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BIOL 2301 Human Anatomy & Physiology I - BIOL2301_lecture04_0608
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00:02 So I think I got everything covered . Um I'm, I'm just gonna
00:13 up front today is not gonna be most interesting day to y'all. I
00:15 , some of you might actually go , wow, this is really cool
00:18 for most of you, you're gonna like, yeah, can we
00:20 can we start talking about skin or ? Because um this is physiology
00:26 and it's really not the most interesting . This is when I told you
00:29 that professor tried to recruit me to work in their lab, you
00:34 this is the type of stuff she doing and it was like, please
00:37 me. All right. So I'm try really hard to make it
00:42 Um But I, I understand that not necessarily gonna be so, so
00:46 what I would encourage you to do you come across stuff like this,
00:50 know, where it's like I want avoid it because it's boring. That's
00:53 you have to lean into it really . And really what we're gonna be
00:56 about is we're gonna be working at membrane and we're gonna be asking some
01:00 about how do cells talk to other ? In other words, how do
01:06 move back and forth across the And then once we understand those
01:10 we're gonna ask questions, how do actually use that membrane as a form
01:14 communication between the inside of the cell the outside of the cell? And
01:18 because we have some time at the , we're going to really kind of
01:20 look at cell division and we're gonna at the process of mitosis. So
01:25 idea of how cells actually replicate. we're kind of summarizing or finishing
01:30 you know, the cell before we on to tissue, which should
01:33 Tomorrow's lecture is really just on And if you think about it,
01:37 I said, you know, one the things we wanna do is kind
01:38 take that step back and kind of , what are we trying to
01:41 notice what we did. We started chemicals, we spent time here in
01:45 cells and now we'll be moving on the tissues tomorrow. So we're just
01:50 of moving up and then we can get into the real anatomy and start
01:54 about anatomy, the whole purpose while in this class. All right.
01:58 our starting point is gonna be it's gonna be about movement. And
02:02 when you first came to class, you were the first person in the
02:07 , you're like, oh, I sit anywhere and you found your spot
02:09 you did notice you sit in the spots for the most part,
02:13 Because, you know, we find spot and it's, now this is
02:16 spot. And if someone sits in spot, you walk in the room
02:18 you're like, you in my you may not say it out
02:23 But you're thinking, and you're and I'll just sit over here.
02:27 when you're one of the last people the room, you look around the
02:31 and you're like, where can I ? Where I don't have to sit
02:34 to somebody, right? You distribute in such a way and if you
02:38 around the room, you can see right. You're all at least two
02:42 away from each other, right? that's comfortable. Right? There's a
02:47 around me and I have movement and free and no one's gonna be breathing
02:51 my neck and it's really uncomfortable when sits right, exactly next to you
02:54 you don't know. And then they to you and go hi, how
02:57 doing? You're my best friend. , let's talk, right? Molecules
03:00 the same way. All right, don't like being all crowded together.
03:05 want to have their elbow room, want to distribute themselves in such a
03:09 that there is an equal space around . All right. And this movement
03:15 these molecules is referred to as right? What they're gonna do is
03:19 gonna try to spread out into their so that there is an equal,
03:25 distance between each of them. And they accomplish that this is what is
03:30 to as equilibrium. All right. , the rate at which they're gonna
03:38 along this line from this crowded state like this distributed or equilibrium or e
03:44 state is gonna be dependent upon two . The concentration of those uh molecules
03:52 they start and the temperature that's being to the system at the time right
03:58 , the way you can think about is um when you have a whole
04:01 of things jammed up together, you , everything wants to get their elbow
04:05 . So they actually start bumping into other and they start distributing energy between
04:09 until the energy is equally distributed. that they're running into each other at
04:14 a similar rate, right? So of like a mosh pit. You
04:19 know what Mosh pits are, OK. I don't know if they
04:21 did that. We started it back the eighties, right? Slamming into
04:26 other, breaking each other's noses having . Right? Then once you get
04:32 elbows out, everyone can do what wanna do and you can kick and
04:36 all sorts of fun stuff and no getting hurt, right? Because everyone
04:42 equally distributed. That energy is what's that distribution because everything is slamming into
04:48 other. Until finally there's this equal going on. Now, if I
04:53 energy to the system, then what's happen is that idiot begins to start
04:58 around and starts moving around a lot and starts kicking things and so everything's
05:02 distribute a lot faster, right? about it like this, if you
05:08 put sugar in tea, right? you have an iced tea, if
05:12 put sugar in, what happens to sugar? Where does it go right
05:16 to the bottom? Right? So do you have to do to get
05:19 sugar to mix in? You either to stir it, which is adding
05:23 energy or if you actually have a tea, if you pour sugar into
05:29 , that sugar distributes very, very because it's absorbing the energy from the
05:34 in the system so that it begins mobilize and move around so much.
