VideoPoints

• ••• • •• • ••••• • •
BIOL 2301 Human Anatomy & Physiology I - 2301_lecture14_0628
Help Tour
© Distribution of this video is restricted by its owner
Transcript ×
Auto highlight
Font-size
00:05 Okay, so I sent you guys data for um well at least the
00:18 for where the where the grades are now. Um Which is good,
00:23 mean I'm sure you guys look at and you freak out. And it's
00:27 I said the email don't freak I know it's easy for me to
00:31 that, but I've been doing this 15 years. I know when it's
00:35 to freak out and I'm not freaked . I had one semester where I
00:38 out as bad. All right, um what we're gonna do today is
00:45 going to kind of do, well moving away from the central nervous system
00:50 a little bit and we're gonna focus on the peripheral nervous system. We're
00:54 come back and kind of combine the at the end of the semester on
00:58 , talking about the autonomic nervous system I keep promise you promising you it's
01:02 , it's coming, it's coming. , it's gonna take us forever to
01:05 there. All right. What we're do is we're introducing ourselves to how
01:10 comes into the body. Alright, that's really how we're going to start
01:14 off. So we're gonna look at receptors today. We're gonna look at
01:16 sense of smell today and then what gonna do is we're gonna kind of
01:20 through the rest of the special senses then we're gonna flip at the like
01:24 Wednesday or thursday and then we're gonna about motor pathways, which is how
01:28 leaves the body. So if you're of keeping track of what are we
01:32 ? Well, we've kind of talked how things are integrated, right?
01:35 what the central nervous system is How do we process information? Whereas
01:40 being processed? We don't really talk how it's processed and there's a reason
01:44 that. We don't frankly know real , it's very, very complex of
01:47 we do know not appropriate for this , but we know the areas.
01:51 right. So, what we want ask question is all right. If
01:53 understand that there's this pathway of information in, information is processed. Information
01:59 out. That sounds an awful lot a reflex pathway, doesn't it?
02:04 . But that's why I said that picture was kind of important.
02:07 we want to do now is we to ask the question. How is
02:10 detected? What are we looking at how do we detect the world around
02:15 ? All right. And so, where our starting point is the sensory
02:18 . All right. We're gonna deal that question of sensory receptors and then
02:21 gonna spend a little time how that gets to the central nervous system.
02:25 gonna look at that um that those pathways the dorsal column pathway in the
02:30 thalamic pathway. So, we're gonna dealing with an a different pathway.
02:35 , or two of them actually. . And then we're going to talk
02:40 olfaction, which is not too All right. So, first
02:46 we need to understand some terminology. a sensation. Sensation is simply conscious
02:51 of incoming sensory information. Alright, can only occur if that information reaches
02:58 cerebral cortex. All right. So now I'm standing in front of the
03:02 or the projector, that light is to me. Alright. I'm consciously
03:09 of the light hitting my eyes. ? That's a sensation. Alright,
03:15 someone touches you, if you smell that's a sensation but you're not aware
03:22 it. I mean if you're not of it, if you if it
03:25 if that information of the right cerebral , you're not gonna be aware of
03:28 . There's tons and tons and tons sensory input that that you're receiving that
03:33 are completely oblivious to. Alright, , the sensation is simply when that
03:38 arrives to the cerebral cortex, a is that structure which responds to a
03:45 ? Alright. It's what initiates this into the cns. This receptor is
03:52 of an ambiguous word. It ranges terms of complexity. It can be
03:57 molecule like what we've been talking about we talk about receptors on cells,
04:01 talking about a molecule, right? it can refer to an actual
04:07 All right. And it does. how the cell response or it can
04:12 to an actual organ. Your eye a receptor in your IR receptor cells
04:20 those receptor cells are molecules that allow the detection of light. So each
04:25 those can be considered receptors. So have to look for the context clues
04:30 you're in the discussion. Alright. hopefully it won't it won't be as
04:35 or or scary sounding as that. the idea is is that remember when
04:39 hear the word receptor, it has variety of connotation. Alright. And
04:44 stimulus or stimuli are just basically the of the information that are receptors are
04:50 . So right now I see Right, but when I come over
04:54 I get hit with that. And it's like oh there's a change in
04:57 amount of stimulus my receptors detect that . Okay, so those three things
05:05 terms that we need to be familiar as we're moving forward now. What
05:08 receptor does is it changes the energy what we're detecting into a language or
05:14 energy form that the central nervous system understand what language does the central nervous
05:22 ? Not a hard question. You know this by now. Action potential
05:26 potentials. And really what we're talking here is the exchange of chemical
05:31 Right. If I look at can my brain detect light? If
05:38 cut my scalp or my skull And I shine a flashlight at my
05:42 , will it know that a light being shone on it? No.
05:47 . So what's happening is is my are taking that electrical magnetic energy because
05:53 what light is and it's converting it action potentials. Those action potentials results
05:59 the release of chemicals so that the can then interpret what those signals
06:05 So receptors are transducers, they change one form of energy to another so
06:11 our brain can understand it. So there are two features by which
06:20 work as transducers. They're going to establish a resting membrane potential. You
06:26 ? We gotta come back to Yes, that's the nervous system.
06:29 always these stupid action potentials. So gonna have this resting membrane potential that
06:34 going to then change up and down upon our experience or the stimulus that's
06:39 for it and then those receptors. , so here what type of work
06:45 you think we're looking at here? this a molecule a cell or an
06:51 ? So they have modality, gated . Now remember modality just simply refers
06:57 the type of of change or the of thing that you're trying to
07:02 Alright, so we're gonna use that open and close channels and that's how
07:08 that's kind of defines what we're detecting then how we're creating those changes.
07:15 what we can do is we can down our senses into two basic
07:18 We have what is called the general receptor and the special senses. I'll
07:22 down here because this is easy to past the special senses. Are these
07:27 complex sense organs in our bodies. . They play a role in our
07:32 understanding of taste, smell, hearing and our balance or equilibrium.
07:41 , so those are the special The general sense primarily deals with the
07:48 of touch. Alright. They're typically very simple in terms of their
07:54 Right? So they're usually a cell maybe a group of cells. All
07:58 . They'll be found either on the to detect the movement in the in
08:03 surface we call the somatic. So it's gonna be the skins were
08:06 at touching the skin or looking at in the joints in terms of stretch
08:11 position. And if we're down in guts and the viscera, the viscera
08:16 are responsible for looking at changes in viscera. So, we're talking again
08:21 temperature, chemicals, stretch, paying sort of stuff. So, the
08:28 sense you can just can think about terms of Okay, anything that's not
08:34 really cool or interesting. Yeah, makes sense. Another way to classify
08:42 is asking the question, what what are you detecting are you detecting out
08:47 the body? So we call these receptors. So we're looking for things
08:51 are going on out here. So looking at is basically touching things at
08:56 surface. So it can be a receptor or it can be found in
09:00 mucous membrane. So we're talking about skin and mucous membranes exposed to the
09:04 environment. that doesn't mean we're only for touch. It means it could
09:07 chemical changes, it could be temperature that are occurring on the surface.
09:12 . But the idea is it's my with the external environment. What do
09:16 think an eye is doing? Is Xterra receptor? Is it trying to
09:21 things that are going outside the body coming from the outside of the
09:24 Or is it detecting things on the of the body outside? So it's
09:27 Xterra aceptar. Alright, so just that question of the origin,
09:33 in terror receptors are detecting things of origin. So again, we can
09:39 this down. And is this stuff in our guts or is it happening
09:42 our structures of the body? visceral sensory receptor is gonna be looking
09:47 the visceral organs, all those things we just talked about, temperature,
09:51 , chemical or perceived pain. We're about somatic here. Now, what
09:56 looking at is we've taken this group , we said here's somatic, it
10:00 be stuff that's going on in the or it could be or the muscles
10:03 bones or can be stuffed with the . We're basically saying it's just this
10:07 because that's all we're interested in what's on inside the bones or inside the
10:13 . I'm looking at stretch. I'm asking the question of what's touching me
10:17 the outside. I'm asking what sort interactions are taking place inside the
10:23 So we have different ways that we these receptors. Is it a general
10:29 , is it a special receptor? the information external or is it
10:33 So is an extra receptor or is an internal internal sector? And then
10:39 can classify the individual sectors based on modality. Right? That special term
10:45 basically says the thing that actually So these are examples of different
10:50 Thermo receptors detect changes in temperature. , that's easy. Chemo receptors detect
10:57 chemicals. Alright, that's a nice . Mechanic receptors which we're going to
11:01 a little bit of time talking about deal primarily with touch pressure, vibration
11:07 stretch. Right? And so there specialized, this is what we're gonna
11:12 focusing on. But they're specialized Have you heard of barrel receptors
11:18 Bear receptors deal with the concept of . Right? So when you're detecting
11:24 pressure in your body those are barrel . Osmo receptors. This deals with
11:31 concentration again it's a specialized form of mechanic receptor appropriate receptors. This is
11:36 one you should become familiar with is position of body and space. So
11:42 you're moving around and you can kind feel yourself moving that's appropriate sector.
11:49 kind of saying okay I'm in an position. But if you start falling
11:52 like oh my body is not in position it's supposed to be in.
