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BIOL 2301 Human Anatomy & Physiology I - 2103_lecture24_0426
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00:02 Alright. Y'all kind of excited. week of classes, one head is
00:09 the rest of you are like, , give me more classes.
00:14 yeah, yeah. So how many you guys saw this stuff And when
00:27 reading it was like, I don't it. Good. You're normal.
00:33 many of you read it the first ? In Easy mode? No one
00:37 gonna make fun of y'all because you normal. What we're gonna talk about
00:41 , we're gonna talk about motor And the problem with motor pathways is
00:46 make it incredibly complicated? All And the good news is it's not
00:51 complicated as it's made out to Alright. When we talk about motor
00:55 , this is the basic rule, are two neurons in the motor
01:00 Motor pathways going from the central nervous out to some muscle making the muscle
01:06 so, so far. Pretty Right. So, is this movement
01:12 movement? Yes, that movement or Right. So, you have movement
01:18 the head. You have movement of body? Right. And so in
01:22 pathway, we're basically dealing with two . We have an upper neuron and
01:25 lower neuron. That's the complexity of system. The first one is called
01:30 upper neuron. The second one is the lower neuron. Do you
01:35 is that is that tough? But far we Okay. Is that is
01:37 It's not too bad. Right. right. And then the other thing
01:40 gonna do is we're gonna name the based on where they originate and where
01:45 go to so far. So So that's it. Let's go
01:52 Well, You drove here at 8:00 horrible traffic. Might as well get
01:57 done. All right, So that's we're gonna deal with. We're gonna
02:01 with the motor pathways, we're gonna those. The other thing we're gonna
02:04 is we're going to look at how or movement, locomotion is um arranged
02:12 controlled in the central nervous system. , that's complex and scary.
02:19 It's like trying to describe the inside a computer because that's hard.
02:25 But what we're gonna do when we at this is we're gonna look at
02:29 through a lens of just asking the , what is this area of the
02:33 do when it deals with movement? already looked at all these structures and
02:39 just gonna now plug it in and , okay, this part of the
02:42 does this when we're dealing with All right. And that's how you
02:46 approach it in terms of learning. pretty much what you're going to kind
02:49 do is come up kind of come with lists, right? When you're
02:54 , I'm not gonna ask you how this one talk to this which is
02:57 by this and regulated through that? going to see a picture where we're
03:00 see how the artist goes. here's arrows, just pointing at stuff
03:06 we're gonna just go ahead and yeah, that's complex and kind of
03:09 on. All right. So, we're looking at this, remember what
03:12 want you to do is focus in what is this structure doing? Generally
03:17 , when we're dealing with the question movement. That's it. Alright,
03:21 , that's our starting point dealing with motor pathways, Right? Motor pathways
03:26 policy synaptic. How many motors neurons the motor chain? I just told
03:33 two. What's the top one Upper? What's The Lower one
03:38 Yeah. All right. Now, are gonna be multiple parts of the
03:42 that are going to be involved in . All right. As we
03:46 there are going to be inter neurons we're not going to look at.
03:49 understand that if you have multiple parts the brain, they're talking to each
03:52 . There's got to be some sort inter neurons involved. The general
03:56 As we said, you're going to some place in the central nervous
03:59 it's gonna be this cortex or it's to be the brain stem. You
04:01 see in a little cartoon, here's cortex, there we are in the
04:04 stem. You can see we're starting there, we're starting down there and
04:08 going to travel down the spinal And what we're gonna do is we're
04:12 that's the upper chain or the upper . And then down here we're gonna
04:15 apps to the lower motor and the motor goes on to innovate the
04:20 All right. What we're dealing with movement. So, skeletal muscles.
04:25 right. Now, we're going to something else on actually doing the autonomic
04:29 system. There is motor pathways in autonomic nervous system and we're gonna deal
04:32 that later and just ignore. This about movement. So, we're gonna
04:35 talking about muscles today. All So, when we're dealing motor pathways
04:41 general, we're talking about skeletal muscles autonomic contractions, which is going to
04:45 thursday. So, what are we with posture, balance and musk?
04:54 muscles? It's one of those All right. So, as I
05:07 said origin when we're talking about our pathways, cerebral cerebral cortex, we're
05:12 about the brain stand. There will input from these different structures we've already
05:16 at, for example, the basal and the cerebellum. The thalamus is
05:20 involved in all this. We're gonna regions of the frontal lobe as well
05:24 association areas. These are all going come into play in terms of regulating
05:29 type of movement that we're making. this is our starting point when we're
05:33 with the actual sending of the it's going to be here in the
05:37 or it's going to be here in brainstem. We've already mentioned the names
05:40 the two chainz upper and lower. , very simple. And then in
05:45 of the pathways they are defined as being a direct pathway or an indirect
05:50 . Alright. And this kind of gets confusing even though you know what
05:54 and indirect means. Alright. Is a direct way to get from here
05:59 your house? Right. No stops between. Just you can get in
06:03 car and you can drive it until get into your parking spot or your
06:08 . Yes. Okay, that's If you went to the grocery store
06:15 and then stopped at circle K. get your 44 ounce dollar big
06:19 I don't know if they call him gulps there. All right. And
06:22 you went home, is that No. What is that indirect?
