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BIOL 2301 Human Anatomy & Physiology I - BIOL2301_lecture08_0919
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00:00 All right. So what you guys looking at up here is the
00:04 uh, current uh, distribution of exam scores. I still have six
00:09 , four people, I can't remember who needed to take the exam.
00:12 average is about 61. A high , uh, perfect score, low
00:17 18. Uh, the median is 62. So that's, that's actually
00:21 . You can see the curve is pretty standardized standard deviation to 15.8.
00:27 you're wondering what that means, it means that it's very wide. We
00:30 it around 13, I think would a better, better standard deviation.
00:36 So this, this will change again like I said, there's gonna be
00:39 people, but it won't change that . So, it kind of gives
00:42 an idea of, uh what the was and this is not atypical.
00:45 is, uh, uh, I'd it to be a little bit higher
00:49 to COVID averages were around 65 through and, and to date, it's
00:55 to about a 60. Um I'm it will eventually move up,
00:58 uh, it just kind of gives an idea of, of uh of
01:01 performance in general. But this uh you know, it's just a
01:07 . So what we do is we at it and say, OK,
01:10 , let's see, what does this mean? And so this is probably
01:13 graph that's a little bit more important you all because it kind of tells
01:16 where you stand in the class. . So the way you can think
01:19 this is if I got a grade and I, and this was my
01:23 grade, what would my grade look ? And this shows you what the
01:26 is without extra credit. Remember, don't do extra credit until the end
01:29 the semester after I figured everything And so what I would do is
01:33 the, the semester I'd come up this curve and then I'd add your
01:36 credit on top of that. So it doesn't change the curve,
01:40 extra credit actually is added to whatever grade is. Ok? And,
01:44 the curve stays the same, but kind of gives you a sense of
01:47 things are. So again, you , there's no pluses and minuses up
01:50 . I just went flat and I do this until the end of the
01:54 because it does matter what a plus a minus is until the end of
01:57 semester. But it kind of gives a sense of what's going on.
02:00 A begins around 89.3. Um A begins around A 74 AC begins around
02:07 and then D is at 50 it is at 50. If the curve
02:11 that direction, we lose DS and gain CSS, we don't move that
02:17 . Uh, this stuff down these represent students who, uh,
02:20 taken the exam yet. So that's those grades are low. And
02:23 that has an effect but not a big effect on this. Um,
02:27 you find yourself in a place that don't like, which should be everybody
02:31 for this group right here. And then I know some of them are
02:34 upset that they're where they are, , all is not lost.
02:40 it's not a time to panic. not a time to worry. What
02:42 need to do is you first need adjust how you think about numbers,
02:46 ? So you look at your number you're saying, um, because I've
02:49 , I get lots of emails, . So I had one email was
02:52 , I'm panicking. My grade is and I look it up and it's
02:55 , no, you've got to you know, but because they look
02:58 a number that normally would be ac freaking out. So first thing is
03:03 that the scale that you're used to not the scale that we use,
03:08 ? It's a curve. This is it works in the sciences for the
03:11 part. Right. I don't like . And the reason I don't like
03:15 , it doesn't tell me anything about . All right. Hundreds. Tell
03:18 the test is too easy. That we got 100 on one of
03:23 tests. I'm, I'm happy, at the same time I'm like,
03:26 it not hard enough? Yeah. didn't really say that. I did
03:31 to my wife. I'm like, , maybe that means I need to
03:33 an a harder exam. I I know. I know. I'm
03:38 pulling your leg. All right. gonna make it any harder. It's
03:42 same exam I've given all uh since beginning of time. All right.
03:47 you look at this and you find where you don't want to be if
03:50 are up here. OK. great. But if you're down
03:54 it's not the end of the Don't say, oh no, I'm
03:56 going to nursing school. I need change my major and go to law
04:03 . That's not the, that's not proper response. The proper response
04:06 is ok. Why did that? did? And so the extra to
04:12 a question? And what was that ? Am I ready? Have I
04:18 ? Have I done everything I can achieve the goal that I'm trying to
04:23 ? All right. And that's not easy thing to answer sometimes. And
04:27 what you're going to do is extra should open up on Thursday after everyone's
04:30 the exam, and again, we people who are taking exams today.
04:34 my expectation is that exams should be on Thursday to look at on
04:39 Not Thursdays. Right. And you'll a new extra credit. The extra
04:42 now is like, all right, , so you did and you know
04:46 you did. So what are the that you're going to do differently?
04:51 are you going to adjust, Because if you keep doing the same
04:55 over and over again, do you change? What do you think if
05:00 do the same thing? Am I to see a change? No.
05:04 . So that means you've got to some adjustments and you got to know
05:08 . All right. So first I'm gonna say this is the big
05:11 that you need to be thinking about . What's number one on the
05:15 Don't panic right now. For the , red Hitchhiker's Guide. You know
05:20 we're talking about here for the rest y'all. You need to read Hitchhiker's
05:24 because one, it's funny as See, I even kept it clean
05:28 . Well, it's funny but it the first thing you need to do
05:31 don't panic, right? Panic leads destruction, it leads to ruin
05:36 Things that are become irreversible. Imagine driving between two semis, right?
05:43 in your little tiny car, whatever happens to be, let's put you
05:45 a smart car and your car starts . If you panic, what are
05:49 going to do? You're going to under the wheels of one of those
05:52 and you're going to be a pancake 45. So, we don't
05:56 What we do is we maintain or we adjust what we're doing.
06:00 down, let the two semis speed up, do something that's not
06:05 . All right. So, what some of the things that you should
06:09 ? All right. Well, the thing I'd point out is this is
06:11 class of 400 students. You remember first day of class? And everyone
06:15 , all the seats were taken up it was hard to find a
06:18 Look for how many people are not up. About a quarter of the
06:23 is not showing up. Right. , if you're listening online, you're
06:27 learning, you cannot learn on your . Being online for the rest of
06:32 all good job sucks. Getting up dark 30. I know I can't
06:38 it either. I am not a person. Right. And they're doing
06:42 on my highway. So I have find alternate routes. Those alternate routes
06:46 . It all sucks. I got work today. They wouldn't let me
06:49 my garage. I got to my . My, I'm telling you this
06:54 the worst morning ever. I, got my one drive wasn't working,
06:58 had all the grades and everything I to talk about, including the slides
07:01 going to present today. I was to just call class, say,
07:05 it, just go home. I know we're not doing all
07:08 But anyway, the point is you to class, why there's something about
07:13 in a classroom where you're more alert you, you start associating behavior or
07:19 I say to things that you've Right. So there is something about
07:24 interaction here, even though this is lecture and it's very boring to sit
07:28 and you fall asleep half the time see this in every single solitary class
07:34 matters. I don't take attendance because all our adults and you should know
07:38 to come and when you shouldn't the answer is you always come to
07:41 unless you're really, really sick. ? Or if you have some other
07:45 that is more important to do. . For example, if you have
07:50 interview with a program, you or if you're an athlete and you
07:55 , uh, a competition that's paying you to come to school here.
07:58 , those are more important. We that all right. So that's the
08:01 thing. Second thing is do your . I went through and I
08:04 generally speaking, most of you all doing all your assignments, but there's
08:09 population of, aren't doing their Why? Well, I forgot,
08:16 , I didn't feel like doing I you know, there's all these
08:19 excuses. But let me explain Those assignments aren't there because of busy
08:23 . Right. When I first started this class, I came in,
08:26 lectured, I gave a test. was it. There was no
08:28 You just did what you did. . And that's how college has been
08:32 almost. Oh, I don't 150 years, it's only within the
08:36 20 years we've started giving homework because now have technology that allows us to
08:40 write almost an infinite number of questions you guys to work with.
08:44 The purpose of this is practice, ? You all have all done stuff
08:49 your entire academic careers where there's sports some sort of music or acting or
08:54 of something. And the only way get better at anything is if you
08:58 it right. You, you, , you give somebody like my son
09:04 keys and say, go drive. , he had to practice before we
09:10 him a license. So part of is the exercise of doing things so
09:16 you are learning along the way. I know I'm saying something that you
09:20 know, but you'd be surprised how people don't do it. Right.