11:57 pro preconception and then finally we have weird word. No c no C
12:04 . No. See scepters deal with . No C comes from obnoxious.
12:10 you ever smelled something so bad that made you want to throw up or
12:14 your head away? Yeah, smelling come on you. You guys never
12:21 with smelling salts. I see one smiling play with smelling salts.
12:26 smelling salt is you know you get out while you're playing sports coach comes
12:33 , snaps that thing sticks underneath your and what do you do? Oh
12:38 . And then of course if you out that they're smelling salts in the
12:41 office you go get those and take out to your friends, pass them
12:45 and watch people jerk their heads It's to wake you up to keep
12:50 from being, it's a natural Your body basically says this shouldn't be
12:55 me. So that's why you Oh yeah, absolutely. MTs.
13:00 think of it in terms of coaches that's where we stole ours. I
13:03 that's where we borrowed our results. right, So no C.
13:12 there's another one. Have you ever ? I mean this is another
13:15 I think like you inhale something you just you can that noxious. It's
13:22 . Right? I mean actually spicy stimulates different types of thermo receptors but
13:28 can also stimulate pain receptors. It , it's so hot, it's not
13:32 . It hurts. It hurts. , right, noxious, That's where
13:37 comes from. Alright, so we're different types of damage. They're actually
13:42 kind of cool. Some are can detecting polly so many different types or
13:47 are mono, they detect a single , so it can be stabbed,
13:50 type stuff, mechanical damage, or can be chemical damage, is
13:55 heat damage, that sort of So no c sectors, there's a
13:59 of them in different types of Another way we can classify them as
14:03 can look at their structure and this more what thomas does they say?
14:07 , well you know what does it like? And so it can be
14:10 an encapsulated or un encapsulated. So example this right here that doesn't have
14:17 connective tissue sheets. So that's un . That would be an example of
14:21 free nerve ending. Right here, can see we have this connective tissue
14:25 around it. So that would be example of encapsulated. Alright, so
14:30 terminology is not particularly hard, you got to kind of look at and
14:33 , okay, what surrounds the ends where the detection is taking place?
14:38 right, century cells can also be coupled cell. Alright, so for
14:45 you can have a neuron that's associated the actual receptor cell. So
14:51 right here is an example of a a mechanic receptor that you might see
14:56 your ear that cell right there is all the reception and it talks to
15:00 neuron that then sends the signal on or you might actually have the actual
15:07 itself during the detection and um it no associated cell with it.
15:15 so there's different types of cells that different types of reception. We're hopefully
15:20 to point out a couple of these we move on. Alright, so
15:24 anatomical classification, there's physiological classifications And the last is another type of physiological
15:33 . And this really just asked the is like all right, so how
15:36 this receptor respond to stimulus? and so you need to kinda understand
15:41 to read this kind of graph because they don't put anything on there.
15:44 so what you can imagine is this the bottom, no matter which one
15:48 looking at, this is time. , so this is action potential.
15:53 that's going to be voltage. This a receptor potential. So that's going
15:57 be voltage. Right, so voltage time. And then this over here
16:01 basically an on off over time. , so it's a binary state.
16:08 ? So down here on the bottom would be off, up here at
16:11 top, that's on And so it over time here I am, I'm
16:15 and then I get turned on and stay on and then right here is
16:18 I turn off again. Okay, the stimulus they're asking in this particular
16:23 is when is the stimulus occurring starts turns off there and then it continues
16:29 the off state. Over here, the off state, I turn
16:32 I stay on for some time and I'm in the off state again.
16:35 that's how you read that. Very binary. It's like the
16:40 it's in the on state, press button, it's in the off
16:43 there's no in between state. And when we're looking at a receptor,
16:48 ask the question, what happens when turn on? When you're talking about
16:53 rapidly adapting, what you're talking about is a type of receptor that is
16:59 phase IQ receptor. Alright. In words, it gets turned on uh
17:07 then when it gets turned on then detects that change and it sends action
17:12 as a result of detecting that but it doesn't stay on.
17:18 In other words, even though the is still there, you don't send
17:21 signals, the only time you're gonna another signal which this one should have
17:25 is when the state changes again. ? So in other words, when
17:30 turn it back off, you should another receptor potential change in the you
17:34 a series of action potentials. In words, with a phase IHC
17:38 you're only detecting when change occurs. right, now, when do we
17:44 these types of receptors? All An example, I hate telling this
17:50 because once I do it then all a sudden you're like, oh
17:53 can I see it now? All . Which is why it's a good
17:56 . But is it You'll see? right, up until this second when
18:00 say these words, you do not the clothes on your body now you
18:06 your clothes, don't you? But prior to this, you didn't
18:10 your clothes on your body, You just going through your day, you
18:14 up, you put on your you felt the clothes get on your
18:17 and you're like aha, I now clothes on my body and then you
18:21 going about your day and you didn't there and clothes on my body close
18:24 my body, close to my Close on my body. You will
18:27 to go through your day without recognizing the clothes on your body unless something
18:33 to those close, whether they're pulled or whether they're released from your
18:39 Right? So the important thing is that first that you got touched by
18:46 piece of clothing and for the rest your day, it doesn't matter whether
18:49 not you're being touched because your body knows you're being touched. It's only
18:53 that next change occurs. Yeah, ahead being touched and stuff like
19:09 That's a good question. I don't the answer to. It probably has
19:12 do with the other types of in other words. So one of
19:15 things that our brain does that filters a lot of that sensory input that
19:19 receiving. So like I said right you're unaware of the unnecessary noises going
19:25 the room. Like back there, hear rustling and stuff. When I
19:28 listening around the room you'll start hearing if you start focusing in on
19:32 But your brain basically says this stuff important to me right now because I'm
19:37 in any sort of sense of like having to be aware of all my
19:41 of everything going on. There is a predator in this room about to
19:45 you. And again, when I predator I think big giant cat or
19:51 , you know, not some creepy in a mask. All right
19:56 is that true? Yeah. You what your brain does, It
20:01 look, this information is important. information is not important. This is
20:06 . And that's how you get your of your environment. It's basically removing
20:11 a person who has that that that sensory responsiveness basically doesn't filter out the
20:19 that's unnecessary and that's where they you know, overly alert and what
20:23 gonna see. There's different types of , both tonic and phases that are
20:28 in the skin. And so the ones, not the basic ones are
20:32 what they're responding to brain. correct. So I mean let's give
20:40 an example of this. Have you seen the pictures or watched a video
20:44 like the coal walkers where they get hot coals and they walk across and
20:48 like man you guys are crazy and they act like oh yeah it doesn't
20:53 , It still burns, it's it's 400 some odd degrees, it's
20:57 burn your skin like you are a sitting over a fire but they don't
21:02 to it. Why this is because aren't responding. No the receptors are
21:06 there going red alert. Red What's happening is you were cutting it
21:10 at the brain saying this is insignificant unimportant. You've heard the term mind
21:16 matter. That's how I think of . Is it actually mind over
21:21 I don't know it's a good way think about. Right So basic receptors
21:28 with this idea of when does things on, when do things turn
21:32 That's when I send the signal. the example I gave is a crappy
21:37 but it's an example that should help remember that. Okay, tonic receptors
21:42 the other hand are basically the receptors when stimulation takes place you're going to
21:49 doing action potential but when there's change increase the rate and maintain that
21:55 Alright so it's basically always sending a . Always always always. All
22:01 so there the sensitivity is always on very very slow in terms of
22:06 This is trying to show you that adaptation right here it is and then
22:10 kind of just kind of fades Right. But really it's just always
22:15 you're being touched, your being touched being touched or being touched or being
22:18 again. There's some receptors that do but you can think of it like
22:22 , your appropriate receptors receptors and the receptors that are responsible for the sense
22:27 posture are always sending signals right there the stretch in the muscles in your
22:34 and in your you know in the regions as well. And are there
22:38 to ensure that you're sitting in that position. And so they're always sending
22:42 up to the brain saying this is degree of stretch that's taking place.
22:47 ? Oh you're not doing enough stretch you need to make modifications.
22:52 It's not just the on and the . It's always always always.
22:56 Yeah. Yeah. Thank you, are always Mhm. Why why is
23:14 information? Not conscious? That's a question. And part of it probably
23:18 to do with that. It's not for conscious work. It's necessary for
23:22 body to maintain the activity but you need it's your brain is basically being
23:29 of this idea of having to be aware of everything that's going on in
23:33 body at all times. All I'll just give you another example of
23:36 tonic receptors would be your osmo receptors your body. Are you currently aware
23:42 your osmotic state? No. But you kind of are see are
23:49 thirsty? Yeah and that's basically your saying um my water salt bounces a
23:55 bit out of whack, I think need a little bit of water to
23:57 the amount of salt that's going on my body, right? And so
24:01 is a consciousness that occurs, it's oh I feel like I'm hunching
24:07 you know, maybe I need to up right or you feel that stretch
24:11 to pull yourself back. Those would examples of your being consciously aware of
24:15 activities. But what happens is your puts that into the I'm gonna let
24:20 else that's not conscious, deal with it needs to deal with and when
24:24 need to be aware of it, will let my brain or let myself
24:27 , you know, my conscious No. Yes we can So more
24:37 I mean but really it's just it's that focus, right? I mean
24:42 know how many of you guys feel you're slouching right now and seeing that
24:45 I love it. You say that of a sudden it's like everyone kind
24:48 goes, oh wait a second mom me to sit upright, you
24:52 you know are you aware? not really until someone points it out
24:57 you okay, the basic receptors are in a lot of different places.