05:39 . So those two things are going have a major effect on distribution,
05:44 steepness of the gradient. Now, say steepness here because you can just
05:47 of it here. I got zero here. I have 100 over
05:50 Things are gonna move from an area high concentration to an area of low
05:54 , right? Until equilibrium is That's how you can kind of think
05:57 it. If I'm on a skateboard the top of a hill, I
06:00 move down the hill quickly. But I'm on a skateboard on flat
06:03 I don't move that quick. If on a slope, that's one
06:06 I don't move that fast. So steeper, the slope becomes the faster
06:11 move. That's an easy way to about this. So it's a
06:14 It's a difference in the two All right, the more energy you
06:20 . So again, remember think of energy, the faster things are going
06:24 go, of course, have to the button over here right now with
06:33 to movement diffusion. And if you at this previous picture and I now
06:37 go back notice there's nothing here. basically, it's a contained area,
06:41 there's no barriers or anything, So basically, I'm in a,
06:44 in a jar or I'm in a and I can uh the distribution is
06:48 equally along those lines. But we're about cells and we're talking about barriers
06:53 cells. So simple diffusion. The when you put simple in front of
06:57 really means the movement of any nonpolar . So something that is lipid
07:04 moving across a membrane, right? can do so because it doesn't require
07:10 . Remember if it's lipid soluble, thing which is made up of a
07:14 bilayer can't prevent it from passing So things that can diffuse simply will
07:20 so without any sort of help doesn't a transport protein to do.
07:25 All right, it's not regulated, solely dependent upon the gradients,
07:30 And the temperature. So if you a high concentration of stuff over here
07:34 a low concentration of stuff over it's gonna move quickly if it's almost
07:38 . Well, depending on which way gradient goes. If there's more over
07:41 and less over there, but it's that steep, it will move.
07:43 the rate of diffusion is gonna be upon the steepness of that slope.
07:48 . But most substances in the body not lipid soluble. Most substances in
07:52 body are water soluble. So they pass this membrane. They need help
07:56 do so. And so this is we refer to as facilitated diffusion.
08:00 I want to move something from over to over there and it's not lipid
08:04 , it needs some sort of Now, these helpers, the things
08:11 facilitate, hence the name facilitated diffusion different types of of uh uh molecules
08:19 are, you know, they're integrated , their trans membrane proteins is another
08:24 to think about it. The first that we're gonna be looking at here
08:28 a channel. All right. So mediated diffusion is a form of facilitated
08:33 . What you have here is you have a protein that creates a water
08:37 through which materials can pass. if you want to visualize this,
08:43 these doors not existing right here and door uh just being a pathway and
08:47 the other doors on the other side a pathway. So things can move
08:50 and out of the classroom based upon direction that material needs to go.