09:26 too much of a pain. I don't want to spend the time
09:29 it. Oh, I'll do it . I mean, how many of
09:31 are procrastinators? I'm a procrastinator. . I, I'm proud to be
09:35 procrastinator, but I get my stuff . Right. Don't, you
09:40 I attach a grade to it because the little stick to get you going
09:43 the little carrot, whichever way it for you. Right. But in
09:47 grand scheme of things, if you an assignment, it's not a big
09:50 . I get so many emails. missed this assignment. The reason you
09:53 to do the assignment. Do you keep talking that loud ladies? I
09:58 hear you up here and everybody over can hear you. All right.
10:05 idea here is when you do these , you're actually teaching yourself the
10:11 the score in the homework is less than doing the work in the,
10:15 the assignment, right? So treat as what it's supposed to be the
10:20 to launch you forward and get you . How many of you hate
10:26 Yeah. And you have to read you're like, man, I don't
10:29 to read and then you blow the up and you, that gets you
10:33 . It's the, it's the, the juice or the pilot light that
10:36 you moving into the, into the . So the idea behind all of
10:41 assignments are not because I'm just I wanna make you work harder,
10:45 know, I don't, I want to learn the information. All
10:49 I want you to achieve your I want every one of you who
10:53 planning on nursing school to get in nursing school. I don't want you
10:57 be the person who sits there and , I don't know what I learned
11:00 the class, you know. So the assignments. Now, this middle
11:06 studied for exams differently. I realized the first day of class I didn't
11:11 actually tell you guys how to We ran out of time and I
11:14 like, uh, exams, 90% you are gonna come to my office
11:20 this class. Let's get this over real quick because this is what I'm
11:24 ask every single one of you. did you study and every one of
11:27 are gonna answer for the most Oh, I read my notes.
11:31 , I wrote quiz letts. I went back and listened to your
11:34 four times. Oh, I went youtube and watch videos of people that
11:38 know who put videos on youtube. . And they're not bad. Trust
11:42 . These are all good things but not study what they are, are
11:47 to keep you from studying. They like study but they're not study.
11:51 ? You want to know how to really good in the classroom and actually
11:55 less work and get good grades and more. Do you want that?
11:59 . That's what I want to Every one of you should have
12:02 Yes. Show me, tell look, I've been in school for
12:05 long time. Right. And I a crappy student. I got a
12:09 grade. I was a crappy I was the type of student you
12:13 . B plus is no study. didn't I get a minuses? That
12:18 too much effort. It wasn't until school until I figured this out.
12:23 I'm just going to tell you, going to cut through it all
12:26 When you study, this is what do right after class, when you're
12:30 and you're dealing with this stuff and is true for every class. When
12:33 brain is putting, what you do you say I am going to go
12:37 this information now because it's all fresh my brain and solidified it in my
12:43 . So the first thing you do you have some free time after
12:47 So if it's directly after class or it's after the next class, whatever
12:50 is, you sit down and you all your notes. All right.
12:55 , what you're doing is you're taking slides of information and what you're doing
13:00 you're organizing it so that it makes to you. You're putting it in
13:04 order and you're identifying the things that the most sense. You're looking for
13:09 learning objectives. Well, I don't what the learning objectives are, Dr
13:12 . Yeah. Remember I created those hat assignments where you says, what
13:16 this? What about that? Can explain this. Can you compare these
13:19 things that helps you with the learning ? Right? The idea here is
13:24 is it? I'm trying to That's what the question is. You're
13:27 to answer every class, not just , every class. What am I
13:30 to learn here? If you write that information out, you'll end up
13:34 about 1 to 3 pages worth of . Now, in the grand scheme
13:38 things, what's the difference between 30 and three pages in my brain?
13:43 27 pages. But the truth it's the exact same amount of
13:47 The difference is that you've organized I didn't organize it. My notes
13:52 for me, your note should be you. Right. Does that make
13:56 so far? So, what you're doing is you're actually creating the notes
13:59 you're going to use to study for exam. But by writing it out
14:04 time you're actually already starting to When's our next exam? Do you
14:08 know? It's three weeks away? . It's six classes. Every one
14:13 like every six classes. So, now today you're actually starting to study
14:17 that exam. You do? I told you all right. Now you
14:21 this after every class it's gonna take 30 minutes. That's 30 minutes to
14:25 hours. You don't have to study night before the exam. All
14:30 And you'll see why here in just second. All right. You do
14:33 after every class and now you have little stack of notes. How many
14:36 depends on how big you write and much information you put down. But
14:39 idea here is I'm trying to learn information. I'm trying to understand what
14:43 is. It is that I'm but I've got my notes and what
14:46 don't want to do is I don't to go and do what all of
14:49 do, which is to go through read those notes over and over and
14:52 again. Because what you're trying to , you're trying to memorize information,
14:56 not trying to learn it and your gets overwhelmed. One and two,
15:00 says, oh, I've seen this . So instead of focusing here on
15:03 I'm looking at, what I'm going do is I'm going to start thinking
15:06 all the other things in my life I'm more interested in? All
15:09 And so you might be flipping through . Have you noticed that when you
15:13 , you kind of go, what I just learn? What did I
15:15 read? Yeah, because your brain against you. It doesn't want to
15:19 there more than you do. So have to be the mean person in
15:22 life and you have to make yourself , right? So what you do
15:27 you take those notes and send them here to the side, don't look
15:29 them this is scary. All you wrote them, you know what's
15:33 them now prove to yourself that you what's in them? Blank piece of
15:38 . Lecture? One. What did learn today? We're talking about the
15:42 . Hm. We're actually the So, what did I learn?
15:46 . Well, I learned about the and the dermis. So, that's
15:49 of the skin. I learned about . I learned about nails. I
15:51 about glands. Oh, I got things I gotta learn about.
15:55 Well, great. Well, what I need to know about the
15:58 What do I need to know about dermis? What do I need to
16:01 about? You? See how it and what you do is you start
16:04 out all the information after you've written out for each lecture back, you
16:08 at your notes and you do a . All right. Everything you wrote
16:12 over here should match what's over If it doesn't, that's something you
16:19 . That's something you missed on the . Everything you wrote down over here
16:23 matches over here is something, you , pat yourself on the back.
16:26 right. Now, how many times I do this? Well, you
16:29 through, you write all your go through correct. Anything that you
16:33 write down or wrote down wrong, it, you know, punish
16:36 Oh, I forgot this. So writing it out. Oh, I
16:39 it down wrong scratch it out. right. If you do this twice
16:44 night, like three or four nights the exam, by the time you
16:49 the night before the exam, you have, be able to create all
16:52 notes from scratch from now. Some , it's gonna be less, some
16:56 , it's gonna be more right. you don't have to do a lot
16:59 doesn't take that much time. if you're a person who likes to
17:02 really slow and big, it's going be a little bit longer if you
17:05 30 colors to do your notes. ? That's gonna take a little bit
17:09 . But if you're like me and all about chicken scratch and drawing pictures
17:13 abbreviations, it's gonna go by quicker remember who are the notes for
17:19 Yeah. Not me. You I know, I know you
17:23 So no one's gonna look at them for you, you know your own
17:26 , you know what your picture represents as you're doing it, you're gonna
17:30 and you're talking to yourself a whole , right? You'll be like,
17:34 , it is and that's good because what you're doing is you're doing the
17:38 of explaining to yourself. Now, you have to study in groups,
17:42 do the same thing. It's let me explain to you what's going
17:46 . Let me describe this process. me walk through and explain everything.
