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BIOL 2301 Human Anatomy & Physiology I - BIOL2301_lecture14_0628
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00:07 It's not about being the smartest. right, I'll have, um,
00:14 , I'll have blackboard up to uh, uh, later this
00:18 Um, because of the homework being last night, like midnight, there
00:23 like a, I couldn't upload those . I had to wait. So
00:27 all sorts of things I was waiting , so it'll be done later
00:30 Um, probably right after class. , I don't even know what the
00:36 on the tests were. Uh, know, like I could care
00:40 I just want you to learn the grades are there for the end of
00:42 semester. Um, I know you're there going really screw you. I
00:46 hard on that. But, you , whatever, um, what we're
00:49 do, uh, the rest of semester is all about receptors.
00:54 that's not true. There is. do talk about the autonomic nervous system
00:58 the very, very end. But what we're doing is we've already talked
01:01 the peripheral nervous system. We talked nerves, right? We talked about
01:04 cranial nerves and spinal nerves. We about where information is processed. That
01:08 all about the central nervous system. today, what we're doing is we're
01:12 go outside to the peripheral nervous system say, all right, well,
01:16 do we detect the world around Right. And that's what this whole
01:19 is on. And so today we're talk about the sense of touch and
01:24 we're gonna then talk about, I remember what the order is, but
01:26 gonna talk about the eyes, the , you know, the sense of
01:29 , the sense of taste. I we do smell and taste first.
01:33 we're going to your eyes and then go into ears. I think that's
01:35 order we do it. So we're with this with the senses and we're
01:40 look at then how does that information up to the processing centers or into
01:43 processing centers? And one of the we've already learned and you're gonna,
01:48 , you know, I know that of us dump that information it goes
01:51 . We study for the test, go take the test and we vomit
01:54 right back out or it's like, , that's I can clear my brain
01:57 I can put Taylor Swift songs back , right? It's, it's that
02:01 of thing. But remember what we , right? We had uh a
02:06 that looks something like this, I mean, here's our spinal cord
02:10 we had information go in and then have information coming back out again,
02:18 ? Something something like that I should that over there. OK. So
02:23 that look familiar to you guys? we use this for the reflex
02:27 And I said, hey, don't this thing right here because it tells
02:31 a lot of information, puts peripheral system into perspective relative to the central
02:35 system, right? And today we're about the special senses which uses this
02:44 . This is why it's one of important images. All right. So
02:49 can see up here on the slide talking about sensory receptors. So we're
02:52 be way down here at this end this fiber and asking the question,
02:58 do we detect information? All that's, that's ultimately what this is
03:02 about is how does our body know going on around us? So first
03:07 , what is a sensation, a simply is the conscious awareness of incoming
03:12 information? All right. Is it in here? Yeah. Are you
03:17 little cold, little heart? Are thirsty? Are you aware of these
03:25 ? As you chug your water drink what is water? How uninteresting?
03:32 right. All right. But So your awareness, your your your
03:37 knowing like oh I am blank. is a sensation. All right.
03:42 , this only can happen if the input around us actually makes it up
03:47 the cerebral cortex where we talked about frontal lobe, being aware of our
03:52 , being able to understand the thalamus basically serving as a information filtering
04:00 but it's the cortex, the frontal and the information that goes to all
04:05 different parts for the sensory input forced be aware of it. That is
04:09 . All right. So if I it's hot and you perceive it's
04:14 that is us processing that information and perceiving for ourselves what our environment is
04:22 . We are both correct, And we can play those fun philosophical
04:27 is my color blue. The same your color blue. Who cares?
04:32 doesn't matter. Blue is blue. we point at the same color and
04:36 you look at it may be different me, but it's still blue as
04:39 as we're concerned. All right. what is a receptor receptor is simply
04:43 structure that responds to some sort of , right? And initiates that sensory
04:50 to the sensory or to the central system. So remember it's down here
04:56 and then it sends information into the nervous system. So when we come
05:01 to this picture over and over you understand why I say it's so
05:04 . Now, receptors range in All right. So we may look
05:10 a cell and say that's a receptor we may look on a cell and
05:15 at the proteins in its surface and that's a receptor or what we may
05:20 is we may look at an organ the eye and say that's a
05:25 All right. So, contextually, should be able to pick up when
05:28 talking about a receptor, what we're about. But a receptor can be
05:33 along any of those ranges, A molecule, a cell or a
05:40 of cells working in conjunction together as organ system. And what then is
05:45 stimulus? Stimulus simply is a change the symmetry information. Right now,
05:49 room is bright. Would you Let's see if this actually works.
05:58 you perceive that it is now So what have we changed in the
06:05 ? What have we changed? You have light receptors, you have
06:10 light you perceive or receive less So you that information gets sent up
06:14 your brain and it says now it dark, see. So these terms
06:22 very basic, right? And they're to help us understand what it is
06:26 we're talking about. So when you the word stimulus, think it's not
06:30 the specific thing that I'm dealing That's modality, modality is what it
06:36 . I'm actually looking at whether it's , whether it's um you know,
06:40 , whether it's um smell, whatever is, right? Stimulus simply talks
06:46 the degree of change that's taking place that particular modality. Now, receptors
06:54 what we call transducers. All What does it mean to transduce something
06:58 means to change it from one form another. All right. Now,
07:02 brain communicates in one fashion. What the mechanism that your brain uses to
07:07 to itself? In other words, do cells talk to themselves inside your
07:14 ? Tight, tight junctions where we about it in terms of, of
07:18 type of signaling that takes place. kind of signaling takes place in the
07:27 as an chemical? If you'd said , I'd say sure that's fine
07:31 Right. But the idea is that use action potentials and graded potentials to
07:35 in the release of chemicals. So I cut a hole in your brain
07:40 shone it or shined, it it shined. I think if the
07:44 is shining, I'm looking for, ? We cut a hole back here
07:47 the occipital lobe. We know the lobe plays a role in visual
07:51 And if I shine a light into back of your brain, can your
07:53 perceive it? No, why? not a chemical? And it's not
08:01 potential, it's a light energy. light energy is useless unless there is
08:05 receptor to receive it. So what receptors do is it takes all these
08:12 modalities, the different things that we to experience the world around us,
08:17 externally and internally and turn those signals electrical impulses, what ultimately lead to
08:24 signals. All right. So that's whole purpose of all these different
08:29 All right. So see, I you, I never ask you a
08:32 . The answer is not right up on the board. So if I
08:35 at you guys and you're like, don't know, just kind of scan
08:37 , it'll be there. All So the first thing that receptors do
08:41 notice this is nothing new. We've learned. This right receptors are responsible
08:45 establishing and maintaining a resting membrane potential the plasma membrane of the cell.
08:51 right. So the idea here is I'm going to be creating action
08:57 I need to have some sort of potential in order for it to
09:00 All right. And then I'm gonna the right types of channels to open
09:06 close. So that then I can my resting potential. All right.
09:12 if I am a light receptor, have to be something that detects that
09:17 of energy, which causes a channel open, which allows a change in
09:22 membrane potential. That's all receptors It's changing the modality, changing the
09:29 form from one form to that electrical so that I can produce a chemical
09:35 . Now, we divide our senses two types. We have the general
09:40 and we have the special senses. right. So we have the special
09:45 and everything else. OK. General are very, very simple in
09:51 They can be either somatic or they be visceral. All right. So
09:55 , those terms come up again. does visceral mean pertaining to what organs
10:00 guts, right. So that's all means pertaining to the organs. So
10:04 are the things that are gonna be or housed in the walls of your
10:08 and they're detecting things like if you your coffee and it's too hot.
10:12 you noticed that it burns all the down? Have you noticed that?
10:17 , we have temperature receptors that are to see, make sure that,
10:22 , um, damage is taking place here and we just want you to
10:25 all right chemicals. Have you noticed everything that tastes sweet is awesome.
10:32 , even if it's horribly dangerous and for you. Yeah, those are
10:38 receptors and they're looking for specific shapes molecules that look like sugars. All
10:44 , they have stretch receptors, pain . These are examples of things that
10:48 going to be visceral with regard to . What we're doing is we're looking
10:53 uh either the sense of touch, is touching me or what we're doing
10:57 we're asking the question of what is position of our muscles and what is
11:02 position of our joints relative to where want them to be? So that
11:06 know with regard to movement where we . All right. So we have
11:12 that are detecting the degree of stretch our muscles. And in doing so
11:18 us understand the position of our This is what allows you to move
11:24 . Those would be the ex examples sense receptors or the general sense
11:30 That's where we're gonna be kind of today. The next two lectures are
11:36 be focused on the special senses. right. So these are the complex
11:40 organs. So notice this these kind have this implication that they're really dealing
11:45 the cell level stuff or receptor level . Here, we're talking about your
11:53 of taste, your sense of your sense of hearing your sense of
12:01 and your sense of balance. Now, equilibrium is one of those
12:06 things. So let me just, mean, not, not horrible in
12:10 sense but on the exam, equilibrium balance are interchangeable words, but balance
12:17 means other things. Doesn't it? homeostasis refers to kind of a balance
12:22 the exam. We're not talking about , we're talking about equilibrium. All
12:27 . So if you see the word in the context of this exam,
12:32 we're talking about equilibrium. All don't go oh I didn't know that's
12:38 we're talking about today. OK. , and this kind of shows you
12:44 the exception of the equilibrium, what dealing with nose, eyes,
12:49 an inner ear K. So that's of where we're gonna go so
12:55 Pretty simple. Straightforward. Yeah. . Good. I think you'll find
13:00 stuff interesting. Most people find this like the best unit in a MP
13:07 because it's like, oh OK. I know why my eyes work
13:10 I know how my, how things and how I integrate information and
13:15 All right. So what we're gonna is we're gonna first understand what anatomist
13:19 they like to categorize stuff. You've figured this out by now. We
13:23 to throw things in boxes, So one box that we can do
13:26 say, OK, where is the located? Is it detecting things on
13:29 outside of my body or is it things on the inside of my
13:33 That's an easy, easy category, ? Is it pointing outward or is
13:37 pointing inward if it's pointing outward and external origin stimuli, then what we
13:43 is an exteroceptor? All right. here we're talking about receptors that are
13:49 the body's surface. We're probably dealing tactile and also things in the mucous
13:53 because we don't really think about our membranes as being outward pointing our mucous
13:59 just in case you don't know mouth , right? Anus vagina,
14:05 Those are the outward pointing structures. guys, if you're staring at me
14:10 vagina, that's not you. All . And interceptors are inward pointing.
