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BIOL 2301 Human Anatomy & Physiology I - 2301_lecture23_1123
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00:06 although you haven't gotten your ice cream . Thank the classmates in the group
00:11 who turned that in. Yeah good guys. Um And for that you
00:17 gotten any come and get some. mean come on it's ice cream all
00:21 it's going to melt. And then be sad and we'll all be sad
00:25 we wasted ice cream. So a of guys went to a football game
00:30 be fine. Yeah. Yeah. know football is like life. You've
00:34 highs, you've got lows and then the half you come out and you
00:38 play and then you come back and quarter and you start playing again.
00:42 So that was the last game of season. So last home game we
00:46 against UConn and then against Cincinnati. we'll win out. I'm kind of
00:52 between the Cincinnati game right? I I want us to beat Cincinnati because
00:57 right? But if Cincinnati wins then have a better chance of screwing with
01:01 C. F. P. Which like my lifelong goal. I'm really
01:07 . I've never ever liked the football that we've that we've done ever
01:13 Well 1998 when my my college went . That was like the second year
01:18 the BCS. There are two other undefeated teams at the time. It
01:22 Tennessee and I think it was C. L. A. And
01:26 had all had a common opponent and all the teams to lane beat them
01:31 most and we were completely ignored and was of course it means to line
01:36 , you know? And so that's I first really got angry about the
01:39 thing and ever since then I've held personal grudge against the BCS, the
01:44 F P. O. Yeah, mean if I could, I'd hunt
01:46 people down and punch him in the , but since I can't do
01:51 what we're gonna do today is we're to talk about motor pathways and really
01:55 the gist of this lecture is is how do we send signals from our
01:59 down to our muscles? All And it's not just the muscles that
02:03 can think about controlling, but also that are under involuntary control, the
02:07 that are beyond just conscious thought. so, so when we look at
02:13 , just kind of think in terms , okay, how do I move
02:16 is really what this this lecture is about. And it's, you
02:21 sometimes when you look at this I promised I wouldn't do this,
02:23 I'm just gonna do it anyway. you look at the stuff it's kind
02:25 like, but don't do that. . Because really what it boils down
02:30 is is this right here, is there's a general pathway, All
02:35 These are all polly synaptic, there's general pathways that you can understand and
02:40 you understand the nomenclature then it just of falls into place and especially at
02:44 level, the freshman level where we have to actually track everything and identify
02:48 everything is going. Just kind of what each of these individual tracks are
02:53 and where they go. That's that's all. That's where does it start
02:56 ? Where does it go too? right. And what does it
02:59 So it's actually a lot easier than he presented. So I probably could
03:03 done to lecture in like six minutes then we can just go out and
03:05 out of here and eat our ice . But if I did that,
03:08 you'd be really mad because you paid lot of money to take this
03:11 So we don't do that. So I want to point out here
03:15 we're talking about motor pathways, what do is conscious skeletal muscle and autonomic
03:21 . Alright. So remember autonomic contraction be somatic in other words, it
03:26 be a muscle that you have conscious of. Right? So if I
03:31 your knee, right? You do the thing, you get that
03:34 reflex. That's an autonomic response. ? So that's kind of what we're
03:39 about. So posture, balanced muscle is what we're talking about turning
03:44 So the muscle tone, that's not you think about all day long,
03:49 ? It just is right, posture balance is not something you think
03:54 It just is, right? So what we're trying to get to
03:59 All right. So what do we the general path we're gonna start up
04:02 the cerebral cortex or the brain And it's going to be easy to
04:06 which ones which. All right. gonna travel down the length of the
04:10 cord and they're going to innovate a or a gland. All right.
04:14 that's the idea. All right, . Forget when you press one
04:21 it changes to that. All So all motor pathways All right.
04:27 going to get input from the basal in from the cerebellum. Remember these
04:31 the planning centers and we're going to at these planning centers and see how
04:34 make this thing really complicated looking but going to kind of take that step
04:38 and just say yeah, these other are involved, 2ndly. They're always
04:43 always always Well, there's probably some . There's always an exception but for
04:49 purposes is always to neuron chains. right. Which is kind of nice
04:54 remember what we're talking about century. said there was 123 chains up.
04:58 ? And now we're dealing with And so I have to change is
05:02 simple. We have one that's upper . That's lower. All right.
05:05 that makes it kind of easy. like all right. So I just
05:07 to know where the upper is the basically begins along in the cerebral cortex
05:12 in the brain stem and then it down into rates? Um the lower
05:18 neuron which then goes on to the . That's kind of easy. And
05:23 pathways are either going to be director . Those are the terms that they
05:27 doesn't mean that I'm going directly to or indirectly. Although it kind of
05:31 . But that's the terminology they The one is called the direct
05:34 One is called the indirect and then some sub pathways in with within.
05:39 we're gonna start with the lower motor and the lower motor neuron is going
05:44 be found in that ventral horn. ? So we're going to be uh
05:49 going to exit from the spinal We're gonna travel out the ventral we're
05:53 to move to the muscle and then going to be one of two different
05:58 of fibers. It's gonna be an motor neuron or a gamma motor
06:02 All right. Now, there's something the slide that is going to be
06:06 to read. And I want to it so that you're not horribly
06:10 Alpha. Simple. All right. you're looking at a muscle structure,
06:14 you're going to see is that the itself is actually divided into two
06:18 You have fibers that are found on outside of the structure and inside you
06:23 this kind of specialized capsule that has on the inside. We've talked about
06:29 before. We call these the extra cell muscles and then inside we have
06:33 interview cell muscles. All right. so it's a unit that looks at
06:37 degree of stretch. So the outer extra Feustel muscles are the muscles that
06:42 being used. And so when you you're stretching them or when you cause
06:46 to them, the muscles on the are moving and the muscle on the
06:50 is moving in response to the alpha the gamma. All right. ALF
06:54 the outside game on the inside. it's that inside interview cell muscle that
06:59 also have sensory fibers that are associated it. That you're looking at the
07:03 of stretch. The stretch is too . Then the muscle contracts um to
07:09 oppose that overstretching. And so, you're doing is you're you're changing the
07:15 of stretch in response to two little stretch or too much stretch. But
07:19 measuring inside in that interview cell All right. And so when you
07:24 the word motor neuron, remember that's sending a signal to cause contraction.