17:50 be the teacher being a teacher is of the best ways to actually learn
17:56 . But if you're by yourself, yourself, just repeat this process the
18:00 time you do it, it's going suck because you're going to see that
18:02 don't know anything. The second time do it, you're going to see
18:05 you're going to see improvement third time it's going to encourage you and you
18:08 doing this until you prove to yourself you've learned it all. Once you
18:11 yourself that, you know, all information you can stop studying, which
18:15 a foreign concept to many, many . How many have you got to
18:18 till you're tired? Yeah. Doesn't suck? You're like four o'clock in
18:23 morning, eyes one open and it's , ok, maybe I should go
18:26 bed now. All right. And you're in bed because of all the
18:29 and you're shaking. You can't go sleep, imagine the night before the
18:34 becoming a normal night where you can out with your friends, right?
18:39 you can do the things that you do because all you need to do
18:43 prove yourself. I know this information I know the information I can go
18:47 take the exam and here's the right? And I know that none
18:51 you guys believe it because you just the exam. I don't write trick
18:55 . It doesn't know, you if he feels like it go back
18:57 watch the exam. 00, She good. She agreed with
19:00 Good. I don't write trick I'm not trying to figure out ways
19:03 fail you. All right. I'm to show you what you don't
19:07 All right, that's all this is . I'm shooting for a specific average
19:13 I already told you what do I ? I want you guys to achieve
19:16 goals. I want you to be best that there is. And so
19:19 got to be pushed a little bit make that happen. By the end
19:22 the semester, most of you guys be just cruising along just fine.
19:25 have a very, very, a smaller failure rate than what that last
19:29 kind of showed you. All But you gotta change. All
19:34 you gotta study for those exams Don't just read your notes. If
19:39 read your notes, you're gonna get that you're not happy with. All
19:43 , you have to be proactive, passive in your learning. I mentioned
19:49 evaluating your exams. So, like said, look at your exams,
19:52 the reason why did I miss this ? Did I not know the
19:55 Did I not study it or did read the question too fast? What
19:59 ? All right. I, I see how much time each of you
20:03 took on the exam. Some of . It's crazy. 14 minutes,
20:07 minutes to take the full exam, , you know, it's not,
20:15 mean, it's time to get you of there. Right. I
20:18 you should be able to get through exam roughly in about 30 minutes and
20:21 gives you about another 30 minutes to review and make sure you made,
20:25 the right choices and stuff. Read questions. But yeah. Did
20:29 did you rush through the exam and questions? Did you not know
20:33 adjust how you're taking the exam accordingly on that? Right? And then
20:38 , if none of this stuff makes or if you're truly panicking, come
20:41 see me, I would wait till look for at your exam. Don't
20:44 rushing to me today. I you can, I'm here. I'm
20:48 gonna kick you away, kick you of my office and say go
20:50 All right. But right now there's lot of emotion about how you,
20:55 you perform on the exams, I mean, you feel something,
20:59 angry, I'm some, you really good grade. I'm happy,
21:04 ? But don't let the emotion control look at it and go through it
21:08 an analytical way and ask that How can I be better at what
21:11 trying to accomplish here because you're all of doing it. You got to
21:15 . That's the first, that's the step. The rest of this is
21:18 changing habits so that you can do . But if you're struggling and you
21:23 see why you're struggling. Come, see me, we can walk through
21:26 exam, we can look at some the questions that you missed. Not
21:29 one of them. There's like I , there's 400. If we go
21:31 every test, uh we will be on that first exam till the end
21:35 next semester. It takes a long . All right. So does all
21:41 stuff kind of make sense. All . It should be, I
21:44 you should be encouraged and, and shouldn't feel like who is me if
21:50 not happy with your grade, we three exams. We have a long
21:54 to go. I've seen people bomb exams and actually do well in the
21:57 one and actually get a satisfying Right. Yeah, it's possible.
22:02 know you're like, I don't it's a curved class. I
22:06 it's not, it's not static The curve that I showed you here
22:10 going to change on the second exam it'll change on the third exam and
22:13 change for the fourth exam because we're in 400 plus variables per exam.
22:19 right. So we're gonna see some , we might see it move a
22:22 bit down, we might see this a little bit up. I don't
22:25 yet. Typically the same type of year after year. So,
22:29 usually we'll end up with around an average for an A, we'll end
22:33 around a 55 or to a 60 that c and the number in the
22:39 changes too. So I don't know it's gonna look like. Hopefully everything
22:43 the other direction. Everyone gets a and we can have our cake or
22:47 kegs. I, there's a lot these so we might need to.
22:51 right. Any questions so far. , ma'am. Yeah. Mhm.
22:59 , yeah. So, the, a, there's a question, you
23:01 , I got a couple of like, hey, is there an
23:04 exam that I can study? The is no. But what happened
23:07 is that previously when I taught this ? 121212 over and over again,
23:12 know, you have a friend who the class previous semester. If you're
23:16 a fraternity sorority or something else, might actually have an old exam.
23:19 so it's just a question I hey, did you use an old
23:22 to help you study? I'm I don't release them but, you
23:26 , students get a hold of I'm not gonna pretend like they
23:29 you know, and if you I'm not, I don't look at
23:32 answers because one, I'm lazy and , it's none of my business how
23:37 studied. Right. But I, , it's, again, it's not
23:40 strong way to study. There I, I'm, I'm just,
23:46 was, this was like 10 12 ago back. So there used to
23:50 that when textbooks and everything was not , they would actually send out test
23:54 , like book books full like this . And there was a student who
23:58 every question in the test bank and and took the test and got a
24:02 score. And they, it it was clear that she didn't know
24:07 she was doing, but she had the test bank and it's like,
24:11 , this is a resource and they trying to, you know, it
24:13 an academic dishonesty thing. It's like is a resource. If she got
24:16 hands on one, it's not illegal her to do so she didn't steal
24:20 exam. She memorized 800 questions for 50 question test. Yeah. So
24:29 , so what I would suggest is is not a strong way to study
24:33 it does. It shows you what of questions are, how I ask
24:36 question at this point. You now how I ask questions. So,
24:40 know, hippie. All right. other questions about this? Because I
24:48 I'm going along here, we're going catch up. We're probably not going
24:51 get through everything today, but we play, we have plenty of room
24:54 play, catch up, especially when talk about joints and stuff. You'll
24:57 that this unit has a lot of to it, right? It's because
25:01 changing subjects over and over again, each lecture is basically one thing and
25:04 we slow down again. All And what we're gonna do is we're
25:07 basically going through the skin. We're go through the bones and the joints
25:12 we're gonna look at muscles and we're gonna cover this over this unit
25:17 What we're doing is we're talking about in which is a fancy word for
25:20 the skin and, and its All right. So that's kind of
25:24 we're looking at. Our starting point going to be the skin. And
25:29 reason we're talking about the skin first because once we understand the skin,
25:33 other ones kind of fall into And when we say that these are
25:36 , what we're really saying is that , these structures originate from the same
25:42 material during development. So your glands going to develop from the same structure
25:48 give rise to skin and same thing the hair and the nails. Those
25:52 the big ones that we're talking about . Um If you look at the
25:56 and this is our picture that we're look at, we have two basic
26:00 , we have the epidermis and When you see the word or the
26:03 epi, what does mean high or , right? So your epidermis is
26:09 your dermis and that's as simple as is right socios layer, this is
26:14 epithelium and if it's epithelium, it it's a vascular, what it also
26:18 is that we can see that it's layers. So it's a protective layer
26:22 that is the dermis. The dermis where you see all the blood
26:25 This is where you see the, nervous tissue. It's gonna be a
26:29 of, of, of connective Um We're gonna see that there's some
26:33 in there. Um It's the stuff everything is attached to and is held
26:37 by it. All right. Um is gonna be some smooth muscle associated
26:44 affiliated you can see in our little here, there is a smooth muscle
26:47 that's associated with the hair follicle, it's, it's different. It's a
26:51 tissue relative to the epithelium. depending on who you read and how
26:56 want to define it. There is third layer that's really sometimes considered to
27:00 part of the dermis. But in case, your authors are saying
27:03 no, it's below. So it's hypodermis. It's primarily fat tissue,
27:08 blood vessels in it as well. so it's like it's, it's just
27:13 as and we we're mentioning it, I don't know how to count
27:17 You know, like I said, authors use different things. So we're
27:20 going to say hypodermis, we're going use your book air is basically just
27:24 connective tissue. So it lies underneath dermis. It's a shock absorber,
27:28 serves as an insulator. It's that layer that basically serves as another protective
27:35 between the dermis and the rest of body. Now, we're gonna look
27:41 some of these in more detail, I just want to show you when
27:44 think of skin, we think of and there are different types of
27:48 Here. We have chemical barrier, physical barrier, a biological barrier.
