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BIOL 2301 Human Anatomy & Physiology I - BIOL2301_lecture25_1128
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00:01 All right, good morning. Y'all like I'm finally wired up. You
00:07 have a good Thanksgiving. Did you lots of turkey or soy turkey or
00:14 or ham? Whatever. Um let's see if we can get this
00:20 up here. Today is our last . Oh, I like that.
00:26 you. Yeah. Yeah, you cheer too. It's, it's
00:29 It's like, hey, I'm finally with this guy. Um What we're
00:33 do is we're gonna talk about the nervous system but before we get started
00:37 things, remember we have a test Thursday. It's our last test.
00:40 you broke your, what did you ? Fell down? Like did you
00:43 down? Like like 20 ft? make up a good story. Just
00:47 yes, yes. Fell off the while doing lights. Yeah,
00:52 Didn't mean to point it out but just saw it. Um It's
00:56 We have a test on Thursday. this is I call it final
00:59 That's just a word that comes out my. It is our last
01:02 So it just covers the material uh this unit. It's there is no
01:06 super exam. No uh exam that every thing. This is, that's
01:11 . All right. Um So that's and then we have an extra credit
01:16 uh due before that. All So that extra credit, normally we
01:19 a pre exam, extra credit and post exam, extra credit,
01:22 There is no post exam, extra because we don't open up that last
01:26 . Um So the pre exam, you might want to write this down
01:29 pre exam, extra credit counts, , it counts as both of
01:32 So you get double the points. make sure you get it done.
01:36 open up again Wednesday at six. closes at 9 a.m. on Thursday,
01:42 like it normally does, but it's double. So that's why I'm making
01:47 announcement. All right. So with in mind, what we're gonna do
01:50 we're gonna go in and we're gonna with our last subject for the for
01:53 unit. It's something I've been talking probably since the second one, which
01:56 the autonomic nervous system. It was , oh yeah, autonomic nervous system
02:00 . So this is what we're gonna dealing with. And what you're looking
02:02 in this picture here is the organization the peripheral nervous system. All right
02:08 , just to kind of put this perspective. If you say nervous
02:11 we have the central nervous system, ? Which is your brain and spinal
02:15 , then we have your peripheral nervous , which is everything else. All
02:19 . So what we're looking at is looking at that organization and said,
02:23 , we've already talked about, we , hey, uh in the peripheral
02:25 system, we have motor neurons, are the nerves that travel down to
02:30 muscles and glands and make them do . And then we have information coming
02:34 the central nervous system. Those are sensory neurons. And what you can
02:38 is you can take this motor uh , you can divide it into two
02:42 . There's the compartment or the portion the nervous system that we have voluntary
02:48 over. All right. So when wave, when you blink, when
02:52 uh you know, hold your this is, this is what we
02:56 to as somatic. These are the muscles that we control. Ok.
03:00 it's voluntary, but we have another which is the autonomic and this is
03:06 stuff that we can't voluntarily control. functions independent of conscious thought. And
03:13 fact, you have no conscious control it, right? And an example
03:19 put would be like your heartbeat, cannot control your heartbeat, you can't
03:24 it up, you can't slow it by sheer will. Now, if
03:28 want to increase your heart rate, can you do? You can run
03:31 and down the stairs really quickly and heart rate will go up. So
03:34 that this system is not a function you actually controlling it, but it
03:40 to environmental input to determine activity. right. So autonomic deals with the
03:49 , all right. And then what can do with the autonomic is we
03:52 divide that into two different components. we refer to as the sympathetic and
03:57 we refer to as the parasympathetic and easiest way to think of these is
04:02 acts as a gas, one acts a break. Caveat. One doesn't
04:08 act as the gas, one doesn't act as the break. Instead,
04:14 particular circumstances, one will behave as gas, one will behave as the
04:19 when you're looking at that particular So for example, if you ran
04:24 the stairs and ran back down, it again, in this particular
04:29 the sympathetic would be acting as a pedal to increase your uh heart rate
04:34 increase your respiratory rate and you would regulate the parasympathetic when you are eating
04:41 . On the other hand, the acts as a gas and your sympathetic
04:47 act as the break. All So the idea here is I'm going
04:51 increase the digestive process. So that's the parasympathetic is acting as a gas
04:57 . All right. So you can't say sympathetic is always gas. You
05:01 always say parasympathetic is always break because circumstantial depending upon which uh kind of
05:07 you're looking at. All right. what we do is we can divide
05:10 up and say, all right, regard to the sympathetic, what we
05:14 is we call that more or less fight or flight system. So,
05:18 sympathetic is gonna be activated under the of your life, excitement exercise.