07:30 right. So lower motor neurons are always always, always no exceptions to
07:37 rules excitatory. So, that means you're contracting a muscle you have to
07:43 a signal to it if you want stop contracting a muscle, you stop
07:48 the signal to it. All The alphas are the ones on the
07:52 , the gammas are innovating on the . And what they're doing is that
07:57 . So, this is where the part. It says innovating interventional skeletal
08:01 which serve as appropriate receptors. So is the is the problem. It's
08:05 bad proposition that I used right? I'm not an english major,
08:11 So the witch is applying here to muscle fiber. Alright. The skeletal
08:16 fiber service appropriate receptor, not the motor neuron. Okay, the motor
08:23 sin signals. So it's not acting a receiving is not acting as a
08:29 . The muscle fiber is acting as sensory. All right. And so
08:33 the muscle fibers that detect the degree stretching the muscle. I had to
08:38 that because when I read it this , like, oh good.
08:41 I was just screwed it all up everybody. Okay, so lower motor
08:47 innovate muscles and cause them to contract excite them, cause them to
08:54 Okay, so they begin in the cord in the ventral horn and that's
09:00 they travel. All right now we've about this, but I'm going to
09:08 going to reiterate a couple points that already learned just so that they stick
09:12 . First off the organization of the matter. Alright, so down here
09:18 the ventral horn, in the lateral are going to be exhibiting some a
09:24 and remember what summon utopia. Is basically demonstrates the proximity or the location
09:30 where a neuron enters into the gray . So, if this is trying
09:36 show look for medial collateral, you basically say, okay, immediately by
09:42 the neurons are higher up than what's here laterally, which would be lowered
09:48 more distal to the body. All . And so again, it's not
09:52 this strange. Just jam in these and hopefully they'll they'll eventually end up
09:58 they need to go. There's a degree of organization to all this
10:01 which is really, really beneficial because means that we can learn what that
10:06 is so that we can then learn the fibers are coming in. Going
10:10 the second thing is that every motor in the body is going to be
10:16 of this organization. And what is motor unit? Well, remember,
10:19 that alpha motor neuron and all the that that alpha motor neuron innovates.
10:24 , again, this is just a of us really understanding when we talked
10:28 back then about muscle fibers, What they do? All right. They
10:34 part of a muscle fiber goes in innovates a whole bunch of different
10:37 And then those fibers contract in response a single signal coming down. All
10:42 . And so again, not that picture is going to demonstrate this in
10:46 way, shape or form, that never clustered. So it's like they're
10:49 spread around the muscles so that you disperse the force so the muscles can
10:54 evenly. Now with that in mind that the lower motor neuron is one
11:02 innovates then we got to get down that lower one. This is where
11:06 upper motor neuron is. And for of you who are late there's ice
11:09 . So, if you want to down and get some you can that
11:11 me. I'm not gonna take any for this awesome classmates. All
11:17 Yeah. So anyway, So what the motor neuron basically it's going to
11:22 the cell body is gonna be located the cerebral cortex. This is a
11:26 picture. Not for you to but just to demonstrate. We talked
11:29 this said, look cortex, organizer six layers And I said previously that
11:33 layers have different sizes depending on where located. And this is just kind
11:37 showing you that. And so here we're looking at is we're going to
11:41 in layer five. And these are sells. I'm not going to ask
11:43 remember Betz cells? I've never called about selling my life. But these
11:47 the pyramidal cells that are in the cortex and the motor cortex that basically
11:53 a role as the upper motor All right. And you can
11:58 you know here in the primary motor that's a really thick area. So
12:02 doing a lot of processing in that region. All right. Now,
12:06 they're going to do is the motor for the most part are gonna deck
12:11 state at some point when they're going to that lower motor neuron. Most
12:17 them deca state. All right. you can think I'm starting on one
12:21 and then at some point I have cross over so I can do the
12:24 side of the body. All They're gonna directly synapse with the lower
12:29 neuron or on some sort of interneuron gonna synapse directly. You're like wait
12:34 second. That sounds like three motor chain. There are some exceptions to
12:38 rules. All right. So primarily the lower motor, so it's upper
12:42 lower and then in some very small there might be an interneuron in there
12:47 well. All right. Now, what we said with the lower the
12:51 is always always always always under no . Is there any thing? They're
12:57 excitatory? Okay. Now this might help you understand the interneuron part.
13:05 uppers can be excitatory or inhibitory. right. So if a lower motor
13:12 is always excited tori and always causes . I can have an upper come
13:17 and basically prevent a lower from becoming . All right. So think about
13:24 muscles, right, antagonistic muscles or muscles that oppose one another. If
13:28 causing one to contract what I want have the other one. Do
13:34 All right. So what I can is I can send an excitatory signal
13:40 to the one that causes the But I can send an inhibitory signal
13:45 the one that would oppose it. I'm causing relaxation and preventing it from
13:51 . So that's why you get that excitation and inhibition at the same
13:59 All right. So where in the cortex do we regulate? Where do
14:07 upper neurons come from? Well, first is the primary motor cortex.
14:11 called M1. This is where we the conscious control of voluntary movement.
14:16 want to move my hand so I'm moving my well, I should do
14:20 this way. That's moving my It's doing something like that,
14:23 All right. And so here you see here, is that some of
14:26 typical organization, Right? That's that it doesn't exactly match the body,
14:31 you can see there's organization for the in the trunk or the trunk and
14:36 axis. And then when you get to the face and head, it's
14:40 of swapped all around and kind of . All right. So what we're
14:44 is that there are specific areas that responsible for controlling specific muscles. Um
14:49 there is a certain degree of plasticity . So, for example, if
14:53 were to lose your limb um then going to be, you know,
14:57 areas are going to shrink down as areas compensate and start learning how to
15:04 around that limb. And so you're to see areas kind of shrink and
15:07 depending upon need is the idea in of plasticity. They're going to make
15:13 . Yeah. Okay. Just in of the motor cortex. The primary
15:19 cortex is here in the pre central . Alright, so just in front
15:24 that, the yellow area is called pre motor cortex. So it sits
15:28 front of it. Right. And this is where you're going to have
15:32 some other types of pure middle cells do play a role in regulating.