27:52 have bacteria and all sorts of horrible crawling around in your bodies right
27:56 Um It's just part of life. think you learned this or I might
27:59 said that you have more bacteria cells your, in your body than you
28:03 actual cell that your body created, is crazy to think about. All
28:08 , um temperature barrier, radiation Um So basically anything, it's basically
28:14 as the boundary between the outside environment the internal environment. Uh it is
28:19 resistant, you don't absorb water, are not a sponge, you do
28:23 leak water out, you, you water. So it's a purposeful
28:28 Uh It plays a major metabolic activity we think about metabolic here, we're
28:34 thinking about vitamin D but there's other uh processes that are involved. Uh
28:40 can secrete material, we can absorb materials in terms of absorption. It's
28:44 , very selective. All right. we're talking about basically lipid soluble materials
28:49 be absorbed through. So some organic are capable of absorbing through the skin
28:55 they're lipid soluble uh in terms of , it plays an important role in
29:01 you against all the things that are here trying to come inside your
29:05 And again, I'd remind you you're doughnut. So when we talk about
29:09 structures that are internal, that are to the external environment that is part
29:13 the surface of the body. It's material in between the outside skin surface
29:18 the inside body that we're trying to . All right. So when we
29:23 about immunity, we're talking about things are trying to penetrate through the outside
29:27 surface skin. All right, with to the dermis plays a role in
29:32 regulation. So again, this is all the blood vessels are. So
29:35 you get hot, they dilate more goes in there, heat moves to
29:39 surface and then uh you secrete uh . And so when you secrete the
29:43 that heats up and it wicks away evaporates and that carries the heat
29:48 So, temperature regulation, when you're , you got adipose tissue as
29:51 There's also a whole bunch of different . These are the mechanical receptors,
29:56 touch receptors, there's some chemical receptors well. I am, let's see
30:02 pain receptors as well, chemical When you itch, that's a combination
30:07 touch and chemical and meca there's all of crazy things in there. All
30:12 . But the idea is that I detect the things that are going on
30:15 the external environment. So the two cell types that we are concerned with
30:21 the carno sites, the melanocytes, Caratti sites are the majority population.
30:29 name tells you everything you need to about them. They produce Carotin.
30:32 so when they produce Carotin, that's makes them tough. That's a tough
30:37 filament. It's the thing that provides protective properties. And so in this
30:41 here, everything you're seeing um other that one little brown cell, those
30:46 representing the Carroo sites in different The melanocytes on the other hand,
30:53 in between the Carroo sites. So can see its cell body in the
30:58 and you can see that it has little processes that penetrate through uh and
31:02 between the cells. Now, the of the melanocyte is to produce
31:06 Melanin is a pigment that is used the Carroo sites to protect themselves from
31:12 . Light. We'll see how that's in just a moment. So the
31:16 produce the melanin, it releases the , the carotenoids pick it up and
31:21 they place it in such a way the UV does not go to the
31:24 and damage the cell itself. whenever you see different names, we've
31:32 this already, there's a reason those are named differently. In this
31:35 they're named differently because of what they like, but they have these unique
31:39 . So when we look at the . What we're going to see is
31:42 are five layers to the epidermis and of these layers are doing something slightly
31:47 . Now, this is the original name, but you can just see
31:51 the, it's the basal uh um layer. Then we have the spin
31:57 spiny layer, then we have the layer, then we have the clear
32:02 and then we have the corny layer the corneum. So it's basically bali
32:06 granulosa lucidum and then finally, those are the five layers working from
32:12 the lowest layer upward. All Now, when you look at
32:18 what you're gonna see is that these layers here from the basal up to
32:23 um the uh granulosa, those are layers of cells. Once you get
32:30 the granulosa, the cells begin to . And so the latter two
32:34 the lucidum and the corneum are dead . All right. So the outer
32:40 of your skin, you've heard it cells and you can do this and
32:43 can flake them off and that's the and all that fun stuff that we're
32:46 is other people's skin cells, mm just gonna kind of walk through.
32:53 when we look at the bali, a single layer of cells. So
32:57 nice and simple. This is the layer. It's like the layer of
33:00 cells that give rise to all the layers. So it's in a constant
33:04 of division. All right. And can see pattern wise, what we
33:10 is we kind of go up and . All right. Now, it
33:13 connected by a basement membrane to the . And this up and down pattern
33:17 you see here is going to be on the surface as well. All
33:22 , it's not as deep or as looking, but you will see that
33:26 that's actually what gives rise to All right, those are called epidermal
33:31 or this is called an epidermal ridge gives rise to those things on your
33:36 . And this is what allows you grip stuff. All right, those
33:39 basically create points of friction for All right. Now, if you
33:44 here, you'll see these are mostly sites, but every now and then
33:48 might see a melanocyte and then every and then you may see a another
33:52 of cell that we're gonna get to little bit later. All right.
33:56 the dividing carotenoids producing the carino sites gonna be filling up the next group
34:03 cells or group or next uh So when we get to the
34:09 why do you think they call it spinosa? It's spiny looking,
34:13 So they're, all these cells are by desmosome with each other and they're
34:18 kind of in that state of But what you're doing is you're dividing
34:21 , you're pushing them up and what do is they start differentiating into a
34:27 uh cell. So what they're doing you start moving up, they stop
34:31 and they're starting to differentiate from the layers and they have this appearance because
34:36 this, of these desmond, they pulling and so they start looking like
34:41 have a spiky appearance. All And so there's several layers thick and
34:48 on where you're looking at, it's be a different thickness, then you
34:51 up here and it's not very This is the granulosa. And what
34:54 now done is that the cells have pretty far away from the sources
35:00 of, of nutrients and, and that they need in order to
35:05 And so this serves kind of as signal to start differentiating even further,
35:10 start producing a type of carrot that creating a granular appearance. So it
35:17 like there's a little tiny dots in . So that's the granulosa, all
35:21 little Granules, all right. And this point because they're lacking all those
35:27 and those cells begin to differentiate and , they lose their organelles, they
35:31 their nucleus, some of the organelles they have begin to dissolve and
35:36 And then what happens is you start the cells getting thinner and thinner and
35:40 as they start getting pressed or pushed . All right. So this process
35:46 , is ongoing and as they move away, then that's when you're gonna
35:51 getting to completion. So the granulosa quite dead yet. They are on
35:56 way to dying. All right. we're seeing this major shift from not
36:02 as much carrot to producing more carrot getting thicker as they go. Lucidum
36:11 a weird one because it's only found what is called thick skin. All
36:15 . And we have a picture a bit later. But I'm just gonna
36:17 you if you look at the palms your hand, that's thick skin,
36:20 you look at the back of your , that's thin skin. So you
36:23 kind of tell the difference. It different. It's thicker, right?