14:19 right. This is when we're talking those visceral sensory receptors and the somatic
14:24 receptors. So again, visceral, talking about what's going on inside the
14:28 . We've already talked about a little about the different types of things that
14:31 detecting. So temperature pressure, chemical so on and so forth. So
14:36 you're sitting around and all of a your stomach starts making that gurgling noise
14:40 you're like, you know, and can kind of feel the, that
14:43 in the stomach saying it's time to visceral because you're dealing with chemical and
14:49 dealing with stretch and all sorts of stuff here. The somatic sensory,
14:54 is going to be position and we're to talk about these, uh specifically
14:58 two types of receptors that we'll deal a little bit later. I'm not
15:02 if it's today's lecture. I think a little bit further on. I
15:04 it's on like the second last All right. So again, positions
15:09 the bone, right? Where are arms? Where are my hands?
15:16 hope none of you have ever had do the field sobriety test. You
15:19 , the Phil sobriety test is, know, there's some really funny ones
15:24 youtube like OK, recite the Now, tap dance. Now,
15:29 the shuffle, do you know? mean, they come, but the
15:32 is like the reason I can do is because I know the position of
15:36 body in space. But I want alcohol impaired, I can't do it
15:40 well because I'm confusing my position of in space. I'm not getting that
15:46 quite as clearly. So that's one outward, pointing, inward pointing,
15:52 and tero. Then we have uh based on their modality, right?
15:59 modality is just this freaky word. basically means what it detects.
16:03 That's all it means. What mode it? So these are just an
16:09 , this is not the entire All right. But for example,
16:13 have thermo receptors and it tells you the name I'm sensitive to changes in
16:18 . This is how I detect temperature and outside. Right? Notice it's
16:22 detect, telling you which way I'm here. It's only what I'm
16:27 Ok. Chemo receptors, chemicals, receptors, touch and pressure,
16:34 stretch, anything that is manipulating cells causing them to change their shape.
16:41 is what I'm actually detecting. There are different types of mechanical receptors
16:46 fall uh that are, are mechanical nature, but actually don't feel like
16:51 when you look at them. So receptors. So barometers, pressure,
16:57 , that's osmolarity. That's gonna be the concentrations of solute in uh your
17:05 and in your bodily fluids, proprioceptors with uh the detection of your body
17:13 space. So the idea of like have you guys been down to chemo
17:19 to Natural Science Museum? And they that, that human gyroscope?
17:25 it's really, really awesome. It's three rings you get into it and
17:30 have so many you pay a fee then one ring spins one way,
17:34 spring uh spins the other way and third one spins this way So then
17:38 like going all over the place. really awesome around spring break when you've
17:42 drinking a lot too. So, . All right. Maybe you don't
17:50 that one. ever been on a go round. Ever gotten dizzy on
17:53 merry go round, right? Because head is like, I don't know
17:56 I'm supposed to be. Right. . All right. When you stand
18:01 , you feel like you're upright, ? When you're upside down, you
18:04 like you're upside down, right? reception. And then the weird word
18:08 no C acceptor, no C section simply the detection of painful stimuli.
18:14 think I've said it before in the , but just in case, no
18:17 is the same route as noxious. the noxinoc I is the same route
18:23 so noxious is yucky, painful, . So that's the same sort of
18:28 here. Where does that pain come ? Well, all sorts of different
18:32 . So you can have specific chemical receptors, you can have heat,
18:36 receptors, you can have mechanical nose , you can have polymodal, meaning
18:42 the different types of pain receptors. no C section. So you may
18:49 other terms, different types of But typically this is kind of where
18:53 , we land in A P is this is like how we limit
18:57 But there are other types of things your body can detect. All
19:02 but usually falls into these categories. direction I'm pointing is what way I
19:10 look at it. What I'm That's another way I can look at
19:13 . And the third way is by again, anatomist, like, like
19:17 throw things in boxes going OK. what we're really doing here is just
19:21 of figuring out what are the That's, that's kind of why they
19:25 this stuff. And so when we're with classification by structure, we're asking
19:29 simple question, is there a capsule is there not a capsule when it
19:34 to um our, our uh neuron we're looking at our receptor? So
19:41 un encapsulated structure will have free nerve . In other words, the nerve
19:47 lack any sort of connective tissue surrounding . They just kind of infiltrate into
19:51 surrounding tissue. And so what ever to actually uh uh interact or uh
19:59 this particular nerve ending is enough to that cell? That's all there is
20:03 it. When you're dealing with encapsulated will be, for example,
20:08 this where you have connective tissue that the surrounding nerve ending. And so
20:15 gives it a much, much larger which it can detect from because any
20:20 of stimulation or manipulation of that connective will impinge upon or act on that
20:28 ending. All right. So that's way we can do it. Another
20:32 is we can ask the question. right. So is the receptor part
20:36 the neuron itself. In other is the neuron a receptor or is
20:41 a cell, a sensory cell associated the peripheral neuron that actually goes and
20:48 its way into the central nervous That's what these two are trying to
20:51 you. So in this latter right here, just making sure.
20:57 . So this is one cell. . And you can see here here's
21:02 processing, those are the dendrites. is where it's picking up the
21:05 there's the cell body and out here the axon traveling to the central nervous
21:10 . So the cell itself actually is the detecting. It's one long
21:17 In this case over here, what have is here's our neuron and it's
21:24 with the cell that's doing the All right. So this cell gets
21:29 , releases a chemical signal to stimulate axon or sorry, the dendrite of
21:35 neuron. That's what that is supposed represent. And that is what activates
21:41 signal to go up to the central system. So we're gonna see mostly
21:48 but in some cases, these exist well. OK. So when we
21:55 about the Merkel disc, the tactile , remember in the skin way back
21:59 and that first discussion of the anatomy I was like, OK, I'm
22:02 bored of you talking about all this stuff that is in anatomy. And
22:06 we finally jumped in the skin and threw all these things at you.
22:09 Merkel cell is that thing, It's a sensory cell associated with a
22:19 . All right. So far are with me? So, so far
22:23 different ways we can classify. Which are you pointing in or out?
22:27 you a general or are you a sense? What's your modality?
22:31 What, what sort of things are detecting? What's your structure? That's
22:36 thing we can do. And then , this is a fun one.
22:40 type of receptor response do I Are you a tonic receptor or are
22:45 a phasic receptor? Now, what is really referring to is the degree
22:52 adaptation that the cell actually does. right. So I just wanna make
22:59 . Um so with a tonic what you're seeing is this right over
23:05 , it's a slow adaptive receptor where phaser receptor is a very fast adapting
23:13 . Now, when you look at pictures, they don't mean a lot
23:15 you, right? I mean, basically a bunch of lines going up
23:17 down and you're sitting there going, have no idea, right? So
23:19 me help you interpret this. All . I want you to look at
23:22 top thing, this stimulus here. right. And I want you to
23:26 about the stimulus as being on or . OK. So when you're down
23:30 , that's off, when you're up that's on. OK. That's all
23:34 means. So you can say here am, I'm moving along at that
23:39 , stimulus occurs. So the stimulus on and it stays on and then
23:44 stimulus disappears. So now the stimulus off. So it's a binary state
23:49 off, right? Light dark as example. OK. So what we're
23:57 at here is we're saying, all . So no stimulation, I'm getting
24:00 receptor potential, right? In other , I'm not getting an action,
24:04 not stimulating the cell, but when turn it on, I can see
24:09 stimulating the cell. All right. what the second line says. And
24:14 down here, the third line well, what kind of action potentials
24:17 for me stimulating the cell? So showing you down here the act,
24:21 what those lines represent are the action . Notice it doesn't look like
24:24 Nice, cute little waveform because what did with the wave form is we
24:28 something and we stretch it out because the wave form is about 0.4
24:33 And here what we're saying is we have this time space to show you
24:36 that stuff. So it's just going and down. So 0.4 milliseconds is
24:40 place within that little line. All . So let's take a look and
24:44 what tonic versus phasic means. Tonic are very, very slow, adapting
24:49 that means is they're basically there to the brain the central or not just
24:53 brain. But the central nervous hey, stimulation is occurring. So
24:57 long as stimulation is occurring, it's to send a signal. That's what
25:01 means. All right. So let's here. I am no stimulation,
25:05 turns on, I get that initial of the cell and that cell stays
25:11 until the stimulation disappears and then it off and disappears. So notice it
25:16 adapted a little bit in this particular , but it hasn't adapted a
25:21 And what are the action credentials that produces? It keeps firing as long
25:29 the stimulation is taking place? All , when you're dealing with phasic
25:35 on the other hand, these only signals when changes in the stimulation or
25:42 in the stimulus have occurred. All . So when do changes in the
25:47 , just look at the top, do changes occur, has it changed
25:51 here? Yeah. Is a change here? No. Does it change
25:55 there? Yeah. All right. , the artist did a poor job
25:59 the bottom part. They're just focusing one half. They're saying look when
26:02 change occurred, I get a receptor . So I get a series of
26:06 potentials and then you would expect nothing happen because I've already adapted. And
26:12 what should happen is at this point there's a change again, you should
26:15 another a a series of action All right. So phasic receptors only
26:21 when or phasic responses only occur when change is taking place. Now,
26:27 example I use to help you understand is up until me saying these
26:34 you did not recognize that the clothes wearing are touching your body. Can
26:39 fit your clothes now? Yeah, you become aware of it because I
26:42 out now what's happened is you have receptors in your skin that are
26:48 right? And so this morning when woke up, you put on clothes
26:51 your body said very good. I now dressed to go outside. I
26:55 feel the clothes on my body. placed them there and I can forget
26:59 it now because I know that they're touching my body. So it's like
27:03 change has occurred, the clothes are on your body, but I don't
27:07 to keep telling my body or my . Hey, you're still wearing
27:10 you're still wearing clothes, you're still clothes. By the way, you're
27:13 wearing clothes, that's unnecessary. The time you need to be aware that
27:18 clothes are still touching your body is they leave your body. Ok?
