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BIOL 3324 Human Physiology - 3324_lecture10_0927
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00:11 Alright, y'all So here we Tuesday morning. No afternoon,
00:17 So you can see kind of where brain is. Many of you guys
00:20 that the assignment was actually put in wrong date. I put like august
00:25 . So I had the date right day right? I had the month
00:27 so at least you guys get an on that um coming up. What
00:32 we have? We have introductions due friday. I double checked the date
00:39 . Um Although it's hard so I'll say so turn it in is different
00:43 the way we set it up, now one assignment instead of two
00:47 And so I don't necessarily see the assignment. So it may be wrong
00:51 if it is we'll just add an . That's alright. What do we
00:54 next thursday? An exam or Alright. It's it just goes
01:01 I mean just this is what it's and I'm just gonna let you
01:04 it doesn't ever slow down as you older and older and it's just gonna
01:10 fast. Next thing you know, gonna be 90 years old, wondering
01:13 it all went. That's kind of I feel, where I'm at.
01:16 right. Yeah, I'm not 90 old though. If I was I'm
01:21 really good looking 90 anyway. All , so what we're gonna do
01:25 we're going to deal with some uh aesthetic uh as a sense so basically
01:32 sense of touch, we're gonna look vision and um hopefully what I'll do
01:37 I'll get through this fairly quickly. truth is is I get really excited
01:42 vision, it is incredibly any optometry opt. Okay, so just a
01:46 of you. All right, so let you know this is barely dipping
01:49 toes in. You got four years school in front of you right to
01:53 about the eye. So this is we're gonna dip the toe in and
01:57 we're gonna walk away so everyone can your pain. All right. And
02:02 we're gonna do is I I do of go off on on the wild
02:06 sometimes when I talk about vision because really, really interesting and really cool
02:09 incredibly complex. We never go in deep as we should or or
02:14 But what we're gonna do is we're start right here, we're just gonna
02:17 about this, this feature of this of different types of receptors.
02:22 so there are reception in your We basically classify receptors all these different
02:27 . And so one of the ways we can classify receptor is asking the
02:30 , how well do they adapt? type of adapting are they a tonic
02:34 or they aphasic receptor? And so sometimes see the term slow adapting versus
02:39 adapting and even the images they have here are not going to be real
02:43 as as indicators, but I'm gonna to explain this though that you can
02:46 of get a sense like, I get this All right, so
02:50 adapting receptor and if you look at graphs, what you're gonna see up
02:53 at the top is stimulus. This what the receptor potentially use the action
02:56 that are being produced. And so want you to focus first on the
03:00 . Think of it as a binary . Alright. The bottom line,
03:03 one that's down here that goes across off and then the line up here
03:08 the top that's on so you can I'm off and then I'm I'm providing
03:12 stimulus that extends for a period of and it turns off again and that's
03:16 I what we want first going to on here is just stimulus is being
03:19 on and it's gonna be turned off . All right. And so the
03:24 is, is when do I want types of receptors? So with regard
03:27 slow adapting primarily, you're going to these receptors in areas where you're trying
03:32 give information all the time to the nervous system so that they know what's
03:37 on. 100% of the time. , so an example of this would
03:41 posture. All right, all your , in your back, in your
03:45 your anterior regions and everything that's involved posture. They want to give the
03:50 of your body all the time to central nervous system. So it will
03:54 what it needs to do at any time. Right? So if you're
03:58 too far back, it's like, no, no. We need to
04:01 you know that you're leaning too far . So you need to adjust and
04:05 and bring yourself forward. Right? kind of get that sense. So
04:08 posture is not just a one time , it's a constant signal all the
04:14 . Right? And you have that signal to at home, right?
04:18 mom always tell you sit up Yeah. Okay. So there you
04:21 . That's an easy way to remember fast adapting. And this is this
04:25 what you kind of see here. with here it's basically telling you the
04:31 . I'm trying to make sure if is actually true. Yeah. This
04:34 I did used to be their flipped I was like wait a second.
04:37 didn't look right. So you can here at the very beginning beginning the
04:42 potential is given. And so you that receptor potential being maintained throughout the
04:47 of the stimulus. And what they're to do is be more realistic
04:51 And it shows you that the front , it's fast in a series of
04:54 have been slowed down. So eventually of these slow adapting will basically adapt
05:00 not respond. Not always, but they will. The other type is
05:06 fast adapting or physic and again look what we're looking at here. So
05:10 stimulus turns on and it turns look at how the receptor responds,
05:14 only responds when there's a change in stimulus. Right? So you get
05:18 series of action potentials when stimulus is on, you get a series of
05:22 when the stimulus is turned off. here the body is only interested in
05:26 does change occur? Like when have made modifications to what we're doing?
05:32 , so the easy example of this the touch receptors that are located in
05:37 skin. Alright, so right now I started speaking about this, you
05:43 no idea that your clothes were touching body. Now you're all very aware
05:47 your clothes are touching your body now I pointed out right? But up
05:51 this point you got this morning you on your clothes and you went around
05:56 day and you weren't going closer touching , closer, touching me,
05:59 touching me close or touching me close touching me. That would be more
06:03 what the phasing is doing. It's saying closer touching me and all the
06:07 your brain is going yes, closer you. Really? What's important for
06:11 brain to know is when the clothes touching you and then when they stop
06:16 you, right? So when you're along in the tree rips off your
06:21 because that happens all the time. ? Then that's like, oh I'm
06:25 now shirtless, that's fast adapting. I know I'm using hyperbole here.
06:31 you can imagine when I feel something when I put my clothes on it's
06:36 yes, I've accomplished the goal. now when I remove the clothing is
06:40 something different has happened and now I'm that something different has happened. So
06:46 you see what we've done here is looking for when things change, that's
06:49 we're marking or using these types of to note those changes. Okay,
06:55 when we look at these very often will see receptors being referred to as
06:59 fast adapting or slow adapting or physics tonic whichever, you'll see those terms
07:03 tonic or physic. Alright, so I wanna do is I want to
07:07 with the specific types of mechanic receptors are located in the skin, the
07:12 that are responsible for your sense of . All right now, these types
07:16 receptors are gonna be located primarily in dermis. There are there is one
07:21 actually located in the epidermis. if you don't know the difference between
07:24 two, That's okay, we don't go into the anatomy here, but
07:27 skin has two basic layers, the layer, which is the epidermis.
07:31 no blood vessels. It's a bunch dead cells except for the lowest
07:34 And so it's basically the protective layer then the underlying layers, The
07:39 that's where your blood vessels and your are primarily located, there's connective tissue
07:43 that area. And so it's like you get cut and you don't
07:48 you've only gone through the epidermis if cut and you bleed your down,
07:51 in the dermis. Alright. To of give you a sense of where
07:53 are. So the predominant number of are gonna be located down on that
07:58 region. Now these receptors are going be either very, very simple or
08:02 can be complex. And in this when we're using simple and complex,
08:06 saying we have a receptor cell that some sort of complexity to it.
08:11 this case, what we've done is wrapped it up in different types of
08:14 tissue. And so that's what it . Is it broadens or increases its
08:19 range by encapsulating it. So instead having to touch specifically where that cells
08:24 now because it has this connective tissue it, you've made a much bigger
08:28 to which it responds. So, type of receptor we're gonna look at
08:32 into one of these two kind of now to give you an understanding of
08:36 a receptor. I guess. I do that yet. I don't know
08:40 it is. I can't look at slides here. All right. So
08:44 un encapsulate ones are the simple Alright. And they're they're fairly basic
08:49 actually the one that's really easy. not even shown here that you can
08:52 is everyone just grab a hair on head, You can grab a hair
08:54 your head and pull it. Can feel? Yeah, you're pulling down
08:58 , you're you're feeling lots, get little tiny one. You can feel
09:01 like oh, I got it. , yeah. Yeah. All
09:03 So that tug, that pull is result of stimulating a root hair
09:08 a root hair plexus and a free endings are very, very similar.