36:26 we fall down, we want to down on this side. We don't
36:28 to fall down on that side because gonna scrape everything away. All
36:33 Part of the reason this thick layer there is because we get this unique
36:38 of carrot that's formed. It's called . All right. Now, the
36:43 is unique in that it is not a protective uh material. Um but
36:49 also is protective against UV light that matter the uh the color of your
36:56 . But if you kind of look your palms versus the back of your
36:59 , you'll notice that your palms and soles of your feet are lighter,
37:04 ? The darker skin, the more it is for me, it's a
37:07 bit harder, right? But if look closely, you can kind of
37:10 , oh yeah, this is kind more of an olive color. That's
37:12 of a peachy color. You see , right? And that's because that
37:17 and absorbs the UV light, the that causes melanocytes to produce melanin is
37:23 . The more UV you have, more melon you're gonna produce, we'll
37:32 to the more complex complexity of All right. But think of it
37:37 this in the summer when you're out the pool and you're having fun,
37:40 tan up a little bit. that's because more UV light in the
37:44 when you're inside and it's gross and and you never go outside ever
37:48 You know, put the blankets on . All right, you lighten up
37:54 . All right. Now. Uh else have I said here? Um
37:58 , it's thick, protects against of . So you can start seeing that
38:03 starting to see these changes and finally get to the very end. So
38:07 you can imagine again, that lucidum not present in most of your
38:11 it's only present in that thick So if you're in the granulosa,
38:16 either going through that stage of creative if you're in the sts or the
38:21 . But are you gonna move on into this last little layer? And
38:25 last layer is that corneum and cornia scaly? All right. When I
38:30 , you know, think, think grandma, if she has corns,
38:34 know, it's not a term we recognize as young. I'm gonna just
38:38 as you guys are young, I'm longer young. All right. But
38:41 have corns on your feet. If wear high heels all the time,
38:45 get those really pointy ones, you'll getting that, that really weird
38:49 That's a corn. All right. it's, it's kind of the scaly
38:56 . So the corneum has that scaly , right? Which is why it
39:02 its name. All right. Now , what's happened is is that that
39:07 that was going through that transition of Carotin gets and losing its organelles is
39:12 dead. And what's happened is is getting pancaked and the materials that fill
39:18 now is primarily that carrot protein and the fatty layers of the plasma membrane
39:25 basically are pancaking this hard protective And so what you end up with
39:29 basically a layer of protein and protein and fat, protein and
39:33 And you get as many as 30 of this stuff. So this is
39:37 outer surface of your skin that serves an incredibly protective structure. Now,
39:43 will flake off. There are pieces look flake off over time and this
39:48 called desquamation. Say it, Desquamation. I want to put a
39:53 in there. So disco and what doing is that's just, it's,
39:57 just normally flaking off just over the of your normal life and you're slowly
40:01 those layers. If you ever gotten and started peeling. That's an example
40:06 declamation right here. You're dealing with cells. So you're actually producing more
40:11 . So it pushes it up All right. But it's just an
40:13 layer. All right. So they're , very tightly packed. You don't
40:17 nuclei, they're just squished together like bunch of pancakes. And what we
40:22 is because of the presence of those . All right, what you're doing
40:27 you're actually creating a water protective So you have basically water protective
40:32 That's 30 cells thick because of all platinum membrane that's been squished close
40:38 So you can hit it with all of horrible things. All right.
40:44 , you had done a K lab accidentally poured something on yourself.
40:47 uh, you know, one OK. I did hydrochloric acid one
40:50 sulfuric acid in a, in a thing. I'm, I'm, I'm
40:54 in the laboratory. Just, let's , just pour it all over
40:57 I didn't know about the sulfuric acid I went home because then I did
41:00 little laundry and I took my shirt and it was nothing but holes on
41:03 because it didn't do anything until after had the water. Terrible.
41:09 it was my favorite shirt too. was really bummed. But, you
41:12 , but like hydrochloric Acid, it's like a movie where it's like you
41:15 the acid on, you're like running and I'm melting, your skin is
41:20 pretty resilient against most chemical insult. , there are things that will eat
41:25 skin like that. Right. But the bacteria get in your body?
41:30 , you have to create a hole them to pass through. So,
41:34 have a hard time breaking through. . Have a hard time breaking
41:38 What else do I have up Uh Yeah, physical, I
41:41 it takes a lot of effort to through the skin, right? I
41:44 , fingernails are pretty sharp, You know, it's not cutting through
41:52 . I mean, I you're gonna this a little bit, it's gonna
41:56 all nice and red in a little . OK? But now it's tough
42:02 . It takes a lot of physical to get through. This is what's
42:07 you. Basically squish cells, proteins fats. So here's the thick and
42:13 thin skin, the difference between them skin, five layers versus thin
42:18 four layers. It's a really easy to look at this, right?
42:22 This covers most of your body. whenever you think of skin, you're
42:25 thinking of thin skin thick is just of hand soles of feet. We
42:29 sweat glands, anyone anywhere here and like public speaking. I mean,
42:32 that most of y'all like, what's of the things you do when you
42:35 up there is your hands start right? So that's the sweaty
42:39 Ok. So we do have sweat , but you don't have hair on
42:43 hand, hair, no hair on palms of your hand. You don't
42:46 sebaceous glands which are the oily You don't produce sebum on the palms
42:50 your hand. It's just that wet, um type of ari type
42:55 sweat. All right here, you'll have sweat glands, you'll have
43:00 follicles, you have sebaceous glands. just think of your face, that's
43:04 oil seba or sebum. So the difference is right? This one has
43:12 , this one is wet, but one doesn't have the hair follicles or
43:15 sebaceous glands. So know those So this is kind of going through
43:25 next couple of slides or to kind look at, you know,
43:30 One of the roles as we said that the epidermis plays a role in
43:34 . So it protects against foreign And so one of the ways that
43:37 does this is not simply by being physical barrier but hiding inside and or
43:43 kind of hanging out inside the layers the epidermis. Primarily in this ban
43:48 these cells called Langerhans cells named after guy who discovered them. They're now
43:53 epidermal dendritic cells. So you may either of those two terms. I
43:58 when I put them on the I put both terms because I'm
44:01 I like the old term, the term is what you guys will mostly
44:05 . And this is a type of , it's a resident macrophage. And
44:09 it does is just kind of hangs and it waits for something to be
44:13 to it that is foreign. And something that is foreign is presented to
44:17 , that activates this cell and it signaling for the rest of the immune
44:22 to become alerted to whatever that pathogen to be. All right, it
44:28 capable of migrating. It doesn't just there, it can migrate around and
44:31 to sites of damage. But typically see them kind of just localized in
44:36 single spot because they just kind of out because very rarely do you get
44:40 penetrating through the skin, right? pigment. Um There are more than
44:48 two types of pigments that are found the skin. Um So for
44:53 um one pigment is hem in blood you your skin kind of flushes,
44:59 is an example of a pigment And so we all have that pigment
45:03 our bodies. We all have different of melanin. Everyone has melanin and
45:08 are different types. We have a type and a lighter type. So
45:12 melanin is more of a black whereas the melanin is more of a
45:15 , yellow and so you can produce types in different quantities and kind of
45:21 the unique colors that we all All right. But really the whole
45:25 of melanin is simply to protect the sites. All right. So this
45:31 a pigment. It's a means it's light absorbing material. And what it
45:36 is that the melanocytes, which are the same number for everybody, it
45:41 matter the color of your skin, has roughly the same number of
45:45 It's how much melanin they're producing and more or less genetically determined. And
45:50 again, the type of melanin. so what it does is it starts
45:54 these Granules and then the carno sites them up. And if it's uh
45:58 to be a lot of UV that's going to stimulate the melanocyte to
46:02 more and more and more of the . And then the melanin is absorbed
46:07 these uh carino sites. And what do is they arrange it like an
46:12 on the light facing side of their . So it's, you have your
46:17 and it's out here and the site all. And so it kind of
46:21 as a protective barrier to absorb that light so that the UV light doesn't
46:25 down and get absorbed by the DNA UV hits DNA. Whenever you find
46:31 uh thymine or thymine, what it do is if you have two side
46:35 side, they'll cause them to uh um rearrange themselves so that they get
46:41 weird dimer and then, then the reading, uh, you
46:46 the polymerase and whatnot, they see and it's like, no,
46:48 this shouldn't be like that and they back and try to fix it,
46:51 they're really, really bad at, making fixes. And so this is
46:55 of the ways we get mutations in DNA is simply through UV light.
47:00 right. So this is how we ourselves. We have Melo.