27:22 you can imagine here you're going you put on your clothes in the
27:24 . But as you walked outside that , that's right next to the door
27:28 you've never cleaned up, grabs your and it tears it off and all
27:32 a sudden you're like, I don't a shirt on. And so you'd
27:35 that response again, right. That's example. It's a terrible example of
27:41 . It's, but it helps you of see it's when the changes
27:45 that matters. All right. So what phasic is. So it detects
27:49 onset and the offset of the All right. So far, so
27:56 . So four different ways that we define AAA receptor, right? Internal
28:04 modality, the different types of phases then whether or not you're encapsulated or
28:09 encapsulated. All right, and all them are legitimate, you just have
28:15 ask the question. All right. term that we use to help us
28:21 what area we're responsible for our receptor responsible for is called the receptive
28:27 So it's simply the area over which receptor can detect, detect that
28:33 So you can see over here in particular example, here's a receptor,
28:38 a receptor cell, there is, a free nerve ending. So as
28:41 as I'm able to stimulate this nerve this neuron along this area, anywhere
28:48 that area, I'm going to stimulate neuron, right? Anywhere where I
28:52 in this area, it's going to that neuron. Here is a larger
28:57 field that covers roughly the same So again, the same area,
29:02 it doesn't matter if I stimulate over , stimulate over there, I'm still
29:07 that one neuron. So the receptive here is larger, the receptive field
29:13 is smaller. If I touch with caliper, what would I perceive two
29:22 if I touch over here with that caliper spread apart? The same
29:25 how many things would I perceive just good? Now, you can do
29:31 at home, right. Find find a buddy, find a
29:39 get a pen or two and you your friend and say, hey,
29:43 , let me show you something. that way. Do you feel
29:51 Do you feel this? Ok. then you can walk it up,
29:54 me when you feel just one it's the same. Now, it's
30:02 same 11 sensation. So see how apart there look, you're in a
30:10 receptive field now, hope I didn't a lot of dots on you,
30:18 you can, but this, this in different parts of your body have
30:21 size receptive fields. So like in where we need to have fine
30:28 we're going to have receptive fields that very, very small so that you
30:32 get all that information to the So like on your fingers and on
30:35 hands, you have receptive fields that incredibly small, but like on your
30:41 and on the backs of your especially right. You do it on
30:45 back of the legs. It's like like this far apart and you're
30:47 OK, I feel one sensation. like because that's the receptive field.
30:50 whole field is very, very All right. Now, it's not
30:58 in touch that we're gonna see receptive . All right, we see them
31:03 the eyes and I'm just gonna show this for you real quick because we're
31:06 to talk about it a little bit . I want you to look down
31:08 your document, whatever is in front you. And I want you to
31:11 in on a word and see how clear. If it's not crystal
31:14 If you're standing staring at it, need to go see an optometrist because
31:17 probably need glasses. Ok. But you see if you just focus right
31:21 on that one thing and look at ? It's nice and crystal clear right
31:25 without lifting up your eyes, keep on that one little thing. Notice
31:29 everything around it without moving, your around is kind of blurry,
31:35 And your eyes desperately want to move and take that blur away,
31:39 It wants to shift. So you to see how clearly it is and
31:42 can see out here in the peripheral , how everything you can kind of
31:45 a sense of where things are, you can't see clearly what they
31:48 It makes you want to look over that item, right? The reason
31:53 is, is because your receptive fields your eyes are focused specifically at the
32:00 . All right. So when light in all the receptors are right there
32:04 the bull's eye, in the middle your eye. And as you move
32:08 , you have larger and larger receptive . So you get a sense of
32:12 out there, but you don't have expend all the energy to know what's
32:16 there. And if something catches your , what are you gonna do?
32:20 just gonna turn my eyes to look see what that thing is and why
32:25 made you look at that piece of . Because if you look over that
32:28 , you know, if you look that document, you'll notice that all
32:31 words around the one you're not focusing are kind of blurry. And so
32:34 you do is you move your eyes read and get your eyes to focus
32:39 the thing that you're actually looking So receptive fields have different sizes,
32:45 larger the receptive field, the more or the more um undefined the sensation
32:53 the stimulus is to the the central system, the smaller the receptive
32:59 the clearer the the uh stimulus is the central nervous system. Now,
33:06 probably should have put this up a bit earlier when we were talking about
33:09 potentials, receptor potential is simply a potential generated in the receptor. All
33:14 . So here's an example of the cell, right? The stimulus comes
33:20 opens up channels, we're going to things flowing in that's going to cause
33:23 greater potential when the greater potential reaches certain threshold, right, what we're
33:29 is we're changing the modality going, that transduction, we reach a certain
33:33 , we're going to cause release of chemical signal. That receptor potential is
33:38 an ax potential because it's happening in little tiny cell. So it releases
33:42 chemical and that chemical then activates the . And if I can get enough
33:48 to activate the neuron, then I'm to get an ax potential in the
33:51 to send it up to the central system. So the receptor potential is
33:55 to what's happening inside the receptor It is a type of graded
34:00 All right, it's just a fancy for graded potential telling us where it's
34:04 taking place. All right, but nothing that you haven't learned already.
34:11 just throwing another word on top of just to help you understand this
34:16 this concept that I've been trying to you throughout the idea what is a
34:22 ? If you had to define, you had to define to an
34:25 you know, what is a What would you say a ball
34:29 it's round, it's a toy or used in sport, right? But
34:33 round. Ok. So what is basketball then? Something that's around,
34:40 used in a sport, but it unique fixtures, right? That's different
34:45 what you find in a volleyball or soccer ball or a snowball?
34:53 What's a snowball? What's a snow packed in around thing that I throw
34:57 people. So it's still a toy sport, right? And then we
35:03 the weird one with football. So now we have to say,
35:07 , well, in terms of a , football is oblong, it's no
35:12 around. But what do we start ? We started with a single definition
35:17 we can use that as our ground move outward. And so with like
35:21 definition like a graded potential. All , we can move outward, things
35:26 potentials or EP SPS or IP SPS GP PS GP SPS, right?
35:35 see how we did that far easier remember one thing and then add things
35:39 top of it to broaden yourself rather trying to memorize 40,000 different things as
35:45 general rule. So adaptation is simply ability of sensory stuff to become less
35:57 to the continued presence of a So um this can occur at different
36:04 . So it can occur at the receptor cell or it can occur at
36:08 level of the central nervous system. simply a way for our body to
36:13 regulate or modulate the information that it receiving. All right. So when
36:19 hear that word adaptation, um it is um like for example,
36:26 that uh like the your clothes touching body, it's still happening, but
36:32 body doesn't want to waste the time the energy constantly telling itself that you're
36:38 being touched. That would be the . There's other terms that we may
36:42 . I can't remember if I teach in this class or if I the
36:45 one. But there's other terms that similar to that adaptation, like
36:50 you know, that have similar meanings are different. There's situation, there's
36:57 , which we saw a little bit when we talked about memory, there's
37:01 like um depression um which are just inverse of, of these things.
37:08 . So this stuff gets not but it's, you have to kind
37:12 pause and think about it. So language of the central nervous system is
37:18 potentials and chemical signals, right? chemical that's released is dependent upon the
37:24 potential that the cell produces and then gets down to that, that axon
37:30 . All right. So if I a little needle and I poke
37:38 I'm not gonna poke you this, gonna poke her at this time.
37:40 I'm gonna take the needle, I'm poke her and she'll go, what
37:43 you say? You wanna get She says ouch. All right.
37:46 now that wasn't a really hard Was it with that needle? It's
37:50 invisible needle. But if I take running start from over here and then
37:54 at you and jam as hard as can. Are you just gonna go
37:56 . Ouch. Now, what are gonna do? You're gonna scream loudly
38:00 then sue me and the university for of dollars. Right. Notice,
38:06 didn't even pretend. Right. so obviously the same receptor is receiving
38:14 , that signal, right? And needs to code in its action
38:20 the, the strength of that Now, in a greater potential,
38:26 could do so simply by saying, , greater potentials. Well, that's
38:30 . They have magnitude and duration relative the stimulus. That's that's stimulating
38:35 right? But an action potential I do that. An action potential is
38:38 all or nothing response, right? either get it or you don't.