05:26 I'm blanking all of them. uh energy usage emergency. Thank
05:32 That's the last one. Good. , people take classes and learn these
05:36 and I forget them because reasons. right, in terms of the
05:41 we think of it more as the . So it's a rest and digest
05:45 idea of when I'm sitting around eating bowl popcorn, watching a movie by
05:50 is dominating. All right, and gonna go into, you know,
05:54 in terms of what they're doing and they're doing it. But that kind
05:58 a, a brief general overview. right. And so uh in terms
06:03 what they're actually controlling would help if actually turn this on. Uh somatic
06:10 gonna always be skeletal whereas autonomic is to be homeostatic. So gland smooth
06:16 , cardiac muscle. All right. that's the easiest way to kind of
06:21 that down. If I'm thinking about I can control, it gotta be
06:24 . If it's something I can't it's autonomic. All right.
06:29 I wanna be clear here. You gonna confuse sometimes. Thank that are
06:36 with autonomic. Like for example, breathing is regulated through the autonomic nervous
06:42 in other words, your respiratory Yes. Right. Because you don't
06:46 to think about your breathing. But you hold your breath? Uh
06:50 Yeah, you can, can you yourself? Yes. All right.
06:56 , notice that what we have here we have a system governing something that
07:01 somatic in nature, but it's the that regulates it does that kind of
07:06 sense. All right. But there things that are clearly autonomic,
07:11 I mean, so like, can you say digest faster or slower
07:16 ? So, work harder, you know, that doesn't happen.
07:21 right. So with that in we're gonna look here at the
07:26 Now, there are gonna be some here in terms of the anatomy are
07:30 be kind of scary when I sat your seats saw it the first time
07:33 went, ah, and I freaked and I said, I'm not gonna
07:35 this. Put my fingers in my , covered my eyes and said,
07:38 , no, no, I All right. Not that hard.
07:40 really is actually a lot more easier it's, than it's gonna appear.
07:44 right. But the nice thing about is because we're dealing with the system
07:47 is this or that all we gotta is do a lot of the comparisons
07:52 versus that. All right. So kind of the idea. And so
07:55 is kind of a comparison between the or sorry, the, the autonomic
08:01 the somatic. All right. And not gonna have you memorize this,
08:04 it's an easy way if you ever of get lost. Say,
08:06 let me go back. You can a look at these differences. Like
08:10 muscles versus, oh, yeah. the other smooth and cardiac and
08:14 Ok. That's easy. Oh, about the neurotransmitters? Yeah.
08:17 neurotransmitter. I'm always using Aceto colon the somatic in the autonomic. I've
08:22 a new uh group of tran neurotransmitters . We're gonna see about these receptors
08:27 stuff a little bit later. But is just kind of a, a
08:30 little chart to do this comparison. here is a kind of a visual
08:35 comparing the somatic versus the autonomic. right. And so we're going to
08:40 into this here in the next slide , and moving on. But you
08:43 see here like in the somatic, am I innervating skeletal muscles in the
08:48 ? What am I innervating? I'm smooth muscles. I'm innervating cardiac
08:53 I'm innervating the glands, you structures that play a role in maintaining
08:59 function as opposed to movement. All , or locomotion. But our first
09:06 , our first thing I want to out here in terms of interesting things
09:10 the autonomic nervous system is its motor . All right. So in terms
09:15 what is it innervating when it When we saw the somatic, we
09:19 we have this neuron that's leaving the cord and it travels out to our
09:25 and innervates it directly. We call the lower motor neuron. I'll remember
09:29 . Right. Everyone should nod their and said, of course, Turkey
09:32 affect my thinking at all. Now, we're starting to get a
09:39 of little tiny knots. All With the autonomic nervous system, the
09:43 thing that stands out and makes it to go. Oh, if I'm
09:48 in a body because you will have do this at some point in your
09:51 . And you're like, oh, a neuron that terminates on another neuron
09:54 goes on, that is probably So here are, we don't have
09:58 single neuron, we have a two chain and so we have nomenclature for
10:03 . The first neuron leaving the spinal is called the pre ganglionic neuron.