09:12 one goes out into the skin, is wrapped around the base of a
09:15 . So, that's the difference between two. All right. And what
09:19 have is we have a single neuron basically has a bunch of dendrites that
09:23 dendrites then wrap around the thing that trying to detect. So, if
09:27 stimulate the area around that dendrites, are mechanics receptors located in that dendrites
09:33 then detect the movement in the which then tells your brain something is
09:37 on here. There's that sense of . The Merkel disk is the one
09:42 found in the epidermis. And it's in the very, very baseline layer
09:47 the epidermis. So it's right next the dermis is here that merkel cell
09:52 right there and it's basically talking to neuron that's in the in the
09:58 But again, it's looking for manipulation the skin and looking to see if
10:02 any damage that's uh done there. these fibers are very, very
10:07 They're annihilated. Which means that their are particularly slow. And they're dealing
10:12 some of the really basic understanding what's on on the surface of our of
10:16 skin. So pain that's no see some light touch. There's some chemo
10:22 in there as well when it comes all of these different things. But
10:26 easiest to think in terms of So while I expand this thing,
10:31 just wanted wanted us to focus on here. Now when we get to
10:37 other types is encapsulated. They're all after people, the people that actually
10:42 them. And again, we can the sesame street principle here,
10:46 One of these things is not like others. And so that's the first
10:50 . Which one is not like the . Now, the cartoon doesn't do
10:55 thing as much justice as I'd like to. But I'm gonna just point
10:58 first off the crowds bulb is the thing that's not like the others.
11:02 located the mucous membranes where your mucous located. Oral cavity, nasal
11:10 urethral opening, vaginal opening, and anal opening. So basically all the
11:17 to the tubes of your body. right. And so that's where these
11:21 are primarily located there there to detect pressure is really the way you can
11:26 about it. Now, we're going see that there's others that deal with
11:29 pressure. But those are in your , right? So they're not in
11:33 mucous membranes are out in the crowd structures. So that would be my
11:38 core puzzle. Alright, Meisner score is found up here. Hi.
11:44 right. So it's that little blue that they're trying to show you
11:48 This deals with the question of light or light touch, which basically is
11:52 and shape of an object. All , close your eyes for a
11:55 envision you're holding a tennis ball. can understand the shape of the tennis
12:01 , you can feel its roundness, can feel its fuzziness, right?
12:05 , that is a result of you that surface and and being able to
12:11 those fine minute textures as a result my listeners corpuscles found right here in
12:17 upper dermal layers, right next to epidermis. Alright then we have Ruffini
12:25 which are found in the in the range. That's these things right
12:29 The brown things are actually just glands our picture. So they kind of
12:33 in the mid range and then down we have Pacini ins or Pacini
12:38 Pacini and would be the the So up here is light pressure.
12:43 here is deep pressure in here in middle. This deals primarily with fluttering
12:48 . Now, if you have a in front of you. This is
12:49 easy thing to do. Get that and roll your fingers across the
12:54 You can feel kind of the There's kind of a vibration to
12:58 What your skin is doing is one blah blah blah blah blah blah on
13:01 surface and Rufin eases picturing it And what you're doing is you're actually
13:05 and turning the connective tissue that's down in those dermal layers and that broader
13:10 being twist and turn so that those tiny dendrites that are hidden inside it
13:15 pick up those vibrations. So different of touch are the result of or
13:24 of touch are the result of the of pressure, the amount of vibration
13:28 occurring and different receptors are located at depths to allow you to perceive those
13:34 . Okay, so the hard part remembering which one belongs to. Which
13:38 one's the one that stands out as different. It's like Meisner, Meisner
13:43 the shallow Ruffini is middle is And if you can remember where they
13:49 , that kind of gives you a of the type of touch you're dealing
13:54 . Now I get to receptive All right, so, a receptive
14:00 is not only going to be found touch, but it's an easy way
14:03 explain a receptive field. So receptive is simply the area in which a
14:08 is being is able to detect the that it's supposed to detect.
14:13 So typically you can think of if have a free nerve ending like.
14:20 right each of those little branches comes where it terminates that area around it
14:27 what it's able to detect. if you have multiple branches, you
14:31 see that there's a slight degree of for those different areas, right?
14:36 if I take this whole thing and it up in connective tissue, what
14:38 done is I've broadened out where I I can press over here that can
14:42 be detected by those layers and layers connective tissue. Right? So,
14:46 can see I can make very, large receptive fields now are receptive fields
14:52 the smaller they are, the more detail they can detect. Right?
14:57 , on our hands, for we have very very small receptive fields
15:02 really specifically in our fingers. We to be able to detect the things
15:05 we're touching, right? But like the back of our legs, we
15:08 to understand when we're being touched by . But we're less concerned about what
15:13 actually is. We just want to that it's something touching us. And
15:17 told you about me having the scorpion ? My arm. Right, did
15:21 mention that now? Okay, I two classes. I give the same
15:25 . Sometimes I forget which class I've . All right. So, when
15:28 was in um probably six or seventh , I was over the girls house
15:32 a movie and this was in the eighties. Yeah, about early
15:36 Um Maybe. I know. I'm like I'm stranger things.
15:41 Um But for many reasons. All . Um And this was back when
15:47 still had shag carpeting. So you , shag carpeting is the most horrid
15:52 thing ever. And I'm sitting she was like on the couch and
15:54 on the floor and I'm sitting there kind of watching whatever the show is
15:57 the movie. I don't even This is what I do remember is
16:00 kept feeling something brushing up against me I thought it was a shag
16:04 So I kept just kind of you know, nudge it off and
16:06 I feel it again, nudge it . And finally three or four times
16:09 looked down, there's a scorpion trying crawl up my arm, you
16:12 And of course that's when you like up and go, oh and then
16:14 get a cup and you catch it in the in the toilet and you
16:17 it and you know, goodbye Let someone else deal with it.
16:21 ? So it didn't matter that, what that thing was, right?
16:26 skin was just kind of telling me touching you and you should pay attention
16:30 that, right? But if I touching something with my fingers, I'm
16:36 I can understand much more clearly what is. I'm actually dealing with because
16:41 have smaller receptive fields that are dealing all these different levels of pressure and
16:47 and texture and shape. And so better. I can understand my environment
16:53 better with with those small receptive Now, this is gonna be
16:58 Also, for example, in the we have a very, very small
17:02 fields in the center of our vision we have very, very large receptive
17:06 . And so what that means is our vision outside of that, that
17:10 point is kind of blurry. All now, you can just prove
17:14 Look down at your notes for a or your sheets and try to just
17:19 on one word, right? And look at that one word. And
17:23 moving your eyes and focusing on that word. Kind of look at the
17:26 of the page. Does the rest page seem kind of blurry? And
17:29 eyes are tempted now to move to you're trying to look at,
17:34 And the reason for that again is we have these small, small receptive
17:39 , what we call visual fields for center vision where our clearest vision
17:43 it's unimportant that we know the details here. We just need to know
17:47 things out here. So when we movement, what do we want to
17:50 ? We turn our head to look whatever it's moving right? So that
17:54 can detect whatever the danger is or the exciting thing is or what
17:58 All right. So we focus energy creating small receptive fields where we need
18:05 have that view. So when we're forward, that's where we're looking.
18:09 I gotta do is just point that the right place. All right.
