I
33:23 do is I can withdraw one of synapses and now I'm focusing my energy
33:29 that interaction. Right? So, haven't created new neurons. We just
33:33 and changed the interactions between them. right. So, that's the plasticity
33:38 . It's not adding in new It's adding and changing the interactions between
33:44 . All right. So, I'm going to get the name of the
33:48 , Right. It's like this It's Jim Carrey movie from a couple years
33:52 Sunshine of the mind. I can remember. Thank you. Eternal sunshine
33:57 a of a spotless mind. All . You'll find out that I have
34:02 1000 movie references and that's like the movie I can never remember the name
34:06 because it's just too dang long. right. And that's the premise of
34:10 movie is uh Jim Carrey is and is the actress titanic boom mm kate
34:21 . Alright, Kate winslet. They . They found out they were that
34:27 sort of issue came up between they up. She wanted to forget that
34:31 was ever in a relationship with And there was a company. It's
34:34 fictional movie can actually erase the write and erase all memories of the
34:39 with this guy. And so, idea was I can go in and
34:41 can and I can attack each individual that holds a memory. And what
34:45 is is the memory trying to trying escape through before it gets erased is
34:51 what the principle is. It's an concept. The problem is that's not
34:56 memories work memories are in these neural . And so it's how these cells
35:03 interacting and firing within that network that you to recall whatever it happens to
35:08 . Whether it's a memory or an . Yeah. Here. Mhm.
35:19 will. So, no. the question is well what if I
35:21 a memory that I don't think All right. Well remember we have
35:25 term memory. Right. We have term memory and then we have a
35:30 short term memory basically it's right now blanking on the name. But basically
35:35 the idea of I'm seeing something. can hold on to it for just
35:38 brief second before I put it into short term memory. Would be like
35:44 that someone's phone number just before you them. Right. It's not the
35:48 . It's like okay you gave me phone number. What's the number
35:51 10 digits. Just three numbers at time please. Right. You can
35:57 the three numbers. Right. Long memory is this right here? All
36:03 . And so long term memory is permanent memory. It's not stored
36:09 There is a use it or lose . Right. Just to give you
36:12 example of use it or lose I spent good six years of my
36:17 studying a specific molecule And after those years I moved on to other
36:23 And if you ask me if I everything about the things I learned over
36:27 six years I would look at you go Mhm. No. Right.
36:33 it's just just an example of Right. I mean can you remember
36:39 mean I can go down to this like can you remember something traumatic that
36:42 when you were like five, Like going over the handlebars and face
36:48 . Can you remember something like Yeah. You know, falling.
36:53 shown you guys the scar when I like, Y'All's age. I fell
36:57 a cliff 20 ft. So I a hole in my leg and scar
37:00 my chin and I broke my Do I remember that intimately? I
37:05 pulling the plant out, looking at like a cartoon time stopped. It
37:09 really cool. All right. But know, things like that. You
37:13 forget. Right? But for the thing I taught you on the
37:19 day of class that you studied and and studied, you know, you
37:23 have forgotten it by now, haven't ? Right. So practice makes
37:29 Is how memory works is again very complex. All right. So
37:36 integration then is simply the coordinated integration the neurons that are grouped into these
37:44 pools. So there's these complex patterns are going to be created. And
37:51 what is The neuron pool is basically group of neurons working together. So
37:55 take this incoming information they process and decide what sort of outcome to needs
38:01 . So, sometimes they're made before get to another pool or they may
38:04 it out through the motor neurons to some sort of action. So that
38:08 these neural pools can be localized or can be distributed. All right.
38:12 so here when we're talking about neural being localized. That means all the
38:16 are right there next to each All right. We're talking about they
38:20 be distributed. That means that they be spread out over the full distance
38:24 the central nervous system. We're going learn a little bit later where the
38:29 cortex is. We use the word cortex. We see the visual cortex
38:34 back here in the occipital lobe. . And it's like, okay,
38:38 want you to know that That's that's the fact that you walk away
38:41 All right. What you don't learn this class, is that about 80%
38:46 your brain deals with visual processing? , they're like multiple layers, like
38:51 we have what we refer to the visual cortex. That means V
38:55 There's a V two V three V V five V six, V
38:59 V eight V nine. Some people described all the way up to V
39:03 . All right. And that means your brain is really responsible for understanding
39:07 environment through visual context. All So, that would be an example
39:12 distributed networks. All right. They have a restricted number of sources,
39:19 input and output. That means information coming in from a specific location.