06:29 the indirect pathway doesn't go directly to it needs to go. All
06:34 In other words, when they were discovering these things, they're like,
06:37 here's a pathway that's straight and it right to where we need to
06:41 And then they started looking it was , oh well there's these other pathways
06:43 kind of bounce all over the So direct and indirect. So the
06:50 thing to do is to start with lower motor neuron. Alright. The
06:54 motor neuron we call whenever we're innovating , we're starting in the central nervous
06:59 , right? Motor neurons originate in ventral horn, right? Or they
07:05 in the lateral horn. If it's lateral horn, you're part of the
07:09 nervous system which we're not talking about ? So we can ignore that autonomic
07:13 system is thursday. So when we talking about leaving the central nervous
07:18 everything starts the lateral horn. But we're talking about motor movement. So
07:24 ventral horn. All right. So can see right there there's the ventral
07:30 . And so we're going to leave ventral horn. Travel out the ventral
07:34 and then we're just going to form motor neuron or our motor nerve.
07:39 , so ventral roots, whenever we're with movement and motor, it is
07:44 always always no exception to the Which is surprising in science, it's
07:50 excitatory. So, when I send signal that's going to create a
07:56 when I stopped sending the signal the the contraction stops. All right.
08:03 , there's two ways to stop. can actually stop sending the signal or
08:05 can inhibit the signal from getting Alright. But that neuron will always
08:11 always be excitatory. And there are basic types of motor neurons. We
08:17 the alpha motor neurons and the gamma neuron. This goes back to when
08:20 were looking at the um the motor and we're looking at regulating the degree
08:27 stretch. So these are stretch The alpha is what it's contracting the
08:33 muscle. So you can see out here's a motor neuron, innovating the
08:37 . So when you're contracting a you know how much to contract it
08:41 sending signals to the alpha. The is an inch. Is goes to
08:45 inside of the muscle. It's wrapped a special connective tissue. This is
08:49 muscle spindle fiber. Here's your It's still a motor neuron. But
08:54 you're doing is you are creating stretch there and when the stretch on the
08:59 doesn't match the stretch on the that's a signal to tell you you're
09:02 doing the right work. And so sending signals back to ensure that the
09:07 contract to match what's going on inside intra Feustel fiber. Alright, so
09:13 basically inside with the gammas, we're degree of stretch. Now, this
09:18 a motor neuron, this is not sensory neuron, their sensory neurons associated
09:23 this. So you're looking at the of stretch, but it's the
09:26 That is responsible for creating a certain of stretch and you're trying to match
09:31 two. Alright, so that's the motor neuron begins in the ventral
09:37 goes out through the ventral route travels as a motor neuron innovates with both
09:42 alpha or a gamma. We've seen before. So this is nothing new
09:48 we're dealing with the nerves and the along the ventral horn, they're gonna
09:54 the organization of the body. So as your medial, you're more
10:00 to the head as you move further the body, you um down to
10:05 the feet and stuff like that. sorry, I flipped those around my
10:10 . So the further down you are , that's where you're gonna be medial
10:15 you're basically working your way up and you add in fibers, they end
10:18 more laterally. All right. that's kind of the organization of this
10:24 horn. Third thing we've seen already just reiterating. It has to do
10:31 the motor unit. Remember we said we innovate a muscle, what we
10:35 is we have multiple motor units going a muscle. A single motor unit
10:40 simply the single fiber and the number cells that it's innovating. So in
10:47 particular case, this particular motor neuron innovating five cells. You can have
10:53 motor unit that innovates one cell. can have a motor unit. Innovating
10:57 cells. A motor unit is simply one neuron because that signal doesn't discriminate
11:03 it's gonna go. Once a signal traveling down, it's going to go
11:06 each of those cells and cause a in each of those cells. And
11:11 going to determine how much attention we're to produce in order to move the
11:18 . All right. The second thing said fibers are when when you're looking
11:23 a motor unit, they're not clustered . Artist doesn't have enough space so
11:26 can't do this. But the idea that you're not going to innovate all
11:29 muscles on one side, or muscle on one side. You're gonna have
11:34 muscles innovated all over so that you kind of create an equal pull as
11:40 producing that tension. So upper motor . All right. Now, first
11:57 , you don't need to know all different layers of the brain.
12:00 This is what it's showing us the . And I just showed this up
12:03 because we've mentioned this before. We , hey, there are six layers
12:06 the cortex. And you guys okay, that's cool. Whatever.
12:09 I said you never had to learn . Just know that some at some
12:12 someone's gonna ask you to learn So today is not the day.
12:16 you can see over here, here's primary motor cortex. If you get
12:20 still has those six layers and it the upper motor neurons begin in the
12:25 , right? Some of them Some are gonna be in the
12:27 But we're looking at the ones that here in the cortex and they begin
12:32 at layer five. Alright. And are special cells inside layer five is
12:36 the bet cells. And these bets are the origins of those upper
12:42 So that your upper neuron you can it's traveling down and it's going to
12:45 all the way down to that lower neuron. Lower motor neurons located in
12:50 spinal cord in the ventral horn. hear me repeating myself? Just nod
12:55 head and say of course I Yeah. All right. There will
13:01 other inter neurons that can be in there as well? All right.
13:08 , you remember whenever you have an IQ muscle, what do you have
13:11 the other side antagonistic muscle? So can have a motor neuron. Upper
13:19 neuron go down and innovate the lower neuron to the agonist muscle. But
13:24 can also send an inhibitory signal to antagonistic lower motor neuron so that it
13:31 fire. So I can contract the . That kind of makes sense.