10:08 it's called preganglionic because it synapses with second neuron in a structure called a
10:15 . So that one's preganglionic, the coming out of the gang on is
10:21 and then that goes on to innervate structure. And so it doesn't matter
10:25 you're sympathetic or parasympathetic, we're gonna these two neuron chains leaving the central
10:31 system going on to the structure of . All right, easy enough.
10:39 , in terms of the subdivisions, do we have here? Well,
10:42 already mentioned fight or flight. exertion, excitement, emergency. This
10:48 when the sympathetic is gonna be So I want you to picture
10:52 you know, Shasta, right. talking the, the, the cute
10:55 cuddly guy, uh, mascot, , in the uniform at the football
11:00 the basketball game. I'm talking about actual animal down at the zoo.
11:03 right. That's just, uh, number anyone know, seven is
11:08 Shasta? Seven. Y have you guys wondered why this is our
11:12 Do you know why? This is right? I'm just gonna tell you
11:16 little thing. You should know a bit about your history as a
11:19 You notice that in Texas, every has some sort of hand thing,
11:22 ? Like the Aggies Longhorns and the , you know, and there's some
11:27 , right? We got the we got SMU, we got the
11:30 frogs. Baylor. Did you? , no, you don't.
11:34 All right. So why this All right. So we used to
11:37 Shasta on campus back in the This is what you used to do
11:41 in the fifties and sixties. And earlier, you had your mascot live
11:45 lived on campus. You could go at it and make it angry.
11:49 sorts of stuff. Don't ever do to the Cougar, right? But
11:52 a football game, Shasta or prior the game or at the game,
11:56 don't remember. It got its paw in the cage and they had to
12:01 and amputate that off. And so Longhorns whom we happened to be playing
12:05 week or whatever, started making fun us going, ha ha ha ha
12:09 . So we picked that up and is now our symbol. All
12:13 That is where we get that Cougar because, and if you go,
12:17 at the statues, right, the like in front of the stadium go
12:20 look, it's missing that claw or , that finger that, that Bay
12:27 . All right. Anyway, imagine Shasta now, Shasta is, is
12:33 wild animal and Shasta, if it you in its cage, it wouldn't
12:37 . Oh, I want to cuddle you. Wild animals don't do
12:40 Wild animals. Wonder what you taste . And so Shasta would come at
12:45 and now you have two choices. , you have three choices. You
12:48 fall on the ground, cover up cry. I don't think anyone would
12:52 that. You'd die because the bite of a cougar is pretty, pretty
12:58 . What's another thing you could I'm gonna fight this stupid cat.
13:03 not probably a good idea. And the third thing you can do?
13:07 ? All right. So that's why call it fight or flight. All
13:10 . So, fight or flight system really, really simple. I'm going
13:14 alert my body, wake my body I can respond to some sort of
13:19 . Some, something in terms of . So, what am I
13:22 I might be increasing heart rate, rate, I'm increasing blood flow to
13:26 the muscles work. That includes the muscle, I'm going to sweat because
13:31 my body is burning energy quickly and really, really inefficient in terms of
13:35 uh uh production. So we're going produce a lot of heat. So
13:38 need to get that heat away from body to prevent ourselves from cooking and
13:42 . All right, there's a couple other things involved there, but that's
13:45 real simple way to think about sympathetic regard to parasympathetic. I was always
13:50 rest and digest. Apparently that was through the other one, feed and
13:53 whatever. Um So what are we with here? This is anything that
13:59 a role in maintaining uh bodily function energy conservation in a very generic
14:05 So you'll see this sometimes slood lacrim urination, defecation. So basically
14:12 the things oozing out of your Um One way or the other,
14:16 going to counter what sympathetic is. , if this is increasing heart
14:20 this decreases heart rate and blood All right, what it's gonna do
14:24 it's going to increase the uh the of materials into the digestive tract.