39:24 going out to a specific location. not just gonna be well, just
39:28 whatever information or those neurons aren't working now. Go ahead and send them
39:31 there because they can do something. right. Every network is receiving specific
39:37 and they can be very simple or can be very complex in terms of
39:40 circuitry. Now, I don't know many of you are going up into
39:45 medical or dental school. The requirements those two schools is you have to
39:49 physics. All right. I'm not about P. A. School.
39:52 haven't paid very close attention to A. And all the other allied
39:56 things. Alright. So usually when talking to the pre meds I asked
40:01 why do you think you need to physics? And they're like, I
40:05 know if it's because you need to circuits. You need to know how
40:07 work. Right? Because the nervous is made up of circuits. It
40:12 has optics in it. You need learn optics. It's how scary than
40:16 really is. Yeah. We're not do that though. But we're gonna
40:20 at a couple of circuits in the the very simple sense. All
40:23 So we have what are called simple . So we have complex circuits.
40:27 circuits are simply when one cell communicates another. So we've already seen the
40:32 of a simple circuit. Right? we're looking at the neuron and the
40:36 , we're looking at a simple one cell communicates with another cell.
40:40 circuits is when there are these multiple between neurons. So, the simple
40:45 is very uncommon in the central nervous . All right. We don't want
40:50 just have one cell, one One cell situation in the central
40:54 We want to process information. That integrating information means information from different areas
41:00 to be processed together to come up some sort of output. So,
41:03 complex circuit is more common in the nervous system. Now, these are
41:08 basic types of circuits. Alright. not looking at a neuronal pool and
41:13 the question how to smell work. . We're just asking the question.
41:17 does the brain organize itself? And these are some examples of some of
41:22 circuits. These four basic ones. have the converging circuit in the diverging
41:27 . These two are the easiest. right. And then there's two others
41:30 a little bit more complex. So, with the divergent circuit you
41:34 see here is I've got a single right? That then terminates on multiple
41:39 . So, what are we doing the signal? Is we are amplifying
41:42 signal or sending it to multiple All right. So, we're spreading
41:50 the output. All right. when we're talking about walking,
41:55 walking is is kind of a simple . Would you agree with me with
41:58 ? I mean, walking is I we've already find it as not
42:03 Right? You lift your foot? put your weight forward. You catch
42:06 before you fall. All right. it's not just one muscle that we
42:10 contracting in order to walk. All . The act of walking. We're
42:16 , okay, this is what we to do. So we need to
42:19 all these different muscle cells. And that would be the example of
42:25 All right. So stimulating balance and neurons that then go off and deal
42:31 those other muscles. A converging circuit the other hand, concentrates information on
42:36 single cell. And we were looking the grand post synaptic potential. This
42:40 kind of what we were looking We're looking at all these neurons converging
42:44 a single cell. All right. , for example, these are very
42:49 common. You can see I've got neurons going to one cell. The
42:54 would be salivation salvation Here you can of. I'm going to have
42:58 So things that are touching the So I'm getting chemicals on the
43:02 Visual. When I look at something makes it look tasty, right?
43:08 ? It smells good. And also it touches my tongue it's velvety and
43:13 . Right? All those factors together make it go mm and caused me
43:18 salivate. But when you see gray sitting on the plate, yeah.
43:22 just the visual of it, There is like uh It might taste
43:26 ambrosia but it's gray and sticky and pick it up and it kind of
43:29 mass to it. It might move little bit, you're like, that
43:32 going in my mouth. Kind of oysters. Oysters are like the living
43:39 of the universe. Yeah. So saying with the divergence circuit like,
43:50 , that's where it starts. The is when a diverging circuit kind of
43:55 working here, It's information is oh, I want to go over
44:00 . All right, That would be that's the input some things over there
44:04 I want. So, how do do that? Well, that single
44:07 then spreads that signal out to multiple so that the decision can be that
44:13 not just contracting one muscle, but muscles to lift that leg and then
44:18 my weight forward is other muscles Cause that to happen. So divergence
44:23 the sense that the signal begins in spot with one neuron and then expands
44:31 . Here are the two complex We have the rhythm generating circuit and
44:36 we have the parallel up to discharge generating circuits. Just think of rhythmic
44:41 . The easy ones here are breathing the sleep wake cycle. Let's concentrate
44:46 breathing for a moment. Right? we're all doing that right now,
44:50 don't know where you guys are on sleep wake cycle. All right.