25:13 not gonna say that they're not internal I think they're easy to perceive and
25:18 probably this group of of ones that probably listed here are probably the most
25:24 obvious ones. So right before class went and I looked up a paper
25:28 I was trying to find out the of one of the receptors that we're
25:31 look at. Is this a tonic phase of receptor? In every paper
25:35 looked at and I mean again this a brief just kind of skim
25:38 I never saw the word physic or . I think this is more of
25:41 term that we use to try to you guys of how some receptors
25:47 It's not something that they really kind use all that often in the scientific
25:51 or anything like. Right? So speaking and when you hear these words
25:56 , think always on, always telling telling the body information on or off
26:04 it's on when change occurs and that's the kind of the take away their
26:12 right, receptive fields is something else need to consider when we're looking at
26:17 receptor receptive field is simply the area which a stimulus is being detected.
26:22 receptive field sizes are gonna differ very depending on where you are. So
26:27 example, like on your hands, you'll have is you'll have very
26:31 very dense receptive fields and that gives a greater degree of interaction with your
26:37 , right? Because if you have receptive fields you can have lots of
26:41 . And so you can have discernment terms of your sense of touch as
26:46 example, this is all gonna be in the eye and we're going to
26:48 this in the eye, but it's to explain without talking about the eye
26:52 first. So have you ever done ? Have you ever played with calipers
26:56 this? Alright. If you've not this is something you do if they
27:00 do in the lab, it's really to do. Just go get two
27:04 right? I mean you just take a pen and a pen like
27:07 Take them out, recognize you're probably get marked up. And what you
27:11 is say, hey friend because you're friend, hey friend, let me
27:14 your arm. Now I want you look the other direction. And what
27:17 gonna do is I'm gonna poke you . Can you feel that? Of
27:19 you can. Can you feel How many different sensations do you
27:24 How many you feel? Only one feel to write? And what you
27:28 is you walk one toward the other until they feel just one sensation and
27:32 you'll find actually the size of the field because see I told you you're
27:35 get marked up right? Because the receptive fields are gonna give you bigger
27:42 . And so it doesn't If you touching within that receptive field, you're
27:46 going to detect one thing, It doesn't matter. It doesn't matter
27:52 I if I stimulate over here over , it's the same neuron. Does
27:56 make sense? Right. So your your sensation is the sense of being
28:04 by one object. Now, where larger receptive fields are are where you
28:11 need to have that greater sense of and discernment. So, for
28:15 the back of the legs, the , you typically have large receptive
28:19 but on your fingers and on your , that's where you're gonna see a
28:24 density of uh of smaller receptive Yeah, Okay. You can't look
28:37 words kind of, But I want keep those two ideas separate. I
28:44 that. You're trying to bring them , Right? So, you could
28:47 convergence, right? And in you can even see divergence in some
28:52 these in some cases. And one the ways that our body actually makes
28:57 stronger is it uses very closely related fields. So let's say we have
29:03 of them and we have a third in the middle, then what it
29:05 do is if you're stimulating this it'll actually suppress the two nearby
29:10 Right? And so what it does gives you a sense that this is
29:13 larger stimulation, that is because these have been inhibited. So, you
29:18 this weirder look, we'll talk about . It's called lateral inhibition. All
29:24 . But this isn't just touch. mean you're going to see this in
29:27 systems as well. The visual eye in particular, you really see receptive
29:34 really, really tight in the center very, very large as you move
29:39 outwards. And this is clearly If you look at your piece of
29:43 in front of you or your screen straight ahead at an object, is
29:47 clear? And if it's not clear you're looking straight ahead at something,
29:50 you probably need glasses. All So it should be crystal clear.
29:54 without moving your eyes from whatever it you're looking at kind of get a
29:57 of everything on the periphery. Is kind of fuzzy? Yeah. And
30:02 reason it's fuzzy is because the density the fields that are receiving light as
30:07 move from that central point become larger larger. And so your body doesn't
30:14 as long as I get the general of what's going on over here,
30:17 fine. Because if I really need see what it is, I can
30:20 my head or my eyes and I focus on that object to make it
30:26 notice when you read right? You're on one word and the words around
30:30 are a little bit fuzzier and as read, what you're doing is you're
30:34 your eyes to make the words clear you can go across them. So
30:39 fields are the areas in which we stuff. They vary in size when
30:45 have small fields, you have higher . When you have large fields,
30:48 have less density. And so finer in small fields lest find detection.
30:56 don't know. Now when we talk a receptor and the action potential that
31:04 produces, or the potential that we just call them receptor potentials.
31:09 , They're basically a form of graded that can generate up an action
31:14 So, it's just another fancy word someone just threw in there to just
31:17 things confusing for us. It's a potential. All right. And
31:21 remember what we said. Is that receptor? So, here's an example
31:24 a receptor cell associated with its Every cell, whether it is a
31:31 cell or if it's a neuron that does, the detection itself has to
31:35 through this process of producing a greater that then is strong enough to ultimately
31:41 in an action potential. All So here we're detecting something specific,
31:47 don't know what it is. It's stimulus. Alright, so let's just
31:51 it's detecting, oh, I don't a chemical. So, if you
31:55 enough chemical that's gonna cause the channels open channels open. That's gonna allow
32:01 to rush into the cell. If get enough sodium to rush into the
32:04 that's gonna create a signal that causes release of the neurotransmitter that will then
32:10 the next cell down the line. if you get enough of that in
32:13 of enough neurotransmitter you get strong enough potential, you can act potential that
32:19 sends it off up to the central system. If this is one cell
32:24 , ignore this one for them again just say this is a chemo
32:28 If the chemo receptor gets strong enough potential that will that will be that
32:33 potential results in action potential. It a signal forward. Now what we've
32:39 is we've done transaction right we've converted energy form to the other. So
32:45 it is that we're detecting is being into that action potential chemical signaling process
32:51 we discussed earlier, um adaptation. we're back to the same picture and
33:02 might some of these cells might be pictures might be out of order,
33:05 don't know remember I did. It have been the last unit but there's
33:10 two or three of my kind of around right adaptation simply refers to the
33:17 of a sense of a receptor becoming sensitive and so you need a stronger
33:22 to get it active and that really of has to do with this rapidly
33:27 slowly adapting. So physic or tonic . Um This can occur at the
33:35 of the individual receptor or it can at the level of cns. The
33:39 I kind of pause there is I you to think about um your eyes
33:43 a second. You go to a theater, right? You're in the
33:46 for a little while and we're all . So we go to the
33:49 We don't go to the midnight shows night shows because those are too damn
33:52 . How much is it for a ticket now? Like 12 15
33:55 Yeah, that's still too much. mean I used to go to movies
34:00 like $2 and I'm not like my which was like a dime. I
34:05 can you imagine going to a movie a dime? You go in with
34:08 cents. You buy coke, you your popcorn. You get I mean
34:11 like you take a date to get of that is just crazy.
34:14 it was two bucks. So this what we do. We go to
34:16 movie, we pair two bucks. go get back in line pay two
34:19 and this is why we will be to see Star Wars seven times in
34:22 row, right? That's just how did it. All right, But
34:26 going to the movie, you're going say I'm sorry I just went down
34:28 tangent a rant and old man yells cloud. Um All right, You
34:34 to the movies. You go to matinee, you're in the dark,
34:37 open up the door, right? hit that texas sun. And what
34:44 ? You're blinded. Right? And you're walking to your car like
34:48 right? What has happened there is your eyes have been overstimulated and it's
34:55 to take a while for them to to that brighter light. Alright.
35:03 , if you walk from a bright to a dark room, right?
35:08 what happens is you takes a while you to become dark adapted.
35:13 You walk around and you're cooking you smell that smoke the first time
35:18 smell that smoke. It is right? It's just like,
35:22 barbecue. But if you're working around barbecue for a while, do you
35:26 the barbecue anymore? No, because brain says, oh, I recognize
35:31 chemicals in the air, they're supposed be here. That's an adaptation.
35:36 gonna take a lot more to get smell like when you lift up the
35:40 and that comes rushing at you. right, These are just examples of
35:46 right now, we talked about how potentials have different magnitudes. Alright.
35:58 we mentioned this, but I haven't talked about it with you that,
36:03 when we are looking at signals, . A greater potential, respond with
36:10 . So if I have a really signal, I'm going to get a
36:12 strong graded potential. But how is or what is it that action potentials
36:17 like when that happens and this I does a really good job of how
36:21 encode uh magnitude and frequency. So how intense that signal is in terms
36:29 how the action potential looks. so, again, you can look
36:33 here, remember what does this graph ? It's the off and then the
36:37 . All right. And what this also showing you is how strong the
36:40 in the office. So that one's weak. This is stronger. This
36:45 strong guest. Right. And then can see it's like all right,
36:48 , what if I was measuring, does that potential look like?