18:14 for example, large receptive fields we're have is we will have um uh
18:21 . Well, I guess what I trying to say is basically all the
18:24 things. I said we can't localize exact spot of stimulation. There's a
18:27 little trick that you can do. a stylus. What happens when you
18:32 in the front row? All give me your arm, put your
18:36 way up other arm, other arm here. Right? You can take
18:39 stylist like this and then you can look the other way and then what
18:42 can do is say tell me when feel one feel one. Okay,
18:48 does it feel like one pressure or one look how far apart those are
18:53 receptive field, isn't there? But I did it on his fingers,
18:56 could probably get like right next to . And I was like,
18:58 I can't I still still feel to . We'll get to pain in just
19:07 second. But it's there's two levels or there's multiple levels of pain tolerance
19:12 we're gonna be dealing with. All , So just understand receptive field vary
19:16 size. They're dependent upon how much one neuron is able to detect
19:23 So basically it's the size is dependent how many neurons are in that small
19:31 . Alright. With regard to know sectors are pain receptors. There are
19:37 variety of different types of receptors. . We have things that are specific
19:42 the type of things that they Like we have mechanical, thermal or
19:45 . No. So receptors. So respond to that specific type of modality
19:51 we may have a pollen model which responds to a combination or any individual
19:56 of modality is not specific enough. so they're very very different types.
20:02 we could go on for probably 45 or so. But I want to
20:05 this really really basic. And so idea here is that your body uses
20:10 as a way to determine what's causing or damage to the body. All
20:15 . And so what it's doing is not only monitoring pain but it's modulating
20:19 response to it. So there's a bunch of different types of chemicals that
20:22 lower activation thresholds or even raise activation so that your your body responds more
20:31 um more quickly to pain or less . So this is kind of trying
20:36 address your question right? And so can think about like this. Alright
20:39 skinned your knee or gotten a cut some sort and then afterwards you get
20:44 scab and when you touch that area just painful. Right? What's your
20:48 telling you to do? Don't touch . I'm trying to fix it.
20:53 , that's what it's basically telling you do. And so the idea here
20:56 that it actually up regulates the sensitivity the of the pain receptors in that
21:02 so that you'll stay away from that . Right? So that that's an
21:07 of that modulation because normally just touching area wouldn't hurt. But now that
21:12 damaged it, it's like I want work on this area. So I'm
21:14 to up regulate the receptive or that of those receptors. There are three
21:22 types of fibers. I think you'll that there are actually others these and
21:27 what this does it boils down to and Myelin Nation. And since we've
21:31 learned about my elimination size, this be too difficult. Alpha Betas.
21:35 are the big Myelin ated fibers. if they're big and they're violated,
21:39 fast are they? They're fast. , so that's what we're going
21:43 We're going for fast. Not a of these do not deception, but
21:47 of them do. All right, we have the alpha deltas or the
21:51 delta. Excuse me, These are and my eliminated. So these aren't
21:56 as fast as those. But because violation, they're still very very
22:00 So these primarily deal with fast Alright. Anyone here have been hit
22:04 a baseball, isn't it fun. that small right? And you get
22:10 immediate pain. Alright, I'm looking a couple of guys in here.
22:14 somebody been slapped inappropriately for inappropriate Alright. Yeah. So you get
22:19 slap across the face. There's that pain, right? That's an alpha
22:25 a delta. Okay. It's sending information saying something bad has happened.
22:31 it. Which is also what the is there for. All right,
22:37 we have the C fibers, C , they're small, so small and
22:41 . Notes were not caring about size there is variation in the sizes.
22:45 we're dealing with violated versus unvaccinated. these fibers are going to deal with
22:50 pain. Alright, so again, the baseball baseball hits you in the
22:54 , immediate pain out that hurt. then what happens for the next couple
22:59 hours? The throbbing pain, C fibers. Yeah, damage has
23:05 . Just letting you know just it's here, damage is still going
23:09 And so that's really what those last last fibers are for. So,
23:16 is being sent down multiple pathways to you know first stop doing what it
23:20 that you're doing. And secondly, has occurred. We're working on
23:24 We're gonna get systems back to normal soon as possible. Alright, anesthetics
23:32 analgesia. Alright. Which there is difference and this I think is a
23:37 good picture to kind of show you these things occur. All right,
23:42 , an anesthetic is something that we that suppresses the sensation Doesn't mean that
23:49 isn't occurring. It's still occurring. what you're doing is you're blocking that
23:53 from even getting into the central nervous . All right. And so you
23:57 show you what am I doing? , local local anesthetics or basically stopping
24:02 signal from going past into the central system. And analgesic, on the
24:07 hand, basically is not even allowing signal to exit. In other
24:12 where the signal can't even be allowed get. I'm not doing a good
24:17 of explained that. Alright, so what I'm trying to get at here
24:21 that the receptors there, but it's responding appropriately is what I'm trying to
24:25 out here when you're dealing with the the analgesic, The signal may go
24:31 , but it's not it's not stimulating central nervous system is what I'm trying
24:35 get at. All right. what this is trying to show you
24:39 that is primarily done through uh pre inhibition. So, you can see
24:44 this particular example of here, here's noxious stimulus that goes up because the
24:48 of their neurotransmitters that sends that information to the brain. But there are
24:54 of the brain that say no, , no, no, no,
24:55 go ahead and suppress that. And what we're gonna do is we're gonna
24:59 an opiate and endogenous opiates basically brock . So that that neurotransmitter never comes
25:06 . Alright, So let's think of that do this you guys like to
25:10 out. Yeah, pump that extra , you can feel the pain,
25:16 the burn and then if you let sit around for a while there was
25:20 analgesia, that pain would persist while muscles rebuilding themselves, right? But
25:26 was your body do, it's even there in the word, where is
25:30 ? There we go. Endorphins. are your body's way of saying,
25:36 worry, I got your back and you that and you're just like and
25:42 what does it make you want to ? Go back and do it again
25:45 it makes you feel good. All . See I like to think of
25:50 food, eat spicy food. hot hot. Oh, scary,
25:55 . I'm I'm damaging my body, ? And then your body says
25:59 no, I got your bag releases endorphins, give me more spicy
26:04 All right, what we're doing is blocking that that sensation from ever reaching
26:10 central nervous system here. An we're blocking along the way before it
26:17 gets up there. Alright, So kind of the basics that I wanted
26:22 get to. Oh I forgot about . 12, we're gonna come back
26:26 these two structures in more detail when deal with reflexes. But I wanted
26:30 kind of talk about appropriate reception as . So we had what I'm covering
26:35 , if you can't see is touch sense of pain and then the sense
26:41 balance, appropriate reception, your your of your body and space. You
26:46 all recognize you're sitting upright. Okay. That's because you have a
26:51 understanding, you guys know where your are in your body right now.
26:56 . Alright. Let's say we had couple of drinks, I don't
26:59 Let's say half a bottle of Yeah. And that's a lot for
27:04 . You don't know. That's a . Right? Could you stand and
27:07 your nose? You could try but you? No, no. It
27:14 be like, you know, you've with the appropriate exception. Your body
27:20 know where its parts are in Alright, So that's really what appropriate
27:25 movement. Alright. Um so there's structures in particular that play a major
27:31 in this. And we're gonna go more detail here, we have the
27:34 tendon and what it's looking at is amount of tension in that muscle being
27:39 to the tendon. Alright, so muscles are attached to your bones via
27:44 and so to move a bone, need to pull on a tendon and
27:49 pull the bone. So what you're is you're detecting the degree of tension
27:54 that tendon so that the tendon doesn't . That's number one. So how
27:59 I move my body basically move my , number two is looking at the
28:04 of stretch in a in a So this helps determine where that muscle
28:08 supposed to be, right. So have both intent and I have I
28:13 , as to where I want to the muscle and I want to see
28:16 much work I'm doing on that So, for example, if I
28:19 trying to lift £200 And my muscles not ready to lift £200, I could
28:26 the muscle and the Tendon. So is there to make sure that a
28:34 not gonna damage it, but be I put in the muscle in the
28:36 place, if that makes sense? . I think I'm gonna actually skip
28:42 these two things because we're gonna come to it in two days. All
28:46 . But I want to understand that body uses these types of receptors located
28:50 muscles and tendons to help you understand your arms and your hands are.
28:59 . No. So what you're So can occur for multiple reasons.