15:37 typically what it does is it's going work with the primary motor cortex to
15:43 movement. All right. So what doing is we're initiating the impulses um
15:48 then six sending signals up to the motor cortex. The idea is I'm
15:52 to initiate what we think we want do and tell the motor cortex what
15:56 do? Motor memory. You guys motor memory. Yeah, you
16:01 I mean the easy one since I'm at a bunch of people with laptops
16:04 if you close your eyes, put fingers on the two keys that had
16:07 little bumps on there. You can without looking, couldn't you?
16:11 No old people like me can't. . I'm a hunting pecker. You
16:17 , I cannot pick fast. You ? All right. That doesn't work
16:24 you. What's another motor running where guys have riding a bike? What
16:27 have instruments? Right? Playing Yeah, I have a dance shuffling
16:35 . Okay, good. I like one. That's a new one no
16:38 ever offered. Yeah, taking a of cards and shuffling it. How
16:41 over here? What do you guys some other memory? Yeah.
16:48 yeah, you can't whistle. I actually uh for those of you just
16:53 that. I mean, what did just play? Yeah, super Mario
17:01 . Mhm. Uh Those those those evil evil video games, I just
17:06 here. No, I didn't. . No, I mean, so
17:09 mean, whenever I hear that, can I can I could literally play
17:12 first level of super Mario brothers without . Yeah, the the I
17:22 I played so many times. I even have to look at it.
17:25 just muscle memory, Right? And are games that we all play like
17:31 , right? You know, there's , basketball, soccer, right,
17:38 , dancing, diving, as we , musical instruments. These are muscle
17:42 all right. The other thing that , it controls muscle movement in terms
17:47 context I have here. The way the high five. I put my
17:50 up, that's a wave that's also five. So my brain knows what
17:57 do in context because of what the motor cortex tells us we're going to
18:02 . This is the situation where you to do this, right? As
18:06 to doing this, That makes All right. Also it plays a
18:12 in movements to visual and auditory All right, now, again this
18:17 not reflexive, right? But this the idea of like when I see
18:21 . This is what I'm supposed to , Right? So that's the idea
18:26 their response to visual or something. right. I'm not going to call
18:30 guys out. But have you ever uh like a drill team?
18:35 I mean, whether it be the team in high school, you
18:38 you know, doing that or maybe just a military drill team,
18:42 Just watch them. I mean, incredible what they do there. It's
18:46 all sound cues. They know when supposed to do whatever they're supposed to
18:50 and they practice practice practice. So they have to do is hear the
18:54 and they know where they need to . Right? All right, now
19:00 it's not just sending signals to the motor cortex. It can send signals
19:04 the spinal cord to initiate activity, it does talk to the pre motor
19:11 are sorry, the primary motor Alright, Association cortex is remember are
19:16 for taking information processing and sending it so that we can understand it.
19:21 right. So here there's two different cortex is that becomes more important.
19:27 prefrontal cortex uh places place an important on both the pre motor and the
19:33 cortex and what it does is it ensures that the muscle movement behavior that
19:38 doing is appropriate for whatever it is you're doing right now? I
19:42 we can we can have fun with . But I mean, the idea
19:44 I'm not going to raise my hand I'm trying to move my foot,
19:48 ? I want to walk. I raise my hand up. I move
19:50 foot forward. It would be an of that. All right. And
19:54 we're talking about the posterior parietal association well. Where's all the motor stuff
19:58 guys remember? Where's motor primarily all motor things that we do? Frontal
20:03 . All right. So over we have the visual cortex. Over
20:07 we have the sensory cortex. what we're really dealing with when we're
20:11 with the posterior parietal is basically understanding what's touching us and other sensory
20:19 visual and then coordinate movement with Like, have you ever touched something
20:24 kind of withdrew your hands? that's gross. Yeah. All
20:27 The idea is like, I'm touching cookie and then I don't want to
20:31 the cookie things anymore. All That would be an example. All
20:37 . This is a very complicated Don't get freaked out about it.
20:40 right. Because previously I didn't have picture. So, I just now
20:44 a picture. Right. And what I want to show you here
20:46 All right. We said in the we have the motor cortex or the
20:49 motor cortex, promoter cortex. We the association areas. What's going
20:53 The brain stem from motor neurons start either the cortex of the brain
20:57 Where are they starting? Well, starting to see the little green little
21:00 right here. These are the vestibular found in the brain stem. All
21:06 . And so it's a really good . Except that it's a really complex
21:10 complicated picture without a strong background and get lost in it. All
21:15 And so, I'm just trying to out here here. We are in
21:17 brain stem as opposed to way up in the motor cortex. And actually
21:22 is showing you hear somatosensory. it's basically saying, look how the
21:25 comes up. Right? So, we're doing is just focusing down here
21:28 the vestibular nuclei and this is basically group of nuclear. They are going
21:33 form the vestibular nerve um uh, where that information for the upper motor
21:41 in the brain. So we're gonna all right now. Also, the
21:44 formation is the other area. And we're talking about here is we're talking
21:49 the formation of the indirect tracks. the direct tracks are cortical the indirect
21:55 . Our vestibular. All right this little picture again, going back
22:03 jelly beans that you're seeing here. pulled them out and that's what that
22:06 is down there is trying to shoot here's the jelly beans. All
22:09 Again, picture is not so I just wanted to be able to
22:13 them to you. All right. we are going to start in the
22:18 stem or we're going to start in cerebral cortex for the upper neurons.
22:23 how do we influence them? there are different parts of the brain
22:28 are influencing both the cortex and the stem. All right. So,
22:36 we're looking at here is first off the basil new clay. And what
22:40 do is they look and monitor the nuclear. Remember all these different
22:44 They monitor the intensity of movement initiated the motor cortex. All right.