14:30 that's promoting the digestion. And let ask anyone ever tried to run after
14:35 a large meal, like, you , it's like, oh, I'm
14:37 go eat something big and then it's , no, I'm gonna go run
14:40 . And it's like it doesn't does it? You feel terrible?
14:43 . Because what you have now is have the two systems fighting each
14:46 Right. And so that's the idea we're going to primarily deal with things
14:51 are gonna be playing a role in digestion process, getting rid of waste
14:55 actually even sexual arousal, it's sympathetic a role in that, but we're
14:59 gonna go into it. Um, your body is predominantly being um under
15:05 control of parasympathetic. And like I , you can think about this a
15:09 or break. All right. What don't have here is a system that
15:14 100% in either case. All All right. In other words,
15:19 you're doing is you're kind of bouncing the two systems like this. All
15:23 . So sometimes what you'll do is move a little bit more towards parasympathetic
15:28 you'll probably stay there more often, then you'll switch over to a little
15:31 of pa uh sympathetic. Only rarely you really dip one way or the
15:36 more than the other? Ok. you're really kind of bouncing very,
15:40 close to the line. So, right now, what are you guys
15:44 parasympathetic? Yep. Ok. And I told you, you have a
15:49 right now and it's worth 100% of grade, what would happen just quickly
15:56 over to the sympathetic, right? you noticed that when you watch
16:00 you actually do that as well. , if you, like, if
16:02 like a scary mo movie person that like parasympathetic, sympathetic and then you
16:06 yourself back, sympathetic, back and . Yeah. All right. So
16:12 gonna move into the anatomy now. right. Um, and then we'll
16:17 back a little bit more to, , regulation here. All right.
16:20 this is like a big long list the differences between para or parasympathetic and
16:26 . So the first thing I'd point here is in terms of where these
16:31 cell bodies are going to be We're going to see this more in
16:34 next uh pictures. All right. the idea here is the parasympathetic and
16:39 are divided from where they exit out the spinal cord. All right.
16:44 really the parasympathetic isn't just spinal So the way that you can think
16:48 this is the parasympathetic is head and . All right, it exits out
16:55 the cranial nerves or the sacral nerves the sp coming out of the spinal
16:59 . So head and butt. So two regions there and then the sympathetic
17:04 the region in between. It's basically your back. So thoracic and
17:09 all right. And so even though going to see some cervical stuff coming
17:13 , you're really not exiting out of cervical region, you're coming out of
17:16 thoracic or the lumbar region. So the first thing is so how they
17:20 out of the central nervous system is distinct between the two in terms of
17:26 length of their preganglionic fibers. So said we have these two fibers.
17:31 sympathetic, has very, very short fibers. All right. So what
17:37 gonna see here in just a moment if you have your spinal cord
17:40 the ganglia for the sympathetic nervous system located right next to the spinal
17:46 So you leave the spinal cord and go right out to that ganglia,
17:49 right there. But when you're like about the parasympathetic, they leave the
17:55 region or the sacral region, they some distance away. And then the
18:00 for those uh uh parasympathetic fibers are near or in the organs that they're
18:07 . So they are very, very , so very short, sympathetic,
18:13 long parasympathetic. And so then the would be true. The post ganglionic
18:18 would be long versus short if that sense, sympathetic with long post ganglionic
18:24 , um the uh parasympathetic, very post gangly fibers in terms of where
18:31 locations of those ganglia are. I've just mentioned that mentioned this one as
18:35 . So these three things just kind go together and you can use this
18:38 a visual to help remind you of that looks like. The other two
18:43 here, we're talking about the number pre ganglionic branches. And so with
18:47 to the parasympathetic, you don't see lot of branching. And so preganglionic
18:52 goes in, it doesn't have a of branches to go to a lot
18:56 post ganglionic fibers. It's usually fairly anywhere between one and four. So
19:00 that means is is that the pre singles are very localized, they're going
19:05 a very specific location to act on very specific place. In contrast,
19:11 sympathetic branches quite a bit, there's and lots of branches. And so
19:16 will happen is that a sympathetic signal to a lot of different places?