44:54 could be, you know, at different points right, breathing. It's
44:57 I breathe in right? My lungs outward and then the rest or come
45:04 a stop and then I relaxed and air pushes out and I just repeat
45:09 process over and over again. All . In essence, what we're doing
45:12 we're sending action potentials that are increasing muscle contractions that are responsible for expanding
45:19 chest area, the thoracic cavity and they stop and then when they
45:24 that's the relaxation. And we build up again. So it's basically serious
45:28 potentials. A series of period of or no action potentials rinse repeat over
45:33 over again. Alright, that's a pattern generator. If you can't picture
45:38 , think about dribbling a basketball. right. Think about riding a
45:43 right, chewing gum, right? are all rhythmic patterns. Alright.
45:48 so here what we have is we a positive feedback loop. Alright.
45:52 if you look at the picture, a little bit wonky. You can
45:55 here is our original neuron neuron number . It actually has two axons or
46:00 to actually, but one acts on . That's what's the two collaterals.
46:05 , so here we go. The comes down the first collateral stimulates this
46:09 which also has two collaterals. It's to create the action, but notice
46:13 feeds back on itself re stimulates that cell so that I have a feedback
46:17 in this pattern, This other collateral this particular case is going to this
46:21 cell which comes down here stimulates And so what you have is you
46:25 a series of repeating actions on the cell so that it is continually working
46:31 producing a signal through that pathway. only way you can stop that is
46:37 exhausted of its ability to move which is very rare. Typically what
46:43 is is that you have some sort external signal that comes in that says
46:49 and basically prevents it from happening. right, So what you're doing is
46:53 creating a cycle of activity and then period of rest than a series of
46:59 and then rest over and over and again. All right. So these
47:03 what are typically called central pattern generating , rhythmic circuits. The last one
47:09 a parallel after discharge. There's a bit more complex. Again, these
47:13 just examples. They don't actually look this, this is just trying to
47:17 you the sense of what it And so you can see here,
47:20 got a single neuron with four I've got my receiving cell on the
47:24 and you can see I have a bunch of neurons in this. And
47:28 what's happening is is that this cell here is receiving multiple signals from the
47:34 source at different times. So it's the first thing that gets there.
47:38 second signal gets here than third signals signals. So you create this larger
47:43 that is sustained in this latter cell an example. So we see these
47:52 in the areas where we're going to , like higher order thinking.
47:56 So when you're processing information, the cells are just talking to each
48:00 and creating many action potentials that influence last cell to result in a specific
48:08 . Alright. I know this is , really I'm not the word.
48:13 not esoteric, but it's really Right? What I'm trying to show
48:18 here is that there are different types circuits that create different types of
48:23 And so those different types of circuits used to create different types of patterns
48:28 the brain. And so those patterns then create action. So the neural
48:39 are going to be developed very early during fetal and neonatal growth. All
48:44 . They display that plasticity. So other words, they expand or change
48:49 response to activities. All right. as you do certain things practice makes
48:55 . Have you ever watched babies? babies fun to watch. Have you
48:58 just have you ever given them keys anything? What do they do?
49:02 first thing I would go straight in mouth. Why there's a thingy,
49:06 know? Well, it's they're exploring environment right there. Trying to see
49:11 just presume everything is food. And so they're like their body is
49:15 saying, what is this? What this? What is this? You
49:19 , their their ability to explore their and that tactile response of grabbing and
49:26 everything is training their brain to understand going on around them. And so
49:32 an example of figuring out what That's the practice makes perfect. You
49:38 , watch a baby trying to learn to walk, watch, watch how
49:41 times it falls on his butt. cry. Does it kind of looks
49:46 and then it just kind of pulls up and you know, and then
49:50 and stops that whatever it is for while and then tries to stand for
49:53 second and it falls down. It up again. It's actually generating a
50:01 so that it learns how to maintain and learn how to walk. All
50:06 now, these circuits that are formed early on are modified during your
50:13 So every time you learn something new you're creating a new pattern within these
50:17 networks. So any sort of physiological gonna be dependent upon proper interactions.