13:35 , when you're looking at the muscle trying to contract. It's going to
13:38 upper. Lower. But if you're to inhibit the antagonistic muscle, you'll
13:43 an upper probably an interneuron and then have lower motor. All right.
13:49 so that's not going to be direct . It's an indirect pathway. It's
13:54 part of the indirect pathway that we we said is going to be part
13:57 the thing later. Okay, so if the lower is always excitatory and
14:05 allowed to inhibit the antagonistic muscle. means the upper motor neuron can either
14:12 excitatory or inhibitory. All right again, the context there is not
14:18 the direct pathway. So if I'm upper to lower, that means I'm
14:23 excitatory. Right. But if I'm to an antagonistic then that interneuron is
14:28 stimulated to be inhibitory. Right. you want to stop your car?
14:35 do you have to do? Press break are you being Are you being
14:41 in pressing the brake? No, have to have some sort of activity
14:45 force yourself to stop the excitation is to create the force to press on
14:52 brake. The brake. Does the of inhibiting. Okay, so you
14:57 be excitatory, interneuron is inhibitory. is what's stopping the antagonistic signal.
15:06 this could be excitatory or inhibitory in . Here's something else you've seen
15:11 So this is just showing you where we in the cortex? It's
15:15 One the primary motor cortex. And the signals that cause your fingers to
15:19 cause your toes to wiggle to make tongue wag. All that stuff is
15:24 right up here in the primary motor . Alright. Again, Samantha typically
15:29 . This is not a new picture you've seen. Alright, there's stuff
15:34 we've already talked about now, what telling you is that that's where that
15:42 motor neuron originates is in that primary cortex, but the primary motor cortex
15:49 just send signals. It needs to some sort of input to tell it
15:53 to do. So one of the where this happens is going to be
15:57 pre motor cortex. So the peak here is the primary motor cortex.
16:02 it's that slide right there. All . The yellow represents the pre motor
16:08 and what the pre motor cortex does again, it's telling the motor cortex
16:15 is the intent or trying to give the idea of what kind of movement
16:19 going to be making. So one the things I like to point out
16:23 is this Alright, everyone knows how wave wave at me. Thank
16:28 Now give me a high five the motion, right? But how do
16:33 know how to do this versus Alright. The plan is programmed
16:39 Right, So you need to know you'd wave, what you all
16:43 You need to do that and when time to give a high five,
16:46 don't go like this, right? put your hand up and say it's
16:50 for the high five. Alright, that programming is done in the pre
16:56 cortex, it stores motor memory, you know what to do.
17:01 It controls the muscle movement in meaning here's the plan. And then
17:08 it's going to help you know what do based on visual or sound
17:14 All right, Track and field. we have anyone track and field?
17:19 . All right, swimmers. Okay. Get on the block
17:29 How do you know when to Are they waving at you now you
17:35 the gun right? Or the you the annoying beep, But that's your
17:41 your cue. That's what we call sound cue in order to cause you
17:46 leap forward and propel yourself into the . Okay, now, interestingly,
17:55 pre motor cortex can actually directly send impulses down the spinal cord.
18:00 So it can talk to our down pathways. But what we're trying to
18:07 of here in really simple terms is telling the primary cortex what to
18:12 All right then. We said there's areas. Remember we talked about association
18:17 , Association areas, take information process decide what to do with that
18:22 So, the two association areas I to refer to here are the prefrontal
18:27 and the posterior parietal association cortex. right, prefrontal cortex basically is going
18:34 speak to the pre motor cortex and going to speak from the pre motor
18:38 as well as directly to the primary . And what it's doing is basically
18:43 aha I know what you're supposed to doing. Are you doing what you're
18:46 to be doing? Right? this is the wave versus the the
18:53 five. Right? It's looking in context of stuff and saying All
18:57 So people are waving at me what's my response back? What should
19:02 be? Should it be this or it be this? So, it's
19:06 the pre the pre motor cortex this what I think we need to be
19:11 . You initiate that plan? Pre cortex says, okay, the plan
19:15 to give a wave not a high . So primary cortex this is the
19:20 of movement I want you to You see how what we've done here
19:24 we've basically gone from understanding what needs be done to looking at the instructions
19:31 what needs to be done to actually what needs to be done. That
19:35 of makes sense. All right. you're dealing with the posterior parietal right
19:42 you're dealing with somatic sensory cortex. right. So this is where the
19:46 muscle movements are concerned and you're relying touch and vision to coordinate movement.
19:55 right. So touch, what would an example of touch to coordinator movement
20:02 when the cat comes up and rubs you pers at you and immediately that's
20:10 a reflex. What do you Oh, cat wants to be pet
20:14 the cat and the cat is all or maybe it's soaking wet and you're
20:22 , I don't know, trying to of something. All right. So
20:27 now dependent upon that sensory input. information is being set forward. Information
20:33 being sent forward. You're trying to what movement is needed in the context
20:39 the input that I'm receiving. That's what the association association areas are
20:48 for. All right. So, is not a picture from your textbook
20:55 . And I picked up this picture I wanted to show you because there's
20:59 a really good picture and this is even a very good picture because at
21:02 on your slides it should be But trying to show gray in a
21:08 like this doesn't really do a lot good. But really the only thing
21:12 want to show you here is just you where the nuclei are.