47:16 All right. So, Carrot is little bit different, right? So
47:21 here ever watch the Jersey Shore? guys know what the Jersey Shore
47:25 OK. Right. All right. you remember Snooky? Do you remember
47:29 she had that color? That special of the loa color, right?
47:32 know I'm making fun of her because can and she made millions and I
47:35 . So. All right, that , that orange color is a function
47:42 , uh, it's a, it's a spray on, but you can
47:45 rub it on. All right. there is a tanning cream. You've
47:50 heard of it? Ban De right? You can go to your
47:54 and usually in the summer you can , just grab a tube of that
47:57 . And what you can do is just rub it on and it kind
47:59 gives you the color as if it's a bronzing cream is another way
48:04 you can do it. And so kero, it is the, the
48:07 that's found in carrots, right? so blush is simply something you put
48:13 the surface. Carrot gets absorbed in stays in the fatty layers of,
48:18 like the Hypodermic. And so that is reflecting outward. That's that
48:25 Yeah. So not blush, blush just a color you put on your
48:29 like chalk. Like you could literally and get pool chalk and like for
48:35 pool view or sidewalk chalk. Imagine little blue. Yeah. Ok.
48:46 . All right. One of the that we can do is we can
48:50 the external surface. Now, most the nerve fibers you're going to see
48:53 we're going to talk about are found the dermis. But there are two
48:56 move or work their way into the . All right. So we have
49:00 that are called tactile discs or their name is the Merkel disc named after
49:04 guy discovered it. And so these going to be found in the strata
49:08 . And again, there's not a picture. I thought that they had
49:12 but they don't. But it would like it would be one of these
49:15 instead of it being a carno site be a Merkel disc. All
49:19 That's the idea um with this. then they, so again, they're
49:24 to say, oh, look those little ends, right? There
49:27 supposed to be associated with that Merkel and what they are is they're a
49:31 of mechanoreceptor and they detect light touch the epidermis. All right.
49:38 they have very, very small receptive . A receptive field is simply the
49:41 in which you're able to detect something other type of cell are going to
49:45 the free nerve endings. You can up here, here is the
49:47 it's penetrated into the epidermis, it's all out. And so those are
49:51 dendritic endings and again, small receptive , but they're detecting things in the
49:56 . Things that are going on at surface of the cell or surface of
50:00 skin, right? So what type things tickling, for example, or
50:05 would be like touch, itching, again, chemical and touch and a
50:10 bunch of other fun stuff. So are the basic types of receptors that
50:14 going to find in epidermis. But the picture, I just want
50:17 I'm going to note it now and going to come back to it.
50:19 notice we have all these other things are here down in the dermis.
50:24 right. So most of the nerves the neurons that you're going to be
50:28 about are going to be located in dermal regions. Another thing we
50:33 we said, hey, there's metabolic . Vitamin D is one of the
50:38 that we produce through the skin and depended upon UV light when I was
50:44 . Actually, I was a post , I was working in a lab
50:47 you do an experiment and you usually these long wait times between, you
50:51 , when you start something, when in something. And I would
50:54 II, I was in El Paso doing my post back work and I
50:57 go and say, hey, I'm go make some UV, light or
51:00 UV, I was gonna go make vitamin D and so it got in
51:05 lab. I mean, he just , he was working hard but he's
51:10 not a smart guy and he's I can watch, you make vitamin
51:14 . Ok. Sure. So we up and there was like this place
51:19 sit up out on the, like had a breezeway near the roof and
51:22 just sat out there and, you , it's a nice hot summer,
51:25 degrees or something. I'm just sitting there and he's like, when are
51:27 gonna go make vitamin D? I'm , um, we're, we're doing
51:30 . You just, I'm being a . I'm, we're sitting around and
51:34 doing anything. So why is it to go outside? Vitamin D?
51:41 is just showing you the pathway you need to know it. But you
51:44 see, um, you have from skin, you take cholesterol, you
51:49 it into vitamin D and it goes a whole bunch of different steps and
51:52 that stuff becomes the stuff that strengthens , et cetera. You can notice
51:59 name out there? Um, what , what vitamin D does, it
52:05 you to absorb calcium and phosphate, strengthens the bones. Have you ever
52:09 why we have it in our What's in milk besides? Well,
52:15 do we fortify? We fortify with , we fortify with vitamin A.
52:18 what do you find in milk? does it make, uh,
52:22 So, if you put it with and it's gonna help you absorb the
52:24 fairly quickly. Oh It's phosphate. . So calcium and phosphate. These
52:31 the two substances to uh molecules that make bone. All right, any
52:41 about epidermis. So if you're trying follow along saying, all right,
52:45 just, I'm just gonna give you hand here. What is my learning
52:48 here? Well, what does What are, what is its
52:51 What are the five layers and how they different from each other?
52:54 That's, that's really what we just . And so it's when you're
52:59 that's kind of how, that's how would organize it. I am
53:02 what am I trying to learn about ? And we're just gonna do the
53:05 thing with the dermis. We're gonna the same thing with the hair,
53:07 nails, so on and so All right. So dermis. All
53:11 . So this is the layer underneath epidermis. You can see it actually
53:15 two layers to it. You can see in this picture. This is
53:20 a cartoon, although it looks like , it's colorized. But you can
53:24 there's kind of this dividing line. so we can see up here we
53:26 a papillary layer and reticular layer, . When you see that, that
53:31 fingerlike, the kind of like Yeah. OK. So again,
53:36 like we said, there's lots of vessels, there's nerves that are found
53:40 . It's a type of connective you know. So what we expect
53:44 find in connective tissue would be So we're going to see lots of
53:47 . We'll see all sorts of immune , all sorts of fun stuff like
53:51 . Now, the upper layer is of aerio or connective tissue. All
53:57 , if you're wondering why we had memorize all those stupid definitions or why
54:01 because we're going to see them over over again. And it just immediately
54:03 say, oh, this is kind its characteristic. So it's an aerial
54:07 connective tissue. It has these dermal , right? So we also refer
54:13 that up and down process as those ridges because this is the epidermal
54:18 But on the dermal side, that's pail. All right. So we
54:24 these paille and really we're looking at two D image, but you have
54:28 imagine this is three dimensional. And you can imagine it's kind of like
54:32 cartons, right? Like fingers on egg carton. You have like an
54:36 carton mattress. You know what I'm about? Ok. I need,
54:41 don't want to feel like I'm that . So, you know, a
54:44 mattress be just ok. Yeah. . So that's kind of what it
54:48 and it grips everything and that's one the reasons why the dermis and the
54:51 don't slide against each other. they're connected to each other via that
54:55 of membrane. But you also have these pail so nothing can slide
55:00 All right, they're attached very Now, up in this region,
55:04 gonna see capillaries move up. Capillaries the smallest blood vessels. This is
55:08 you're gonna see material exchange and it the nutrients as close as possible to
55:13 epidermal layer. Right? You'll see these free nerve endings. You'll see
55:18 pain receptors, you'll see touch Um It's, it's basically as close
55:25 you can get to the uh to dermis to hold everything in place.