50:27 circuits can regulate complex behavior that we're to see. What they do is
50:32 produce what are called reflexes. And going to be looking at reflexes
50:36 But there can be what is referred as a cranial reflex or what is
50:40 to as a spinal nerve reflex. , where we're moving, it's a
50:47 . What's a reflex? It's a from Duran Duran in the early
50:53 I'm glad, like three people laugh that press you in the back.
50:56 to wake up. That was a funny joke. No, it
50:59 It was stupid, but it wakes up. All right. So what
51:02 the reflex? This is a direct use this as Because it's a definition
51:05 you need to just kind of carry you. It's a rapid pre program
51:09 reaction of a muscle or gland to sort of stimulus. And so that
51:13 there's a lot of words in there have definition of what the stimulus
51:16 basically. Simple sensory input that initiates reflex. One of those words,
51:20 a definition in a definition. All . It's rapid meaning that doesn't have
51:25 lot of neurons that are involved. program means you're gonna get the same
51:29 every time and voluntary means you have conscious control of it. It's going
51:34 happen regardless. You cannot suppress We've all done the stretch reflex,
51:41 ? You can do it. It's it's really, really easy.
51:44 if all this stuff wasn't up here sit up here on the desk and
51:47 you. I can sit on the and I can actually just bang that
51:50 and I can make my knee just up. Don't even need a
51:53 The hammer. Just makes it Right this right here. This is
51:58 feeding reflex that you're showing. If basically tickle newborn right there, they're
52:03 to try to suckle on whatever it you're putting by their face.
52:08 That's what they're trying. It's not . It's an eight. Alright,
52:12 the spinal cord is responsible for lots lots of reflexes. Part of the
52:18 central nervous system is that it processes . All right. So, what
52:23 means is that there's things that are on at the unconscious level in terms
52:27 reflex. So, there are two of reflexes. There's the basic one
52:31 unlearned built in responses and that's the . Those are right there. You
52:35 learn how to kick your leg. stretch reflex just happens. And so
52:40 you stretch that tendon, that's what do. When you're applying pressure to
52:43 , it causes the jerk, The suckling reflex. It just is
52:49 a survival reflex. This is where get my food. So I'm gonna
52:53 try to suckle. I want you try to touch my face with.
52:57 are also conditioned reflexes and these are that you acquire after practice or
53:04 All right. So for those of who are athletes, the reason you
53:08 practices because you're trying to train you do something that happens all the
53:15 All right. Under particular circumstances. , I'm gonna go to football one
53:20 the worst types of offenses that you play against if you've not trained against
53:25 is the triple option. Rice runs army runs at navy runs it.
53:29 ? Why is it awful? because the ball can go to one
53:32 three people in any given time. . And so basically you run and
53:37 you're about to get tackled, you start to the next person and the
53:40 person. So it's a it's a offense to run against because most of
53:44 or most teams don't practice against But once you know what to do
53:48 you basically say this is a man man running offense, you are responsible
53:52 the quarterback, you are responsible for fullback and you're responsible for the half
53:56 and don't let that person pass. doesn't matter if they have the ball
54:00 all of a sudden. Now that's offense that you can't go against.
54:04 right. What we've done here is conditioning people to behave in a specific
54:11 . Now I'm talking football because I to watch that triple option on thursday
54:15 friday night. The high school, kids goes to play against a team
54:18 had that and I just watch people I'm sitting there pulling my hair out
54:22 I had this like the easiest thing defend against if you know what you're
54:26 . All right, you don't want talk about football. Fine condition reflex
54:31 alright. You remember good old Pavlov had a dog. What did
54:36 do? He had a bell and feed the dog, You feed the
54:39 and ring the bell feed the Ring the bell, feed the
54:41 ring the bell. Or what was other way? Reading the bell,
54:43 the dog, Ring the bell feed dog, ring the bell feed the
54:46 , ring. The bell didn't feed dog with the dog. Do
54:49 He bit Pavlov because like, where's food? Know that he did.