21:15 so remember up here, this is . You can see there's a somatic
21:19 area showing you going down. So as you're moving down, here's
21:24 mid brain, This is the ponds here. We're now in the
21:28 this is the spinal cord. So what that picture is. Trying to
21:31 you. And all I wanted to is just kind of focusing on those
21:34 green areas right here. Okay. are the vestibular nuclei. Alright.
21:39 formation is represented by kind of this area in here. Okay. But
21:44 when we're talking about we said that motor neurons original one or two
21:49 One was the cortex, one was brain stem. Alright. When we're
21:52 about the vestibular nuclei, that's what green things are. All right.
21:58 are nuclei that originate from the vestibular . All right now without having to
22:05 forward. And I know you guys this stuff. So you guys already
22:07 internalized everything. So, you know all and don't need to be up
22:10 at all. Right. Right. what is the vestibular nerve responsible for
22:17 ? All right, so you're getting from the inner ear to tell you
22:24 how to maintain posture and balance. . So, notice you don't need
22:30 go up and think about, am I upright? It's simply the
22:35 coming from the inner ear going to vestibular nuclei. That's what those green
22:39 represent. And then here that's that's upper right there, showing you here
22:44 is coming down and where is it ? It's going down to the spinal
22:48 and it's showing you here where in spinal cord, ventral horn and from
22:54 ventral hornets, innovating the muscles of back or what we're going to
23:00 It's going to innovate the muscles of head neck region. Now, why
23:05 you suppose I need to innovate the of the back posture, right?
23:15 up straight. Sometimes they get people snap your mom never did that to
23:21 never sit up straight. You Okay, so that's not a visceral
23:25 . You know? My mother said would be right up. Okay,
23:31 you can see that, that would that. You're just you're just having
23:33 do that. All right, the one? Head neck. Why would
23:36 innovate my head and neck movement. good if I'm running. Do I
23:42 my head bouncing around all over the ? Nice and neutral, straight forward
23:48 I can see where I'm going. right. Try to bounce your head
23:51 a little bit and see if you focus and not very easy.
23:56 so here the basal nuclei basil nuclear very, very important. You guys
24:02 heard of Parkinson's disease? That was really slurred that Parkinson's disease.
24:07 Parkins does red leather, yellow red leather Parkinson's disease affects the basal
24:17 . Alright, so we've we've looked these, the purpose of of this
24:22 to inhibit antagonistic or unnecessary movement. . They do not talk directly to
24:28 pathways, they're talking to the thalamus is going to be talking to the
24:35 cortex. Alright, so what we're is we're looking at the movement of
24:41 bodies and asking the question is the and the action actually going forward the
24:46 we wanted to. And we've already this, we talked about the tremor
24:50 Parkinson's disease. Do you remember Alright. And what we're doing is
24:55 we're trying to prevent the movement that don't want. All right.
25:01 in the trimmer, what we're not is we're not removing that, but
25:04 sort of movement you do. You not making the correct movements. Your
25:08 is already correcting and making adjustments before even move, which is incredible in
25:15 mind. All right. And it's being done here in the basal
25:20 So there's lots of structures here. already learned all of these, so
25:25 no need to walk through every single of them all over again because do
25:30 guys feel like being tested again on . Okay. James says no.
25:34 we're not gonna be tested on Good answer. All right. What
25:40 wanna do is we want to just here. Alright. And again,
25:44 not so much about knowing each of individual parts at this point. This
25:48 help you kind of look at and , oh I see now. I
25:51 how this is where information is being and that information is gonna be sent
25:56 to the thalamus, right? And I'm gonna do is I'm affecting them
26:00 cortex. Now. We haven't really about neurotransmitters. Alright. We've we've
26:05 them, you know here and We we mentioned and said, you
26:08 gaba glutamate and aspartame. We mentioned way back at the beginning of or
26:13 middle of the semester and I said don't need to memorize this big giant
26:16 of stuff. I said it's probably good idea to understand that Gabba is
26:20 inhibitor and I said it's probably a thing to understand that glutamate is excitatory
26:24 that was like what six weeks Something like that. So, but
26:30 want to point it out here because will help us to understand this,
26:34 we're regulating things. Alright. How basal nuclei works. Alright, so
26:39 thalamus is basically sending constant excitatory signals the motor cortex to tell you how
26:46 move. All right, So it's saying do this, do this,
26:50 this, do this, it's like instructions coming all the time at the
26:55 cortex. And so your motor cortex responds to the signals it's receiving.
27:02 right. That's because that's what it . But we need to get rid
27:05 the things that we don't need to . And so what we're gonna do
27:09 we're going to block some of the that are coming in from the
27:14 Alright. I'm making up numbers to that there's 1000 of them. Let's
27:17 say we're gonna block half of So 1000 signals. Let's just get
27:22 of 500 of them so that our only needs 500 signals to do the
27:26 to pick up the cup or All right there. See, I
27:31 that up. There's no shaking That's good. All right. So
27:42 where the part of the basil nuclear in. This is going to be
27:46 globus pilatus. Alright. Now its is to release gaba so that you
27:54 the thalamus. All right. You the thalamus. It can't send a
27:59 . So you're not stimulating the motor . All right. So it normally
28:05 Phil Amick activities. All right. , the direct pathway is from the
28:12 striatum. Alright. So in other , the corpus striatum up here is
28:16 saying, hey, I'm going to gaba onto this. Which is going
28:21 inhibit this. Which means I'm no going to block this. Do you
28:24 what I did there, it's a negative, I'm going to block the
28:30 if I block the blocker does the still block you're you woke up
28:37 you're a morning person, aren't Yeah, Yeah. You've had the
28:41 . If I block the blocker, blocker no longer blocks these signals allowed
28:46 go forward. But if I don't the blocker right then the blocker blocks
28:54 the signal can't go forward. So you see the double negative
28:58 So what's happening is is the corpus is inhibiting the internal globus pilatus.