38:42 how do I do that? it has to do with the number
38:45 action potentials that are encoded in the . OK. So remember it's how
38:51 can I put together? So here have different stimuli, right? Weak
38:58 , little pokey, middle, pokey start pokey. OK. What happens
39:06 regard to the receptor potential? receptor potential is a greater potential.
39:09 get a small grade of potential. get a medium sized grade of
39:13 I get a large grade of potential matches up to the stimulus right
39:16 remember what is a greater potential? just a signal that gets the uh
39:21 inflow of ions to the axon hili the neuron, right? And if
39:25 reach threshold, then I'm going to an action potential, right? So
39:28 I gotta do is get up to threshold. But if I have a
39:31 amount of chemical mass amount of ions to the Axon Hillock, then every
39:38 those uh those gates shut, they're be reopened again. Right? There's
39:42 this constant stimulation to try to keep gates open. So here I didn't
39:49 a strong enough signal. So I even reach threshold. So I don't
39:54 any action potentials, no action no action potentials, no, no
39:59 of chemical, right? But here get enough of a stimulus that causes
40:06 opening of those uh receptors or not of those channels, which causes a
40:12 of ax potentials at the axon hili you don't really get one, you
40:16 lots and then those are continued on results in the release of a certain
40:22 of chemical. So you can say action potential represents a certain amount of
40:27 being released. All right. But here, I get this massive
40:31 So I'm not just getting a few potential. So I get a lot
40:35 action potentials, a lot more action are carried on through the axon which
40:41 in a lot more chemical signal being . So the signal's intensity,
40:50 Bright light, right? Not bright , dark, bright light, I'm
40:54 gonna use that. That's an easy . Instead of being poked, not
40:57 light, lots of light don't detect light. So I see nothing,
41:02 black, it's blinding down here. would be simple staring at the sun
41:12 around the room as an example. , I'm trying to use hyperbole
41:17 to spread those things. So the that uh receptors code intensity is through
41:24 number of action potentials, that's primarily they do that. So magnitude equals
41:30 increase in the number of action A second way that we can encode
41:40 is by increasing the number of neurons are sending the signal, right?
41:48 you want to make a broad you don't keep yelling it louder and
41:51 because there's only a point where your reaches a max. So how do
41:57 get more your message louder? You people along the way to help spread
42:03 message. This is what this graph trying to stimulate or show you say
42:07 here's a receptor, it's just so on this one line, right?
42:11 down here, that's very little action up here. This is the maximum
42:16 of action potentials it can produce. so you can see as I increase
42:20 stimulation, I'm increasing the number of potentials in that particular receptor, right
42:28 that particular neuron, all right. surrounding that one receptor are other
42:36 And so as the stimulus gets bigger bigger, it starts spreading outward to
42:41 other receptors. All right, you kind of see this again, take
42:46 pen, pull out your arm look your arm, take your pin and
42:51 take that point and just poke it the skin and look, is it
42:55 a little point that goes down or your skin surrounding the tip of your
42:59 go down? Is it like a area that goes down? What do
43:04 think? It's a broader area? . It's not a single point.
43:08 , it starts as a single but the further you push it
43:11 the more skin and dense as an , right? And that's, and
43:16 is again, this is touch, you can apply this to any of
43:19 different ones. So you can imagine the surrounding skin, I have other
43:25 . So the harder I push down more receptors get recruited. So here
43:30 am, I'm going up. So receptor is pretty darn excited, it's
43:35 a quarter excited. And now what I doing? I'm recruiting in more
43:40 . So here's my second receptor I up to about what are we gonna
43:45 that? Like? 60%? And I'm down here at roughly 20%.
43:49 look, I'm recruiting a third receptor this one gets up to its
43:54 All right, I'm, I've reached . I'm as excited as I possibly
43:57 be. I'm just producing as much as I can. The second receptor
44:00 almost there. The third receptor you know, three quarters there,
44:05 fourth receptor which is nearby is starting get stimulated. And each one of
44:09 are sending their own signals, big , almost big signal kind of big
44:14 just starting to produce a signal. all of those are being received simultaneously
44:19 the brain. And the brain oh all these signals are coming from
44:22 same location with this degree of this is a really strong signal.
44:29 they must be being in this case with a pencil pretty hard as an
44:39 . So when we talk about intensity comes from two things,
44:45 The first slide we just saw the frequency of the number of action
44:50 Are there lots of action potentials? how quickly are they coming? Number
44:54 , how many fibers have been recruited to make it happen? Does that
45:00 sense? So previous slide number of potentials, so more action potential means
45:09 stimulation and then more neurons means more . So the two together is how
45:18 encode greater stimulus to the central nervous because we can't make bigger action
45:26 That's ultimately what we have to we can't make bigger action potentials.
45:29 it's in the number and how many number of actions plus number? All
45:40 . Now, don't you take a ? So you're poking yourself and you
45:43 feel the it feels pokey right? you do that, does it feel
45:47 when you do that? Yeah, of turn it over. Do the
45:51 edge does it feel pokey? it feels dull, doesn't it?
45:57 mean, you can still feel the . But yeah, I'm being touched
45:59 but it doesn't feel the same. is focused. This is not so
46:04 . Ok. Now, one of things that your brain does or your
46:09 nervous system does, and this is the peripheral nervous system is something called
46:12 inhibition. Now, again, this not limited to the sense of
46:16 This can be found in all these areas. And again, here we
46:19 see here's the pin and you can the multiple circles, I mean,
46:24 kind of hard, but there's like circles up there. Do you see
46:27 or does it just look like one looks like one look over there?
46:32 you see three circles there? C ? OK. What this is trying
46:38 show you is that this is that that you saw when you're poking yourself
46:42 that pin, right? And what saw is directly under the pin,
46:48 the point of highest stimulation. And you move outward, there's a little
46:52 stimulation and, and as you've moved out, there's even less stimulation.
46:55 you can just think of series of rings moving from center to out,
47:01 . So the more center you're the more stimulation you're getting right.
47:06 here in the center, there's a of neurotransmitter being released because I'm getting
47:10 of action potentials out here, I'm getting quite as much stimulation. So
47:14 producing less action potentials, but I'm getting some and then way out here
47:19 is no stimulation. So I'm not any action potentials. So there's no
47:24 . But if all three of these arrive at the same time in the
47:29 nervous system, the brain would perceive whole area is being stimulated. All
47:36 . And that would be like turning pins over and poking yourself with the
47:41 end of your pin. It would like, yeah, all of this
47:44 is kind of being stimulated at the time. So this is kind of
47:47 it's like, but your brain needs know specificity. See that little pin
47:53 there is causing damage, right? bad. So your brain probably needs
47:58 know where that damage is occurring, some generic location so that you can
48:03 that part of the body away from point of damage. All right.
48:06 grew up in the desert. Ever poked by a cactus cactus suck,
48:12 . I remember walking underneath. There a prickly pear. The uh I'm
48:18 pronounce it, right. It's like , I think I can't remember,
48:23 it's the cactuses that have like little like this and they're all in a
48:27 and if you get them, they have hooks in them and they
48:32 you and then when you walk they break off so that you now
48:37 that whole section. I remember that . And it's like, what did
48:40 do? I felt the poke and like, ah, I'm, I'm
48:43 away from it. Right. But it was still stuck there.
48:47 All right. But I had to where that pain was coming from so
48:52 could move away. That's important. , what we have is a process
48:57 the strongest uh, neurons in the , so, here we have this
49:02 , this is where we're detecting But here when we get to that
49:05 level of neurons, this is where do some modulation. It's like wait
49:09 second. Um I'm the most important . Uh the signals that are around
49:14 , they're not so important. So I'm gonna do is I'm gonna block
49:18 signals. This is lateral to the inhibition. I block the signal.
49:26 the signal, the only signal that up to the brain is that central
49:30 ? All right. Now, this nullify what I told you on the
49:35 two slides. This is just a of enhancing a signal so that the
49:40 perceives it more strongly. All this is what the brain would look
49:46 . Look would see without this sort lateral inhibition and see OK, here's
49:51 stimulus come from there and there's a bit of stimulation around here. But
49:55 lateral inhibition, what I do is completely block. So now look at
49:58 the brain perceives this is really important to the surrounding area. There's a
50:05 of stuff going on, right. a lot bigger than, than
50:11 And so the brain can respond appropriately that particular stimulus. Now, we
50:16 this a lot of places in the . Um Have you ever done any
50:21 those optical illusions where you're dealing with and whites and grays where it's
50:26 I used to show them in the , but I always used to run
50:28 of time. But it's like there's like shows you like a checkerboard pattern
50:33 then it shows like a an item top of the checkerboard and it says
50:38 can see the shadow on there. says, is this, what color
50:40 this? Gray? Is it the ? And your, your brain
50:44 oh no, that is a shadow I see this, but it's actually
50:49 same color white or the same color or whatever it is. That's lateral
50:54 . It's basically your brain looking at very, something very, very light
50:57 something very, very dark and they're them next to each other. So
51:01 wants to contrast those. But when put something next to those in between
51:06 like in between, it's gonna well, the grade is slightly
51:11 So it's using these contrasts via lateral to make them more dark, makes
51:17 blacks more black, the whites were white when you're doing this type of
51:21 and stuff like that. So that's an example of lateral inhibition. It
51:26 a greater contrast. So the brain then use that contrast to help it
51:33 with regard to its perception. So far, are you OK?
51:41 the letter or you, you got later on a look like I have
51:44 idea what you just said. I take the five minutes to look up
51:50 look up the I'm not gonna do . All right. Do I need
51:56 explain it a little bit better? . OK. You sure.