22:50 , the idea here is that every that you do should be perfectly timed
22:54 the right amount of of tension, ? To produce whatever action that you
23:00 . Right. When you lift up like this, you don't want to
23:02 the same amount of force that you to lift up the table,
23:06 That's the idea. And so the of the basil nuclear is to make
23:10 that that's happening All right. That applying the right amount of tension to
23:14 whatever the job is that you're trying accomplish. All right. So,
23:18 they do is they inhibit antagonistic or movement. You guys heard about Parkinson's
23:24 ? Yes. All right. Did talk about it last time we talked
23:26 the brain stem. Yeah. So that movement If I'm trying to create
23:30 smooth movement and I've got muscles that being told to control over contract in
23:36 time, it makes corrections. so it's like, oh no,
23:40 you're shooting too far to the you're producing too much power. So
23:44 doing that. And so there's this to ensure that that doesn't happen.
23:48 is why you make a smooth All right now, the brain of
23:52 basal nuclei and do not actually deal with the motor pathways. They're just
23:58 information up to the cortex. So the processing is taking place at the
24:03 of cortex before the signal is actually . Does that make sense? So
24:09 like making the checks before you actually the action. All right. And
24:14 lots of structures we learn them I'm not gonna ask you to memorize
24:19 all. Again, I'm just trying point out again, just as a
24:22 that there is a lot of different . They have lots of different roles
24:27 with regard to regulating motor activity. right now, how they work is
24:37 this through these basic mechanisms. All first off, here's your motor
24:41 it's producing the muscle contractions. So arrows mean, I'm stimulating through glutamate
24:49 is inhibition so that when you see red line with a little at the
24:52 that is telling you that I'm blocking preventing it from happening. So with
24:58 regard of the motor cortex it's the that produces the muscle contraction. Motor
25:03 is stimulated by the thalamus and the is always sitting out a positive signal
25:08 contract contract, contract. The motor is okay, contraction, contract
25:13 And it's sending that signal down to contraction. Obviously our body is not
25:17 complete state of contraction all the is it? So that means that
25:21 is regulating the thalamus and this is the basil nuclei come in. All
25:26 . So we have the internal globus and what it does is it usually
25:31 that inhibitory neurotransmitter gaba to block the of the thalamus. So we now
25:37 is we have an excitatory neuron that's stimulated by an excitatory neuron that's being
25:43 . That makes sense. So I do is remove the block and then
25:47 allows the signal to move forward. kind of makes sense. So everything
25:52 like not that I've ever done but it's like pressing the gas and
25:57 it going and then pressing the brake not letting the car move and then
26:01 the brake and then applying the brake and over again. All right.
26:07 the idea. Now in the direct . What we're gonna do is we're
26:13 to release gaba onto the internal globus . All right. Here we get
26:18 . All right. So you can here that would be through the basil
26:20 collect. So what I'm doing is inhibiting the inhibitor right. Two wrongs
26:27 make it right. But to nose a Yes, something like that.
26:31 right. So, if you inhibit inhibitor then the inhibitors no longer
26:36 So now you have excitation good. is where it gets, you
26:40 like, okay, just whatever. ? But what we're doing is we're
26:44 the antagonistic ideas. Right? if you block the globus pilatus.
26:50 ? So basically, if you block then you're blocking this. All
26:55 And so that allows for this to forward. Now, the other thing
27:01 can do here is the indirect right? You can see I'm blocking
27:03 blocking and then I'm turning on. , if I uh somehow basically blocking
27:10 , I'm not activating this. But I activate this, in other
27:14 I stop that signal, then I activate through the sub thalamic nuclei just
27:18 an example. All right. So idea here is if I stimulate this
27:23 either indirectly or directly then what that , it releases the inhibitory neurotransmitter that
27:28 the thalamus. If I block the , the thalamus can't stimulate the motor
27:33 . Which means I don't get a contraction. So it's a complicated
27:38 isn't it? It's basically saying I'm to have all these different controls.
27:43 turning things on, sometimes turning things and then ultimately what I'm turning on
27:48 off is going to affect the thalamus the thalamus plays a role in exciting
27:55 motor cortex. So if I block thalamus, I can excite the motor
28:01 . If I um did I say right? If I block the thalamus
28:06 I am blocking the uh make sure I'm blocking the thalamus and I'm blocking
28:12 pathway. If I stimulate this, I if I block this then I'm
28:19 excitation to occur. All right. so really what the basil nuclear is
28:25 here because I can go down this trail over and over again and get
28:28 more confused for all of us. idea here is I'm regulating through the
28:33 nuclear, whether or not the thalamus doing its job. That's really what
28:38 ultimately trying to say here. All . So, it's a mechanism of
28:42 . So other information is being You can go back and look all
28:46 , what am I doing? I'm with the thalamus is adjustment of muscle
28:51 , Right? So, I can through any of these other systems to
28:57 whether or not this is going on it's all being done at the level
29:00 the basil nuclear. So, what something like nucleus do? It stimulates
29:07 to cause that to go alright, this To block that block that this
29:13 happen. Other areas that do For example, the substantia nigra
29:17 Good old substantial nigra that's found the stem its job is really dope them
29:21 what it does, it activates the pathway and it inhibits the indirect
29:28 Okay, so it's just showing you regulating this process. So maybe what
29:34 should do in learning this is If the thalamus is excitatory and the
29:40 global politicizes inhibitory, I just got figure out what happens if I turn
29:45 one on or turn it off. I turn off this then I can't
29:51 . But if I turn this on I do block. That's the easiest
29:55 to say it. The other part regulating movement is the cerebellum.
30:08 I'm going to pause here for a . What's that? Mhm. Makes
30:18 positive for a second. All Do you remember when we first started
30:22 about movement a long time ago, said with regard to the nervous system
30:27 general, we like to do like throw things into boxes, right?
30:30 we said, okay, if you at this area, this is what
30:32 area does look at, that. is what this area does. And
30:35 we're going through and throwing things in boxes, we kept throwing things into
30:38 movement box. It's just like throwing into the into everybody's box.