55:29 all that is the reticular layer on other hand, is a dense irregular
55:35 tissue. Remember how I said that going to see that there's a variety
55:38 types here. So the upper layer reticular damn lower. It's a dense
55:44 . All right. So again, gonna see more fibers, but they're
55:47 gonna be all going in the same . All right. So these are
55:50 collagen fibers and they typically run parallel the skin. And so you can
55:55 of see here. This is an of what that would look like and
55:59 form what are called cleavage lines. cleavage line is beneficial because,
56:05 I mean, in the, in field of medicine because it shows you
56:08 way we should cut if we're doing surgery. So, I mean,
56:12 you had an appendectomy? I'm the one you lucky people. All
56:20 So an appendectomy is they take out appendix. Your appendix is located in
56:23 region. Which way do you think cut, did they cut this way
56:26 did they cut that way? Added ? No, it's just one
56:31 That's all right. No, that's . That's fine. Why? One
56:35 ? Because the, if you look , the cleavage lines go like
56:40 and what that does is when you along a cleavage line, the,
56:44 wound that you create is like But if I cut perpendicular to the
56:50 line, then those collagen fibers pull then pull this way and then you
56:54 up with this big gaping horrible hole much harder to repair. So you
57:01 tearing and cutting along the cleavage you don't want against it, that's
57:05 , much more difficult to repair. right. So we mentioned highly vascular
57:10 . So you can see up here lots of blood vessels, they're working
57:13 way up to the papillary region, ? We got big old nerves,
57:18 all over the place those nerves are to be of different types, they're
57:21 to detect different types of stimulation. The other thing that we have is
57:29 have points of attachment that are referred as flexure lines, right? So
57:34 can look at the palm of your , that's the easy one. And
57:36 can see flexure lines. And what's here is that the connective tissue is
57:41 downward and attaching inwards so that when bend in a specific way, your
57:45 doesn't fold up. All funny. right. So like here you can
57:50 there's flexure lines, right? Or the wrist, flexure lines. All
57:54 . So they, they, they as a way to fold the skin
57:59 movement to ensure that the skin doesn't in the way of the movement.
58:03 probably the best way to think about . We're gonna come back to
58:11 This is our first introduction to We're gonna come back to it again
58:15 the second unit. All right. I want to introduce this idea.
58:19 again, we have these different names on uh on who discovered it.
58:24 right. And then they've tried to the names out. And what I
58:27 you to do is I want you look at the positioning of these different
58:31 of receptors and where they're located because of where they're located kind of tells
58:36 what they're doing. There are three types here. We have the tactile
58:41 Mesner core puzzle. We have the or a Pacinian core puzzle and then
58:47 have Ruffini. So here's Mesner, Pacini, right? And there's
58:54 All right. And you can see kind of have different shapes and
58:56 And again, we'll go into more of these at another date, but
59:00 just want to kind of point it because what are they doing? Well
59:03 here at the top where I'm near surface, I'm going to be dealing
59:07 light touch, light pressure and simple . It tells me what I'm grabbing
59:12 . It's up in the Popil. like if you run your fingers across
59:16 table, you can feel that movement of the presence of these core
59:21 Miser core puzzles down deep. You the laminated core puzzles. These are
59:27 Pacinian. All right. So if deeper, how do you get,
59:31 do you detect something that far What do you think? Would it
59:37 to be light? It'd be right. So that's it. So
59:41 we're dealing with these, we're gonna dealing with deep pressure and deeper
59:46 right? So like when you grap and you can feel something, you
59:51 , or something hits you hard, what these are doing. And then
59:54 we have the Ruffini and you can here the shape, it kind of
59:56 like Sty's head, you all. Yeah, I remember that show Family
60:03 . So it looks like Sty's right. So here what we
60:06 we have a different structure and this more about distortion. So when your
60:10 twists and turns, what you're doing you're pulling on these collagen fibers and
60:15 can detect the movement in those collagen . So it's detecting kind of in
60:20 mid-range pressures. All right. So we have different types of receptors located
60:26 different depths in the dermis to detect degrees of pressure and different degrees of
60:40 . Any questions about the Dermot, straightforward stuff. Yeah. All
60:50 Just looking at the time here here got hair. Very flexible,
60:59 But it's a bunch. It's just the skin, it's dead uh
61:04 All right. They have a layer living cells that are way down
61:08 And what you're doing is you're producing dead cells. They are producing
61:11 So they are Carroo sites. All . But it's a different type of
61:15 than what's found in skin. Uh they're much, much more durable and
61:19 way that they're arranged CRE uh creates way that they don't flake off,
61:25 don't, you know, move off skin or, you know, they'll
61:29 away from the hair as easy as falls off the in. All
61:34 So you can kind of see it's of an overlapping shingle like structure.
61:40 right. Now, I give this , these pictures up here because one
61:46 AAA horrible exaggeration. Which is this right here. This is Phil
61:52 You guys know who Phil specter No, I wouldn't expect you guys
61:56 . Phil Specter was the Beatles He produced several of their albums and
62:01 was in California and he was very and girls would like flock to his
62:05 and he was a sociopath. And of the things he did was he
62:09 threatened um a model or something like , that was over there. I
62:13 a gun to her head and she away and actually they went and arrested
62:16 . This is his trial and he up like this, but his hair
62:21 this big. It was like this someone you, you know, had
62:24 with Photoshop, right? So I this as an exaggeration because it's an
62:30 picture. So what does hair Well, it protects. All
62:33 And so in terms of protecting sunburn injury, um I went to a
62:38 , I went to one of Stevie VNS, one of his last concerts
62:41 he died. And it was again near El Paso in the middle of
62:44 desert. We showed up at 6 or 8 a.m. and started drinking and
62:48 concert wasn't until four and we sat there all day long until the concert
62:52 when I got home, I actually sunburn on my scalp. Yeah,
62:55 was awful, awful. You it was not the best concert I've
63:00 to Stevie was great, but everything sucked. All right. Um,
63:05 your nose you'll, you'll notice that time your hairs will get longer and
63:09 . Especially you men, it'll get and your wives will complain,
63:14 Um, but this is there to material and particles from going in your
63:18 and into your ears. Um, your eyes, you have eyebrows.
63:22 talked about this, the eyebrows are sweat bands. They direct water to
63:27 away from your eyes. So that doesn't directly drip in your eyes or
63:30 , it doesn't directly drip in your plays a role in heat retention
63:35 Uh, sensory, uh, ever spider crawling on your arm.
63:39 So that's because they're touching the hairs there's, there's actual receptors associated with
63:44 hairs. And so that's how, know, I have, I told
63:47 guys the Scorpions story yet. Ok. This is awesome. So
63:51 were at a girls health, eighth . I remember this is back in
63:54 early eighties. So I'm already, already telling you how old I am
63:58 they were shag carpet from the seventies the house because they hadn't changed it
64:01 yet. And I'm sitting there watching . She's up on the couch,
64:04 on, I'm on the floor watching it was and I kept feeling something
64:10 to crawl on my arm because you , the hairs I'd feel I'd brush
64:13 feel it on my arm and brush . Finally turned over to look and
64:16 was a scorpion trying to crawl up arm. Yeah. Yeah,
64:23 you know, there's fun out Right. So, that's why I
64:26 this. That's not a scorpion. , I like the jumping spider
64:29 uh, visual identification. Um, of the things in looking at,
64:32 , a person's hair, you can kind of determine age, right,
64:36 I've got that salt and pepper, know that I'm older than you.
64:39 . Right. Uh Sex, you , I know that there are unis
64:44 style hairs, but generally speaking, can look at somebody's hairstyle and most
64:49 95% of the time you can determine sex simply by looking at them,
64:53 . It's also a way that we identify people. You have, you
64:57 like when someone gets a haircut and like, I don't recognize you because
65:01 brain puts that hair, you as a way to kind of
65:06 All right, it also plays a to identify um uh I, I
65:11 say uh is through pheromones, This is one of the ways to
65:16 um uh chemical signals. And there's a lot of things around pheromones
65:21 we're not going to get to. uh basically the axillary region. So
65:26 in the pits and in the pubic , basically that hair kind of grabs
65:30 and holds two chemicals and So it's way that we can actually send signals
65:35 to partners or potential mates and so . And whenever I say this,
65:40 what I'm saying, that is that very subtle in humans. It's,
65:43 not dogs, we're not cats. mean, you know, dogs and
65:47 and heat can detect each other miles . Humans, we can look at
65:51 other and have no clue. um, anyway, but that's part
65:56 the reason why we have hair appear puberty is because it's one of the
66:01 to signal that we're sexually mature and it appears where it does. All
66:07 . Now, in terms of hair is very basic, we're gonna
66:11 it very basic. All right, have the shaft. All right.