29:06 So typically when I think of what I'm thinking of is no signal
29:10 making it down to the motor neurons cause those muscles to move. So
29:14 signal may be occurring in the central system, primarily in the brain
29:19 but something along the way has prevented signal from continuing on to the structure
29:24 you want moved. Alright. Is always the case? No, But
29:30 when I think of paralysis when I Wayne specifically thinks of paralysis, that's
29:34 I think of is damage at the of the spinal cord so that the
29:37 neurons aren't receiving their signals. I've got good examples for these but
29:43 don't want to waste our time here I'm gonna come back and talk about
29:45 . Okay. All right. I want to jump into it.
29:50 want to jump into vision. Make pre optometry students happy. Right.
29:56 off, what is like, y'all physics one, right, Or is
30:00 physics to physics? They don't talk it. Never taken it. Oh
30:05 goodness. Well, here's your physics the day. Alright, first
30:09 if you don't know, light is form of electromagnetic radiation. So,
30:13 purpose of our eyes is to detect radiation. The thing is we only
30:18 a very, very small band of electromagnetic radiation, what we call visible
30:24 . And so you can see up , that black thing shows you what
30:27 the different bands of electromagnetic radiation And it's just talking really about these
30:33 and how much energy they have to . In fact, if you think
30:37 particles when you think about photons. you think about electrons, When you're
30:40 biology, if you just think about as just quantities of energy, it's
30:46 much easier to kinda understand what's going with them. All right.
30:50 we are looking at a very, small small small band of electromagnetic
30:56 You can see where that band is try and hold still. Right,
30:59 , right there. Okay, this wavelength and it has amplitude.
31:04 When we talk about wavelength, I about a rope and I snap a
31:07 and I can see that wave in rope. That's not the type of
31:10 . This is it's far more weird complex. And that's what this bottom
31:15 is looking at. I pulled this of of Wikipedia. It's a it's
31:20 gift. And so if you go it, it's very mesmerizing because this
31:24 going up and down up and down this one's going back and forth and
31:28 as you can see they're asynchronous and they're in constant motion. So there's
31:34 two aspects, there's that electrical field that magnetic field along the length to
31:40 you're traveling. But we're gonna keep simple and just say wavelength equals the
31:45 of energy being carried by that particular . Alright. For our purposes physics
31:50 tell you something different. And that's , don't worry about it.
31:55 its amplitude amplitude refers to the So wavelength is basically from peak to
32:02 . Right? But amplitude is from to peak. So, I can
32:06 the same wavelength but have very very amplitudes. So, think of bright
32:11 versus dim light. Alright, that be amplitude. Although that also represents
32:17 number of photons that your eyes are . So there's two reasons why you
32:21 have that. Alright, so visible is just a very very small sliver
32:25 what we're trying to detect to understand world around us Now there are lots
32:31 anatomical structures that we're gonna be going and I'm just gonna sprint through
32:35 This is stuff that you should just of look at an eye and start
32:38 okay, what are these different pieces ? So first off the eye has
32:42 layers, Alright, the outer the whites of your eyes plus that
32:46 of your eyes. The core And this clara. Alright. The
32:50 Oid is the white part. Sorry said corduroy. Excuse me. Back
32:56 up, cornea chords the middle Alright so the cornea is the clear
33:01 . It's actually living cells. Light able to pass through it. It
33:04 no blood vessels so light is not to be deflected or absorbed. It
33:08 basically passes straight on through all the are gonna be provided by fluids that
33:12 behind that cornea. The white the scleral is basically a bunch of
33:19 tissue that's continuous with the the dura and basically it serves as a structure
33:26 kind of holds and maintains the shape the eye in its semi spherical
33:31 Alright, underlying that that's the vascular and so in there that's where the
33:36 oid is. That's where your irises where the cord bodies are. So
33:40 you can see core Oid is and muscle as well as blood vessels.
33:45 that's why we refer to as the layer. Right? So core Oid
33:48 all the nutrients for the school It provides all the nutrients for the
33:52 layer which is the retina. It the muscles that are gonna be responsible
33:56 pulling on the ligaments that are attached that lens. And it also is
34:04 for making the fluid that's gonna fill that area just behind the um the
34:13 which is called the aqueous humor. inner layer. The layer where we're
34:19 spend our time is basically the black . That's that's part of this.
34:22 the white is the is the outer of the red. Is that inner
34:26 that core Oid? And then so retina is not even really being shown
34:29 . And so there's two parts to . There's an outer pigmented layer.
34:33 remember which way is the outside? it on this side or is it
34:37 this side? It's on this Not on this side. Thank
34:42 I mean I appreciate that. One act in my humor. Yeah.
34:48 . So yeah so the outer layer gonna be between the core oid and
34:53 the nervous tissue. And its job really as it says pigment is to
35:00 light. So if you've looked at , have you ever looked deep into
35:04 eyes. Alright right, That person attracted to and you're just like I'm
35:08 going to stare into the deep pits your soul by looking at you.
35:13 you ever done that? Have you that the pits of their soul or
35:15 black there? I got a good out of that one. Now the
35:23 is because light goes into those eyes into this area, right? And
35:29 hits it goes through those nervous tissue it hits that pigmented layer and it
35:35 go back out. It doesn't It basically gets absorbed. So the
35:39 of your eyes, when you look something, you're looking at their pupil
35:42 you see that black circle, you're looking into their eye and no lights
35:46 back out at you. It's like into a dark closet. And so
35:50 you go to the optometrist, what they like to do? They put
35:53 in that chinstrap torture device? And then what do they do is
35:58 shine deep light right into the back your eye and you're just sitting there
36:01 , I can't see anything. And like, oh no, I can
36:03 everything just fine is because they're basically the flashlight and going into your
36:09 All right? So we have the humor on the front, this is
36:13 all the nutrients for all the living that are up here for and we
36:17 the vitreous humor in the back. is more like a gummy gel type
36:21 . It helps to maintain the We don't actually make a lot of
36:25 humor as adults. I think it's or less kind of recycled. Um
36:30 so you ever had floaties in your , You know that driving nuts,
36:35 ? Those are actually dead cells that floating around the vitreous humor.
36:39 so you can't get rid of they're just there. Um And then
36:44 course the lenses also living cells that there to hope the focus on put
36:49 focused um Focus light onto the back the retina. And I just want
36:53 point out here, see right this this this little point right
36:56 the phobia, that's where we're trying focus light that little tiny pit at
37:00 back of the eye. Alright, when we think about focusing light,
37:04 not just trying to focus light everywhere the retina, it's really right there
37:08 where we're trying to go. So can see where pictures, trying to
37:13 this. So the purpose of the of the lens or structure of the
37:18 . Everything we looked at the Aquarius humor, The lens itself as
37:23 as the vitreous humor, they all different capacities and they also have different
37:27 to cause refraction of light. And that's what all these numbers are trying
37:31 represent. Even the air has a refractory index. And ultimately, what
37:36 these structures are doing is they're taking which is coming at you more or
37:39 in parallel lines and trying to get to focus in on that single point
37:43 the phobia. Right? So that one is going to be taking place
37:49 the cornea. But then what we do with the lenses, we can
37:52 the shape of the lens to change degree of refraction that we're getting.
37:57 again, just trying to focus in the back of the eye.
38:03 So the process of changing the shape the lens is going to be called
38:09 . All right. And so you imagine what we have here and I
38:12 I'm gonna say this wrong, the time I do this is so we
38:16 a muscle that is basically wrapped around lens that then kind of goes up
38:23 the eye. Alright? So when relax that muscle, what it's gonna
38:28 when I go uh that muscle falls . And what it's gonna do is
38:33 attached to these ligaments that are attached the lens. And so it pulls
38:36 the ligaments and it causes the lens squeeze thinner. All right. And
38:42 this is gonna give me that far vision Now when I'm concentrating on something
38:48 I want to look at something like on a page, especially it's like
38:52 . I'm taking a lot of So those muscles there now contracting and
38:57 they do is they fall forward and they fall forward they loosen the ligaments
39:02 then that lens gets fatter. And this is our nearsightedness and farsightedness through
39:07 process of accommodation. Now. How you remember which one's which?