52:00 All right. So let's talk about sense of touch. All right,
52:07 receptors. So as I said, that stuff we just did is kind
52:12 this generic understanding of receptors. So we talk about the nose, when
52:16 talk about the eyes, when we about the ears, all those things
52:20 applicable and are, are being used these different types of receptors, the
52:26 sensory. So the sense of touch important or is not important is,
52:31 , is uh done through these tactile . These are meca receptors. What
52:38 doing is they're detecting the changes in surrounding tissue or the surrounding cell or
52:43 cell on which they're associated. So are primarily in the dermis. There
52:47 be some found in the sub Q . So the subcutaneous layer that's way
52:51 here right there. It can be simple or they can be encapsulated in
52:57 . All right. So we have characteristics of the terms that we just
53:05 . There are three different types of sensations. All right, we have
53:09 sense of touch. This is basically going to tell us where, where
53:13 being touched, right? So that's . What is the texture of the
53:18 touching us? What is the the shape, is it moving when
53:24 were kids? Did you guys go Halloween parties? Yes. No,
53:29 , no. Ok. We would to these Halloween parties and they would
53:33 off all the lights before the smooching . That was, that was junior
53:36 when the smooching began. But prior the smooching parties, uh, you'd
53:40 to Halloween party and they turn off the lights and they bring out like
53:45 of, of stuff and say, what's in the bowl and they'd be
53:48 , it'd be like grapes and, know, like you're touching eyeballs,
53:52 like eyeballs and then they'd bring out spaghetti, cooked spaghetti. It's like
53:56 touching brains, it's brains right Part of that is, you
54:02 the I'm telling you what you're touching so your, your perception is being
54:07 by what you're being told what it . All right. But really,
54:11 know, cold spaghetti kind of feels brains. Well, at least what
54:17 think brains would feel like brains really like warm butter. Yeah. And
54:22 told you already didn't have a good to it, but there's things that
54:29 can do. Like, um, went to a conference once where it
54:32 like to demonstrate that they had the mystery box. You put your
54:35 in the mystery box and it was , what are you feeling and write
54:39 all the different things that you feel the mystery box which you think you're
54:43 and it's to demonstrate, you that you are informed by simply by
54:48 with the receptors that we're looking You can determine what it is based
54:52 what you feel? Right? Is hard, is it soft? Is
54:56 , is it fuzzy? Is it ? Does it wiggle? That's scary
55:01 it wiggles, right? What's Well, that's the deformation of the
55:05 tissue. So that kind of informs and usually when you're dealing with uh
55:11 , it's what's pushing against you, , what are you pushing up
55:15 And then we have vibrations which are , repetitive sensory signals to inform you
55:21 of, of pleasure necessarily, but gives you a sense of grip.
55:25 so like I, I've told you , you can run your fingers across
55:28 table and you can feel the movement your fingers along the table. But
55:33 movement is a function of vibrations because those raised uh epi epidermal ridges,
55:39 basically bumping up and down and they're that smooth uh movement along the surface
55:46 would be, uh, a particular of vibration. You guys seen those
55:54 ? That's, that's the old timey . People thought you could lose weight
55:58 doing that. Instead of exercising. come back in every 20 or fif
56:04 , 20 years. So you'll see advertised on late night television.
56:09 yeah. You guys don't watch There you go. They'll, they'll
56:14 up with something every single solitary Yeah, it's, it's, it's
56:18 . You stand on them, you a drink, watch a show.
56:21 know, you feel like you're doing and you walk off and your whole
56:24 is like, yeah, my grandparents one of them and I was,
56:29 I was like 8 10, I'd in. It was awesome. All
56:38 . So here's where we're going to back into those receptors that you've already
56:42 . All right. So, part this is like, if you learn
56:45 the first time, then there's very for you to learn here. But
56:49 just gonna like, add, a little bit to the things that
56:53 already learned. If you didn't learn the first time, here's your opportunity
56:55 learn it again. OK. So have the un encapsulated tactile receptors.
57:00 are three basic types. We have said that they have these dendritic endings
57:04 lack any sort of encapsulation. They , they don't have a protective
57:09 They're basically free nerve endings. And three types, one called a free
57:13 ending. All right. So we the free nerve ending root hair
57:17 Do you guys remember that word? . When we talked about hairs and
57:20 the last one is the Merkel disc the tactile disk. So these are
57:24 gonna be found at the level of um uh really kind of at the
57:28 all throughout your epithelium. Anywhere you epithelium, you'll see these things and
57:34 are mostly unmyelinated. So when you the word unmyelinated, what do you
57:38 of in terms of the speed of signal? Slow? All right.
57:45 they're very slow. All right. let's walk through them. Now,
57:53 free nerve ending, the root hair is we lump together because they're really
57:56 same structure as just where they're All right. So the free root
58:00 plex, uh the root hair plex , is wrapped around the base of
58:03 hair. So here you can see it is. So when you tug
58:07 a hair, you can actually feel pulling on that hair. All
58:12 And then here you can see the nerve endings, they're just kind of
58:15 up, they're going up in here the epidermis in this particular model,
58:19 they're trying to show you. So lie close to the surface. They
58:23 very slow, they can be rapidly . So they, they are the
58:28 complex, but they can, they under all different types of ranges?
58:32 they there to give me a quick ? In other words, do
58:35 they constantly tell me I'm being touched are they telling me here's the change
58:41 the stimulus? They can be either the fast adapting, they can be
58:43 or they can be phasic is what trying to tell you. Right.
58:47 other thing is that they're not just touch, they can be all
58:52 they're polymodal. All right. So can be detect touch, they can
58:58 pressure, they can detect stretch, can detect no c so they cell
59:04 . So no, some so no acceptor are free nerve ending, they
59:09 detect temperature. So they can be as well. So they run the
59:16 , they can be in many different of receptors, but we typically think
59:20 them in terms of the touch The tactile disk or Merkel's disc is
59:27 tonic receptor. It's located in the basi. So here's our strata
59:34 right? So there's our Merkel disc is a sensory cell. The neuron
59:41 associated with sensory cell. So this where the receptor potential would be because
59:45 releases the chemical stimulates the neuron signal sent back up to the central nervous
59:51 . This is what allows you to fine touch texture and shape is what
59:56 looking at here. All right. there are three easy ones. Then
60:05 come back to the four. I we only learned three last time.
60:10 ? OK. So the fourth one is just, it's not really um
60:16 new other than where it's located. right. So we have Mesner Ruini
60:21 PA which is what you've learned So, Kraus is the new
60:25 All right. So again, what we have? We have connective tissue
60:32 around the ends of the neurons. right. And they're putting crafts in
60:40 , but it shouldn't be in that . Now, these are mostly mechanical
60:44 . So they're detecting uh manipulations or in the skin. Now, here
60:49 get to kind of see how they're located, why it's not just where
60:53 located within the depth of the It's also their structure is different why
61:00 guys got to when they discovered it like, oh, this is different
61:02 the other ones that I'm seeing and was really what they're detecting came
61:07 It was their discovery in terms of . So here what we have is
61:12 dendrites come up and they get all and they're wrapped into each other and
61:17 arranged in these horizontal uh Elli these basically these layers and then you
61:24 the connective tissue and you wrap each these things up. And what this
61:27 is it broadens the detection area. right. So in the free
61:35 you have to actually stimulate the end the, of the nerve or the
61:39 . Excuse me, not the nerve , I can stimulate over here and
61:43 stimulate this because it's going to impinge the connective tissue. So where do
61:50 find these papy dermal layer? So can see here is the paille
61:58 And if, if it helps OK, what do they deal
62:04 Light touch? Makes kissing feel The first kiss, the deeper kisses
62:11 gonna be something else. All And then the light vibrations that's that
62:15 these are phasic receptors. So they're telling you you're being touched.
62:21 , the touch has been removed. here, we have um collagen part
62:33 the connective tissue. And what we're is we're taking the neurons and the
62:39 nerve endings of that neuron and wrapping around the collagen. And then what
62:44 gonna do is I'm gonna wrap that with connective tissue. So when I
62:49 on the collagen or bend the what am I detecting? I'm detecting
62:57 in that collagen. So that's what actually detecting. Now, this is
63:03 tonic receptor. It's found in the ranges, right? So it's in
63:07 dermal layers down the middle ranges. so this is going to allow us
63:13 detect movement in that material. the example your book uses and so
63:19 put up here is like you have lot around your fingertips. And so
63:23 you're grabbing onto something, because that's we do is we grab with our
63:26 . And when you feel the things along your fingertips, that's telling you
63:30 losing your grip on that thing. that's what it's actually detecting.
63:35 skin distortion, deep pressure. And , how do I remember? Deep
63:40 ? It's because of where it's It's in those middle ranges. The
63:49 one is Krause's. Krause is like , all right, similar in all
63:59 , except for one thing. It's it's located. So Myers's is located
64:07 in skin like in the in, know, the epithelium on the
64:12 Kraus, on the other hand, a little bit deeper. So it's
64:16 found in the dermal layers. So in the reticular, not in the
64:20 layers and it's located in the mucous . OK. But again, light
64:27 detects temperature vibration, all that All right. So, but it's
64:32 oral nasal vaginal and anal cavities. where you have a mucous membrane,
64:38 is replacing for the most part OK. So if you have to
64:44 it's like OK, if I know , I know Kraus Kraus mucus
64:51 then we have Pacinian. Remember Pacinian the one that is um kind of
64:57 that. Did I get that? ? So I think Ruini is actually
65:00 deepest layers can never trust the OK. Um Sorry. Uh So
65:11 , this is gonna be reticular. , this is deep particular. So
65:14 is the deepest, it deals with deepest pressures, high frequency vibrations.