19:21 right, on top of that, enforced by something that is more endocrine
19:27 nature. And we're going to talk that at the very end of
19:30 And so when you see a sympathetic , it's rather widespread, right?
19:35 think about when you run or exercise whatever what happens, your breathing goes
19:42 , your heart rate goes up, start sweating, your eyes, start
19:48 . There's all these different things that simultaneously, whereas the parasympathetic goes
19:53 we're going to turn that off and we're going to turn that off and
19:56 we're going to turn that on, know, so it's, it's very
20:02 . And so the reason for that again, with the sympathetic response,
20:05 dealing with things that may be And so we don't have time to
20:11 about what your, you know, brain to think about what it needs
20:14 turn on in the case of the again, you run into Shasta,
20:18 walking down things. Shasta shows Do you want your body to
20:22 Oh, I don't know. Do need to open up the blood vessels
20:24 the legs? No, you just it to go. You don't want
20:29 have to pick and choose. You to just be ready for that response
20:33 then as you turn things off, OK to turn things off as you
20:37 need them. Why it's more localized parasympathetic? Alright. So here's the
20:47 news, parasympathetic as I mentioned is straightforward and this picture just kind of
20:52 that um and I'm showing here just the purposes of balance the types of
20:58 that are involved here. So here can see these are your cranial nerves
21:02 so these cranial nerves specifically are parasympathetic nature. I've mentioned the vagus nerve
21:08 the really important one already. Because it innervates all your viscera.
21:13 it's the one talking to the heart the lungs and the stomach and the
21:18 intestines and the small intestines and, , and, and it's someone's regulating
21:24 going on inside that viscera. But can see up here, we have
21:28 the cranial nerves that are going to eyes, cranial nerves, going to
21:32 nose, cranial nerves, going to glands of the mouth. They're playing
21:35 a role in activating these systems when . All right. So their outflow
21:43 through the crane, right? And down here we have the sacral outflows
21:50 these are what are uh referred to the uh splanchnic nerves. And so
21:55 gonna see sp planktonic used twice. so there's, it's part of it
21:59 digestion, but notice we're dealing with , we're dealing with uh the reproductive
22:04 . So, really, the things in our viscera are being regulated through
22:08 sacral nerves, but everything else is the cranium. Nothing's coming out of
22:13 spinal cord anywhere else. All So there's the anatomy for parasympathetic,
22:18 straightforward. Heads and butts. This where it gets complicated. Isn't the
22:25 ? All right, it's a lot complicated. Not just because reasons.
22:31 , I mean, so they're all and lumbar. So you can see
22:35 thoracic and lumbar. But what we're do is we're going to have these
22:40 fibers going in different directions and any that you're gonna see sympathetic, you're
22:46 see parasympathetic or vice versa. With exception. All right, I'm just
22:50 tell you the one exception, I'm gonna ask you about it. The
22:53 exception to that rule is your blood . All right. It only is
22:57 innervated and I don't know why the decided to go that way. It
23:01 is. All right. So, else in the body, if you
23:04 sympathetic, you're gonna have parasympathetic or versa. With that one exception.