29:06 it inhibits the global pilatus then it not inhibit the thalamus. If it
29:12 not inhibit the thalamus hypothalamus stimulates the cortex and you get a contraction.
29:17 right. So that's that's how we're with this. All right. It's
29:22 negative. So that would be the pathway. Alright? So inhibits the
29:26 pilatus thus allowing the thalamus to excite cortex. So, if I block
29:32 then it can't block that. If can't block that the missile is allowed
29:37 go forward. But that's not the way we can do stuff we can
29:43 stimulate in different ways. Right? there are other signals that can go
29:50 . All right now, we don't to know those other signals. The
29:56 here is that there are different pathways promote the activity of the internal globus
30:03 ? So, for example, the thalamic nucleus can activate the internal globus
30:10 so that will block the thalamus and I block Thelma's it will not allow
30:16 motor signal to be sent forward and think that's what the next slide
30:21 So the sub thalamic nuclei. All now it can be still stimulated again
30:27 the corpus striatum through of multiple Alright. Don't worry about the multiple
30:32 . I'm not interested in you knowing multiple steps. Alright. There's other
30:37 of the brain. Do you remember substantia nigra? Remember that word?
30:44 a region of the brain stem. job is to release dopamine. You
30:48 like dopamine? Oh yeah that's why look at your phones 24/7. It
30:54 pulls out the dopamine. It's like guess right. What it does,
30:58 activates the direct pathway inhibits. So it goes this way and it blocks
31:03 way. All right. So it's the brain stem it's called the substantia
31:08 because when you take a slice through basically that dopamine has a darkish appearance
31:14 so it makes that region of the kind of blackish. Alright. The
31:19 substance is what it's called substantial substance Black. All right. You can
31:28 back and look at the picture of brain stem and you'll see it.
31:30 big. Um Doctor Dryer. Do guys know who dr Dreyer is
31:35 No. So he's he's in the department one time he explained it to
31:39 . I thought it was just He says the way they that he
31:42 . It's like a sprinkler system of . Alright. Just constantly releasing dopamine
31:52 control different parts of the brain. right. So what does the basal
31:58 do inhibits unwanted movement? Okay, . We learned about the cerebellum.
32:08 cerebellum is job is to figure out the plan is going to be
32:14 How do I make a from here that wall? What are the things
32:20 I need to do? What I to contract? These muscles need to
32:23 those muscles, yada yada yada. . So it's going to tell the
32:29 the primary cortex through these different systems we just looked at what the plan
32:36 be. You want to get from to there, this is what you
32:39 do. Pre motor cortex looks at and says okay I got this plan
32:43 this plan in this plan. So are the things that we can
32:46 The thalamus says. All right. keep sending that information from the association
32:52 from the pre motor cortex or sorry the frontal lobe. And what we're
32:56 do is we're gonna keep track of that sensory input coming in and the
33:01 nuclear saying weight. You've lifted your too high. Stop doing that.
33:04 then all this information being sent back the cerebellum and saying in the course
33:08 doing whatever the activity is. We've to make adjustments along the way.
33:15 this is primarily dealing with coordination tone the actual movement itself but it's not
33:26 directly to the muscles. It's talking all these other parts. Now.
33:32 information. So you see it's sending impulses to the motor cortex and all
33:37 other places around. Alright, So cells are right here. These are
33:41 perkin ji cells. Alright. That layer right there. They're the ones
33:46 send the impulses to the cerebellum I All right, Sara Bella,
33:53 Beller, cerebellum. So the area you're processing information, the mossy fibers
33:58 what's receiving the information. So that's this is trying to show you.
34:03 up here in the cortex is where gonna see those nuclear, where you're
34:06 be processing information. But you have be getting information from places where where
34:11 gonna be getting them from the muscles , telling them how much they're
34:14 You're getting it from the regions like vestibular apparatus to sell you your position
34:20 your body. What am I Right. We described this a little
34:25 , said when I'm walking along and looking at my phone and I'm not
34:28 attention to the sidewalks in Houston because all up and down and I tripped
34:33 of falling on my face and breaking phone. What do I do?
34:37 catch myself? Right? I tripped I do this. Look around.