65:18 the ones that get down, the uh low frequency is just gonna be
65:22 there on the surface. Typically, find these uh palms of your
65:26 soles of your feet and in some the funner areas. So anywhere you
65:30 hairless skin, um what we have is, here's your nerve ending goes
65:37 and then you're just gonna keep wrapping in, lay over and over and
65:42 again. And so what you have again with each of these is you've
65:47 the receptive field. So if I from this side, I don't have
65:52 just there, I can simulate I can stimulate there. I can
65:54 on the side because any direction from that stimulation is going to occur,
65:59 is going to impinge upon this uh tissue which is then going to impinge
66:05 that nerve ending and going to create mechanoreceptor. All right, this is
66:12 adapting. So it's a phasic type receptor. OK. So those are
66:23 tactics. How many of you guys spicy food? Like really spicy?
66:32 ? What's your, what's your level spice? What do you think?
66:38 go hire ghost pepper and I'll go someplace in there. Maybe Serranos.
66:45 . Serrano peppers. So I lie ghost pepper and Carolina Reaper.
66:52 Right now I'm running out of my Reer sauce. I'm really kind of
66:57 in it. I don't like just . It has to have good
67:00 If it doesn't have good flavor. don't like it. Right. So
67:03 my wife likes poblano peppers. I Poblano peppers taste like dirt.
67:07 so I don't like to eat I don't think they're spice. I
67:10 don't like to eat them. Um Habaneros are, you know,
67:16 got a good spice level to Right. But they're, to me
67:19 too sweet. You, you have have them with like with sweet things
67:22 mangoes and stuff. And so you the compliment there. All right.
67:26 I bring this up because when we of spicy food, right on
67:32 we we call it hot food, ? I mean we say it's spicy
67:35 if it feels hot, it makes mouth burn, doesn't it?
67:39 And the thing is, is that we have is a chemical capsacin that
67:46 to a thermoreceptor in our mouths. the same thing that like when coffee
67:51 those receptors, you know, hot , starbucks level coffee, you
67:55 it's like molten and it's like ah , it's the same types of receptors
68:01 our mouths that respond to spicy foods other types of things. So,
68:06 receptors are the things that detect changes temperature and they belong to a class
68:12 , of receptors called TRP channels. it's transient receptor potential cat ion
68:19 I'm not gonna ask you this. right. It's just I want to
68:22 you that they're all related to each . And so here they are.
68:26 you can see here's top one eight TRP, uh, it looks
68:32 a four or 30, yeah, , they have different pre, uh
68:37 . So there's V one V so on and so forth. All
68:39 . So you can see there's a bunch of different types. All
68:44 these are, uh, channels that up and allow calcium to enter into
68:48 cell. And so that causes the to polarize and that's how you detect
68:52 heat. They uh primarily deal with temperatures, they don't deal with
68:58 And so anything below 10 degrees Celsius don't really detect. So,
69:04 anyone here ever been burned by dry , I'm gonna just use the word
69:08 by dry ice. Like you got get dry and play with it.
69:12 , never played with dries. It's funnel toy. You go in the
69:16 , unsuspecting, do not do I did not teach them this,
69:19 is just blah, blah, but dry ice burns, doesn't it
69:53 ? I mean, that's how you rid of warts. Alright.
69:57 it doesn't burn it. Just, body can't tell the difference between
70:00 really hot and really, really It's just, I'm gonna give you
70:04 sensation of burning. All right. we have a lot more coal receptors
70:11 the hot because at a certain you know, um, do you
70:16 it's important for you to distinguish between and like molten is boiling, gonna
70:22 and burn your skin. Yeah. do you think Moulton is gonna
70:27 It's gonna burn your skin. So not important for you to know how
70:35 hot something is. All right. as long as you can understand the
70:40 where danger is occurring, that's really you're more interested in. It's more
70:44 that we're more cold resilient than we heat resilient except for us crazy people
70:49 live here in Houston. But so why we have more of the cold
70:57 . All right now. So thermo respond to temperatures, primarily cold.
71:03 up to there are some heats and showing you that range, but they
71:07 have some of them that can respond specific chemicals. So menthol, we're
71:13 gonna pretend like menthol cigarettes don't exist um like mint, you know,
71:18 you ever eat New York peppermint You do this afterward. It feels
71:23 of like cool, gives you the of coolness, right? Caps.
71:31 mentioned spicy food, right? What doing? It's binding to a
71:37 Look at the list up here. is cinnamon spicy kind of,
71:44 When we were kids, you could to the pharmacy and get a cinnamon
71:50 . You could, you could buy and you'd take toothpicks and you'd,
71:52 would soak the toothpicks in the cinnamon you take them to school and you
71:56 just suck on the, basically like candy. Now they just let you
71:59 candy in the classroom, you But mint camper, you know,
72:05 came for us chili. It's spicy , more camper. So it just
72:12 you, you don't need to know ones activate what that's not important.
72:15 just showing you, you know why things have that kind of, that
72:20 of spicy or cool. Yeah. see that question. No,
72:25 no, no, no, I'm trying to show you these are just
72:28 because I think you know what Mintha right? And I think, you
72:31 what is now, it's the spicy the chili. So mammals have receptors
72:37 these receptors. Birds don't. So you have squirrels in your bird
72:43 what you do is you Sprinkle your with chili powder. Squirrels don't like
72:50 want to do something really fun. know how the squirrels all beg you
72:53 food. All right, you wanna something fun, give them a jelly
72:58 or whatever and they're just gonna oh, that's great. And then
73:00 give them a pickled jalapeno. It's , I'm not in, I'm not
73:09 uh recommending torturing animals. Just, experimentation type stuff. All right,
73:19 receptors, no cers. So this a subtitle of the free nerve
73:24 So we already kind of mentioned free ending. So this is what we're
73:26 , they're very slow to adapt or don't adapt at all in other
73:30 they are just gonna be telling you , pain, pain, pain,
73:32 , bad things are happening, which sense, right? Because pain simply
73:38 I think I have it on the slide. Let's just say protective mechanism
73:41 prevent tissue damage. All right. a pain receptor, you want it
73:47 con continually tell you bad things are because you want to stop doing
73:53 All right. So there's a whole of different things that it will respond
73:57 . It will respond to cellular it will respond to specific noxious
74:01 it will respond to cellular signals. in other words, other types of
74:06 messages telling you damage is occurring or damage has occurred. So these
74:12 things that cells might release to tell that damage is happening. There's different
74:20 of pain, fast pain, that's that felt, it's like the sharp
74:25 . So, you know, you yourself, you're like, oh,
74:28 would be a fast pain, slow would be more of an ache.
74:33 that's, you know, as you older, that's what you have always
74:37 , that would be chronic pain. uh, you know, so this
74:40 that dull, unpleasant pain. You actually define where it's coming from.
74:44 the, where the sharp pain, could say it feels like I've been
74:49 right here. That would be an , acute, sudden onset. But
74:54 you remove the stimulus that goes so you go to the doctor,
74:59 start poking around and it's this, is an acute pain, you
75:02 they press on your belly. ok. You have appendicitis. That
75:06 be the acute pain. Right? pain is simply that which originates from
75:11 abdominal organs. All right. So can have an acute visceral pain.
75:16 are just terms to help you kind understand. All right. Typically visceral
75:21 is local or is not well it's kind of diffuse as well.
75:27 we have this fun one referred So referred pain is interesting. So
75:34 is more for, for your sake really, I'm probably gonna ask you
75:38 is referred pain, you know, really what this is, is the
75:43 of pain from the viscera felt in region or a dermatome. That isn't
75:51 the pain isn't actually originating. All . So it's a false sense.
75:55 so this is kind of a map show this. There used to be
75:59 show called Sanford and Son. You have seen it in syndication on Nick
76:03 night, maybe, maybe. All , probably not, right? Redd
76:09 . Uh would at least once an , if not twice an episode would
76:14 like he's having a heart attack and be calling to his dead wife,
76:17 know, Elizabeth I'm coming and what he do? What, where would
76:21 grab, he'd grab his chest. where would, where does someone with
76:24 actual heart attack usually grab their right? Guards on your arm.
76:31 why? Well, the idea here that the tracks, the sensory tracks
76:38 up through the axilla are the same that are going to join up coming
76:44 the sensory receptors around the heart and originate in different places, but they
76:50 along the same pathway. And so information isn't what the brain really
76:57 It didn't know where that sensation is coming from. So it perceives that
77:03 it's traveling the same pathway that it's from. The, the this the
77:09 from which the sensory fibers in the are coming from. And so your
77:13 has a whole bunch of these and just kind of, you know,
77:17 makes sense. It's like, oh , well, my ovaries are kind
77:20 right here. So it would make that I've get sensory pain in this
77:26 dermatome, right? The heart doesn't all that much sense, right?
77:32 I'll see another weird one. Spleen in your spleen. Oh, my
77:40 is killing me. You know where spleen is located back over here.