23:09 so what you can see here is off, you can see just
23:14 we have this sympathetic ganglionic trunk. basically a stack of ganglia that sit
23:20 outside that um that spinal cord. right. Generally speaking, when a
23:26 nerve nerve leaves, there's going to a ganglion just outside that particular
23:32 Now, you can see up we have some uh uh ganglia up
23:36 . These are called the cervical ganglia they coincide with the cervical region of
23:40 spinal cord, but they're getting their from the thoracic region. And here
23:45 can see we have these lumbar located ganglia and they're getting theirs from the
23:52 thoracic and lumbar regions. So we're getting spinal nerves down there or up
23:56 . They're all coming out primarily through one, through L two. All
24:01 . Uh What did I also want mention here? Oh, so in
24:06 of what a spinal nerve can do , what a sympathetic fiber can
24:10 So we're just talking about the preganglionic preganglionic fiber can go in and then
24:17 uh uh synapse with some sort of and then travel out. I'm gonna
24:21 about each of these in turn, that's a really generic thing,
24:24 If I have a pre gang on post, post gang on it,
24:26 can go in, I can synapse I can move right out. So
24:30 my preganglionic there would be my Another thing I can do is I
24:33 go in and then I can travel and I can send apps or I
24:37 go in and travel down and send . All right. And then that's
24:42 moves on. All right. But third thing I can do, which
24:46 it really weird and makes it, think a little bit more complicated is
24:51 , and the artist did not do good job here is that I can
24:55 in without synapses and I can keep going and I can go out to
24:59 Gang Leon that sits way out All right. And we're gonna look
25:03 at each of these in turn because have specific terminology that goes with
25:08 But the first one is the easiest like, all right, I've already
25:11 pre game and post game. So go in, I turn, I
25:14 and I just move out. That's too hard. All right. Second
25:17 is not so hard. I go and instead of synapses there, I
25:20 go up or I can go All right. That's not too
25:22 And then I go out. But third one that doesn't follow the convention
25:26 we've already learned, it goes in passes through and go on over here
25:30 another gangland. And so this type anatomy stands out in contrast to something
25:38 simple, doesn't it? That's really right there. OK. So I
25:42 want you to be panicking like I , I don't want you to
25:44 I'm not gonna learn, just put fingers in my ears and cover my
25:48 . All right. I did that with the kidney. All right.
25:51 just gonna let you know kidney is do the same thing to it when
25:53 taking a MP two. Don't Just say, OK, it took
25:57 Wayne four years to figure this I can do it in one because
26:00 not as hard. All right, tell 40 years cause I took human
26:04 so many times. All right. here we have something that you already
26:10 about. All right. So here our spinal cord, right. Here
26:16 our ventral root. There's our dorsal . So we're talking about a uh
26:21 that's gonna originate out here in the horn because we're talking about the autonomic
26:26 system, right? So, motor autonomic are always going to be in
26:29 lateral horn. It's gonna exit out the ventral root. And what it's
26:33 do is the first place that you see is we're gonna see these
26:37 my communic cans. Now remember when talked about this, we said spinal
26:40 to the root, let's root, do root, root to spinal
26:43 And then we said the spinal nerve into three branches. We had the
26:47 rami which goes to your back, ventral ramus which we spent all those
26:51 talking about the plexuses and stuff like . And we said there's that third
26:53 which we're ignoring for today. But is today. All right, this
26:59 thing right here. So you can there's the dorsal, that's the
27:02 those two little things right. There the ray, my communic cans.
27:05 are like an in and an outdoor the spinal ganglia. All right.
27:11 other words to the sympathetic ganglionic All right. So we have one
27:16 called white, one that's called white is called white because the fibers
27:21 are going in are myelinated. And it looks white, right? Whenever
27:26 have myelin that's fatty. And that gives it a white appearance. So
27:32 is the pre gang fibers. They're into our sympathetic ganglia. All
27:39 So that's our indoor. Always, , always white is in. Have
27:44 ever been to a restaurant where they an indoor and outdoor? Yeah.
27:48 . Have you ever seen, someone carrying the tray through the wrong
27:53 ? You've probably heard it because usually , they're going through the wrong door
27:57 someone hits them, they've dropped the and then you hear the shattering of
28:01 glass and some jerk, usually claps a good job. You know,
28:05 what that, that's why there's an , there's an outdoor. You want
28:08 to go in a particular direction. white will always be going in gray
28:14 the post GF, so gray is the outdoor. Right. You think
28:19 your sy sympathetic ganglia and grays Pretty good, pretty easy. All
28:28 . Yeah. The other type we're to
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