36:51 pretty weak potential, stronger pensions are strong potential. So here you
36:57 that's the axon hillock. So what that look like in terms of action
37:00 ? Well, this when we got , it wasn't strong enough to to
37:03 the action potentials. I didn't get right. That's that's showing. And
37:07 down here you don't see any acts . But look, when I get
37:10 this point, that brings me above , I didn't just get one.
37:14 sustained for a period of time. , I'm getting a series of action
37:18 that fire and as I measure further further down, I'm gonna get those
37:23 action potentials they carried forward. Now first case when I finally get down
37:29 the synapse, I'm not releasing any . But here those acts potential results
37:34 the release of a certain amount of to tell the next cell to
37:38 But when I have a stronger I get more action potentials, even
37:42 the duration. So that duration is same. It's a much stronger
37:46 I get a lot more action That's why we have those refractory
37:52 We can still do stuff but there's be a point where we can't I
37:56 fit them in there and that's what end up with. I get the
37:59 number of action potentials moving down and a result I get a lot more
38:06 . So, intensity here is encoded the frequency of the action potentials of
38:15 stimulus gives me, you know, this case one of that six action
38:20 results in the release of a six of neurotransmitter. Again, made up
38:25 . It's just so that you can that over here, I get 12
38:30 potential. I'm guessing it's 12. not going to count them. And
38:33 a result I release a lot more . 12 molecules a neurotransmitter. So
38:39 is why action potentials stay at that height and stuff is because they can
38:45 represented in terms of the number of potentials that I actually get.
38:53 so their relationship in terms of intensity encoded in the frequency of the action
39:03 . But it's not just that All . I want you to think about
39:09 being cruel to you. I I'm sure that's not a hard thing
39:12 you to imagine, right? So want you to think with me with
39:15 little needle and I come up and grab you and I poke you with
39:18 needle. Right? It would hurt a second. You'd be like,
39:22 , stop it. Right? But me coming in and jamming a needle
39:27 me and just holding it there for while. Alright. And you'd be
39:31 this is not fun, Do I a grade for this? I said
39:35 , I mean, that's how you think, right? And then and
39:38 I make that running start, And I take that needle and I
39:42 at you right? It's gonna be lot harder. Right? So you
39:47 imagine how do we encode? Because there's gonna be a point where
39:52 is met in that single neuron and we need to understand is that there's
39:59 to be a little bit of a with other neurons and so we're going
40:03 use is a process of recruitment. right, so there's gonna be different
40:09 that are going to be localized in different in that same region. They're
40:13 gonna be uh maybe all touch receptors all pressure receptors, but they might
40:17 of different types. And what will is is that as one starts climbing
40:23 terms of reaching its threshold. so this is what this is
40:27 So see here's the frequency of the potentials, right? So it's saying
40:32 a lot of not a lot of potentials but up here that's lots of
40:35 potentials. So as we begin climbing as we start approaching the maximum of
40:41 potentials, the next group begins to firing. Right? So here I'm
40:47 a quarter of the way up and already starting to produce action potentials in
40:50 next neuron. Right here I go . I'm now a little bit over
40:55 , I'm a quarter of the way and now I'm in the third
40:58 I'm already starting to produce more, new action potentials. So when I
41:04 up here, when I finally maxed , I'm now recruiting 1/4 neuron.
41:08 ? So what we're doing is in neuron I have a range in which
41:13 can produce action potentials in terms of and then I have neurons associate different
41:20 that can all be added up, it up. Okay, my english
41:26 my english is Goodly. Alright, happens is I get this summation,
41:31 because I can, you know, my action potentials bigger. I just
41:36 in more neurons so that I perceive stronger response. Yeah, mature
41:47 Well part of it, Yes. so again there will be across,
41:50 gonna look at temperature here, we're look at a couple different receptors.
41:53 don't have one temperature receptor. We many different types of temperature receptors and
41:58 detect in different ranges, right? gonna see. We've already talked about
42:03 once before. And we just kind like said, yeah, okay,
42:06 memorize it for the test kind of our way. We talked about different
42:09 of touch receptors in the skin. you remember that way back to units
42:13 ? Like two weeks ago on a a monday towards Ariana Tuesday, we
42:17 about my course puzzles and free nerve and stuff. Those are all located
42:21 the same area. And what you do is you can recruit different ones
42:26 those, right? And they respond based on the type of stimulus you're
42:32 them. So you can imagine I have one on the surface that deals
42:36 light touch. And then as I in harder, I'm starting to get
42:40 little bit of deep touch, aren't ? Right. Yeah. Sorry,
42:44 needle. All right. So, intensity of sensory information will be the
42:50 folders, that frequency of action potentials is represented in that up down.
42:54 was the previous slide as well as number of fibers that are being recruited
43:00 our understanding of what that sensation Okay. Oh look here's that slide
43:07 lateral inhibition. So lateral inhibition is of the ways our brain or how
43:19 is, I shouldn't say our So take away brain, how information
43:23 through the sensory portion of our nervous is pre processed before it arrives in
43:28 brain. Alright. Our brain isn't only thing that's doing work to help
43:33 understand the world around us, There's things that are pre programmed in
43:39 brain help us discern things what what meets our expectation. But how information
43:45 shows up on our brain is gonna already processed. And this is one
43:48 the ways. And so again, gonna go to this little example
43:50 here's a pen. We're pressing on . I want you to take your
43:54 right now that you're riding with and want you to just touch your
43:57 I want you to look at All right, when you do
44:00 does your skin behave like this when poke in the pen? Or does
44:07 behave like this when you poke in pen? Like number two.
44:12 It does this, Right? And , what you can imagine is if
44:15 is a receptive field and this is receptive field and that's a receptive field
44:19 I kind of crossed over and I have. But then what's gonna happen
44:22 is as I push in. So I first begin pushing and I'll be
44:26 there. But as I go look at what I'm doing is I'm
44:30 multiple fields? This one would be strongest stimulation, right? Then this
44:36 would be the next strongest and then would be weakest. And then out
44:40 there would be no stimulation, So if you did that, what
44:44 brain would perceive if you sent all signals up there, it would be
44:47 like pressing with this pin. It's of this broad thing and it's saying
44:51 there's this broad area that's being stimulating brain. Okay, that's great.
44:55 I want to know where that pin actually poking me. So what happens
45:00 is that in the process the cell is strongest, It has collaterals that
45:06 out inhibitory neurotransmitters. And so what going to do is it keeps stimulating
45:11 its pathway but it's blocking the nearby next to it. And so what
45:17 up happening is that you end up or getting receiving? Just the signal
45:22 comes from that central pathway. So is kind of what your brain should
45:27 , right? But this is what brain actually sees. And look at
45:32 difference, Right? That's the difference the two areas versus that difference.
45:39 , your brain perceives, wow, is occurring from that point because this
45:50 where the highest level of stimulation has has knocked out all the other signals
45:54 it. The lateral signals. Hence term lateral inhibition. All right.
46:05 this does is it increases contrast. right. Yeah. One of the
46:19 you're gonna see this and I keep back to the eye because the eye's
46:21 really good thing is you'll see a of lateral inhibition occurring in the
46:26 Alright. What happens is your brain like gray? I mean it does
46:32 I mean to the extent that it to really kind of distinguish between black
46:37 white, it wants to create those contrasts. And so what happens is
46:42 that your brain basically will darken darken or darkened black areas and lighten wider
46:50 . So that creates this brighter or of contrast. Alright. And so
46:56 become darker things that are out that lights being reflected off become brighter and
47:03 gives us a sense of three dimensions a result of that and that's occurring
47:08 before light leaves the eye which is impressive. All right. So it's
47:16 a mechanism of creating stronger contrasts and can be and a touch receptor,
47:23 can be in other types of So in terms of the tactile
47:32 we're going to start looking at the types. All right, attacked.
47:36 ancestors are the most numerous types of in the body. They're all mechanical
47:42 are located in the dermis. And then the subcutaneous layers.
47:49 Every now and then we'll see a nerve ending finding its way up to
47:52 epidermis. But for the most part found primarily in the dermis. And
47:57 you see a couple of them that's in the sub Q layers. They
48:00 be encapsulated or they can be un . Alright. And their job is
48:08 detect touch pressure and vibration. I gave you a picture so touched
48:13 be easy? That's basically providing information location. Where's the where's the sensation
48:18 from? What is touching me is the texture like? What is the
48:22 of the thing touching me? What the shape? What is the movement
48:26 this object? Alright. So encoded that receptor that detects touch. Is
48:32 specific type of information? So we could blindfold you All right.
48:38 a hood over your head and put in a dark room or you can
48:41 the game with the box. Have seen the box game? You reach
48:45 and you feel things and you It's like okay this thing feels like
48:49 square, right? Or a Right? That's because the touch receptors
48:55 telling you what you're touching, It feels round and fuzzy. It
48:59 be a tennis ball but it's moving a hedgehog pressure. That's just a
49:10 of defamation of deeper temperature or Not temperatures. Right? So pressure
49:15 happen on the surface and then you push harder. So you're gonna have
49:20 deeper sense of touch. But you're gonna get that deeper sense of
49:24 And then vibrations are simply rapid and signals give you an example of
49:30 Take your fingers and drag them across desk. Do you feel vibration when
49:35 do that? Yeah. Why would need to know what vibration is?