54:54 salivated, but it's the same sort conditioning, Right? You have been
54:59 yourselves. All right. I'm not talking weird government stuff. Although this
55:04 a government thing. Outside over there is a street light, that
55:09 light has three colors red, green yellow. What do you do
55:13 Red? What do you do? green. Go what are you
55:17 Yellow speed up. That's right. the person who's in front of me
55:23 slows down. Yes, Yeah. didn't learn correctly. You weren't properly
55:32 . Mhm. In high school your when you heard the bell, what
55:35 that mean? You get up out class or you have to sit down
55:39 classes started, right? You've been . All right. These are natural
55:47 . Right? When you see your give you that look, you know
55:51 I'm talking about? Then immediately the becomes Yes, ma'am. Alright,
55:58 . All right. So, conditioning something that's learned now, A
56:03 All right. I've got a time here. This picture is the picture
56:08 you need to memorize for the rest the nervous system. Now, we're
56:12 it for the reflex. So you see here for the reflex. But
56:15 we're gonna see it in terms of relationship with the central nervous, in
56:17 peripheral nervous system. So once you it, just start going,
56:21 I'm going to see it again and and again and again. And then
56:23 going to see it again and And I'm so glad I learned
56:26 Okay, so here we have the and what you have. All
56:30 so this little line right here which pointing at things, just think of
56:33 as everything over here is peripheral. in there is central. And so
56:38 is kind of showing you how information in and information comes out. But
56:42 the reflex, what we're seeing is seeing a basic functional unit here we
56:46 a point of reception. This is where the receptor is. So you
56:49 see right up here we have the and we have the little lightning boats
56:53 it's an electric nail. Right or , it means it's pain. Have
56:57 ever stepped on a nail? Not a lot of fun. All
57:01 . So that's what that is. it's showing I'm receiving some sort of
57:05 . All right. And then that is going to travel to the central
57:09 system. The pathway which it It's called the affair and pathway.
57:13 , now I'm going to stay with strong a a firm. All
57:17 A ferret. Why? Because I'm texas and if I say it a
57:21 then the other word is going to like different. And that's not gonna
57:24 us any good. Right. So parent is in on the other
57:28 We're going to see a difference which out. All right. But it's
57:31 difference and deference which is confusing. right then you're going to have the
57:39 center. So the integration center is inside the central nervous system. This
57:43 where we're processing the information that we're from the stimulus. So stimulus is
57:50 at the receptor travels the pathway into central nervous system and the central nervous
57:55 information gets integrated. In this particular . We're showing that there's an
58:01 All right. And so this interneuron serving as part of the integration
58:05 Not Oliver will have inter neurons. word interneuron innings in between neurons.
58:11 , that's all it means. And once the signal has been processed there's
58:16 be a response. And so that's to travel along the pathway out
58:22 Some sort of effect or the effect is the thing that causes the
58:27 Alright. In this particular case, stabbed myself with the electric nail.
58:32 moved my arm out of the That got stabbed. Okay, that's
58:38 basic. Alright, so that's what five parts are. To a
58:44 Arc receptor. A different pathway, . Different defector. There are different
58:55 of reflexes. We can categorize them terms of the number of synapses they
58:59 . If you're monta synaptic, that you have how many synapses one.
59:04 , let's look at a mono right? Here is our receptor,
59:08 ? It's the stretch reflex. So basically sensing stretching the muscle and then
59:14 travels in via the different. And , there's no interneuron, right?
59:18 only a single synapse. So this still an integration center and the integration
59:26 , when this gets stretched and what need to do is I need to
59:30 . And so that goes out the pathway to the effect or organ which
59:33 the muscle that got stretched. All . That's mono synaptic. Polly synaptic
59:39 what we just saw where we have interneuron. So at least one.
59:44 at least two synapses. So more one is the answer. All
59:50 Is it just gonna be one interneuron there could be seven in your
59:53 It could be to inter neurons. right. There could be a whole
59:55 of processing that takes place. But , you've already seen this. Look
59:59 , I am burning myself with a burner. Have you burned yourself the
60:03 burner? It's not fun. Don't that. Okay, but if I
60:08 my hand over the Bunsen burner. going to feel the heat That signal
60:11 in processing says, Hey, go the muscle caused the hand to move
60:16 . All right. That'll be polly . Now, a policy synaptic can
60:22 signals up to the central nervous system you've ever stepped on a tack or
60:27 nail or if you've ever burned you're going to move whatever it was
60:31 got damaged. But you're also going perceive that pain, aren't you?