30:45 you can see it's kind of Movement is one that's regulated. And
30:49 this is just kind of showing you like, yeah, there's a lot
30:53 stuff going on. The next slide really going to demonstrate this all
30:58 The cerebellum, remember? Is that that kind of sits off to the
31:03 that basically does the processing compare intent action. This is what I'm intending
31:09 do is my body doing what I it to do. It's not
31:12 calculate in real time. Send the up to the cortex to make
31:18 All right. So, that's really the role of the cerebellum is.
31:22 right now. Again, structurally, do we have? All right.
31:25 sending information the motor cortex. We're information appropriate receptors. Sitting information.
31:30 vestibular organs. That's basically things that balance and the brain stem.
31:35 So, what we're doing is we parking G fibers per Kinji fibers are
31:39 These are we have mossy fibers. fibers are sending information up. All
31:44 . So, these are taking the to the cerebellum so that you can
31:48 information. Information is processed in the in the fiber. Send information down
31:53 the deep nuclei so that your cerebellum figure out what the plan is.
31:58 right. And then from there, when it's sent back onto the various
32:02 of the brain. And so we the vestibular nuclear, the pons and
32:05 , which we're gonna talk about. nucleus of the midbrain which we're going
32:08 talk about in the motor cortex which already talked about. So, the
32:12 cortex remember plays a role in conscious . Vestibular nuclei play a role in
32:19 movement. Alright, maintaining your All right. Have you all noticed
32:25 your faces haven't hit the desk? mean some of your falling asleep?
32:28 understand but for the most for the of this class you guys have been
32:33 up right? Alright. That skeletal that's doing that job. All
32:38 And your body is saying I'm in upright position and this is a position
32:42 need to be in. Oh I'm a little tired so I'm gonna put
32:44 elbow out and I'm going to hold up in this position. Right?
32:50 the vestibular nuclear is making sure that don't topple off your hand or fall
32:55 on your face. You don't have think about. It must set
32:59 must set up. Must sit There we go. So this is
33:09 fun picture. Not anything you've got memorize. It's just a fun picture
33:14 show what's going on. Where does the information come from? All
33:18 So here's your motor cortex, temporal . What's big, what's being done
33:21 the temporal lobe? Simple question. language audition. Sound Okay,
33:32 Um out here at the occipital vision. Over here in the parietal
33:38 , touching right vision, some hearing stuff like that where we have the
33:43 cortex. So basically information is being in all these different areas. And
33:48 is that information being sent up to motor cortex. So you can see
33:52 , I'm processing information. Sound, , touch all at the same
33:57 All these things are being done what's done in the supplementary motor areas which
34:01 the pre motor cortex and the frontal . I'm processing what my plan
34:07 Right? And so all this stuff basically going through and process being processed
34:13 the motor cortex and that information is sent down so that you can go
34:18 vs High five. All right. all uncoordinated. Right. Everyone here
34:24 uncoordinated. Have ever done the high where you completely missed the high five
34:28 you ran up to and did the with right? And then it's like
34:34 you kind of Yeah, that's that's correction part, right? But that's
34:40 idea is like, oh, I see where you are. I
34:42 that you're coming towards me. I'm to slap that hand and you
34:46 all that information being processed. All . And then what about the other
34:51 ? We'll remember the cerebellum, receiving from the position of the body,
34:56 information of the thalamus information is being by the basil ganglia. You can
35:00 here everything is going up and back and back and around and being processed
35:04 reprocessed through the thalamus, the basal or the basal ganglia and the cerebellum
35:09 ensure that the intention matches the action in real time. And then that
35:17 sent up to the motor cortex which that information down and you're still with
35:24 ? All right. That's because we haven't practiced enough. So, motor
35:32 or brainstem we're going to look at motor cortex, folks. Let's look
35:35 the direct pathway. Alright, so are called the pyramidal tracts. You'll
35:40 that word. So when you think pathway, think pyramidal tracts, they're
35:44 to be in the primary motor cortex where we're gonna start and we're gonna
35:48 either to the brain stem of the cord. So there's two tracks,
35:53 spinal cortical bulwark. And you all a sudden you can look at the
35:56 and go, oh, so I'm in the cortex, I'm going down
36:01 the spinal cord. I'm starting in cortex. I'm going down to the
36:05 stem now. Why why would I in those two things? Divide your
36:10 into what are the two parts of body? Yeah. Left.
36:17 That's one way you can divide it my body versus my head?
36:25 We mentioned all those cranial nerves. do they originate from brain stem?
36:32 . So, if I want to , is that a conscious movement?
36:37 right. If I nod my right, that's a conscious movement.
36:43 . If I want a way that's different type, that's my lower
36:46 Right. My upper body is dealing the cranial nerves. My lower body
36:50 dealing with the spinal nerves. So have a cortical spinal tract, which
36:55 everything from your neck downward. And we have the cortical billboard, which
36:59 basically your neck upward. That's not terrible, is it? All
37:05 Just has weird names attached to Why don't they just call it the
37:08 tracking the body track? Because they're smart people. They like to use
37:15 terms to make things complicated. So look at the cortical spinal track.
37:20 right. And again, the jelly , you see a picture like
37:23 What they're doing is they're trying to space and so they're putting everything on
37:28 same page. Right? So you'll the jelly beans like this and you
37:32 , oh no, we're just focusing here on these two things. So
37:36 look and see. We're looking here the big purple jelly bean. And
37:39 looking down here at the little tiny . What color? What's the
37:46 Okay. We're going to turquoise. right. And we're looking at the
37:50 one. Okay, notice, remember said we have a mere image.
37:55 you can just divide the spinal cord half. So you can just look
37:58 one half if you want to. right. So really we're ignoring all
38:02 other things that are down here for now. So this is the direct
38:06 . These two things. The lateral spinal tract in the ventral cortical spinal
38:10 . Sometimes referred to as the anterior spinal track. All right. So
38:16 we have, All right. where we originating primary motor cortex projecting
38:20 to the spinal cord? That's where name comes from. All right.