49:42 trying to grip stuff. Is it in my hands. Do I need
49:44 hold it harder as an example of . All right. So, let's
49:52 through the different receptors. Good news you've learned this once. So,
49:56 is kind of a review kind of right. With regard to the UN
50:03 . These are the simple ones and mean, simple in the sense of
50:07 . They're simple. Alright. They dendritic endings. All right. And
50:11 don't have a protective coat. And there's three basic types. We
50:15 the free nerve ending. That's an one because that's when you picture a
50:19 , that's kind of what your We have the root hair plexus which
50:23 basically a free nerve endings wrapped around hair. And then you have the
50:27 disk or what is called the Merkel . Alright. And you can see
50:30 down here. Alright. These are in epithelial all over the place.
50:34 found as well as connective tissue and they're annihilated if they're annihilated. What
50:40 it mean in terms of their So, Alright. Take your take
50:46 sweet time. And when we say time when we're talking nervous system,
50:50 talking, you know, maybe a . You know, it's it's still
50:55 fast but it's not like super So, here's a free nerve ending
51:01 here's the hair plexus. You can here the free nerve ending, there's
51:05 fiber going up? There's endings? embedded in this particular case in the
51:10 the epidermis. You can see the nerve endings. What's it done?
51:14 wrapped itself around the root hair Hence the structure around the hair follicles
51:21 . All right. These are polymer . Alright. Means they detect all
51:26 of different things. So they can temperature, they can detect touch
51:30 they can detect stretch, they can damage so they can act as no
51:35 sectors. Alright. They can uh along different types of fiber ways are
51:43 fibers. Typically C fibers are the , slowest A Alphen A delta are
51:49 faster. Typically those are my But you don't need to worry about
51:53 . We're gonna get to it a bit. You don't need to know
51:56 fibers are which, but these are fairly slow. These are also can
52:02 slow or rapidly adapting. They can in the category of being tonic or
52:08 . So there's different kinds of of receptors depending upon the need of the
52:14 in that particular location where they're found merkel disk or tactile disk is probably
52:22 the term that they're using nowadays, rarely are we using the names.
52:25 here we have the neuron. So that yellow yellow thing is the neuron
52:30 merkel cell, is that separate cell sits aside? It's a receptor
52:35 It's associated with the neuron, It's part of the neuron. All
52:39 And remember in terms of the it was found in the stratum
52:44 So it's injected in there and so job is to detect the sense of
52:49 . Now this particular type is a receptor. All right. So,
52:54 of the ways you can remember this kind of create yourself a little matrix
52:57 you can just say, you merkel cell tonic, its job,
53:00 touch. Right. So, what's job? Is it basic whatnot?
53:05 we have that information? All So this helps us to detect texture
53:10 well as shape. How you know how you know, it's a
53:14 He said tonic. Right. tonic remember is always sending signals.
53:23 is on enough whenever you get So, yes. So, the
53:35 cell is also called the tactile That might be where you heard it's
53:39 tonic receptor. Its job is to touch a lot of teas in that
53:45 . Sorry? Alright, so, and shape. Uh huh.
53:53 Mhm. On it. Mhm. do you feel? Well? So
54:02 you cut the receptor then you're not feel anything, right? Because the
54:05 now has been severed and it doesn't a way to receive stuff. But
54:09 you ever had an open wound and hurts like mad. What have you
54:13 is you've actually exposed um those receptors new new items. Typically what you're
54:19 . The cells are releasing chemicals saying pain pain pain pain. pain,
54:23 and that's really what they're doing is responding to those chemical signals, you're
54:31 Mhm, yep. Mhm. Yeah. So All right. You
54:38 for some really gross weird stuff when do brain surgery. Right. They
54:44 you awake? Why? Well, because they want to make sure that
54:48 they're touching is they're having they're talking you and they're making sure that you're
54:53 you're able to respond like you're what if I touch you here?
54:56 me, you know, what do hear? Or you know, tell
54:59 who's the President of the United No one's ever gonna get that
55:02 Right. What's what's your name? you say my name is purple then
55:05 probably said well, we probably shouldn't touching that area. All right.
55:09 you don't feel it because they don't touch receptors in your brain because there's
55:15 purpose for touch receptors in your Your brain shouldn't be exposed.
55:20 So, it doesn't need to know touching it if that makes sense?
55:25 . Where do you think you need be touched or where you know,
55:29 be on the surface of your body then there's gonna be areas in your
55:33 , like primarily in the gut, know where you'll see. Touch
55:38 But that's about it. So, thought, like, your digestive
55:47 Mhm. Right. Yeah. So right. So, sensation of
55:52 All right. That's that's an easy . What what do you think
55:54 Is? Is that a touch receptor another type of receptor? What do
55:58 think? Pressure? So, it's barrel receptor. It's a type of
56:02 receptor, but it's a barrel It's detecting the degree of pressure.
56:07 . Thanksgiving dinner. You've had your plates of food and you're sitting there
56:10 at the pie. You've got your pants on and you're sitting there
56:13 praying for death. Right. You what sensation is that again? That
56:17 be a pressure, right? Or stretch receptor in the surface of of
56:24 digestive system. Right. And that's a sensation to say um you're
56:29 allowed to eat anymore food, Because if you bring another drop in
56:33 , what am I gonna do? gonna just get rid of it
56:35 I'm gonna just go ahead, throw up and then you're gonna have to
56:38 deal with that. I don't know your brain actually says that, but
56:44 usually suggests that quite a bit said , don't do that. Alright,
56:48 , touch receptors are really going to in those places where you need to
56:51 your external. Yeah. Yeah. for the weird ones. The encapsulated
56:59 . Alright, so, again, the encapsulated ones. These are primarily
57:03 I mean they're named ones are named the people who discovered them like crafts
57:07 example, he was a German You know through the late 1800s,
57:12 1900s. But generally speaking, you even know that. I'm not gonna
57:16 you who is Kraus an important. right. But the idea here is
57:20 we have is we have these different of receptors. You can see that
57:24 wrapped up in connective tissue in the cartoons. Almost all of these are
57:29 be McCann A receptors and there's four types. And again, this is
57:32 of those things where I'm learning I'm just gonna try me a little
57:35 matrix and just kind of make make matrix and say, what makes this
57:40 from the other things. Right? , that's the best way to go
57:44 doing this. So, the miners cell. Alright, structurally. What
57:48 end up with is you end up these linear uh or what we call
57:54 . So, these linear structures that wrapped in the connective tissue.
57:59 And so what's in there? Those those neural lymphocytes. Remember what is
58:02 your side? It's a Yeah, a glial cell that basically serves like
58:08 it's a Schwann cell that basically wraps up, Right? And then that
58:12 gets surrounded by a connective tissue. , this is located in those Papillion
58:18 are found in the dermal layers, ? So this is the papillary
58:21 And then here's those Papillion. they're kind of right up close
58:26 So, they're near the fingertips. know, in your fingertips. They're
58:30 very common in your lips. They a role in phase detection.
58:36 remember, signal on signal off their . They're right up near the
58:42 Light touch and vibration. I'm not to ask you about the megahertz.
58:48 just that's important, but it's just in in its particular range. All
58:56 . So, those are the ones are up close, moving a little
59:01 deeper. We've moved deeper into the layers. And this is where we
59:05 fini's roof finis. We're gonna have nerve ending that's gonna go around a
59:12 fiber. And then we're gonna do we're gonna wrap that up in connective
59:15 . So when you pull or push stretch or bend or twist that collagen
59:21 , you're going to detect the change the collagen fiber. All right.
59:27 density is around the fingernails. And reason for that is because we're going
59:30 detect a lot of vibration there. ? So, we're gripping and holding
59:36 things as things are moving around or around our fingernails. That's when we're
59:41 detect and it's going to cause us grip harder. Alright? So we're
59:45 skin distortion as well as deep Because remember where are we were deep
59:50 the dermis. We go back. here we are. There's miners are
59:55 . There's my sinners. There's rue . So, the pressure you're feeling
60:00 going to be deeper. All these are tonic receptors are always sending
60:07 . What is the degree of stretch this collagen fiber? Alright. If
60:11 stretch it more, I fire If I stretch less, I slowed
60:15 my rate of firing but there's always be a signal coming through these particular
60:21 of pathways. Yes, sir. . You mean the sensation that you're
60:34 ? So that that vibration feeling? , that would be that would be
60:39 Now obviously when you're doing like that very light, that would be
60:45 one near the surface meisters. But I'm pressing in and trying to grab
60:52 grip something that would be rude, Alright. Again, I think in
60:57 of I mean there's a logic to right? When I'm near the
61:00 it's got to be light as I harder or hold tighter and I create
61:04 pressure. That's gonna be deeper. that would be finis we got two
61:10 and then we'll take a break. ? Cross this is the odd man
61:14 . Remember if Sesame Street remember everything need to know in life we learned
61:18 Sesame Street. One of these things not like the others. This is
61:21 one that's not like the others. I say it's not like the others
61:24 of where it's found it's found within mucous membranes. Alright? And we're
61:31 not quite sure what this one Um The ones in the the mucous
61:37 of the genitals for example? Doesn't this clear. It's kind of more
61:42 more like a blackberry or something like . But in essence it's going to
61:48 found in the reticulated layers. So in the same area that Ruffini has
61:53 . But it's only found in those membranes. Whereas we are looking at
61:58 Finis, it's found in uh just dermis everywhere else. It deals with
62:05 of light pressure. It deals with of temperature. And those are just
62:10 of guestimation because we're really still not sure. We don't have a
62:17 That was why I started looking through because I was trying to figure out
62:21 anyone had an answer to that And the answer was no, I
62:25 know. No one knows, no told me last one. Let me
62:30 . Yeah. Then we'll then we'll there. All right. And then
62:33 Pechiney in named after Pacini is basically nerve ending that gets multiple uh connective
62:42 sheets around it. And what this is instead of being this small little
62:46 as a area of of detection. , what you've done is you've amplified
62:52 grown the receptive field. So, I push from this side, it's
62:56 have an impact on this sheath which then gonna be able to be detected
63:01 that free nerve ending or that nerve that's found within their. Now.