39:12 you've heard of the Three mile stare you're tired, like exhausted, What
39:17 you do? You are you you , focused and stuff for you?
39:24 he's a zombie. Which one are zombie? Right? So just remember
39:29 I'm a zombie, right when I'm , my muscles relaxed and so my
39:35 my lens is gonna be smaller because pulling on the ligaments. I'm not
39:40 doing it. The muscle just because its state of relaxed nous relax.
39:45 basically causes the tightening of those And so basically that's why you're able
39:51 see far. But when I'm concentrating I'm working hard, those muscles,
39:56 I work hard my muscles are working . And so what am I
39:59 My muscles are tightened so I'm focusing on things that are near. That's
40:06 I remember it. I didn't get backwards for once. Usually every semester
40:10 get them backwards. Put your hand front of your face near object.
40:20 look at my hand. Oh I now my hand. Is that a
40:25 object? Put your in front of , your object to my far
40:30 Okay? There you go near and objects, The iris is that thing
40:38 you wanted to stare it in the place before you looked into the pits
40:41 their soul and saw the blackness right . This is the muscle that is
40:48 for determining how much light is going get into the back of the
40:52 back to where the retina is. so there's two muscles responsible for this
40:57 . The sphincter, one's a The sphincter. When it contracts,
41:00 it's gonna do is it makes that smaller let less light. In the
41:05 . On the other hand is a muscle. And what it does is
41:08 you contract it it makes the pupil . So remember that black dot is
41:15 the size of the hole that you're light to pass through that particular
41:20 Right? And the blackness just represents inside of your eye that you can't
41:24 because it's a dark closet. It's by the parasympathetic and the sympathetic
41:30 So the sphincter possibility. The one contract tile that causes the light to
41:36 you know the people to get small parasympathetic. The one that causes dilation
41:43 sympathetic. Now again, how do remember which one is which?
41:46 so if I am being chased oh I don't know a bear
41:53 Whatever I want to find the fastest quickest route to get away.
41:58 I want to be alert to my . And so one of the things
42:02 part of that sympathetic response is to that dilation so that you have a
42:07 understanding of the of your surroundings. that's part of that fight or flight
42:13 . That's how I remember that. right. I don't know how you
42:21 remember if that's how I do. . Well, so your pupil contracting
42:33 a result of basically that time when kind of resting and digesting. All
42:40 . So think about I wanted to wider. Alright, So right now
42:44 room is kind of dim. And let's say I'm I'm an ax
42:50 sociopath, which is probably not too from the truth, right? Maybe
42:55 not ax wielding. All right. now you're sitting there going,
42:59 how do I escape from this guy coming after me? And you can
43:03 all these people sitting around you blocking path to the door. How are
43:07 getting out of here? Right. now it's kind of dim. You
43:12 know who you can step on. know who's gonna kick you over and
43:15 like that. But maybe if you a little bit more light into your
43:20 , the room will seem a little brighter and you might see a clear
43:23 as to how you can escape. that would be sympathetic doing that
43:30 So the drops they put in your and either way, you know if
43:33 can't remember which way by contracting or when I put drops in my eyes
43:37 cause my eyes to get all buggy them. So that's how you remember
43:41 terms. Alright. Yeah, it be the same as as a result
43:50 the same thing. It could be a simple sympathetic response saying oh
43:55 you know? And so it's just minor one and there's actually some really
43:59 stuff that that you can do. is a reflexive response. So like
44:04 now it's kind of dark but if all walked out of this room it's
44:07 little bit bright out there so we're see that's a little bit brighter.
44:10 are gonna kinda and it's gonna we're kind of walk around squinting for a
44:13 bit right? It's easy if you about matinee vs. And then walking
44:18 the back when you hit that texas and then all of a sudden you
44:22 see forever, right? Yeah. . Alright. So the pupil is
44:31 the whole within the iris. So of it. Think of it as
44:34 series of muscles, right? We we have a spiral muscle right?
44:39 basically creates the structure that can go this or like so right, it
44:45 gets bigger, really goes in one because the only way I can spread
44:48 out again as if I have these muscles which are lines, think rating
44:52 the lines on the sun and what do is they pull that muscle
44:55 you know? So you have two fighting against each other? So that
45:01 is simply the space in between where light passes through, right and I
45:07 the muscle that allows the size of space or creates the size of that
45:16 . You don't need to know anything this slide. Just trying to show
45:18 where life is trying to go. always ask me the question. I'm
45:21 and nearsighted. Well that means you focus real well and so you're basically
45:26 . This is normal vision. I'm to focus the light here at the
45:29 . So if I'm nearsighted or farsighted either focusing too early. And so
45:35 light is basically passing its focal If I'm far sighted, I am
45:42 beyond that site. And if you're me, I have a stigmatism which
45:46 sucks. I'm gonna tell you this . I never wore glasses my entire
45:53 . I was I was glass free then one day I looked down and
45:59 could not read the fine print on kids medication. I'm trying to give
46:04 like what is the dose I give of this. I was just I
46:08 not do it and finally I went go get my eyes checked because I
46:11 needed to and I asked, I'm at the pre optometry students, you
46:16 raise your hands, you're gonna be this? I asked her, I
46:18 what's going on? And this is exact word she used. Well you
46:23 a stigmatism. I said well how that happen? Well you're old
46:29 Do not tell somebody that they're old . Oh it sucked 45 years old
46:38 that happened still. Thank you. you go. You get the gold
46:45 today. All right. So, we have these structures. And
46:50 the whole point of all these structures to get the light to that
46:55 Well phobia is part of the And so what is the retina basically
47:00 two layers, one layer of pigmented , another layer of neural cells.
47:06 , as you can see the arrangement . So here is down here you
47:09 see what am I doing? I'm a little bit. So there's that
47:11 layer light is passing down through so can see the direction in which light
47:15 light flows through a series of neural . And one of those cells is
47:22 the photo receptor cell. The cell actually detects the presence of that
47:26 The rest of them are there for for sending the signal up to the
47:29 nervous system. And then if the doesn't get absorbed through those photo receptor
47:33 , it's gonna hit that pigmented layer it's gonna get absorbed there so it
47:37 bounce around and give you all these images and it doesn't shine through the
47:42 . So basically it's it stops all now. The other thing it does
47:48 gonna provide vitamin A. Vitamin Is necessary because the molecule that's responsible
47:54 detecting light is half of a half a vitamin A molecule. So,
47:59 gonna see this molecule called retinal L. Not OL. Which is
48:04 you take vitamin A in Cleveland directly half, you end up with two
48:07 molecules. All right. So neural photo receptor cells and those associated neurons
48:14 are responsible for detecting light and then it into a nerve single signal that
48:19 goes up to the brain to let perceive and know this. So,
48:23 three different cells that you're you've you've to know these three photo receptor cells
48:30 the outermost cells. You can see down below. They are called the
48:34 and the cones. Why they called and cones. They're shaped like rods
48:38 they're shaped like cones. Alright, . So, we've we've learned are
48:42 , valuable lesson. Look at the . Will tell you something.
48:45 so their job is to turn that energy. That interview that photon into
48:52 nervous signal in this case is gonna a great potential that is going to
48:55 turned into and that greater potential then used to stimulate the next cell in
49:00 order. Which is a bipolar What's it called? The bipolar cell
49:05 it's a bipolar. Yeah, it It's one of the two in our
49:09 that are truly like just overtly Okay, so these are bipolar
49:15 They were one of the first cells in the eyes. So they just
49:18 that name. They probably should have called something else. Now, what
49:22 do is they're gonna take information from different photo receptor cells and they're gonna
49:29 that stimulation. So they're kind of that first level of of condensing a
49:36 field and sending that information on to ganglion cell, which would be the
49:41 that represents the the receptive field. , I'm just gonna make up numbers
49:47 . So, for every ganglion cell multiple bipolar cells. So you can
49:51 for one gangland. So I might 10 bipolar cells. And for every
49:54 for every bipolar cell I might have just make up a number again,
49:58 100 photo receptor cells. So, ganglion cell might represent like 1000 different
50:04 receptor cells. So, if I a photo receptor cell over here,
50:07 a photo receptor cell over here, could stimulate this one or that one
50:10 still get the same perception of light that gangland. Right, Because it's
50:16 broad area in which I'm stimulating. right now, there's other cells we
50:23 horizontal cells and in cells. And that's what you can see here.