77:46 . So I don't think you really too much about pain in your
77:51 but lung liver gallbladder, pain in neck, my liver's killing me
78:03 but you kind of get the So it's perceived on the surface,
78:10 it's referring to visceral pain. Why we care about this? Well,
78:14 because physicians use this to aid in , right? You come in jaundice
78:20 you have pains in your neck. definitely have liver issues. All
78:26 Come in, I don't feel so . My arm's kind of hurting in
78:30 . It's kind of this tingly Well, we better go figure
78:33 you know, deal with this heart that you're having that sort of
78:42 So, what we're doing now is going to introduce ourselves to the
78:49 OK. This is where most when you start dealing with the neuron
78:53 where they kind of back away and , I, you know, it's
78:55 hard for me. All right, gonna tell you right now. It's
78:58 too hard for you. It's actually straightforward. Now, if you become
79:02 neuron anatomist and you're like having to all the different tracks, then it
79:06 pretty complex. But for us, pretty straightforward when we are dealing with
79:11 these tracks, you're gonna see that are, we name the order in
79:15 the neurons arise. All right. if it's the receptor neuron, you
79:20 , the first neuron is always going be the first order neuron. The
79:23 on which the first order neuron connects going to be the second order
79:27 And sometimes you'll have a third order , which I think I'm going to
79:30 about in just a moment here. with regard to the pain pathways,
79:33 we hear is we have two All right. First order neuron,
79:38 the one that's receiving the stimulus. here what are we touching attack?
79:45 doing, we're doing the the aurora , right? Sleeping beauty. Don't
79:50 the sharp spindle. If you touch sharp, sharp spindle off to
79:55 you go. All right. So we are temptation, gotta touch,
79:59 touch the spindle. First order neuron which way it comes in dorsal
80:07 Where is it cell body, dorsal , right? It comes in terminates
80:14 . So where it always terminates in dorsal horn has an interneuron.
80:19 Here is our second order neuron, comes outward. OK. So it
80:26 out into the gray matter. So it's not returning, it's not doing
80:30 here. And now we're going up the brain because we're trying to
80:33 So what we're doing here is we and up we go boom,
80:37 boom, boom, boom, we to the thalamus. What is the
80:42 responsible for? Where does this information to go? Right. Thalamus sends
80:51 information to different areas. So in case, what we're saying is going
80:55 the scent cortex, why we got know where that pain is coming
81:00 But that's not the only place the , remember sorts information, it sends
81:05 to different areas, it sends it the insula, for example, remember
81:10 . So the cortex of the insula be the insular cortex. What am
81:14 doing? There. Well, what of pain is this? Is
81:18 is this a pokey pain? Is a pain that is really kind of
81:23 itch? Is it a pain that nausea? You know, all sorts
81:27 things? So here, what we're is we're distinguishing the type of signal
81:31 we're getting in the insula. So things are happening simultaneously, right?
81:36 then we can go to the cingulate . All right. Remember we talked
81:41 that. That was part of the system. The emotional part here,
81:46 trying to say, OK, what this pain make me do?
81:50 If I poke a needle, what I gonna want to do? I
81:54 move away. All right. It's just a reflex. I mean,
81:58 can, I, I don't have have a reflex here. I can
82:00 think if I can. Oh, a pin, I can step.
82:05 guys watch oceans. I think it 13. You watch any of the
82:10 movies. Go watch oceans movies. , they're fun. You know,
82:14 rooting for bad guys. It's the type of sensation. But there's a
82:18 where one of the characters is doing lie detector test and the way that
82:22 make him overcome the lie detector is put attack inside his shoe. And
82:26 time they ask him a question, pushes down an attack so that he
82:30 a visceral response to him stepping on , right? He has to.
82:35 whether it's, he's telling the truth whether he's telling a lie,
82:38 he's, he's in pain. And so the lie detector test can't
82:43 between the lie and the truth that doing. So, what's my
82:50 Right. Normally I'd want to pull hand away. All right. I
82:54 like the pain. Pain is but maybe I need to work through
82:57 pain. Maybe I need a lie a lie detector test. All
83:02 So you can see the signals are in all sorts of different directions so
83:07 we understand what the, what we're to do with that pain. All
83:13 . So the thalamus is where we're from and then off, it goes
83:17 the different areas. All three of , these would be third order neurons
83:21 is what we would kind of refer them as there are different types of
83:27 . They're based on their diameter, degree of myelination. And ultimately because
83:33 those two things, they conduction So you can see here we have
83:36 alphas, a betas, a deltas fibers. I don't know what happened
83:39 the B fibers. They probably but I've never seen a chart with
83:43 . Um And you do again, you think you need to memorize
83:46 No. All right. This is to kind of give you a sense
83:49 like how they're doing this. So A alphas are going to be
83:55 So they're big, bigger the the faster the fiber and they're
83:59 If you're myelinated versus unmyelinated, it's be faster. Right. So,
84:03 are the fastest ones, they're thick they're myelinated. All right. So
84:07 is when you're getting those sharp you're telling the central nervous system very
84:12 . Um, bad things are damage is occurring, deal with
84:15 All right. So, if I you with the baseball, so I'm
84:19 tossing the base R and I fling . You're looking in the other
84:23 it hits you. What do you sharp pain? A alphas? All
84:30 . We get down here to the deltas. So know we skipped over
84:34 . There's a, a betas, deltas and CS. We get down
84:38 these. Now we're, we're not thick, we're thinner, right?
84:43 not so thin. We have we sell myelination. So we're not
84:48 fast, but we're faster than the that are not myelinated here. What
84:52 doing is we're doing the, the pain or the aching pains.
84:56 if you get hit by that have you noticed that it goes
85:02 flump, flump, flump, That's what you'd expect here in the
85:08 deltas. Ok. So that, recurring, hey, uh, damage
85:14 occurred. I'm just reminding you pain , is ongoing. There you
85:19 The C fibers, we're also dealing different types of stimuli. This would
85:22 be kind of that th thudding Oh, you've damaged, there's bruise
85:27 every time you move, things You know. So, but it's
85:31 these other types of stimuli. Hair stepped on a lego. There's
85:49 like stepping on a lego. Four . I think I have over 100,000
85:54 pieces in my house. Grandparents buying after kits, multiple Christmases. I
86:07 probably walk on a bed of I don't know about a bed of
86:11 , but a beta beta legos I I could get, get past.
86:14 right. How do we deal with ? All right. Pain fibers are
86:19 that excitatory um stimulation, right? they can also inhibit stimulation,
86:28 So your body actually has a way deal with pain. All right,
86:35 looking at the athlete. Do you your way through pain? You find
86:39 like man, I can ignore this for right now. There are
86:43 Yeah. Right. OK. So body can overcome things. You
86:51 the different ways that we do this going to be through the binding inhibitory
86:56 . All right. So we have sending, send signals up, but
86:59 we can have signals that come back say, you know what? Quit
87:02 this stupid signal. I, I want to deal with that right
87:05 I I know damage has occurred, I've got to get past it.
87:09 right. So we've used this term . Have you ever used an
87:15 Have you used Ibuprofen. OK. . Yeah, that's analgesic. That
87:23 your perception of the pain. All , pain is still there. Signals
87:27 all going all the way up to central nervous system. But what you're
87:30 is your perception of the pain is . It doesn't feel as bad or
87:35 gone away. I don't know that there. I don't perceive it or
87:40 is a sensation right now. This something we use primarily when we're dealing
87:46 peripheral pain. So this is you know, the aches and pains
87:49 the body, an anesthetic. On other hand, is blocking the conduction
87:55 the action potential. All right. the receptor is still being stimulated,
88:00 action potential is going, but you're , it's really, you're blocking its
88:05 . I shouldn't say it's actually you're blocking the production of the action
88:09 , you're preventing the cell from actually threshold. But the receptors are being
88:16 . Ok. Then this is how body deals with pain. We have
88:24 are called the endogenous. Endogenous means of internally the opiates. All
88:31 So what do we have? You heard of endorphins? All
88:37 When you exercise, it's what keeps going, right? An endorphin is
88:42 natural opiate that your body produces. those of us who don't like to
88:47 , we don't like to exercise because know the moment that I exercise,
88:50 going to hurt. All right. reason people continue to exercise while they're
88:56 is that they are feeding their body opiate and their body goes.
89:02 yeah. Give me more of the stuff and that's why you keep doing
89:07 day after day after day. You're rewarding yourself for the pain that
89:13 going through, but you're also reducing amount of pain that you're experiencing.
89:18 . You guys know what an exogenous would be. Give me an example
89:22 an exogenous opiate. Huh? That's right. It's the same sort
89:29 stuff binds to the same receptors. right. One comes from a
89:35 from Afghanistan. The other one is by your brain. Ok.
89:47 But it's been a long time since actually probably experienced pain when you first
89:52 , right? When you first started ? See, I'm looking at her
89:55 she's the athlete. She has you do you do weekly weight
89:59 Right? Then you go and swim then you're achy a little bit.
90:03 then what's the other horrible things that have to do? I'm saying horrible
90:07 because I don't like exercising. So you have to run, run
90:18 . Do you have to run God, I hate, I hate
90:22 . Stairs were punishment. All And you abs? Oh, that's
90:32 brutal. Right. But think about you were the first time, when
90:36 you start swimming? Three competitively? three? When, when were you
90:43 ? When you were competitive at Ok. So, you know,
90:47 when you actually have to start doing things, do you remember telling your
90:51 how much you hated it? How it hurt? Oh, my
90:54 The four o'clock practices. 4 a.m. . So, like I said,
90:59 had friends who were swimmers, I at a high school that had an
91:02 swimming team and every one of those were diagnosed as a DH D because
91:08 couldn't pay attention in class because they're at four o'clock in the morning,
91:12 day until six o'clock. Exercising. mean, come on and they're
91:17 All right. Anyway, endorphins, what gives you the runner's high.
91:23 allows you to go in there and that ache? But then you start
91:28 iron and you're like, yes, can do this and you're like who
91:33 feels good. We also have the . They're the same sort of
91:39 The di di orphans. These are different, different types of things.