38:23 going to pass through the brain We have to Because that's just in
38:27 way. But we're not stopping in brain stem. We're just going to
38:30 on going down and we're going to the pyramids of the medulla. All
38:35 . So, when we look at pyramids, right, This is these
38:39 as they're traveling down. So, , there's gonna be devastation. All
38:43 . So, where do they Well, it depends on which track
38:46 looking at If you're in the lateral spinal track, the big purple jelly
38:51 over here on the side. You're to cross over in the medulla.
38:55 right. Where are we located? , this is referred to as the
39:00 funicula. So, that's where we're . All right. And where what
39:04 we doing? What are we? are we responsible for the appendix killer
39:09 muscles? All right. Your arms your legs. Okay, So all
39:15 fibers that go our response for the and legs are gonna travel down through
39:19 lateral cortical spinal tract. Okay. not too terrible. All right.
39:24 , here's that. So, now just contrasted ventral, right, down
39:27 . That jelly bean deck state in spinal cord. So, they cross
39:32 a little bit later. All Where they're located down here in the
39:36 of ridiculous. Remember that's the ventral . And their job is to innovate
39:40 axial skeleton. Is that your body your trunk? Okay? Not too
39:47 right now. Just to kind of you something here that kind of help
39:51 stand out, remember this. What do you think requires more neural
39:56 moving your body or moving your arms your legs. Arms and legs.
40:02 , now, granted this is a drawn by someone who has no biological
40:07 . You know, he's copying from some other text but look at the
40:12 of these two tracks. Big that would be the arms and the
40:19 . Itsy bitsy turquoise, that would your trunk. Okay, So real
40:27 kind of compare and contrast for All right. And that's really kind
40:31 what you do when you look at things is just do the compare contrast
40:34 say, okay, what's this one ? What does that one do?
40:36 right now again, you're not going have to track it down the spinal
40:40 . That's not going to be the thing here when you taken your anatomy
40:44 or when you get on the nursing or into whatever professional thing, depending
40:48 where you're going to go. Sometimes gonna get real down and dirty with
40:52 neuro anatomy. All right. But good news is that if you understand
40:55 you're going and where you're coming it kind of easy to figure
40:59 right because when it says it's gonna found in the lateral funicula sit means
41:03 literally gonna always be there and it's going to travel the same path.
41:08 it's just basically okay, once I where it is, I'm just going
41:11 say this area right here is where going to be. All right,
41:14 we don't need to do that today the test on next thursday?
41:20 that's right. Next thursday is a . Should warn you about that.
41:24 the test next thursday? And then done with the class? All
41:32 I mean yeah. Mhm. Except Burek also. Mhm. But you
41:38 come in here and have a party 8:30 AM, no one's going to
41:41 here. All right. So, let's deal with the cortical bulb er
41:48 . All right. Now, they're for the skeletal muscles associated with chewing
41:53 expression, tongue movement and swallowing. hmm. What does that sound
41:57 Head? Alright, there we Alright, so again, there's going
42:00 be the direct pyramidal pyramidal tracts. going to originate in the pyramidal cells
42:05 motor cortex and project to the brain where that's where they're going to come
42:10 the cranial nerves. All right. , again, if you wouldn't look
42:15 the organization of the motor cortex, going to be that region of the
42:19 that your face in your mouth and throat. All right. So basically
42:23 the jaws, The face bearings. ton. All right. Now we
42:29 to this as the indirect pathway or extra pyramidal tracts. Those are the
42:35 terms that they use. All So, um wait, I'm
42:39 That's a critical Bulba track. That's I was trying to get that said
42:42 the face. We're in the next now. I'm sorry. Now we're
42:45 deal with the indirect pathway. Again, notice we're going back down
42:49 the spinal cord. All right. , what we're doing is we're originating
42:52 the brain stem over here. We're in the cortex. We're just going
42:56 the brain stem and then innovating the and the head. All right.
42:59 why we don't spend a lot of . They're four tracks. So,
43:02 we're back down here to the extra als. All right. So,
43:06 have the rubio spinal, ridiculous spinal spinal. Or the vestibular spinal.
43:10 are the names that we're going to here instead of olives. It's gonna
43:13 Aspinall. Okay, now again, naming things for where they originate and
43:21 we're going to tell you where they're to go. All right.
43:26 we're gonna start with the stimulus All right. The stimulus deals with
43:33 nuclei. That's why you showed me horrible picture with the green jelly
43:38 Yes. All right. Because that's they originate. They originate in the
43:43 nuclear. There's two tracks that are a spinal tracts. One that is
43:49 one that is medial. Okay. job control balance and posture. Sit
43:56 straight, stand up straight. All . How do you hold yourself as
44:00 move? All right. So the motor neurons in the lateral vestibular track
44:05 going to be in the lateral vestibular . What they're going to do is
44:09 going to get input from the sensory of the inner ear and the
44:14 What is my position of my head space? All right. And then
44:18 going to protect down via the ventral Nicholas. So they're going to be
44:23 here on the ventral side. And they're doing is they're going to stay
44:28 literal. What does its lateral means gave you a hint they stay.
44:34 collateral stay on the same side. don't cross. Right? Contra lateral
44:42 the opposite side. Right? It's same sides. All right. So
44:48 gonna project down the same side. . Good news. The artist got
44:51 one correct. Alright. And then they're gonna do is we're gonna go
44:54 synapse in the ventral horn and send information down to the right muscles to
44:59 them to contract or or if you're contracting, relaxing them. All
45:05 So that's the lateral medial medial vestibular . So that's pretty straightforward. All
45:13 . What they're gonna do again? ear and cerebellum and what they're doing
45:17 they're controlling the neck muscles. All . So this keeps your head still
45:24 you walk like a pigeon? no one does that when you walk
45:32 head stay still. Right. That's this is doing. The media vestibular
45:38 is ensuring your head still still stay during movement. All right, ridiculous
45:49 track. What do you think particular with something? We've learned? Particular
45:56 . C. All right. really? There's two of them.
46:00 a media in the lateral or sometimes to in this. It will make
46:03 easier for you. The Ponti nor medullary, ridiculous. Final track.