63:05 you're gonna find this in hairless It's gonna be in the deepest layers
63:09 the dermis. So very, very . That means you're gonna get deep
63:13 and the only the highest frequencies of can penetrate that low low vibrations don't
63:20 that deep. This is again a adapting. So it's a phase IQ
63:25 of receptor. Right? Where do see it? Palms and soles,
63:31 , external genitalia. So what we're do is we're gonna take a small
63:41 . We now know the names of different types of touch receptors. You
63:45 see where they are. You got that are shallow, some that are
63:50 the middle of the dermis and then that are deep. That's the deep
63:53 . Right? And so you can if I'm pressing in, would I
63:57 I press in really hard would I I stimulate all three of them?
64:02 do you think? Yeah I'd first with the outer one, then the
64:06 one, then the deeper one. I'm doing a light touch it's only
64:09 be the one that's up top. this is where we kind of you
64:12 see that recruitment a little bit So I'm gonna pause, push
64:18 going there we go. Alright so I wanna do is I want to
64:21 of shift our gear and look at couple of other different types of interior
64:25 exterior receptors. Or stare receptors. Here's the thermal receptor we mentioned just
64:31 that there are different types of extreme or thermal receptors. Their job is
64:36 detect temperature. Um there are more receptors in the body than there are
64:42 receptors and when we say that also we don't detect below 10°C. So basically
64:49 you hit 10°C, anything below that is cold. Right? I mean I
64:54 we could say it's gang cold, know? I don't know. But
64:58 , so the type of reception, do not need to know this name
65:01 I think this is kind of They're called trp so transient receptor potential
65:07 . Alright, you don't need to that but the reason I point this
65:11 to you because here is an example all, not all but many of
65:15 different types of receptors, They all to different temperatures. So this was
65:19 to show you here's your scale. here's 20°C. Here's 60°C. And you can
65:24 that they're kind of on this There's different varieties. They all allow
65:30 in two D. Polarize the cell , not so important. What I
65:33 to show you here is that they respond to chemicals. So thermal receptors
65:39 not just detecting temperature but they can a specific chemical and that's what they're
65:45 to show up here. So for , menthol is going to be here
65:50 mint. Right? And so when bite into a york peppermint patty,
65:56 get the sensation of cool responses. ? It's because that receptor is being
66:05 and you get that sensation of Now how many of you guys like
66:09 spicy food? All right. Like talking like real spicy food like ghost
66:15 . Yeah. Alright good. You I gotta have lunch together because that's
66:20 I live by. Everyone just thinks insane. But yeah, so here
66:26 go, cap Saxon, we're gonna activating these. So it gives us
66:30 sensation of heat. Is it really ? No, but she sure does
66:37 hot, doesn't it? And that's that molecule capsaicin which is found in
66:45 , activates those receptors. Alright, thermo receptors temperature. Yeah. So
66:53 content so we can't we just say cold. What? Alright, so
67:00 you touched something really really cold I really cold. What does it feel
67:06 , feels like it's burning? I'm like Mhm. I really wish
67:14 could take you guys up to the . All right, you can go
67:18 something cold like in a refrigerator, know just say a glass of water
67:23 that you'll feel. Yeah that's But when you get in and pull
67:27 out of the -80, that's gonna really cold. That's what you're gonna
67:30 it's really cold. But what does feel like? Doesn't feel like
67:34 It feels like pain. Right, what are we doing now? We're
67:40 different receptors Here's A FIN one. you guys ever felt something wet?
67:48 know splashed with water? Right? drops a soda in your lap 44
67:52 . Right? We have no wet . There is no such thing as
67:58 wet receptor. It's a combination of receptors that are being activated and the
68:04 of those receptors being activated simultaneously gives the sensation or perception of wet.
68:13 if it's a soda then we get perception of sticky. Also makes
68:18 I watch right begin. So what that something running down your leg?
68:24 would that be touch? Right. . And then it's gonna be a
68:30 temperature than the surrounding environment. So gonna be getting a thermal receptor being
68:35 , right? And so you're getting of those things simultaneously being activated.
68:38 that's what you're feeling and your brain going oh, that's what that
68:44 Yeah, yeah, yeah. Have ever eaten garlic? I mean like
68:54 just like have a little bit of in your food, but like it
68:57 you that same sense of spice, ? It basically probably it's just so
69:05 when you're looking at a receptor, what it's doing is binding a specific
69:08 of a molecule. Right? And there must be something in garlic that
69:14 one. But maybe there's another part it binds the other. That's probably
69:18 idea and again, the sense of does not for me give Cool.
69:24 mean I think of cinnamon, it's falls over here. But you
69:27 again, it's which receptor that all is is a is a showing you
69:33 receptors respond to what? Yeah. . That's temperature receptor. Have you
69:44 , have you ever swallowed like hot ? I mean not like like like
69:48 it's kind of hot. I mean you you're like you put in your
69:51 and you're not actually spitting it out you're not gonna waste good coffee,
69:53 your wallet and then what do you you burn? It burns all the
69:57 down because those receptors are located there kind of give you a sense of
70:02 , danger, danger damage happening to structures. Yeah. Yeah. So
70:22 , what you're doing is you're probably here. Not only this receptor that's
70:26 the far end, right, in in the in the below 10°. But
70:31 what you're now starting to do is activating receptors that are probably uh no
70:35 that respond to cell damage. And when you start freezing cells, which
70:41 what drives -20 and it starts breaking the cell, it kills the
70:47 So they start releasing those chemicals say is occurring, damages, occurring.
70:51 that's really probably the response. And , notice what I'm saying. Probably
70:55 don't know specifically I haven't actually done particular type of work. But that
71:01 to be the most likely answer. . Right. Mhm. What about
71:13 ? That's a good question is probably the blood vessels. But I don't
71:18 , I don't I mean that's that's good question, you know, No
71:21 ever asked me the brain freeze They've asked me about color of
71:24 but they've never asked me about. have to look that up. What
71:28 a brain freeze? Alright, so mentioned those few scepters. Uh
71:34 go ahead. Feel the pain. , actually, Well, I
71:47 alright, not having been shot in head, I really can't speak to
71:52 . But Alright. So what what what would be the first cells that
71:56 be stimulated the skin? So that's be all right? So you ready
72:00 the dumb thing that I did. my son and I were trying to
72:03 a bush out of the yard and decided to go ahead and tie off
72:07 base of the plant and tied it the back of the car,
72:12 and started pulling and it should come , right? Um But I used
72:17 rope which you're not supposed to use , you're supposed to use really a
72:20 or something like that really a chain it won't break. And that plant
72:23 just stubborn, but the rope was . And I told my son stand
72:27 because if this rope goes, it's to get you, This was like
72:30 week ago and he moved out of way, but that rope still got
72:34 and it went right across the lake there. and I was like,
72:39 was like I heard the snap, hope he didn't get him. And
72:43 was like, he's like looking at leg like this going said does it
72:47 ? He's all No. Well because took off the epidermis, took off
72:51 first layer of skin, right? all those free nerve endings, she's
72:57 . It was like instantaneous, very fast, very very quick. So
73:01 asking what would happen if you get in the head? Well remember those
73:03 are moving really, really quick, quack right there, cauterizing the skin
73:09 they go through because they're literally burning away. And then once you penetrate
73:13 the tissue, you know where there's nerves, you're not going to feel
73:18 . Of course if you're getting shot the head, you're gonna be
73:21 So any other signals are are not to be perceived as well is my
73:27 my guess. All right. Hm . With regard to know, see
73:33 , this is just a subtype of . Free nerve ending. Uh Their
73:37 they're concentrated areas prone to injury. of an area that's prone to
73:41 Anyone have an area that's prone to , elbows. Okay. I like
73:46 . I was gonna go with big right? Yeah, everyone's like oh
73:50 dammit. You know, hitting that table, middle of the night door
73:57 . Alright. They adapt very slowly they don't adapt at all.
74:02 so they are tonic receptors, they to all sorts of different things.
74:06 , cellular damage typically what cells are is they're releasing material. Noxious chemicals
74:13 then there's a whole bunch of different of chemicals that cells release that they
74:17 respond to. Please don't memorize the . Mhm. Right. What you're
74:31 is you're literally pulling the hair out the follicle and so you're tugging on
74:36 fog. I mean, you can this without waxing, you just grab
74:38 hair and start tugging at it. . Does that feel good when you
74:41 that hair? You can feel it ? Kind of have that burn
74:47 Alright, So, yeah, what doing is you're literally ripping the hair
74:51 your body, brady kind and these just different chemicals that these cells can
74:58 that serve as pain neurotransmitters or pain neuro modulators. Again, I don't
75:05 to memorize the list. Alright, different types of pain. All
75:09 What is pain asking the two guys lift weights in the back? What
75:14 pain? No, it's weakness. opens up a whole different story.