34:43 , No one saw. I'm And you keep going right. That
34:49 the job of the cerebellum. The was interrupted. I got to come
34:53 with a new plan and I got do it very quickly. All
34:58 and again, where do they They go to the uh vestibular nuclei
35:02 , that's balanced the red nucleus as as the motor cortex. So the
35:07 are being sent to deal with your , your body, your neck,
35:12 muscles that control all that stuff to that you're basically still holding yourself upright
35:19 the movement that you're trying to initiate still going on. So this is
35:25 picture I'd like to show to see how scary and confusing it can
35:28 be. This is the slide, sit there and go, I don't
35:31 to memorize this. This is just visual representation of all the things that
35:36 said, right, it's like all these things are involved in terms
35:43 you know, how is a movement cerebellum is involved? So here you've
35:49 cerebellum, parietal lobe, sensory frontal lobe, you know,
35:56 primary cortex, you know, pre cortex, all this stuff here's
36:03 basil, nuclear are involved in all stuff. All of these play a
36:08 and just simple movement. And I to think about that and go,
36:17 , that is incredible what our bodies do and then move on. So
36:24 incredible. Can you name very simply the cerebellum does. Can you name
36:30 the basal nuclei does, then you're good shape if you don't know,
36:36 that list, Ask the question, does this play a role? What
36:40 it do with regard to movement? . First we'll look at the direct
36:54 then we're gonna look at the indirect . What is the direct path?
36:58 packed? Play? How do you from here to home without stopping?
37:03 . So we're gonna have an upper gonna have a lower go straight to
37:06 muscle. Alright. The other name these are called the pyramidal tracts.
37:10 they originate in the motor cortex. going to project to the brain stem
37:16 down to the spinal cord. 1st . Cortical spinal tract one is called
37:23 Bulba track. Alright. The first should be pretty easy if you look
37:26 that, what does it tell Where does it start cortex? Where
37:30 it go spinal cord? Alright, enough. Second one's a little bit
37:34 . First where does it begin Where does it end in the neck
37:41 ? That's right bulb er is refers the head. Neck region is basically
37:46 region here of the brain stem. right now remember these are motor
37:52 All right. They're not sensory their motor tracks. That means they
37:56 a role in movement and we're not going forward. So if I'm dealing
37:59 this cortical spinal what kind of movement I dealing with my body And if
38:05 dealing with my Bulba region. If dealing with head and neck? What
38:09 I dealing with? Yeah. Its head and my neck. Alright.
38:13 my body is divided into two There was nothing that we haven't learned
38:18 . All right. So starting with cortical spinal track. All right.
38:23 these are the two tracks right the pyramidal tracts. We have the
38:26 cortical spinal track and the ventral cortical tracks. So the purple region here
38:30 the lateral this little tiny aqua just it green. Is that okay?
38:37 ? Okay, so that's really What what would that be teal?
38:42 . See I knew someone would The little teal area right there.
38:46 is the ventral cortical spinal tract. . Now, right down here you
38:52 kind of see kind of the distinctions the two. Alright. It's kind
38:56 a look. So first off with low lateral, it devastates in the
39:01 . So, remember you've already already you know that my left side of
39:05 brain primarily controls right side of my . All right. So when we're
39:10 about that kind of crossover that's taking up there in the brain stem in
39:15 medulla. Alright, so here it in the lateral funicula sis and its
39:21 is to control the appendix color skeletons is the appendix color skeleton. Upper
39:29 lower limbs, right? The things you don't need to stay alive.
39:35 right. We're dealing with the ventral , locating the ventral funicula us.
39:40 . They decorated the level of the course. That means they come straight
39:44 and then they cross over here. . And what they're gonna do is
39:48 going to innovate the axial skeleton, and trunk, right? So primarily
39:56 we're dealing with cortical spinal, it's to be trump right? Barbara is
40:01 to be head. Okay? Cortical . Our head neck region.
40:15 So we have the direct tracks going originate in the pyramidal cells of the
40:19 cortex. They project down to the stem. All right. And so
40:24 going to form the facial region of motor homunculus. You go back and
40:28 at that in one slide. You basically see it's Oh, it's that
40:31 of my of that primary cortex that's up here. It's the stuff that's
40:35 over here on the side. So where it originates. And it comes
40:38 here and it's gonna use cranial nerves get to where they need to
40:44 Alright. And what are we Muscles of the jaw? Face?
40:48 inks and tongue. All right. think of things that we do in
40:55 of movement here with the cortical bulger . Can you swallow? Okay.
41:04 Ferencz tongue. I don't like you . Huh? Okay. Moving food
41:12 the mouth. That works too Same with speech right? His smile
41:19 brown muscles of the face. All . So yeah, chewing as
41:25 So everything that's listed up here, ? Those are the structures that are
41:29 be innovated primarily through cranial nerves. right. That's how the cortical Bulba
41:39 works. All right. And we're of whipping through this primarily because a
41:50 of these things are just reviews Okay, So, that leads us
41:56 these four weird tracks, the indirect . And you can see the names
42:02 the stimulus, spinal particular, spinal tech does final. And if you
42:07 the last thing we learned in unit , were the structures of the brain
42:12 . Do you remember that? I you need to know this name because
42:15 gonna see it later. You're gonna to know this because you're gonna see
42:18 later, yada, yada, yada . Alright. That's what all those
42:26 . Is those things that we named the brain stem slide? I said
42:30 going to need to know that That's what all these are All
42:34 And you can see some of them laterally located. Right? So,
42:38 , you can see here it's two over here. You can see here's
42:42 that are eventually located. We're just walk through them. All right.
42:48 stimulus spinal tract. Alright. Remember we said, they're going to be
42:52 in the vestibular nuclei of the brain . Alright. And what we're gonna
42:58 is we're just gonna kind of break down here. All right. So
43:00 lateral vestibular. Alright. You can it's going to be uh sorry.