46:08 right. Where do you think the manjula spinal track starts in the
46:13 Where is the major? Everyone? a doula. See this just all
46:17 a sudden. It's like, oh , they really do name the things
46:20 what they do. Alright, so where they originate now, what they're
46:24 here is axial approximate muscle movement associated posture, local motion and reflexive muscle
46:33 . So, it's not just Now, remember, the particular formation
46:36 alertness. All right. So, now dealing with what am I doing
46:40 regard to movement and reflexive movement. right. So, with regard to
46:45 ponte in one we're going to project the medial ventral funicula. So,
46:50 that means is is we're sitting here the medial side of the ventral uh
46:58 . All right, ventral, But were immediately located again synapses and
47:03 hore primarily dealing with extensive your So excitation of the X tensors.
47:10 right here with the lateral articular spinal . That's going to be in the
47:15 . It's going to be in the funicular. So the artist here screwed
47:20 one up. He did draw it . It should be out over
47:23 Not down through the middle. Should right there. How do we know
47:28 it is right there. See that jelly bean. All right. What
47:38 we doing here? We're inhibiting the . Okay. Remember, So uppers
47:44 be an excitatory or inhibitory? All . That's ridiculous. Spinal rubio,
47:54 . You're the weird one. Anything name with rubio, actually,
47:57 it's just not obvious. All Remember the good old red nucleus.
48:03 that one big structure. Big old . That Phillip read the word rude
48:10 , is a prefix that means So that's where it comes from.
48:14 right. So they originate the red . Their job is to innovate muscles
48:19 with flexion. So ridiculous. Final extension reflection. Here's the contrast.
48:27 there. All right, a So here it is red. And
48:33 we're gonna do is we're going to deca state to the other side over
48:37 . I'm sorry. I should have out. Um I'm going the wrong
48:44 . They're just just do whatever you like computer the stimulant. Right.
48:51 , notice here, we're not We're staying on the same side.
48:54 this is it's a lateral. All . Here, we're crossing. That's
49:01 . Yeah, we're staying on the side. It's it's collateral. All
49:13 here, contra lateral cross over All right. And what we're going
49:19 do is from the red nucleus. going to travel down, we're going
49:23 stay in the lateral funicula. This over here on the side and then
49:28 going to innovate on the contra lateral . That makes sense. All
49:35 So what are we doing? flexing muscles. Last one, Detective
49:47 detect. Um Remember it's going to up here in the superior curricula asses
49:51 we're really going to be locating or going to be turning our head or
49:55 our head in response to visual It's like, oh look there goes
50:00 bird. All right, that would visual stimulus. So, superior
50:05 getting input from the optic nerves were to cross over. Right. Some
50:11 them aren't going to but what most them do. We're gonna cross over
50:15 then we're gonna move down the anterior Ulis. Alright, and where's the
50:21 ? It's going to be down there ? Our artists a terrible job and
50:26 going to project and be um going to the upper horns. Are the
50:32 , the ventral horns of the upper cord again. Head, neck.
50:39 , so if you look at these things and get lost. Start with
50:45 jelly beans. Okay, I'm down in the ventral or I'm over here
50:49 the lateral and that's really as simple you need to do what am I
50:54 ? What am I innovating? Well on where starting where I'm going.
50:58 right. So we was final detective here, take toe moving the head
51:07 neck. Alright, notice it's just upper part of the neck,
51:15 All right now we're going to just of wrap things up here. This
51:21 gonna be the last bit of And then when we come back after
51:24 Turkey day and the consumption of much And the extra don't forget to set
51:30 scales back 15 lbs. Uh Yeah. And this is why we
51:39 bigger when we get back, all dealing is with the autonomic nervous system
51:45 then we're done. And so this our last little bit here. First
51:49 in your brain you have central pattern . Central pattern generators are responsible for
51:53 rhythm, rhythm movements that your body the easy you want to think about
51:57 walking. But we also chewing is rhythmic movement, breathing is arrhythmic
52:01 So anything that has kind of a to it that's really repetitive. And
52:05 this is kind of a combination of and voluntary movement. Alright. And
52:10 we talked about the different types of um uh clusters in the neural pathways
52:17 And so remember we we mentioned this what the CPG is. Um And
52:23 these are gonna be inside the brain and also in the higher cortex.
52:26 basically there's a pacemaker properties to them basically you can see what we're doing
52:31 we're going to cause extensive hers to and we're gonna repress flexors and then
52:39 is going to activate and we're going repress them. So that's why we
52:42 this this pattern that's basically going back forth. It's easier to see with
52:48 cat. But you do it as right? When you walk that's what
52:52 doing is you're doing a repetitive pattern actually when you move your arms you
52:58 it's going to work in opposite. ? So it's a pattern that your
53:01 is excellent. So these are CPG that are responsible for doing that.
53:10 pretty sure we may not have talked these before. Did we talk about
53:14 stretch reflexes before the golgi And the the a stretch reflex? No.
53:22 . So I did reserve it for and that's good. All right.
53:26 these are types of muscle responses and want you to think for a moment
53:32 um well we're gonna start with the reflex and I'm going to try to
53:36 you a situation where you can kind see how it works. Okay.
53:42 not just talking across your legs and your knee. That's fun. But
53:45 not gonna be an easy way to it. All right. So this
53:48 a mono synaptic reflex. All And what we're doing here. And
53:51 mentioned this when we're talking about the of the interview cell fibers. Is
53:55 what we're doing is whenever we have sort of movement, we're trying to
53:58 the muscle with a specific degree of . Right? And so what your
54:04 is looking for is to is to that. And so it needs to
54:09 the stretch um as your as as happening and then adjusting in response to
54:17 . All right. So, I you to picture for a moment um
54:22 a book out in front of I'm not talking little tiny book.
54:25 talking like a good old £12 biology . Right? And let's say you're
54:30 it out like this. All And if I come along and take
54:34 biology text book and put it on . Just kind of lay it
54:37 What's going to happen to your It's gonna go down. But if
54:41 have a gun to your head and don't move your head, your
54:43 you're gonna want to keep those hands , Right? But there is a
54:47 response because right now your muscles are a particular degree of stretch in response
54:53 the weight that's on it. And you're doing is you're getting this instantaneous
54:57 increase in weight that your body hasn't experienced. So if you're going to
55:00 this natural, Oh, I don't enough tension. But I'm gonna bring
55:04 create enough tension to hold the books . That kind of makes sense.