60:36 . By Stepan attack. I say and I lift my foot. I
60:40 my foot before I say al. the reflex to move my foot is
60:44 place in the spinal cord, perception taking place up in the central nervous
60:49 . Okay? So signals can be up. But the reflex is not
60:54 place up in the central nervous Reflexes can be divided between autonomic and
61:04 . All right, now, this be a little bit confusing.
61:07 Autonomic means affects the organs. Somatic affects muscles. All right. These
61:15 things I can't control. These are that I do control typically.
61:20 When I'm thinking somatic muscles or things can control. But what did we
61:24 about a reflex? You can't control . So I can sit there and
61:29 on that tendon in your knee. that stretch really flex till the cows
61:33 home. Right? And there's nothing can do. You can actually sit
61:37 and say I'm gonna fight it can your foot is just gonna do
61:41 All right. So, what I to be clear here is that when
61:44 hear reflex it's going to occur outside my control, even though I may
61:52 in a system that allows me to it. Does that make sense?
62:00 . Autonomic? It just happens. right. You ready for a dumb
62:05 ? Have your stomach ever growled at ? Right. You walk by the
62:10 truck, you're fine. You're not . You're gonna wait till you get
62:13 . You're not gonna spend the money you walk by the food truck,
62:15 smell it and all of a sudden stomach says, feed me,
62:21 That's an autonomic reflex, basically, smelling of the food basically starts producing
62:26 chemicals that say it's food time. right. No control over that.
62:36 home stretch. We're now going to macro level dealing with the spinal
62:44 Okay? The spinal cord exit at base of the skull, Right?
62:53 , it's an extension. You're gonna gonna talk about the structure of the
62:57 and then from the bottom of the outcomes, the spinal cord. All
63:02 . It's completely enclosed by the vertebral . So, if you think about
63:06 vertebrae and that hole that's in that's where the spinal cord is
63:10 All right. So, it's traveling that. So, I mean,
63:12 protected by the bone. It then all three minute Gs and it has
63:17 spinal fluid and the way we subdivided same way we subdivide the vertebrae.
63:23 difference is is that we're going to them from which the spinal nerves
63:28 Okay, so the little things extending that make it look like centipede
63:33 Those are spinal nerves. All So we have a cervical region.
63:38 have a thoracic, we have a sacral in cock sigil region. So
63:42 like the vertebrae structurally, this is a cross section looks like. We've
63:48 kind of looked at this on that day we started talking about the nervous
63:51 , we said, look, we this region that has white matter,
63:55 has gray matter structurally. It's actually of flattened on the sides. Although
64:00 cartoon here doesn't show that. All . So it's kind of like you
64:03 think of this as I've kind of on the anterior posterior side and created
64:07 kind of flat regions. We have major grooves that we need to be
64:11 with. We have the post syria dorsal medial sulcus and then on the
64:18 side or anterior side we have the medial fissure. All right? So
64:24 on where you're located you're gonna see actually can be kind of small.
64:26 it kind of expands outward. Then gets kind of small again and then
64:30 outward. That has kind of these shapes depending upon where you're looking all
64:35 . And that shape and that size going to be dependent upon where you
64:40 which is dependent upon function. So in areas where you're producing more signals
64:45 go down to say to the That's where it's gonna be a little
64:49 wider and in the middle of the it's going to be a little bit
64:52 again. All right. So you see gray matter is marked here in
64:56 yellow. That's your gray matter has of that butterfly shape to it and
65:01 the white matter is on the external and then you can see centrally
65:06 that's the central canal. It doesn't where you look. You're going to
65:10 something that looks something like this. going to start with the white
65:15 All right. It has three different . So what you can do is
65:18 can take the circus in the fisher that basically divide you into two
65:22 So you can focus on the left of the right half, whatever one
65:25 you happier. All right. And if you think of it as being
65:29 mere image, there's gonna be three columns. And so what you can
65:32 is this is coming out of the going that direction. Alright, so
65:36 coming out. And so this is column here. This is a column
65:39 . And this is a column So what we call these columns are
65:43 the finicky ally because they're fun. fun nick you like? Fun.