91:44 right. Some of you may not able to relate, but we do
91:48 the spicy food, don't we? is spicy when it burns? What
91:54 it feel like? Did it Does it hurt? Yeah. You
92:02 , but oh man, give me . I like the hurt. You
92:06 , I don't like torturing myself. just my body says, oh,
92:10 hurt, the hurt here have some . And I was like,
92:14 give me more of the good All right. So the way these
92:24 is they act, so the receptor still produces the action potential. So
92:30 with the analgesic or sorry, not analgesic, the anesthetic, what it's
92:35 is it's preventing the action potential from produced. Here. The receptor is
92:41 the signal, it's sending an action . But what you're doing is you're
92:45 the release of the chemical message. it never gets to the second order
92:51 . So even though the receptor is receiving the signal, it's still producing
92:56 signal, the message is never Good stuff. All right. Down
93:05 last a little bit here. What we? Three slides? Lots of
93:12 . 10. 0 my goodness. right. This is actually going to
93:16 a lot faster than it's gonna, really not 10 slides here. It
93:20 seems like. All right. So we're doing now is we're going back
93:23 touch. All right. So, pathways, when you see Samata
93:27 this is the sense of touch. are we doing? We're taking information
93:30 the periphery and we're taking it up the brain. All right. So
93:34 have an a sending pathway. So going up, if it's coming from
93:41 the neck, then we're going to the spinal cord, right? If
93:47 not coming from below the neck, from this point. If we're from
93:51 up, we're using cranial nerves. here below the neck, we're using
93:55 nerves and the spinal cord to get information upward. Right now, all
94:00 these are carrying aer information, sensory inward. We have two major pathways
94:06 we're going to use here, which what we're going to break these
94:08 which is why I thought there was more slides. We have the dorsal
94:11 pathway and the antri lateral pathway. pathways are named for where they are
94:17 within the spinal cord. Let's look over at our spinal cord. I
94:22 I should probably draw our gray There we go. What's this region
94:36 ? This is why this is why this stuff because it comes up.
94:39 ? The this this this region Huh? It's white matter but it
94:47 a special name started with ad huh and then, and it's a lot
94:57 fun. It's a lot of funiculus, dorsal funiculus, this
95:13 ventral. What's another word for an interior? What's another name for
95:19 ? OK. Just making sure. right, there's a reason we go
95:22 these things. All right. Not I just think there are things that
95:25 need to know because they keep popping . So the dorsal uh column is
95:31 be found in the dorsal funicular, right, the lateral and the Antero
95:38 Antero. So an interior and it's just telling you where it's going
95:42 be located. Now, in terms what they do, the dorsal column
95:46 primarily with fine touch and proprioception. doesn't matter where it's coming from.
95:51 going to be using that dorsal If you're dealing with pain and
95:54 it's going to be found in these . The anterolateral. Now, with
95:59 to how the sensory pathways um the pathways are are structured. Again,
96:05 gonna have 1st, 2nd and 3rd uh uh structures. OK. So
96:11 first order neuron is simply that neuron has a receptor associated with it and
96:17 it comes into the spinal cord. ? There's your first order, second
96:25 neuron is the neuron that travels from first order neuron up to the
96:34 Now, really, we're going to of two places. So some of
96:38 are just gonna have two neurons so can protect you the thalamus if I'm
96:43 to the thalamus and being sent all the brain. So I'm gonna be
96:48 of that sensation, right? Because gonna go to the cortex. But
96:54 can also go to the bellum. I go to the cerebellum, I'm
96:59 gonna have conscious awareness of it. just telling the cerebellum. Oh That
97:04 of touch is part of the Remember how you told me to do
97:07 kind of movement. I'm just letting know that this movement has occurred and
97:10 know this because I'm touching or this type of appropriate reception that you're
97:16 is just an indicator of part of plan So you're not consciously aware of
97:20 right now, you can see in thing here, here's my first order
97:28 , second order neuron is decoding, ? Here's my first order neuron,
97:32 , ordinary neuron desiccates. So it me, it crosses over at some
97:40 . This is the point where we're about the thalamus. And then here
97:44 it moves onward, that's the third neuron. So you see nomenclature is
97:48 simple. First order, second order third order primary secondary tertiary, those
97:53 be the other terms that you may . Conscious perception is a function of
97:57 going on to the cortex. That's result of that third order neuron.
98:03 I think I only have two slides . You said I have 10.
98:07 are my other slides that I have ? Oh my goodness. Yes.
98:12 we're gonna do it. We'll do affection uh Next lecture. So these
98:15 gonna be part of the next See I knew where I was.
98:20 told you there was only two more . Yeah, I just gave you
98:24 many slides. Sorry. Yeah, . Sense of smell. The
98:31 I more complicated. All right. dorsal. So the dorsal columns have
98:38 name. All right. And it's really, really long scary name.
98:42 at the name, dorsal column, pathway. All right. Meniscal.
98:52 we learn about the media skum? you remember that term? When we're
99:00 at the brain stem? We're looking the medulla, particularly uh-huh, I
99:12 . It's up there highlighted on the too. Said we had the nucleus
99:18 and the nucleus Kia. Do you those two terms? Oh, my
99:22 . Yeah. Well, what we here is we have Faye.
99:31 so think of the word fascist. right. You know, you've heard
99:36 a fascist, those horrible fascists, know, a fascist is all
99:41 You know what is, it's a . OK. So when you see
99:48 , it's a bundle of fibers. right. So we have one bundle
99:52 fibers, another bundle of fibers. the first bundle of fibers? All
99:56 . So these are the primary right? Said dorsal is fine touch
100:01 proprioception, fasciculus gracias deals with the body. So the bundle of this
100:10 is from the lower body. The kiss is the upper body. So
100:15 they're trying to show you here? gray. All right. Grill lower
100:27 , upper, lower upper, the should have put the upper right up
100:32 , but they didn't. OK. the body dis dis or or the
100:42 spinal cord demonstrates somatotopic right? There's topography, it represents how your body
100:49 organized. And so the lower part your body enter first and stay
100:57 the upper parts of your body enters . So it stays lateral.
101:03 Fasciculus gray stays, medial fasciculus Kunis lateral and it enters into the brain
101:14 and terminates where on on second order in these nuclei. And there was
101:21 two nuclei. I told you about nucleus Cary and the nucleus kiss.
101:27 collective pathway of these things is referred as the meniscus. That's where the
101:34 comes from. And what is Do you remember what the word
101:37 I mean, what? That's probably on there. Sorry. But I
101:41 you it was like I came in class. I said I looked up
101:43 word today to find out what it . You guys remember what Nisus
101:47 Do you remember? Ribbon? that's all it is ribbon. All
101:51 . So it's just a pathway. right. So we're gonna terminate on
101:57 second order neurons. So what does order neuron do? Well, remember
102:02 represents cell bodies. So you can there's the cell bodies, the second
102:05 neurons, second order neurons travel up they're going to decoste, they're going
102:09 crisscross here. So notice we're staying the, on the same side.
102:14 so this is paired, you're going see the same thing on the other
102:17 . So I come in, I on the same side. Turn it
102:20 the second order neuron I cross So there's my decosse and then I
102:24 up to the thalamus. All That's the meniscus, I should have
102:31 not down here. Meniscus goes on , goes to the thalamus and that's
102:36 I go to tertiary neurons. So where I go up to the somatic
102:40 cortex. So my brain knows, , where am I being touched?
102:46 doing proper reception that goes to the avoids the thalamus. The intro lateral
102:59 also called the spinal thalamic pathway, is not a particularly helpful name because
103:05 just looked at a spinal phyla pathway well, right? Because these pathways
103:11 named from where they start and where go. So spinal thalamic starts in
103:17 spine, her spinal cord goes up the thalamus. Now, the better
103:23 is anterolateral system because you're dealing where of being up here in the dorsal
103:31 , you're gonna be in the on lateral regions. All right. So
103:35 and temperature, smaller fibers, a and c fibers, first neuron,
103:43 going to be in dorsal region. here you can see primary comes
103:50 comes in, all right, terminates the second order neuron in the gray
103:55 in the spinal cord. So this why we call it spinothalamic. All
103:59 . So if I'm lateral, I'm into the lateral regions. So here
104:05 and then this is supposed to be to be anterior. He did a
104:08 job of doing that. All lateral, lower body, interior,
104:15 body. Ok. Again, you're gonna see, wait a second
104:20 lateral, supposed to be my, upper regions. Yes, you're more
104:24 located. But in this particular you're using the lateral funicular. That's
104:29 it's referring to. So the lower is lateral funiculus, the upper body
104:34 the anterior funiculus, go on to thalamus from the thalamus off to the
104:42 sensory cortex. Oh, pain, hot, touching something hot, that
104:50 of thing. So those are the somatosensory pathways. Notice the direction we're
105:03 . Are we coming down? Does information come from the brain to the
105:08 or does it come from the outside the brain comes from the outside of
105:13 brain? It's bringing in sensory If it's bringing in sensory input,
105:19 always gonna come via the dorsal uh right to the dorsal horn to either
105:29 or the anterior system. Ok. the idea. I know he was
105:35 , not so easy. It, actually is pretty straightforward just to where
105:38 it going? Where is it coming that sort of thing? And you'll
105:40 good to go when we come That's where we start olfaction. All
105:47 , we're doing olfaction gustation together and little bit of the eye and then
105:52 do the rest of the eye and ear and then the last little bit
105:56 motor pathways in the autonomic nervous And we're done. It's hump
106:03 hump day. Yeah. Yeah. right. So I'll see you guys
106:07 if you have
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