08:56 again, direction is always going to based on concentration grades. So there's
08:59 over here, there's less over So in this case, we're moving
09:02 this direction, if I flip this , which way would I be moving
09:07 direction? Ok. So just high low concentration is all we're going to
09:11 looking at, right? So that's type of movement, right? A
09:15 creates this water, pour, the type is a carrier media. And
09:19 there's different types of carriers that exist I'm gonna show you a picture a
09:22 bit later that you don't need to , but is to demonstrate how many
09:26 these different types are. Have you been to the airport or to a
09:29 where they have the rotating door, ? Carrier media transport is like that
09:34 of door, it's only open to side at any given time,
09:39 And so like you here you are your suitcase, right? You go
09:41 to that door, you're like, , I've got to make sure I'm
09:44 go in there and not get myself in and then the door comes around
09:46 you're like, ok, I'm in then you're, then you get to
09:50 other side and you jump to the side, right? That's carrier
09:52 So here what we have is you see I'm open, open to one
09:55 , I'm not open to the other . The molecule comes in, when
09:58 comes in, it binds and when binds, it causes a change in
10:02 shape of the carrier and the carrier up the other direction, so the
10:06 can come out the other side. , this is just trying to show
10:09 can do in opposite directions and so and so forth because there are different
10:12 of carriers. But it's a different of mechanism. It requires help.
10:19 molecule requires help to get across the and it does so differently than
10:24 right, it requires a binding. other type we're going to talk about
10:30 more detail a little bit later in class is active transport. So here
10:35 moving down our concentration gradient because here's concentration gradient to over here on the
10:39 showing you more or less right When we're talking about just general cha
10:45 carrier media transport, we're moving down concentration gradient. So there's more of
10:50 over here, there's a lot further . So this wants to move
10:52 So it's being driven in in its down as gradient but primary active
10:58 sometimes we're going to need to move in a direction opposite its gradient,
11:04 . In other words, there's more the other side and I don't naturally
11:08 to go that direction. So to so I have to exert energy.
11:13 ? Think about a ball on the that needs to go on the
11:16 Will it naturally go up onto the ? No. What do you have
11:19 do? You have to pick it and you have to put it on
11:22 shelf, you expended energy to move ball. Now, if you've taken
11:28 , you understood you had potential energy on the bottom, you applied energy
11:33 actually you had zero energy, you energy to the system and you gave
11:36 potential energy and you put the ball the shelf. Now it has potential
11:40 to move, right? Do you all that stuff for anyone here take
11:43 yet? One person, you remember the rest of you guys guess what
11:47 get to do. You, you that stuff, right? You're gonna
11:50 to take physics at some point. gonna be going, why do I
11:53 to do this? And it's because need to know how high to get
11:56 I V uh stick up so that stuff drips better. That's the entire
12:00 you take physics. That's not actually , but it makes you feel
12:04 right? So here, what I'm is I have a material that wants
12:09 go this direction or needs to go direction. It can't do so on
12:13 own because the concentration is greater on side. So I'm going to use
12:16 system that applies energy either directly, is primary or indirectly, which is
12:22 , which allows me to move this the opposite direction. Now we'll go
12:26 more detail about this and I'll show examples. But I wanted you to
12:29 that we don't always move in the down a gradient, sometimes we have
12:33 move the opposite way. So that's example of carrier mediated transport. Now
12:43 itself, the movement of materials across membrane aren't going to be dependent upon
12:47 factors. The guy who figured this was it was done in the 11th
12:50 the late 17 hundreds. And the that he did under the conditions that
12:55 did is phenomenal that he figured all stuff out, not gonna make you
13:00 look it up. But if you're , the guy's last name is Vick
13:03 you can go on the Wikipedia just look up fix law of diffusion.
13:05 it'll describe all the experiments that he . It's really, really crazy.
13:09 did this in the late 17 All right. And he figures stuff
13:13 . It's like first off, these some conditions. If you're looking at
13:15 molecule size matters, right? The the size, the the the harder
13:22 is for that molecule to move If you have tiny molecules, they
13:27 quick, easy way to remember Adults move, slow, kids move
13:32 . How do you know this? you're holding the hand of a kid
13:34 a crowd and they let go of hand, they're gonna disappear through the
13:37 and you're sitting there trying to catch with them. They move quickly between
13:41 legs and around their bodies. Big people like me. I have to
13:45 , excuse me, pardon me? me, I've got, excuse
13:47 excuse me. I've got to move people. It's harder. That's true
13:51 molecules as well. So the bigger molecule, the slower it moves,
13:55 slower it diffuses. All right, membrane thickness matters. All right.