50:27 , here's my photo my photo my bipolar, my ganglion cells.
50:31 right here, those would be the cells their name because they're horizontal and
50:36 . And then we have the endocrine . I don't know why they're called
50:39 cells. But they sit between the and ganglion cells and these are modulator
50:44 . What they do is they start modulating the signals of light detection before
50:49 ever leave the eye. So we're changing our perception of what light is
50:57 doing even before that information ever leaves eye before it ever goes on to
51:01 visual cortex. And this is all through these different cells. Yeah.
51:10 a result of the different types of that we have. So, we're
51:14 kind of go through each of the cells and look at that there's color
51:17 there. Alright, so, color is simply the loss of one of
51:22 three types of cones. Alright. there's different types of color blindness,
51:26 it depends on which cone that's been . Yes. Okay. So,
51:35 you're detecting is stuff in the S . Right. Alright, so let's
51:39 about what the cones are first, that we understand all right. And
51:44 glad you just said em in the rather than the green and the
51:48 Okay, so historically, what we've , especially in the lower uh lower
51:57 classes, we refer to these cones a color blue, green, or
52:02 . Alright. And you can see here the ranges in which each of
52:06 cones are gonna do. So I'm gonna pick the M cone right
52:09 So you can see the M. detect into the almost into the orange
52:14 length and then I'm losing it right and there. Is that it?
52:20 . And goes into the light Right? So Roy G biv,
52:24 ? So orange to almost indigo. ? That's That's So is that is
52:32 m Is the green cone just limited green? No. Right. And
52:38 is true for all these. first off, do not memorize
52:42 Alright. Do not memorize maximum not gonna ask you that question.
52:46 just mean. Right? But what trying to point out here is that
52:52 of these cones have a range in they're being stimulated, right? So
52:56 L cones are in this upper range cones are in the mid range and
53:01 S cones are in that that what called the super range, so low
53:06 and and supra. And so they across a whole variety of wavelengths.
53:13 we're just talking to Roy Roy G right now, all right. What
53:18 means is is that they're stimulated differently those different wavelengths. And so,
53:23 that peak is what or what these points represent is a degree of
53:27 So, notice what it says over , relative absorption. So what it's
53:31 is is when it's in this range here it's getting about 20% activity in
53:37 particular receptor. But when I'm up at the top, that's my
53:41 This is where I'm maximally stimulated. . And this is true for every
53:46 of them. And so this is their names actually came from. The
53:48 ranges came from where their peaks So we don't use those anymore.
53:53 now use S. M. And . S. Now, how many
53:57 can you detect? All right. with you. I well, I
54:04 detect a lot more than six. can name six colors. Right?
54:08 this is actually true ladies, you name more colors than guys can.
54:12 ? I mean, I'll just prove . Right. What color is his
54:16 ? Read? No one said Okay. Her shirt. See they're
54:28 to argue now. Sky blue, blue. There's a teal in
54:30 I don't know. It could be cornflower, right? Kind of might
54:35 cerulean. All right, guys are like a blue. Alright. That's
54:40 all we're good at. Yeah, is a good question. So,
54:50 not that you detect better colors or colors. Men and women do detect
54:55 the same colors. It's just that define your colors more clearly guys.
55:00 kind of categorize and just say falls this range. Right. However I
55:05 read and I'm not seeing it more than one source. And I don't
55:09 if it was like primary literature. can't remember. But there are some
55:13 who have supervision, which means they 1/4 cone. All right. You
55:18 , who else has 4, 4 chickens? I don't know why they
55:23 to be able to text so many things, but they do. All
55:25 . Hold on a second. All . Now, if you had to
55:29 how many colors different colors do you we can actually see as humans?
55:36 . I heard another number. No, that's not That's not
55:40 Hundreds to little keep going. One point about 1.4 million.
55:54 Now, I can only again, can only name about eight.
55:57 And it's Roy G biv plus black white. It's maybe nine.
56:02 But women you can name about 44 . Right? But think about like
56:08 you're um you know, like if like working in Photoshop or something and
56:12 got those scales and you're doing your s or your C M Y K
56:15 and you can actually create all these colors. You can actually detect the
56:20 between uh two different colors of Not necessarily right next to each
56:24 But you can kind of see this a darker red. This is a
56:27 red and so on, and so . All right. So, that's
56:30 function of perception. Now, look Roy G biv for a second.
56:35 is the problem. I get stuck . Do you see the color pink
56:37 there? No, no, it's not there. That's Roy G
56:49 red, orange, yellow, blue, i indigo v violet you
56:58 pink up there? No, Do see pink back there? Huh?
57:08 notice here what we're doing. So these wavelengths and these color spectrums are
57:15 result of electromagnetic radiation right? At wavelengths. Right. We modulate that
57:24 that color by degree of saturation. right, So it has some that's
57:30 having to do with that energy. has to do with colors overlapping each
57:34 . So white and red together. pink. That's what they told me
57:37 kindergarten, I think. Right. so what you're seeing are two different
57:42 being stimulated simultaneously. Now when you're at a color, what we're talking
57:49 here is the degree of stimulation of different cones. Right? So when
57:55 perceive a color like green, for , we're just gonna go hardcore green
58:00 . Right? Look at how many receptors are being stimulated here,
58:05 We've got rs com being stimulated, a lot, but like 5% at
58:10 in our little graph. And we up and then we see that our
58:15 cone is being stimulated close to about stimulation and then we keep going up
58:19 we can even see that the income being stimulated about 75%. So the
58:24 green that you see and perceive as result of all three cones being stimulated
58:30 different degrees. That kind of makes . Right. So for those you've
58:36 in photo shop or with any sort color when you're trying to get a
58:39 match? What are you doing? sliding those scales, aren't you?
58:43 ? You're doing the red, blue. And you're like,
58:46 I want this much percentage blue, want that much percentage green. This
58:49 percentage read. It gives you a , if that makes sense. And
58:53 kind of the same thing your brain doing, except it's not sliding
58:56 It's just this is this is the . You're getting this percentage of
59:00 this and this and this is what should be understanding. Yes,
59:04 And then back there, I have idea. That's just how they always
59:10 it. Yeah. And you to me, this says zero,
59:13 maybe this is zero down there. don't know. Yeah, yes.
59:18 on, Mark, back back over first. Yes. So that's what
59:28 saying is that I've only seen it and I've never pursued after like,
59:32 , this is so cool. I to discover. It's like,
59:34 maybe so, but yes, it's in some women, not all
59:40 There is 1/4. There can be cone. Alright. And again,
59:47 this true? I don't know, I remember reading about it at one
59:50 . I was like, okay, kind of And then I learned about
59:53 . All right. And then I about dogs. How many cones do
59:56 think dogs have, You have to have to the color that they can't
60:01 . Well, is green versus So when you have a tennis ball
60:07 you throw that tennis ball into the , they're just like, really?
60:13 when you're like way to go. you're pointing out there. Like,
60:17 don't understand any of the words you're , but I'll look over there and
60:20 they'll smell it out, then Then you have no idea. You're
60:26 asking the wrong person. I honestly don't even know what they're doing.
60:31 it polarized light? Is it Red and green. Yeah. All
60:49 . So, again, I don't how those those lights work. Maybe
60:55 they do is they they I'm not gonna guess. I'm not gonna pretend
61:00 I'm gonna. Yes. Right. would be within in there someplace.