75:23 , you've you've heard the phrase pain weakness leaving the body, right?
75:28 . Never heard that one. Pain weakness leaving the body. one person
75:33 like yeah, yeah, that's pain weakness. Leaving the body.
75:37 Pain is a protective mechanism of tissue . So, when you feel pain
75:41 you're working out when you feel pain you're running, what is it
75:44 What's your body telling you? Right, But what do we do
75:49 we continue to work out? Keep . It's weakness leaving my body.
75:55 right. So, it's just a sign that you're doing damage to the
75:59 now. Is it irreparable, irreparable ? No. Right. So,
76:03 of our working out and getting that is letting us know that the muscle
76:07 is actually uh being torn a little so that it repairs itself, and
76:11 why it gets bigger. Okay, , first 10 years. Don't I
76:21 have it here anymore. Okay. took it out because it's because one
76:27 the things that our body does is soothe ourselves to get past the pain
76:31 that we can keep doing things is releases all sorts of analgesics. I
76:36 have that slide here. One of being endorphins. What is an
76:44 Right. It is the same sort chemical right that you find in
76:49 which is I'm blanking on the term now. Help me opioid.
76:54 It's a natural opioid that our body . It says, no,
76:58 don't worry, I've got your back it makes us feel so good.
77:02 is why we continue to exercise when bodies say stop looking at our
77:09 All right. Um No, I call that adaptation, I would just
77:15 that? Just a natural I it's it's a completely different kind of
77:19 . What I wanna do is I want to kind of briefly show you
77:21 different types of pain. Fast That's that sharp sharp pain that can
77:24 localized to like when you step on lego or something, that would be
77:27 fast pain, a slow pain. that slow aching, burning pain?
77:31 usually dull, diffuse, not easily . So it's like, I don't
77:38 , just say something something in your . Maybe a headache might be a
77:41 pain pain. Is that sudden onset when the stimulus is removed? So
77:46 I stab you with the pen, would be a cute when I take
77:49 the pen into the acute chronic is that persistent pain? So how
77:56 relieve that is gonna be dependent on type of source of pain.
77:58 I have a friend who has chronic pain and just has to live with
78:02 . There's nothing they can do. tried everything at this point. And
78:05 there's visceral pain that's basically, that's in the abdominal organs, usually fairly
78:11 , poorly localized and it's usually kind can go radiated around itself.
78:17 Huh. Uh It could be more um, oh, I don't
78:22 like when you get that upset stomach it's kind of like, you
78:26 but I mean, hernia would but again, that's fairly well
78:30 Right? Also, you've heard a pain, referred pain is basically a
78:39 of pain in the in a region the derma tome. You know the
78:45 , even though the origin of that does not come from that area.
78:50 it's basically a false sense of So the easiest one to recall or
78:55 about is a heart attack when you cardiac pain. Where do you feel
79:00 when you have an artifact you clutch chest? No, you clutch your
79:05 , right. And that's what this trying to show you. This is
79:08 referred pain for the heart is along inner part of the arm,
79:14 Yeah, lateral morning. I don't if it does at all. So
79:23 the we're not sure why it but the idea or the thought is
79:28 they're sharing the same ascending track. so what it is is that it's
79:32 brain not knowing from where it's actually because that track is expected to
79:38 I expect signals coming from this area mean this place and that they're sharing
79:43 track. But it's not really quite . So typically what we do is
79:48 use this as a way to help regard to medical diagnosis. Anyone here
79:52 appendicitis. Alright. So I had . I was at summer camp.
79:57 was awesome. You know, you to summer camp, the first thing
79:59 you have is appendicitis. They send to the infirmary going, oh let's
80:02 upset stomach. And then three days and hours and days of diarrhea and
80:06 , you know, they're like, well, this must be something
80:09 And then they take you to the office and then they sit there and
80:12 poke at your belly. Do you that? It's like, does this
80:14 ? Doesn't hurt? Does this hurt ? Does this hurt? Does this
80:17 , son of a and wise, touch that area, it's like being
80:22 with a canon. Alright, anyone had appendicitis can tell you that.
80:27 a lot of fun, you like, this one for the urinary
80:33 , imagine the pain again. It's to share tracks, you know,
80:40 that's this is just observational, It's like, oh, people are
80:43 in with this pain and then you doing it, it's like,
80:47 well, this is what the problem and really what they're probably talking about
80:50 kidney think about kidney stones, you ? You know, they say kidney
80:54 feels like giving birth without the natural . My brother actually had him,
81:00 he said it wasn't that bad it was just praying for death when
81:04 was just like, shooting me Yeah, the Yeah, they can
81:09 the sonic. Yeah, but usually don't want to do that because what
81:13 end up with now is you end with shrapnel, right? And so
81:16 can do more damage than that. , Oh yeah, just drink lots
81:21 lots of water, give you diuretics up those critters. Yeah. All
81:27 . So the pain pathway. And what we're gonna start seeing here is
81:32 gonna see these pathways. So we first order second order neuron and then
81:36 moving forward. So the first order is always what's receiving it. And
81:40 that's going to convey information from wherever stimulus is going. It goes into
81:44 spinal tract. Or excuse me, cord. Right. And then what
81:49 gonna do is it's going to then synapse with what is called the second
81:55 neuron. The second order neuron is traveling up to the thalamus. Alright
82:00 see first one is bringing it 2nd 1 is taking it upward to
82:06 thalamus. What is the role of thalamus remembers to sort information, tell
82:10 where to go. So the thalamus going to project to the cortex.
82:15 is where we're going to distinguish what is relative to other stimuli. So
82:20 gonna be the insular cortex. The cortex. What is what is our
82:24 component here? What does it mean be motivated by pain? Right.
82:30 . You have your you have your right. But you might have other
82:34 . What what am I supposed to in response to this pain.
82:38 And third what is how are we it? So that would be the
82:43 cortex and what this is just showing here is the thalamus setting that third
82:48 neuron. So you see how we these things. First orders one second
82:52 to third order three. So the order neuron in this case they're showing
82:56 going to the somatic sensory. So different places. Information is being
83:00 It's not just one place. There's signals being sent to multiple places.
83:05 we need to understand how to deal pain whenever you have a chart.
83:12 you supposed to memorize the chart? . Good. All right. All
83:16 want you to see here is how what pain fibers look like. All
83:22 . So there's three major pain They're based on their diameter and the
83:27 of mile nation. And because of two things, you know how big
83:31 are and how much Mile Nation they . That tells us also how fast
83:35 conduct signals. A alpha, Deltas and then sees are three different
83:41 of fibers. The alphas are the they're thick and they're my eliminated.
83:47 right. And so they deal primarily sharp well localized pain. I step
83:52 attack. I want that my foot as fast as I can. So
83:55 want a very thick And when I thick it's a relative term, that's
83:59 we're not memorizing numbers. There's there's relative thickness right there. Right?
84:05 . Alright. So I want So that's gonna be a very very
84:08 signal so I can lift up my and then continue on my way.
84:11 right. As we move down to ones so thick is faster than
84:19 Right? But we still have my nation. Alright, so this would
84:24 a slower conducting the A. Now. These types of pains are
84:29 aching pains. All right. And the last one is the c
84:34 c fibers thin. So they have that thinness. And if you want
84:38 do a comparison, you can kind see they're even smaller than the
84:41 Delta's here. But again, the doesn't matter. So they're very thin
84:45 they're so small. They still don't have violation. So the signals move
84:50 very slowly. And again, you kind of see the conduction rates,
84:57 ? So that would be where velocity meters per second here. This is
85:04 the kind of that general information about going on. If I touch something
85:10 , takes a while for that signal get to my brain, doesn't
85:12 So no, or not really my , but to cause me to move
85:17 . Another way you can think about is if you get hit by a
85:20 . Have ever been hit by a . Right? Isn't that a lot
85:23 fun? It's like you get that sharp pain. Initial. It's
85:26 oh that would be your a And then afterwards throb throb throb throb
85:34 . Right. What are we dealing there? That's the sea.
85:42 Thank you. Mhm right. I I've pushed the street. Right?
85:54 the idea is that the information gets . Right? But think about,
85:58 stepping on or you know, the here is if I'm doing if I'm
86:02 mechanical damage, you know, I'm not just destroying cells. There's probably
86:08 things that are going on as So, that's why the A delta
86:11 the A alphas are really, really . And again, you know,
86:16 I'm trying to paint a broader with strokes here. You know, I'm
86:21 the literature would cut this up even more so, Yeah. So,
86:43 question you're asking is do the receptor work? Right? Yeah, the
86:47 still work. It's now what you've . You've severed the pathway,
86:51 So, there's no perception of Because the pathways don't go up to
86:56 brain anymore. They might not cause reflex because maybe you severed where that
87:02 would have occurred. Right? the receptors are perfectly functional. Presuming
87:09 they're still there and they haven't degraded . Right? But again, I
87:13 the best example, think about the walkers, right? They're burning their
87:18 , they detect, Right? But you're doing is you're blocking and that
87:22 has to do with the next Really? It has to do with
87:26 , Right, modulation. All Everyone ever done that. I have
87:34 kids. I guarantee there there Older, but for a very long
87:38 . I never went upstairs without wearing because it's like a shark. I
87:50 I counted up. I think we over 100,000 lego pieces in our home
87:58 on the kits that the kids have over the years. All right.