55:08 , this is the stretch reflex. basically measuring how much stretches in that
55:15 . And when the stretch becomes too . It basically says, oh,
55:17 , no, no, too much . Let's contract more so that we
55:21 bring the right amount of tension in to put the mussels exactly where we
55:25 them. And that's what we're describing . All right. So, the
55:29 is being regulated or monitored by this called the muscle spindle. All
55:34 And this is where that extra fuselage intra Feustel comes in. So,
55:38 can see here here's electron micrografx. , this isn't just some guy
55:41 well, I think this is what's . They've actually got in and look
55:44 these things and you can see it's it's a structure within the entire
55:48 So it's not the muscle itself. these things inside there's portions within the
55:54 monitoring and looking at the degree of through this little tiny thing called the
56:00 spindle. All right. So, you look at the muscle spindle,
56:03 have the extra fuel cell muscle fiber . You have the interviews all muscle
56:08 , you have alpha neurons that are extra fuel cell. So, they're
56:11 ones that are playing a role in sending signals to cause contraction. And
56:16 , on the inside you have the motor neurons that are sending signals to
56:20 contraction of that interview cell fibers and wrapped around it. You also have
56:25 uh sensory neurons that are sitting there the amount of contraction that's taking place
56:31 the amount of stretch that's taking Interview silly. All right. And
56:35 it's going to do is if you that interview cell muscle fiber, you're
56:39 to detect it. So you're going cause the whole thing to contract.
56:43 right. So, that's what you're is internally to it. All
56:46 Now, the interview cell, they're in connective tissues. So they're kind
56:50 separated out. And you're doing this that you can you can innovate just
56:55 . All right. So, when muscle spindle this structure is stretched,
57:01 sensory neurons in there are going to that stretch of that interview cell fiber
57:06 sends a signal outward. Right? then causes contraction of the alphas as
57:12 as the gammas which we're not really about. All right. So,
57:16 , when I put the weight on , I'm stretching the muscle more than
57:20 was I detected internally at the interview , which is going to send a
57:26 right back to the spinal cord which going to stimulate the alphas to cause
57:30 to bring the arm back into the amount of stretch. Uh huh.
57:35 the stretch reflex. All right there's also a reciprocal inhibition going on
57:44 well. But we just kind of that. Alright. So they are
57:47 sending a signal to the other muscle as one is stretching the other one
57:51 going to be contract or relaxing. what you're doing is you have to
57:56 those two signals simultaneously. The second of reflex, It's a motor reflex
58:07 to do with the Golgi tendon Now, this is going to be
58:11 in the tendon of the larger All right. So remember, at
58:14 end of each muscle you have this and so there's gold uh tendon structure
58:19 measuring the degree of stretch inside that . So, again, I'm going
58:23 paint the picture. We have you the books right? And I put
58:28 put the £12 buck. We put £12 book and we keep stacking £12
58:32 . Alright, Again, gun to head. You know, you got
58:35 hold those books up and eventually what's to happen is is, you
58:39 you're strong enough but you're going to muscle is contracting more and more and
58:44 . I remember when the muscle what is it? Pulling on,
58:48 on the tendon which is pulling on bone. And so each time the
58:51 contracts it stretches the tendon a little more creates greater tension in that and
58:57 causes stretch on the bone or pull the bone and what you're monitoring here
59:02 the stress on the tendon. If put too much stress on attendant,
59:06 gonna eventually terror, right? And what you're doing is you're protecting the
59:11 . So what the Golgi tendon is to do is it's looking at the
59:15 of stretch here so that if you , it's going to protect the muscle
59:20 the tenant and say no, you do that and you're going to inhibit
59:24 alpha neurons and prevent them from So, think about when you are
59:28 too much. What do you tend do? Your muscles basically relax and
59:33 drop whatever it is that you're Okay, That's the idea here.
59:38 again, I use the example of gun in your head because when things
59:41 too heavy for me, I'm just , I'm not gonna let them
59:44 right? That's normal. But you think about think about like if you're
59:47 your buddy move for the 47,000 times all done this. Remember you made
59:52 vow, I will never ever ever anyone ever move again. And you
59:56 that phone call, you're like, it. And you go and help
59:59 and you're lifting up that box and all that china, right? And
60:03 like, it's too much and you're like, so what do you
60:05 You come out, right? And you put it down, it's
60:09 right? Because your muscles basically given , there's something done. All
60:14 So what the Golgi tendon is doing it's protecting that muscle. So it
60:17 tear And it doesn't tear that tendon the bone. All right.
60:21 when the muscles contracting the tendon is , your detecting the degree of stretch
60:27 in the Golgi tin or in the itself that sends information up to the
60:31 cord, spinal cord says all not a problem. But when the
60:35 in here gets too great, what going to do is it's going to
60:39 or interfere with the contraction here. , it's an inhibitory effect. Too
60:46 stretch of the tendon. Danger, . Stop the signal muscle relaxes.
60:53 right. Now again, there is activity there as well. There's ice
61:02 up here for those who haven't had . All right. So, we
61:07 one more lecture that's next Tuesday. , thursday, right. We have
61:14 exam, booze. All right. , thursday we eat as much food
61:21 we possibly can as humanly possible. know? It doesn't have to be
61:26 . It could be tofurkey. Mm . You know, or ham.
61:31 your for truth toe for ducky. my goodness, That would be
61:36 Would that be tofu duck and Or would be tofu duck and tofu
61:42 , totally. I mean, I what you're ducking. Mhm. And
61:49 , yeah. So you just do and then stuff it with like a
61:55 stuffing. That's one. And yeah. And then wrap it on
62:04 . Yeah, yep. And thank all for showing up on a Tuesday
62:11 no one wanted to show up I didn't even want to be
62:14 You're welcome, you,
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