14:00 here's thickness over here, right? thicker the membrane, the further you
14:04 to pass through something. So the you go. So it means you
14:08 to move quickly across something, make membrane thin, think about your
14:13 right? Your lungs are very, , very thin between the air in
14:18 alveoli and the space to get to blood in the capillaries. It's about
14:23 microns. That's very, very If am you can think of a
14:28 . A micron is 1/1000 of a . So half of one of those
14:33 the distance between the space inside the where the air is and where the
14:38 is pneumonia is a condition where you up water inside the lungs. Thus
14:46 the thickness between the point where the are or where the blood is and
14:51 point where the air is, it longer for the air to fuse.
14:54 why pneumonia is so hard on the because it's harder to breathe harder to
15:00 the air in is really what it not breathing. It's the air.
15:03 right. Thickness matters of the So the thinner the membrane, the
15:07 I go, the thicker the the slower I go surface area
15:11 All right. How many people do think we can fit through that door
15:14 the same time? What do you ? Should we get you all stand
15:19 and kind of go shoulder to see how many we could fit
15:21 right? Three, you say I, I like your attitude,
15:27 ? 3 to 5. All If we want to increase the rate
15:30 diffusion, the rate at which people move in or move out, we
15:33 have to widen the door or add another one, right? What we've
15:39 is we've increased the surface area through materials can diffuse. So the surface
15:46 matters. All right, increasing surface increases the rate of diffusion magnitude concentration
15:53 we've already talked about. This is represented by delta P. All
15:57 And so really what this says is more stuff you have, the faster
16:00 gonna go. So you can imagine terms of the rate of diffusion,
16:04 at all the material in here, wants to go that way to reach
16:07 very, very quickly. So you imagine, yes, it's that grating
16:11 increased on this side. If I the number of things here, the
16:15 at which they're going to move, not running into each other so
16:17 So they already got a little bit elbow room. So they don't have
16:20 move as fast temperature. We've already , the more energy I add to
16:24 system, more things bump into each , the faster the rate of
16:28 And lastly is viscosity, viscosity refers the thickness of the solution. In
16:33 words, uh typically, what we're be talking about when we're talking about
16:37 , we're talking about water with stuff them, right? That's what the
16:40 is, water plus stuff. So you increase the stuff that's not
16:45 that's more things to bump into, . So um viscosity is kind of
16:51 thickness, it's kind of the And so if something has to
16:55 it takes longer to move through something going to diffuse slower. So that
16:59 make sense. So all of these have an impact on the rate of
17:03 . And and so when we're looking materials, these are things that are
17:06 considered. But for the most what we're going to be focusing on
17:09 we do this is we're looking at concentration gradient. Now you'll see the
17:14 sometimes used flux flux simply refers to rate of diffusion across the membrane.
17:19 here we have a lot of things , we have nothing. So the
17:21 of diffusion is going to be dependent the concentration gradient, the surface
17:24 the thickness of the membrane yada yada . But you can see here the
17:28 at which it's going to travel, the flux. All right, the
17:32 flux is the difference between two solutions two solutes moving in opposite directions of
17:38 other. All right. So here have this red ball right, it's
17:44 this red molecule and it wants to in this direction because there's zero over
17:48 . The blue one is only affected the presence of the other blue
17:52 Are there any blue blue molecules over ? No. So it's gonna move
17:56 way, the difference between the rate in that direction and the rate in
17:59 direction. That's the net diffusion. . Equilibrium occurs when movement in both
18:10 stops. Like up here, we look at this right. So we
18:16 diffusion is going in this direction. now have more red balls on this
18:22 . Those red balls aren't just gonna , well, I made it over
18:24 the side. I'm happy there are moving in this direction. There are
18:29 balls moving in that direction. The that are moving in this direction are
18:34 frequent than the ones that are going that direction. So the difference in
18:38 movement in both directions is also net . All right over here, we
18:45 have an equal number of balls on sides. I think there's five on
18:47 side. Did I count it OK. Right. So here the
18:51 at which those balls are moving or to the rate at which those balls
18:54 moving, some are going this some are sticking around, same
18:58 some are moving this way, some sticking around. So that equilibrium notice
19:02 is still moving, there's just no in the rate of movement. That's
19:06 it's called equilibrium. And then we this weird thing called bulk flow.