88:05 produce both excitatory and inhibitory responses or . They are modulated by descending inhibitory
88:14 . So as information goes up, can modulate them by signals coming back
88:19 saying, don't don't send this We don't need to know that
88:23 I don't need to understand it when see these terms, they have specific
88:28 . An analgesic modifies the perception of . When you take your ibuprofen,
88:36 ? You're not stopping the response. not you're detecting what's going on
88:40 What you're doing is you're blocking the going upward in essence. And so
88:46 brain just says, yeah, It's not that bad, right?
88:50 is peripheral, pray and work for while and aesthetics blocked the generation of
88:58 action potential. So that's happening down the level of the receptor,
89:03 I'm not saying I'm not bothering sending signal on word is what it's basically
89:08 , right? Third is the endogenous . Now there's a lot of them
89:14 what we're doing is we're modulating Endogenous means, internal part of the
89:18 . So we've heard of the Endorphins are found in the hypothalamus and
89:23 , there's also the Catholics and the orphans. So just when you see
89:27 words think, oh these are natural . My body fights pain.
89:32 And what they do is they act a pre synaptic fashion. So they're
89:37 synaptic inhibition. So, here's my , right? Here's my sending my
89:43 here's my post. What I'm doing I'm sending a signal here to block
89:46 release of the of the neurotransmitter at synapse, that doesn't mean that I've
89:53 what I've done here, which I'm letting the thing go right here.
89:59 not I'm not allowing the synapse to occur. I'm not even I'm not
90:04 the pre synaptic cell of fire here I'm dealing with the the endorphins and
90:09 on, the signal has fired. what I'm doing is I'm not allowing
90:12 to release the neurotransmitter. All They also activate those descending inhibitory signals
90:20 would be part of what the analgesics doing. All right. There's also
90:24 whole bunch of naturally occurring opiates as that basically block these processes and of
90:31 , there's stuff that you can get are just chemicals when I first introduced
90:41 introduced to look at the time Alright. To these things. I
90:46 scared when I'm dealing with neural It's easy to look at these and
90:50 of panic. Big names, big names don't be scared, these
90:57 the first to And what we're talking is we're talking about somatic sensory
91:00 So when you're talking somatic sensory, information coming from the sensory receptors up
91:08 the sensory processing centers of the All right. They're the A sending
91:14 . If you're below the neck, going to have to use a spinal
91:18 . Does that make sense? good. If you're above the neck
91:22 have to use cranial nerves. That sense. The three people over here
91:28 yes, okay. Remember our body divided into two parts cranial nerves,
91:32 nerves. Alright, so, the nerves come into the spinal cord.
91:37 , that's what we're talking about. two major pathways and there's a lot
91:41 sub pathways in that we're not gonna about. But here are the two
91:45 pathways. The 1st 1 is called Dorsal Column Pathway. Alright. It
91:51 primarily with fine touch appropriate exception. , so when you see dorsal
91:58 think touch and balance. The Antero pathway is pain in temperature.
92:08 I'm putting these names here so that can see localization. Do you guys
92:13 our spinal cord? Do you remember spinal cord? Yes, no,
92:21 sorta sort of All right. Here's spinal cord. Right. Beautiful
92:27 What do we do make a All right. What's that region?
92:36 white matter. But what do we it? The dorsal particularly over
92:43 Yeah. What's that one? And ? Or interior. Right now,
92:50 at those names dorsal lateral interior. mean? They're naming it for where
93:01 is. Oh, okay, well makes things a little bit easier.
93:08 let's take a look at them. right. I'm just coming back and
93:14 what I stated previously that we name neurons from where they are located and
93:20 name them in order First order neurons going to be located as the receptor
93:28 they're receiving that receptor signal and they're that information in and they're either going
93:34 terminate at the level of spinal cord the second order neuron. Or what
93:39 gonna do is we're going to enter spinal cord, travel up through the
93:44 cord and they're going to terminate some in the brain stem. The second
93:49 neuron gonna travel up to the thalamus upon where it originates. The third
93:56 neuron just goes to whatever portion of cortex it needs to go to so
93:59 we're consciously aware of whatever that signal sending. Right? So primary or
94:08 order neurons bringing the signal in second neurons take that signal to the
94:14 Third order neurons from the thalamus to that final destination is in the
94:23 If it goes to the cerebellum, some of them will do, you're
94:28 going to have any sort of conscious of what's going on. But if
94:33 going to the thalamus, remember what said about the thalamus has a very
94:38 basic awareness of our environment. So going to do get we will get
94:43 conscious sensation. You said comes in the spinal cord, right? It
94:53 always turn it on the second order . So, the question is,
94:56 is it going to do? Is going to terminate where it comes
94:58 Or does it travel in and go to the brain stem and then terminate
95:02 the second order neuron? So it's to be one of two places where
95:06 enters or it's going to go all way up to the brain stem.
95:09 right now, I'm showing you these now, because we're gonna look at
95:13 next slide and we're gonna look at dorsal uh columns. All right.
95:19 , the dorsal column pathway the first neuron is going to enter and travel
95:26 through the dorsal column, shocking. right. So, it's on the
95:34 side. Now, the pathway that going to use in the dorsal column
95:38 a special name. It's gonna be of two. It's gonna be either
95:42 physical isG resilience or the physical It's if it's coming from the lower
95:47 it's going to be the priscilla's If coming from the upper body, it's
95:51 to be the kenyatta's. Alright, , the physical asse if you're looking
95:55 that name going, I'm not sure that name means means a little
95:59 right fashion. And then the ls the little bundle. All right
96:08 what you're going to see is that going to stay on the same
96:13 see how it stays on the same and it's gonna exhibit some manito p
96:18 Samantha topia is it maps or marks body? So this right here represents
96:23 body. So lower body is gonna the priscilla's right here. This is
96:27 to be upper body, see where stays, it stays on the outside
96:31 that's gonna be the kenyatta's and it's to terminate inside the medulla oblon gata
96:36 a specific nuclei, right? The where the cell bodies on which it's
96:43 to synapse the names of those cell . Those nuclei that name I said
96:52 familiar with the nucleus. Godzillas, cuny artists. All right. And
97:01 the other name for this pathway refers the Oculus. Really the door is
97:07 the medial meniscal pathway because up here the medulla, what you're gonna do
97:14 you're gonna cross over first. So there's your deck association. So
97:19 crosses over and it's gonna follow through medial meniscal pathway or the medial
97:25 Excuse me up to the thalamus and your second order neuron. So there's
97:33 deck association. So, I start this side information is coming in and
97:37 it's going to get to the brain and it crosses over and then it
97:40 going up to the thalamus. Um is the medial meniscus. That's when
97:46 get up to the thalamus and from thalamus. I go to the sensory
97:50 . What are we detecting? fine touch appropriate reception. Sorry there
97:59 is. Fine to approach procession appropriate . Got to get the word
98:04 Getting numb. There's a dorsal the other one called the anterior lateral
98:11 . But if that name is too and too long, why don't you
98:13 at the other name? Spinal thalamic goes up the spinal cord up to
98:21 all right. Again, first order , there's anterior and lateral. We'll
98:27 to that in just a second pain temperature. So notice what does it
98:31 in. Goes into the spinal cord onto the second order neuron. Second
98:39 neuron crosses over and if it's gonna lateral it'll be over in this region
98:44 its anterior it's going to basically stay this lower region. That's what it's
98:48 to show you the lower region. ? And then what it's gonna
98:51 it's gonna keep going up, keep up. Second order neuron terminates in
98:56 thomas third ordinary begins in thalamus goes to this matter sensory cortex.
99:02 so lower body this helps you in picture. Lower body is gonna be
99:09 upper body. It's going to be . So the anterior spinal thalamic
99:16 Lower body dealing primarily with pain or temperature lateral. Gonna be upper body
99:24 sorry. Lower body pain and temperature think. Lower body. Twice I'm
99:30 . So lateral lower anterior upper pain temperature. The names are scary.
99:41 not as bad as you think when get to the motor pathways is gonna
99:44 the same thing. They're going to you big long scary names and you
99:49 go, okay, where do they ? Where do they finish?
99:50 the names tell me where they start finish. Alright. I don't know
99:55 much time we have, but I'm try to get this started here.
99:58 got four minutes. Really four minutes talk about sense of smell. You
100:06 see my brain grinding on whether or I should do. Ah Want me
100:12 talk faster tomorrow? You're ready, ready, You're done. All
100:18 we'll talk faster tomorrow. All So when we come back, we're
100:23 to start diving into the special Olfaction Gas station is where we're gonna
100:28 hit and then from there we'll go the eyes and ultimately balance and
100:34 All right, alright. It's gonna a busy busy day tomorrow, hump
100:41 , Wednesday's are so much
-
+