65:50 sorry, dad joke. Alright. name for where they're located. All
65:55 , We've got the posterior or We have the lateral and then down
65:59 we have the ventral or anterior. right. I learned them this way
66:05 , anterior and lateral. Some books using ventral. Now, all
66:09 Now, if you look at the one, you can see that while
66:13 sulcus goes all the way down and butts up to the to the gray
66:19 here. The white matter actually crosses right. There is space in there
66:26 that's called the uh White Commissioner. White Commissioner allows fibers from one side
66:33 cross over to the other side. , that's why it's referred to as
66:37 Commissioner. Now, what these columns our bundles of tracks of axons traveling
66:47 the central nervous system or away from central nervous system. All right,
66:51 me rephrase that to the brain or from the brain. That's better the
66:56 way to say that since we this a central nervous system. All
66:59 So, if you're going towards the , you're taking information that is has
67:04 entered into the central nervous system. you're carrying sensory fibers. Alright,
67:09 , a sending fibers are sensory Alright, information coming from the brain
67:16 descending fibers are moving down the spinal and they're carrying motor information. They're
67:22 to the muscles or the glands or so that you can then do some
67:26 of effect cause some sort of So, you can think of as
67:29 descending or motor. All right. , what these bundles are are basically
67:35 that are traveling together to this roughly same destination or to the same origin
67:41 the same origin. All right. , it's again it has that organization
67:46 it of I'm going to or from same place. And so it's not
67:51 wires that have been jammed in to to the structure so that they can
67:56 get some place little later. We're to break down those finicky ally into
68:03 actual tracks with their names. Which some people because they've got really long
68:07 , but it just tells you where going and where they're coming from.
68:11 right. The gray matter. I it's easier to focus on this side
68:17 on this side for right now, again, has this is centrally
68:21 It has kind of a butterfly The shape of that butterfly changes depending
68:26 where you're looking at, but it's or less a butterfly shape. All
68:30 . Again, you're connected on both . So you can see there's our
68:34 canal and so you have what are the great composure that surrounds the central
68:38 that allows fibers to travel between the and right halves. Again, organizationally
68:47 were divided into regions we have an posterior and lateral horn. So up
68:53 . This would be posterior horn. here. This little area that kind
68:56 bumps out, that would be the horn in this area that sits down
69:00 the bottom. That would be the horn or the anterior horn. All
69:05 . Now, why do we All right. Other than that?
69:09 , we're anonymous and we like to at stuff and things. Well,
69:13 reason. All right. I pressed button. I did not.
69:21 Information that goes in to the spinal is always going to arrive via the
69:28 side. Don't you think about a ? If you've ever worked at a
69:32 , you have to move in and of the kitchen, There is a
69:35 that sits between the kitchen and the . You have one that allows you
69:39 go in, one that goes What happens if you go the wrong
69:44 ? Big crash, everyone in the collapse at you, right?
69:50 Now, that's not gonna happen in body. But what we're dealing with
69:54 is this organization. There's an indoor there's an outdoor. And so we're
69:58 going to talk about the indoor and outdoor just yet. That's going to
70:00 on thursday because it's a kind of cadence that we can go through.
70:05 you can see here on the dorsal , these are the fibers that are
70:08 in and on the ventral side. would be uh the where the fibers
70:12 going out or on the anterior This is where the fibers are going
70:17 . All right. So, coming in the dorsal horn, that's what
70:23 going to see the neurons that are information that is sensory, in other
70:31 , since your input coming this motor neurons are going out that
70:35 And so in here in that region that dorsal region, that's where we're
70:39 to see inter neurons and the cell of inter neurons that are receiving that
70:44 input. All right now, remember we said about white men and great
70:49 . White matter. Are axons, matter are cell bodies. Okay,
70:54 the cell bodies of those inner neurons there in that gray matter. All
70:59 . And then they're going to send information. If we're looking at that
71:02 , are they're going to send their to the fiber, the motor neuron
71:06 going to be leaving. So, this is sensory information, that's also
71:11 a Farrant neuron, you see how names are basically can grow in.