43:05 is. Let's see lateral medial. , so lateral is out here over
43:11 the side media which is just going come straight on down. And what
43:15 do is they're going to receive input the sensory neurons of the inner
43:21 They stay on the same side it's a lateral. And what they're
43:25 do is they play a primary role controlling your posture and your balance
43:32 The media ones. All right. gonna be more immediately located. The
43:36 of the stimulant, nuclear. And , what they're gonna do is inner
43:41 and the cerebellum and they're controlling the muscles to keep your head still while
43:46 moving? We're not pigeons. The stimulus spinal says in the name
43:57 vestibular deals with the equilibrium imbalance as said earlier. All right. Articular
44:11 , what's the thing in the brain that we learned about that starts with
44:17 particular, particular right particular formation. , now this is a region that
44:27 up and down through the brain Alright, so the two tracks.
44:32 remedial ones lateral the media one is ponte in one. The lateral one
44:37 referred to as the medullary. All . Now again, what are we
44:42 to do reflexive muscle movement, Some local motion. So we're gonna
44:48 dealing with both skeletal and autonomic. right. So, when you talk
44:51 reflexes, that's autonomic. Not always . I should be careful saying
44:57 All right now, what I want point out here is the medial has
45:01 effect on the X tensors. This going to be excitatory. These primarily
45:06 extensive muscles. So, what's an of an extension? Is this extension
45:11 is this extension This one right, outward? Good. Alright. So
45:18 are they located? Their synapses down in the ventral horn and then they're
45:24 going out through the ventral horn to they need to go. Alright,
45:28 ridiculous. Spinal primarily deals with extensive , ruby rose final. This one's
45:36 little bit more difficult to recognize, means red. So these originate in
45:41 red nuclei. Okay, Alright, here's the red nucleus. Alright.
45:47 a role in voluntary model function Okay. Collection. All right.
45:57 again, upper motor red nucleus get from the cerebellum project downward. And
46:04 are dealing with a contra lateral, its lattice contra lateral is on the
46:08 side. Right. So dealing with question of flexion. So, we
46:13 sorry, we have extension in the spinal tracts and we have flexion from
46:23 roof bro spinal tract. The last . Tech toe. Tech toe comes
46:33 tech tom. Alright, so the of the brain stem that's detect.
46:39 All right. So here controlling your movement into response to visual stimuli.
46:46 easiest example. Think of as a tournament. Right? Watching the ball
46:53 back and forth. Right. But can also think about when something goes
46:59 past you and you turn your head watch it. All right. So
47:03 visual stimuli. A promoter in Iran curricula sauce. Remember we talked about
47:08 super curricula sauce. Right? Then going to be some decoration or
47:13 depending on where you're located, you're to the opposite side and that's you're
47:17 to go down to the neck the cervical regions, Right? Because
47:22 are you doing? You're moving your to make your head move.
47:26 Visual stimuli. So those are the extra pair middle tracks, right?
47:37 not the direct pathways. So the couple of slides here are to help
47:45 kind of understand a little bit about in general. We have see PGS
47:51 central pattern generators. Alright. The , the easier thing to see here
47:55 than me walking up here because I get it wrong. It's hard to
48:01 walking in front of people, So my arms should be going opposite
48:07 legs now, are they? they're moving with. So that's what
48:11 if you start thinking about it, you're the brain makes you screw things
48:17 . But when you walk, you're supposed to be like this.
48:21 So this is a normal what I do it. I start thinking about
48:28 right. We'll go out there go in the quad and watch people walking
48:31 , you know, as they're trudging the campus, right? Their brains
48:35 been turned off, They're still thinking just hopefully making it into the
48:40 right? And watch them walk. you'll see that they have this pattern
48:45 walking. Now if you watch a or a dot, you'll see this
48:49 more clearly. Alright. And this movement that that you get this opposite
48:54 movement is a result of these CPG , but these are not the only
48:59 of movement that have CPG s involved , for example, I have
49:03 but chewing it's too early to be gum. Anyone chewing gum this early
49:08 the morning, Alright. Two people that stay awake, right? It's
49:12 like just Alright. So I'm gonna at the two gum trees right
49:16 Have you noticed that you're not chewing because you think you're in trouble?
49:19 not in trouble. This is not school. I'm not going to come
49:21 and say spit into my hand. hate it when they did that.
49:26 little lady had this teacher, she like a million years old and she
49:29 spit it out. I was I'm not fitting gum in your
49:33 Crazy lady. All right. But when you're chewing gum, it's like
49:36 say it on one side, And once you bite down the pressure
49:40 you biting causes you to repeat the over and over again, right?
49:46 then you get bored on one side then you kick it to the other
49:48 and you do the same thing. the same motion over and over and
49:52 . That's what chewing is. It's repeated motion that you uh you know
49:59 is controlled through the central pattern breathing is another one. Alright.
50:05 skeletal muscle. You don't have to about breathing but you could if you
50:09 to you could hyper you can hyperventilate on command. I didn't have to
50:15 to make myself hyperventilate like that. ? And so it's controlled. Your
50:22 is naturally controlled by these signals that causing the chest cavity to expand.
50:29 then once it reaches a certain volume stops the signal and allows the muscles
50:34 relax and then it repeats it over over again. So that's why you
50:37 this title breathing pattern that you don't have to think about. It's kind
50:43 nice. Right? So the way works is you have a series of
50:48 neurons that are clustered together that create signals. All right. They have
50:54 pacemaker property to them. And what gonna do is they're going to create
50:58 series of reflections and then they're turned and then another series of neurons which
51:03 them to turn off. Now create series of extensions and then they'll turn
51:08 because there's a build up in reflection that basically go back and forth.