61:08 , not necessarily. I mean, I mean, it should be within
61:11 range, but maybe it it pushes way or the other. Yeah,
61:18 , two of the clones are very closely related. It's mm the
61:21 the blue cone. The S. the one that it's a separate.
61:25 was. So, I think like mm the L word like duplications.
61:29 remember reading this. So, this is I'm going to the back
61:32 my memory, but it's there's a that had a duplication. And then
61:37 gene is actually a unique gene. , that's right. But what what
61:47 can my tissue, Which one mantis ? I wouldn't even think about
61:55 I think you may be right. yeah snakes pit vipers right? So
62:00 detect in the infrared range so they receptors that are like these but they
62:07 way out here. What animal do know detects in the ultraviolet bees?
62:20 do right. You look at a at a flower under ultraviolet light,
62:24 has like big arrows pointing to the of the flower. Say this is
62:29 all the cool nectar is. And bees use that. We look at
62:32 how pretty it is, what we in the visual spectrum looks like nothing
62:36 the UV spectrum. And they use as a way to find their
62:40 But they have receptors that are out . Yeah. Oh so what they're
62:47 is they actually allow their pupils get , massive, massive. So they're
62:52 lots and lots of light in to . So it doesn't have to do
62:56 the cones per se. It has do with the amount of light coming
63:00 their eyes. And that's that's true most nocturnal animals. And they also
63:04 a reflective uh they have that they the the pigment that absorbs light but
63:11 also also have a reflective aspect as . So make sure that more light
63:16 around to be able to see what's them. Yeah. So when you're
63:20 at when you're like you know you're on the highway 90 miles an hour
63:23 you see that deer looking at you you get that reflection in their eyes
63:27 ? Or raccoon when you're like, hear something outside and you're wondering what
63:31 that animal is. And it's staring at you like some sort of demon
63:34 of the darkest pits of someone's right? Yeah, it's it's basically
63:39 bouncing back because they're trying to get to bounce around to get more light
63:44 . Now you can see there's one thing in here, there's your
63:50 right? That's what the black one supposed to represent. And they're also
63:54 melon option up in here as But basically the purpose of rod is
63:58 night vision and you can see it's stimulated across the same wavelength as your
64:05 are, but they have different degrees stimulation which we're gonna kind of go
64:09 here kind of look at these. how bad did I go?
64:14 see I I should be able to through all this stuff and then we'll
64:17 ears are quick, so, you , it won't be too bad.
64:22 , so what we're looking at here this particular picture is trying to demonstrate
64:26 the presence of these rods and these are. And I've already mentioned to
64:29 that your your most um uh your visual fields are gonna be right there
64:35 the front. So like in your you're looking straight forward, right?
64:40 the light hitting the phobia is where gonna see the greatest concentration of cones
64:46 that's what this this picture is trying show you. So the blue dots
64:49 where roger located, Green doctor where cones are. And so if you
64:53 your retina and actually spread it out make it a nice flat piece,
64:56 can see I've got lots and lots rods sitting out here on the
65:01 But when I come in and focus where the phobia is located,
65:04 it's nothing but cones. All So when we look at rods and
65:09 and ask, okay, how what is the degree of convergence?
65:13 remember we said we have photo we have bipolar cells. Ganglion ganglion
65:17 represent a a visual field. So you look at Rod's we're gonna have
65:23 of rods, we're gonna have a of bipolar cells and we're gonna have
65:26 ganglion. So that one ganglion represents lot of photo receptors which are
65:30 But in the phobia we have this convergence. So it's it's very
65:36 We're gonna have like one cone, bipolar cell, one ganglion cell.
65:45 what does this mean? Well, kind of like our understanding of high
65:51 television. What I'd have television. , I know none of you guys
65:58 . Video files like I am or you are. I have no idea
66:02 guys understand. Well, I grew with standard death. Alright. Standard
66:06 . I don't think there's they don't think they make TVs like that.
66:09 don't even think your phones are standard . Maybe if you bought like a
66:13 cheap throwaway phone it might be standard . But look at that picture.
66:17 that picture look clear to you? can you tell what's going on
66:21 Yeah, I mean even if we the other parts, you could kind
66:24 tell what's going on there. So definition if you didn't know in TV
66:28 is 48 p. You've heard that right? 40 p. And what
66:32 means is is there's 480 pixels stacked top to bottom. So if you
66:38 to count these out, you could out 480 pixels. Alright. And
66:43 if you have a massive tv then pixels are gonna be pretty darn
66:46 But if you have a little tiny , the pixels are gonna be small
66:48 doesn't matter from top to bottom. . So that would be for a
66:54 . P. Here's hi def this what you guys are used to.
66:56 know what high def is? 1080 . 720 is what some people market
67:02 death as but they're lying liars who to lie. Alright. So if
67:07 go to like walmart and they're like hi definition tv go look and see
67:11 it at 7 20 or is it 80 again? Same rules applies.
67:15 80 would be 1000 and 80 pixels top to bottom. All right.
67:21 then we have the new stuff that's out. The ultra high def the
67:26 K. How many pixels is that 40? It's 2000. It's you
67:33 think that would be 4000 but no liars who like to lie.
67:39 It's actually it's double it's it's 21 which is just maddening, you
67:45 just angers me that they're selling All right. But let's take a
67:48 at this real quick. All So is this clearer than that?
67:54 . Much much clear. So for same area. So let's say for
67:59 pixel over here you have 2.5 pixels here, right? Which gives us
68:05 much greater clarity. Over here you How much? It's twice that so
68:13 would be about five pixels. So you get even more clarity and
68:19 kind of what a visual field is . So in your phobia for each
68:26 . Well, I'll do it do the other way. So out here
68:28 the periphery for every pixel that you're up and it's not really a pixel
68:33 for every photon you have this big in which you're actually stimulating and saying
68:38 I don't care if you hit I don't care if you hit
68:40 I'm gonna tell the brain that lights over here. But when you're looking
68:43 the phobia, that point of stimulation very, very small because that that
68:49 of convergence. Almost every cone has own ganglion over here. It's 1000
68:57 for every ganglion. So it doesn't . And that's why when you look
69:01 something straight on, like I showed , it's gonna look like this.
69:05 over in the periphery you've got this going on because you have these bigger
69:12 because there's there's more convergence, less , more convergence, more receptors to
69:20 able to detect something. But they're going to the same point. And
69:25 why you're getting that fuzziness. All , That's what all that stuff basically
69:32 . Hi convergence yields larger receptive fields reduced acuity, low convergence shield,
69:39 receptive fields and high acuity phobia, acuity, small receptive fields,
69:45 very low convergence. Now, there's features you can do to fill this
69:52 out. Alright, so with regard this, how many rods do we
69:55 ? We have one type of We have three types of cones.
69:58 you want to say there's four for and that's only hearsay. Right?
70:03 three, what is their shape? the shape of a rod? What's
70:07 cone? There we go. Rolling vision does play a role in color
70:12 , no cones play a role in vision rods play a role in night
70:18 . Alright, so their sensitivity to is very, very high. So
70:23 there's low. Um So think about at night, you know you wake
70:29 because you have to go to the or you hear a bump in the
70:31 or I don't know, some monster around along the floor, whatever it
70:35 , right? You wake up, look around the room, it's dark
70:38 you can kind of perceive things, you? You can kind of perceive
70:41 that pile of laundry over in the or maybe that's the monster. Not
70:45 sure right. It's because there's photons through wherever there's light if it happens
70:51 be moonlight or light outside your window ? You don't need a lot of
70:55 to stimulate a rod. But you a lot of photons to stimulate a
71:00 . Alright. Their Q. We don't have a lot of acuity
71:04 rod because they're sensitive, they actually very active very very quickly. Um
71:10 because of their high degree of there's so many of them with regard
71:14 acuity cones are involved in acuity. they're very very low convergence. Uh
71:21 sco topic info topic. We're gonna to the sco topic is what
71:24 Dufaux topic is, what cones do kind of see foe topic? Vision
71:29 being able to see light. We about convergence already and then their
71:34 their concentrated on the periphery cones are in the phobia in the central
71:42 So with my nine minutes here. , this just sucks. All
71:48 So how do we actually see what's on? Well, we have a
71:53 transaction cascade. Alright, So it's not anything particularly new. In
71:59 , this was the very first one . So, they don't have all
72:01 very interesting names that you see in systems. They're basically named for what
72:05 did when they discovered them. we have this molecule called guan elite
72:10 . All right. And that's what green thing here. That's phosphate cyclists
72:15 . Uh They're they're okay. They're guan cyclists. Right? So,
72:20 basically supposed to be that. All . And what it does is it
72:23 , you know uh GTP and converts cyclic GMP. Alright. So that's
72:28 hard is an enzyme but a Well, this is the ligand.