19:10 I want you to breathe in and out. What did you breathe in
19:15 out? Oh, you're far too air. It's air. All
19:24 What is air? Now? We technical what's air oxygen? And,
19:34 there's a big one in there that all forget about nitrogen, 79%
19:40 20% oxygen, less than 1% carbon . And there's a whole bunch of
19:48 stuff that we just kind of ignore we're basically already almost at 100%.
19:53 there's water, there's dust, there's microscopic elements, there are molecules in
19:58 air. If you're in a smoky , there's stuff like that in the
20:03 and when you breathe that in, breathing it all in at the same
20:08 , right? What of all those does your body want? The
20:16 Right? Bulk flow refers to the of all the things, right?
20:22 don't sit there and go or the don't go. No, no,
20:26 . All I want is the So nitrogen carbon dioxide, you guys
20:29 stay out there. I'm just pulling . Just the oxygen bulk flow is
20:34 movement of all those substances in and . When you exhale, you're trying
20:39 get rid of the carbon dioxide, you are also getting rid of the
20:46 and oxygen. You didn't, uh know, pull into your body and
20:52 getting rid of all that as So that's also bulk flow. All
20:58 , this isn't the only place where gonna see bulk flow. But bulk
21:01 is just simply the movement of the solution. Air is the solution.
21:07 this particular case, solutions aren't always be liquids. All right, it's
21:12 mixture of materials. All right, gonna see bulk flow uh primarily in
21:18 MP two, but we may bring up again when you're talking about
21:22 Blood is a mixture of water plus . And there are materials that we're
21:27 in and moving out of these And it's not for like,
21:31 well, all I want is the . I don't want to worry about
21:34 waste that's in the blood, but waste travels along with the nutrients.
21:39 just is that's bulk flow. we're stopping on this slide for a
21:48 because I'm just making sure we're on same page in terms of us understanding
21:53 . All right. Because we said that the membrane, when we talked
21:57 the membrane is selectively permeable. What that mean? All right.
22:01 permeable simply means a substance is allowed pass through something else or through a
22:07 . So for example, the membrane permeable to gasses. So oxygen carbon
22:13 , these are lipid soluble and they're soluble. So they just pass back
22:18 forth and go wherever they want So when we see like a
22:22 we're, we're that we're basically saying membrane is permeable to this. When
22:25 say that a membrane is impermeable. we're saying is that it is disallowing
22:30 movement of substances. So like for , glucose, which is something your
22:35 desperately wants all the time. That's , right? That can't pass through
22:40 membrane. It's now dependent upon one those carriers to move things in.
22:45 the membrane is impermeable to sub some and it's permeable to other substances.
22:53 what it allows to pass through is be uh why we refer to these
22:59 as being selectively permeable, right? decides what can come in and go
23:05 and how does it decide? it puts those proteins into its surface
23:11 that it says, oh, I want glucose. So I can regulate
23:16 glucose comes in and I can regulate other substances can come in like all
23:22 fun little ions that we're gonna be with them a little bit later.
23:26 selective permeability. All right. It's because it's half the time this or
23:32 . It's because it is impermeable to things. But it makes the membrane
23:38 by introducing those proteins. All That kinda make sense. Right.