66:14 the shaft is the portion that sits the skin. So above the the
66:19 the epidermis, everything below the surface the epidermis is considered the root right
66:25 . All this stuff in the hair the way down. That's all dead
66:29 . All right. It's only down is where you're gonna find in the
66:34 where you're gonna find the living All right. So this region is
66:39 bulb. So you can see that's bulb. This whole thing is the
66:43 . It has the paille here. paille is where you're gonna have nerve
66:48 and you have blood vessels come So it's just like in the pail
66:51 the dermis coming right. Up to uh to the layers of the epidermis
66:56 up there in the basal or the . They're not the same, but
67:00 very similar. And then, so are the living cells of the
67:05 right? So that's the matrix and matrix is what is producing the cells
67:09 are dying off and then forming the in the shaft. Ok. Did
67:16 kind of make sense? So you living cells but they're dying off just
67:21 we saw in the skin, we living cells at the bottom and we're
67:24 upward towards the dead cells. You see outer layer, we have a
67:33 surface layer and then we have an surface. So the outer layer is
67:36 is what we call the cuticle. , the cells are overlapping each
67:40 They are dead cells, but they're like shingles, they overlap each
67:43 So it's very, very hard for to flake off or get away from
67:46 another. The region of dead cells are underneath the cuticle moving inward,
67:51 would be the cortex. So that's near surface. Um These are flat
67:56 , they're made, they have within carrot. So they're most equivalent to
68:00 corneum. Um And then we have medulla, the medulla, again,
68:06 are dead cells, but they're not squish, they're much, much less
68:12 . So that gives hair flexibility. the fact that your hair can stand
68:16 and then kind of fall on itself because that inner portion is soft
68:22 or not as dense, whereas the portion is hard and dense. So
68:26 have strength on the outside, you less strength on the inside. When
68:34 look at the follicle and we're gonna focused here. I think this is
68:38 really good picture because you can see this yellow portion, what do,
68:41 do we call this yellow portion, in this pink portion? Do you
68:47 what we have here? Is we the epidermis fold down inward. So
68:52 hair follicle is formed by the outer of the intent. In other
68:56 the epiderm is folding inward. And what that means is is that the
69:00 follicle actually has two parts to It has an inward epidermal portion and
69:06 surrounded by an outward dermal portion and hard to see here. But if
69:10 look in your book, you can it. So the dark purple here
69:14 be epidermal but those the one layer cells just outside that is dermal in
69:20 . All right. So we refer it as the connective tissue root
69:26 that's the dermal portion. And then have the epithelial root sheath, which
69:31 epidermal in origin. Ok. So two layers there. We can see
69:40 there's a smooth muscle associated with that . All right, it's called the
69:47 py muscle. So each one of hair follicles has one of this.
69:51 right. Now in mammals that are human. One of the purposes this
69:58 is to actually cause the hair to up for two reasons. One to
70:03 other animals away to say, I'm bigger than I am and I'm
70:06 more dangerous. Don't mess with So usually it's a sympathetic response or
70:11 second thing that it could be used is to lift itself up to trap
70:16 air near the body. So if notice like your cat, when it's
70:19 or your dog, when it's it's hair kind of puffs out.
70:23 what they're doing is that heat that's generated at the skin is being
70:28 near the body through that meshwork of . Now you get cold. Do
70:33 get goose bumps? Yeah, you . But is your hair thick enough
70:38 trap heat next to your body? . So what we're seeing is a
70:43 feature of what the skin on the is supposed to be doing the hair
70:48 our skin. It just can't do because we don't have thick hair,
70:53 our dogs and our cats and bears other things. The other time is
70:56 someone, like, if you're watching movie and you get that, that
71:00 feeling what happens, you get the bumps. Right. Right. So
71:06 a, but your little thin here make you look bigger and tougher.
71:12 right. But it's the same response these are remnant responses in mammals that
71:18 have retained because we still have skin hair on our skin. It's just
71:24 and others. Now, if you look into the drain of your,
71:34 , at home and you see a bunch of hair and you're like,
71:37 out like my hair is falling Uh It's always falling out. Your
71:40 actually has a pattern of growth and and then replacement. Ok. So
71:47 you see hair in the drain, panic unless it's like excessive. Like
71:51 you like do this and hair falls , that might be some sort of
71:58 . What this is just trying to you here are the three stages.
72:01 we have an anogenic phase. We a cato GIC phase and a telegenic
72:05 . So anogenic is a growth Cata GIC is a, is a
72:10 of a resting phase or it's not resting phase, but it's a phase
72:12 we're kind of like, all we've done what we need to
72:15 So it's kind of an active phase holding things in place. But then
72:20 a while it's like, ok, get rid of it. And so
72:22 would be the telegenic phase where the gets released and then you rinse and
72:26 the cycle over and over again. at any given time, your hair
72:31 is going to be one of these phases. All right. Uh This
72:35 here is the club hair. This the hair follicle that has become
72:39 And so there is your club hair falls out and then you replace it
72:43 you shave. What are you You're cutting it here at the
72:48 And so you still have an active that comes out and it's still that
72:51 , really long, scary looking I'm gonna finish with these last two
72:59 and then we're gonna just call it and we'll deal with nails and glands
73:02 . All right. But when it to hair, there are three different
73:05 of hair. All right, when are in the womb developing, all
73:09 , you have hair on the surface your skin that's being formed. It's
73:13 la Sorry Leo hair. It's very thin, it's very soft.
73:19 when a baby is first born, , they're just like covered in
73:22 It's like a, it's almost like matty fur, but it's very,
73:26 thin and very, very light. then it slowly gets replaced by this
73:30 that's called vela hair. So if think about a baby, a baby
73:34 covered in vela hair. All Now, you all have Vella hair
73:39 you as well right now. All . So like if you look on
73:42 belly, right, you'll see little hairs. That's Vella hair,
73:48 Some of you on your arms have hair. Many of you don't if
73:53 don't have this thin light hair, you might have a thicker hair.
73:57 actually the terminal hair that's a little differently. All right. So the
74:01 type is the terminal hair and this kind of shows you terminal hair.
74:06 kind of different types. We have hair on our heads. So that's
74:11 gets replaced by terminal. Uh and as we go through puberty, that's
74:14 you're going to start seeing the male , the female pattern of hair
74:18 which is primarily on our legs and arms. So you can see down
74:22 and up there, you can see here and up there. So that
74:25 terminal hair. So some of this might be Vella in nature, but
74:29 the most part that's terminal, it's this stuff over here that might be
74:32 Vella in nature. But then you uh ax or sorry pubic hair.
74:38 then over here a men, we more hair on our chest because I
74:42 we're lions or something. I don't , it's just, it's, it's
74:45 sign of sexual maturity, right? that would be terminal hair. So
74:49 the hair that you start getting later , that's terminal hair. Finally,
74:55 in terms of, of of hair , they're not, it's not just
74:59 round structures. Actually, hair comes different shapes. And again, we
75:04 like ribbon hair. So that would like kinky. So this is more
75:08 a ribbon uh uh shape structure. when we say that, let's see
75:13 this works. So a ribbon is like this, right? And then
75:19 have a shaft that can be shaped kind of oval like and then you
75:24 have a shaft that's round. All . So this would be more of
75:27 kinky type hair. This would be wavy type of hair. This would
75:31 more of a straight hair. All . So how your hair is,
75:37 dependent upon the shape of the And the last thing I'd point out
75:40 is pigment. Uh There are melanocytes , remember we said there are different
75:46 of melanin that are being produced, melanin that are being give rise to
75:51 color of your hair. So I picked the cla alls and so you
75:55 see different clas there's many different colors hair. Um But I would just
76:00 out that if you have gray hair me, when I was a young
76:04 , I had blonde hair and then through puberty and then that was brown
76:08 and then now it's gray, which great. It's pouring gray. That's
76:16 going on. I got the salt pepper. So I'm losing my melon
76:19 production white, no melanin. So you have white hair, that's what's
76:26 . All right, when we come , we will start with nails and
76:30 finish up with glands and then move from there like I
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