72:33 And its receptor coupled together already. so it's there to take light,
72:39 it and turn it into light energy into that signal that that signaling
72:45 Um that ultimately results in a greater . The G protein is called translucent
72:51 it transducers the signal. And that's it was named that. But it's
72:56 it's a G. G protein. job is to activate fossil histories and
73:01 particular fossil diaries. It's responsible. cyclic GMP and converting into GMP.
73:05 it takes that that last phosphate group basically says. All right. You're
73:10 allowed to be bent anymore? Go to your original shape And then we
73:14 these channels that get bound up by GMP that open and close in response
73:18 the presence of cyclic GMP. So those channels are opened, sodium comes
73:23 the cell causes cells to polarize. all these things are gonna be in
73:27 here. But let's just kind of first look at this. That's one
73:32 cyclist is always there producing cyclic So, you can imagine the inside
73:36 cells are just filled up with cyclic and with lots of cyclic GMP
73:41 it's gonna bind up to that And when it binds up to that
73:44 , it's gonna open the channel. when the channels open sodium comes in
73:48 cell that polarizes. So, without light, this is actually what's going
73:53 . So, these cells are already polarized when there's no light.
73:58 So in darkness, photo receptor cells d polarized. Which is really confusing
74:05 we usually think about deep polarization as . And can you see in the
74:09 when there's no light? Can you ? No. So this is gonna
74:13 a backwards thing to perceive. All now, we never really talk about
74:19 . But when you open up a , what you're actually doing is creating
74:22 . And so, I want to here this dark current. So sodium
74:26 rushing into the cell all the But eventually we should reach equilibrium,
74:30 we? So, we're not letting reach equilibrium. What are we
74:34 We're gonna go ahead and have these pumps that basically sit there and
74:38 nope, I'm gonna pump the sodium out so that constantly keeps a drain
74:42 . So sodium is always coming into cell. But if I'm always using
74:46 a sodium potassium pump to move sodium , I'm always allowing potassium to move
74:50 and that's gonna reach equilibrium as So we have channels allow potassium and
74:54 that cycle collectively referred to as the cycle. So this allows the cells
74:59 stay in this deep polarized state because constantly moving sodium and potassium.
75:07 now, the purpose of this, should point out is that that neurotransmitters
75:12 and it's being released. Right? we're releasing neurotransmitter. And what we're
75:18 is we are inhibiting the activity of bipolar cell. In other words,
75:24 neurotransmitter is an excitatory inhibitory in Its inhibitory. So what this is
75:30 basically I'm releasing a neurotransmitter that basically on the break of the next cell
75:35 it can't stimulate the next cell down line. And so in the dark
75:39 there is no light we perceive All right, even though the cells
75:45 on were basically blocking the perception of . Now photo pigment, as I
75:51 , it is this receptor it's a trans membrane receptor. Alright, so
75:57 a g protein coupled receptor and it has bound in it. This molecule
76:01 retinol retinol exists in this shape called 11 Cis confirmation. Now you understand
76:07 you have to take organic chemistry to this class because the word 11 cis
76:10 mean anything to you until you take organic chemistry. Right. It's a
76:15 class like medical term. Don't tell chemists you're really upset when you say
76:22 it's already bound in there. All . And what is dependent upon is
76:28 life a photon coming along and it absorbed here at this uh carbon and
76:35 causes a conformational change. So that cyst confirmation becomes a trans confirmation.
76:41 what that does is when you're sitting in this tight space, what you're
76:45 do is you're going to change the of this receptor and it's that change
76:50 shape of the receptor that allows for to activate the G protein.
76:55 yeah, I'm sorry. Oh yeah. So I'm just gonna go
77:02 to this picture. So you can see so here you can see by
77:04 all this right here, that's that molecule. So together they form the
77:10 pigment. Right? In this particular , we're looking at a rod,
77:13 the rod is called road upson see clever. Right. And so when
77:18 comes along it's gonna change the confirmation that 11 Cis to the all
77:23 And when that happens, that changes shape of the option molecule when you
77:26 the shape of the molecule, you the G protein. All right
77:32 obviously if I change the shape of trans, I've got to convert it
77:35 into the, into the CIS which it does and it actually does
77:40 through recycling in one of two If you're um in a rod,
77:45 sends that off to the photo or the pig minted epithelium. If you're
77:50 cone, you can actually do it house so you can do it inside
77:53 rod. But ultimately what you're trying do is you're trying to recycle these
77:57 molecules because they're what allows you to light if you're in the transform,
78:03 can't detect light. So again, about going from a dark space
78:08 like to the light and it's really bright. What is it like
78:12 you go out into a bright is it kind of like you bleach
78:16 vision, everything is really, really . And it takes a while for
78:19 to to get it back. That's you wiped out what we call photo
78:25 and you wiped out all your your retinol into the transform. And so
78:30 takes a little bit of time to through and start recycling them for the
78:35 cells. Kind of weird. Yeah, outside. So what happens
78:43 now, remember? So if you're , you already have major pupil smaller
78:50 less light is getting in. And you're actually regulating or controlling the amount
78:54 light to convert the forms from cIS trans. It's just when you're going
78:58 dark to light you have these big pupils and it's just like oh and
79:03 goes you know and that's when you're everything out. So do not memorize
79:07 on this slide. This basically just you look, I take that out
79:11 shape trans and I go back and and bring it back. And then
79:14 this is inside I can do it there inside the cell. Do not
79:17 that. What I wanna do. much time do I have? Like
79:20 seconds? So I have one Alright I'm gonna jump to this.
79:26 is just showing you all the But this is what it boils down
79:29 in the dark and I think I like modulation over here. I'll get
79:33 the modulation tomorrow but in the dark is what's going on. My cell
79:38 d polarized as a result of the I'm releasing inhibitory neurotransmitter. That inhibitory
79:46 is inhibiting the bipolar cell. When bipolar cell is inhibited. I don't
79:52 neurotransmitters so no signal moves forward but light comes along I changed that
79:59 All right, the phosphor diaspora becomes . I start chewing up cyclic GMP
80:05 cyclic GMP nothing to buy in that those channels closed cell stops D polarizing
80:11 hyper polarized. If I'm hyper I'm no longer releasing my inhibitory
80:17 I'm no longer inhibiting my bipolar cell cells starts releasing neurotransmitter. And so
80:24 my brain is getting sent a signal says light has been detected at this
80:29 . So it's backwards. We'll start on Thursday and I think I have
80:35 34 slides. Yes. No, , it doesn't need to be,
80:42 transformed. So converting from the cis the trans is the detection of light
80:48 that activates the G protein. it's in the dark. You're in
80:54 CIS form and you're always in the form because there's no right because what
80:58 need light converts this into trans. if you're in the dark you're in
81:04 cIS form. Yeah, we're not don't get it, it's a change
81:15 exists in the system, whether it's the train, but when there is
81:20 light it just stays insists there we . Light bulb went off, see
81:26 I did that. You're welcome. guys have a great day,
81:32 I cannot believe how slow I I want to understand, I used
81:35 do these lectures like with minutes left
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