51:14 so that's why you're able to go and forth between these two areas.
51:18 the CPI GSR all over the But they're reside in the brain some
51:21 the higher cortex to create these patterns behavior. All right. So walking
51:29 I said, is an easy one think about chewing as another one
51:32 But just think of any sort of patterns that are between reflexive and or
51:39 movement. Riding a bike right? have to learn how to do it
51:46 . Just like you have to learn to walk. But once you do
51:49 is riding a bike kind of right? Do you make those
51:55 It's like right that's your legs and . Yeah, dribbling a basketball that
52:08 . The ball bounced, playing with yo yo have you guys ever played
52:13 yo yo's Did you learn how to the dog? Shoot them in.
52:23 . You gotta learn how to do . So you can teach your kids
52:25 to play with the yo yo We'll him busy for like 3 4
52:30 All right. So we produce patterns create movement in certain circumstances. So
52:40 can imagine think about that that swirly and in there just jam in there
52:45 C. P. G. In some cases there's also a reflex
52:50 I can't remember if we ever talked this. I know it comes up
52:53 . So I'm just going to talk it again. The stretch reflex and
52:56 Golgi tendon. Did we talk about before? We did? Okay,
53:00 , I just want to remind you them. All right. So,
53:03 regard to the stretch reflex, remember is a mono synaptic reflex,
53:09 You don't have to think about It's all taking place down here in
53:11 spinal cord. And what you're trying do is you're trying to match the
53:15 of stretch and the extra fuselage fibers the intra and intra Feustel fibers.
53:24 , what are we doing? We I want to put my hands in
53:27 particular position, Right? So, I always try to do is think
53:32 if I want to hold something out this and if the weight becomes too
53:37 , my arm is going to naturally down. Right? And so my
53:41 is saying, no, no, . You need to hold this up
53:45 . And so, what you're doing is you're detecting the stretch becoming greater
53:51 the gamma motor neurons. And what gonna do is it's going to cause
53:55 to recruit more alphas so that you bring your arm back up into the
54:01 that your brain wants. That kind makes sense. So, that's what
54:06 stretch reflexes. Taking advantage of those different groups. That's what all this
54:13 talks about the Golgi tendon, on other hand is another reflex. That's
54:21 motor reflex and what it's doing that's at the degree of stretch here in
54:25 tendon? All right. So, you contract a muscle, remember when
54:29 contracting muscle, what are you pulling ? You're pulling on the tendon which
54:33 on the bone. You don't pull onto the bone. All right.
54:37 vice versa. When I use my I'm pulling on the tendon which causes
54:41 muscle to stretch. And so the here is I'm looking at what's going
54:46 inside that tendon. And so when tendon is being overstretched, the point
54:52 damage, that's gonna be bad for body. Would you agree Sharing your
54:57 ? Is that a bad thing? . Okay. So rather than tending
55:04 the tendon rather than causing damage to body, your body says, you
55:08 what? I don't want that to . So, what I'm gonna do
55:11 I'm going to block the contraction of muscle. I'm gonna let the muscle
55:16 so that the tendon is not going be stretched so that it's not gonna
55:22 damaged. And that's what the golgi reflex simply is it's basically detecting the
55:29 stretching the tendon, recognizing that's over , stopping the signal so that the
55:36 relaxes. So you don't cause harm stretched the tendon the way that you
55:41 think about this is if you're holding bunch of books and you keep stacking
55:46 and more books and that weight becomes than the the force. But let's
55:51 I have a gun to your head you dropped my books, I'm going
55:53 kill you, I'm a professor. ? So what's going to happen is
56:00 a certain point it's just gonna that's much. So your muscles stop
56:04 You dropped the books and then I'm have to kill you. All
56:14 These are the details through all of . All right. Oh,
56:19 see when I'm done. So or one more class. Autonomic nervous
56:29 fight or flight. All right. sounds good. Alright. How do
56:35 guys feel about extra credit? You extra credit? Of course you
56:46 Are you getting excited about the extra over there? She's like whispering,
56:49 gonna say something. Alright. So course, as you know, at
56:54 end of every semester, we have do the uh course evaluations.
56:59 And Normally whenever we do course we get something like 30% participation
57:07 Chairs and departments hate 30% participation They want big numbers. All
57:14 So, what we have is we're to have a group participation.
57:17 Group extra credits. Real simple. this every semester. All right.
57:24 I can I'm going to add up and it's not gonna sound like a
57:27 but one point to your final grade is actually a lot. All you
57:34 do is go and fill out the credit. If half the class Does
57:42 fills out the student evaluation, of evaluation, everyone gets .2 points on
57:48 extra on your final grade. If 60 0.4 If 70%.6 percent .8
58:02 . And then if 90% or more full point just for filling up the
58:09 you should be filling out in the place. Alright. So I don't
58:12 how much time is left in in system being open. It's like what
58:16 another week for some. So just do it. Get on the
58:21 Me tell all the yahoos you're still the group meet. You need to
58:24 fill this thing out, right? after it closes. That's when I'll
58:30 . I'll announce you at once. closes what the percentage is. All
58:36 . One more class. I don't the nervous system is fine.
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