71:17 , a parent information goes to that . The cell body. That interneuron
71:21 up here in the dorsal region and going to send a small axon to
71:27 motor neuron or the parent that's part the pathway that's going to then leave
71:32 through that back door. So that body is going to be located in
71:37 the lateral horn or in the eventual anterior horn. Now, if it's
71:43 in the lateral horn, that neuron going to be autonomic. All
71:50 it's gonna go to the gut, to the internal organs. If it's
71:55 to a muscle it's going to be in the ventral horn. So the
72:00 are located in the ventral horn. this is why it becomes important to
72:05 what these things are. Notice. don't care where that since your information
72:11 coming from. If it's visceral needing from the gut or if it's somatic
72:17 from the surface or from a it just shows up in the
72:21 But the neurons whether their autonomic are to be in lateral or if they
72:26 somatic, they're going to be in . And that motor neuron then comes
72:30 and so now you have your reflex . Kind of pointing out here.
72:34 parent into neuron going to either the in the lateral somatic in the eventual
72:41 that motor neuron then travels via the . Was that confusing enough? It's
72:51 that confusing. There's three things in neuron autonomic somatic. I just made
72:58 more confusing because I like watching your go. Yeah, it really
73:06 All right. The meninges. Uh . The same as you saw in
73:13 around the brain. Right. We've learned them. There's the dura matter
73:16 on the outside underneath. That's arachnoid underneath that subpoena matter, all three
73:20 still there. All right. There's a couple of things that are a
73:24 bit unique. All right. So dura matter is single layered. It's
73:28 dual layered like we saw surrounding the . All right. It helps to
73:33 stability because it has these small ligaments are attached and you can actually see
73:38 there. There's a ligament. There's ligament and so it prevents the spinal
73:42 from wiggling around inside that little tiny . All right. The dura matter
73:50 extends beyond the spinal cord and then along with the spinal nerves for a
73:58 very short distance. All right. then it becomes connective tissue that then
74:03 the protective layers around the spinal nerves you're traveling down. And this will
74:10 more sense when we look at the picture as you're traveling along the length
74:13 the spinal cord. The spinal cord around L. two. Alright.
74:19 , to being the vertebrae lumbar All right. But the spinal nerves
74:24 going down and so the meninges continue follow those spinal nerves all the way
74:29 to about S. two. All . So you basically not only have
74:35 the full length of the spinal you're also going a little bit
74:40 All right. And so those again ligaments that are called the lenticular it
74:44 . All right. And basically they from the pia and they basically keep
74:48 spinal cord from jumping around as you . Oh, epidural space. You
74:52 see it here. It's all filled that. All right. So that
74:55 fat and veins basically packs that So it helps protect it. Here's
75:00 final slide. Yeah. So you see here this is the spinal
75:06 right? It's showing you with these that those are the spinal nerves.
75:13 exiting out in the space where the are okay Right here at L.
75:21 . That's the end of the spinal . The reason for that is your
75:25 grow faster than your nervous tissue And so when you're first born it's
75:29 the same length. But then as grow right, it grows slower so
75:34 gets shorter. So what you end with is a little tiny cone at
75:37 end of your spinal cord is called cones made delores. But we still
75:44 to make sure that that cord doesn't around. Like I said, I
75:49 have stuff that's not going to But if you can imagine a cord
75:53 if you moved, it would just and flip and stuff like that.
75:57 wouldn't be conducive to it. It cause damage to the cord. So
76:01 you have is you have a ligament basically it's not really a ligament,
76:06 basically a cord that travels down and is to the coccyx. The feeling
76:15 . Lastly you can see here these all these spinal nerves that need to
76:21 their final destination. If you look the base of the spinal cord,
76:26 looks like a horse's tail bunch of hair. Hence the name horses but
76:35 , got it backwards. But of horse, cada quanah. All
76:42 Two other things I want to point , Not really clear here, you
76:45 actually see it a little bit. a little bit faster there than it
76:47 there. You can see it's a bit fatter um right in here than
76:51 is everywhere else. Those enlargements are to as the cervical enlargement in the
76:56 sacral enlargement. This is where all spinal nerves from your appendages go in
77:00 that's what makes it bigger and thicker fatter in those particular locations. When
77:05 come back. We're going to have lot of fun talking about the spinal
77:09 , the organization of which is actually little complex. Uh huh.
77:16 Yeah. Yeah. Thank
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