23:46 dreaded term osmosis. If you're anything me, you've learned this thing like
23:57 dozen times and every time you learn , you get a different definition and
24:02 time you learn it, you I'll memorize it for the test and
24:04 flush it down because it doesn't make lot of sense. To me.
24:09 of it is because biologists and chemists osmosis differently. We use different
24:16 All right, even though we're talking the same thing and we mean the
24:20 same thing. It gets confusing because make it confusing. Truthfully, I
24:28 really learn this stuff, osmosis until was in grad school. I
24:32 What I'm telling you is I literally things into my brain and then just
24:36 it right out. So, what wanna do after I go through my
24:40 Poppins bag here is I want to to explain osmosis to you in such
24:44 way that you'll never forget it. it makes 100% sense. OK.
24:48 right. So you can see up , this is what the definition if
24:51 go to the books and stuff like is what they'll say. It says
24:54 is the movement of water. So the easy part we're talking about diffusion
24:59 water, right? That's the the definition. It is the diffusion of
25:04 . So if we know about diffusion is the movement of things from
25:07 concentrations to low concentrations, would you with me on that? Right.
25:11 if this is, if osmosis is the diffusion of water, that means
25:15 is moving from an area of high concentration to an area of low water
25:20 . All right, that's an easy to remember, right? But what
25:25 do is we throw this horrible term the middle of all this to confuse
25:29 . All right. And the term say is we use this uh this
25:34 little statement right here, water is down its own concentration to an area
25:39 high soud concentration. What the hell doesn't make any sense? Does
25:46 I've just throw in a whole different and I'm sitting here talking about
25:49 but I throw in this so stuff this is where the chemists start laughing
25:54 going. You'll never understand what we're . And I'm telling you it's easier
26:00 you visualize this. All right, usually see pictures like this. Let's
26:06 that for a second. All I'm gonna try very hard to go
26:08 a whiteboard here. Let's see if can do this uh white screen.
26:15 I draw my white screen? please forgive my artistic abilities here.
26:24 have a system that I'm dividing into one side, I'm going to put
26:33 solution, right? A solution is plus stuff that is 80% water,
26:40 solute. OK? So if I , I'm just gonna put water over
26:45 on the side and I'm gonna put over here. So if this is
26:51 and that's 20% you can see that whole solution together is how much
26:59 All right, on the other I'm gonna create an environment that is
27:04 from the first side. So we see the osmosis. I'm gonna make
27:07 simple. It's gonna be 50 OK. So based on what you
27:17 about diffusion, what would the solute to do? Does it want to
27:21 from? I'm going to make the so that you can see side A
27:24 side B? So if I am at the solute, that's the part
27:28 the bottom. Which direction does the want to move A to B or
27:32 to A or stay the same B A? All right. That's a
27:35 one, right? And which direction on what you know about diffusion,
27:39 direction does water want to go A B B to A, stay the
27:42 A to B. So it's pretty , you know, the rule,
27:46 ? The rule is basic and What we're doing here is when we
27:51 about osmosis, we wanna focus solely that All right, we need to
27:57 the water concentrations. We're going from area of high water concentration to an
28:01 of low water concentration. You can those numbers. But notice in the
28:06 I gave you, it said we're from an area of high water concentration
28:09 an area of high solute concentration. , how confusing. Well, we
28:14 have solute here but we ignored it the first sentence and we have the
28:18 concentration over here, but we ignored in the second half of the
28:21 So all you need to do is remember when you talk about high
28:26 then you're talking about low water, ? That's the, that's the confusing
28:32 . And in the middle of an , your brain is going short
28:35 you're like, and you're gonna kind freak out. All right.
28:40 oftentimes when we're talking about osmosis, talking about this membrane here being impermeable
28:48 the solute but permeable to the All right. So if that's the
28:54 , if this is impermeable to solute can't move from B to A
29:00 ? Water can move from A to and it will continue to do so
29:06 equilibrium is met. Well, what equilibrium mean? Well, that means
29:10 concentrations of solute on either side is the same, right. Notice here
29:18 switched the definition again, we moved from water and we're now talking about
29:22 solute. In other words, what saying is when we balance both sides
29:25 that they look the same, that's things are going to stop. But
29:30 if they can't reach that? then it can't be reached.
29:35 I'm gonna use an example that I've every year and people seem to understand
29:39 is this. Can I delete this right now? Can I move back
29:42 the original one? All right. you'll usually see, um un wipe
29:51 screen and you'll see something like All right. So see it says
29:57 . That means it's gonna be uh is, is what's gonna be allowed
30:01 move. But solute does not. you count up the number of red
30:05 , these are supposed to represent solute and the blue stuff is supposed to
30:10 the water. And what this is saying is look, you can see
30:14 there is a disequilibrium. So water to move to make both of these
30:18 look the same. So over what will happen is, is because
30:22 is semi permeable to water. Water going to diffuse or osmos to the
30:27 until these two sides are roughly the . In other words, the concentration
30:33 water and the solute inside it is on both sides. All right,
30:39 not too hard, but we have problem. All right, it may
30:44 to the point where there's so much on this side that it doesn't allow
30:47 to keep moving now, I'm gonna , help you visualize this for a
30:51 . You guys know what a smart is. Yeah, the little tiny
30:56 , right? How many people do think can fit in a smart
31:01 Two? You're not trying? I ask that, did I? Which
31:08 it much more fun, right. many people do you think you can
31:11 into a smart car? You're all down to the club? Your friend
31:17 a smart car. They've offered to and no one wants to pay for
31:20 . How many people can you get that smart car? Five? All
31:22 . We're a little, getting a bit better. Come on, we
31:25 , we can get more in Right? I mean, you can
31:27 like people on top of people, can lie them down like a little
31:32 , right? So you can imagine sitting there, you're stuffing people
31:35 you got your driver, you can someone into the driver's lap,
31:38 You got your passengers, someone sitting that kind of middle area, put
31:42 people there. So we're up to and then we could probably put another
31:45 , another person and you're gonna get the point where, you know,
31:49 you're putting people in, they're just in, moving into that car,
31:51 it's a clown car and then finally going to get that one person,
31:55 gonna push them in the passenger side someone's gonna pop out the driver
32:00 Right. Well, what we're describing is kind of what happens in
32:07 All right, we're talking about osmotic . All right. So I,
32:13 know I have something else here, I'm gonna, I'm just gonna kind
32:15 jump ahead real quick. Hydrostatic pressure osmotic pressure are very similar, but
32:22 have different function. Hydrostatic pressure is the pressure exerted by water on the
32:27 of a container. So container like , it has fluid on the
32:31 The fluid is not on the Why? Because the inward pressure of
32:35 container is opposing the outward pressure of fluid inside, right? Think of
32:41 vessel, you know that one, one mine there's fluid inside those
32:45 the water wants to go out on table and wants to spread itself out
32:48 molecule thin. But the container is saying no. So there's an external
32:53 trying to dry the material out, an internal pressure trying to push or
32:57 the material in. So when you're about that smart car and those people
33:01 the car that is like a hydrostatic , the pressure is like the people
33:06 to get out of the car, ? As you're pushing people in,
33:11 are increasing the hydrostatic pressure, The more people you put in the
33:17 the chance someone's gonna pop out, ? When you put that last person
33:24 , right? When that next molecule comes in and it meets that hydrostatic
33:32 that says uh we can't take And so it pops out another molecule
33:36 water. That's the point where you osmotic pressure, osmotic pressure is the
33:43 pressure, right? So the hydrostatic necessary to stop osmosis. All
33:51 So let's say I had 100% water here and nothing but solute over
33:59 water is gonna keep flowing this direction it reaches equilibrium. Except if the
34:06 over here gets too great, it stop osmosis so that not all the
34:10 can go that direction. All So hydrostatic pressure is the pressure of
34:15 fluid inside a container. Osmotic pressure the pressure inside that container preventing osmosis
34:21 happening. Does that kind of make ? One head is nodding. I
34:26 fail today. No. Yes. . So, so you can imagine
34:37 part right here has a uh has pressure, right? That side has
34:42 pressure because it's just the presence of water. It's you and your
34:46 your friends sitting in a car, know, and being stuck inside that
34:53 . You don't wanna be in the , where do you wanna be?
34:57 wanna be at the club, You wanna get out, I
35:00 you want your elbow room, So that's the pressure, that's your
35:04 pressure, right? Remember because we're , we all haven't won our elbow
35:08 , right? So osmotic pressure is a hydrostatic pressure. That's the first
35:12 . It is a hydrostatic pressure. what kind of hydrostatic pressure? It
35:16 . It's the excluding pressure. It's pressure of that fluid that says uh
35:20 , we don't want any more of in here, even though by
35:25 osmosis says you should come here. not letting you in because there's too
35:29 of us already. That kind of more sense. We have 100 and
35:37 seats in this room. I think can't even remember. It's like 100
35:40 330. All right, there's a that says we cannot put more people
35:45 this room. That's what like os pressure is, we can keep putting
35:50 pressure, putting in more people, in more people once we fill up
35:53 the seats, mm mm can't allow else in here. That's osmotic
36:00 So when you reach osmotic pressure, gonna resist further water entry so that
36:07 stops. Alright. Mhm Right. again, right now you guys are
36:20 , very comfortable, right? I open the doors and we can allow
36:23 students to come into the space because know there's infinitely more students outside the
36:28 than there is inside the room, ? So there's a natural diffusion in
36:32 direction, right? So students would to come in. I don't know
36:37 , but we're just just as the what they want to flow in,
36:41 there's gonna be a point where they come into this space anymore.
36:45 the rate at which they're entering in equal to the rate at which they're
36:49 because there's no space for them. every time someone sits down, that
36:54 someone has to get up out of seat and we pop them back outside
36:57 that's equilibrium. All right. really osmotic pressure is when equilibrium is
37:03 in terms of osmosis. Now have made this more complicated for you?
37:09 I make it easier? Yes, made it more complicated. Go
37:14 Yeah. The way like even if not an equilibrium, correct.
37:23 So what it is, it's it's an equilibrium of pressure, it's
37:26 an equilibrium of osmosis itself, So like I said, there's gonna
37:31 a point where it's like we still have equilibrium, we haven't met
37:36 But the laws of physics are preventing from, from reaching equilibrium. We
37:43 be able to, but the pressures , have become too great. You
37:47 , you can't push past that. , I'm gonna go back real quick
37:54 . Just to this part. water is one of these weird substances
37:59 we usually spend a lot of time about water and biology because that's where
38:03 the environment in which all chemical reactions place. So it's kind of important
38:06 kind of understand why water, it's our bodies are full of it.
38:11 , water I say is weird because is a polar molecule. Do you
38:14 remember learning about water being polar and the electrons and it sits off on
38:18 sides and stuff like that. And ranges itself in unique ways to create
38:22 steam and all sorts of fun So it's a polar molecule and we
38:26 the plasma membrane disallows the movement of molecules, right? That was one
38:32 the one of the conditions it's lipid , it prevents charged and polar things
38:38 passing through. But water can pass a plasma membrane. Why? Because
38:44 tiny. So it goes to that first rule. If you're small
38:49 you can diffuse so it can do . But the other thing that we
38:53 is we have a bunch of these channels are called aquaporin. And
38:58 even tells you in the name, is it? It's a water
39:00 water pour. So it allows you to move water back and forth across
39:06 membrane following the osmotic rules. So moves in and water moves out.
39:13 right now for your purposes. And the future, you're gonna deal primarily
39:20 this issue, tonicity. You don't about osmosis so much, but tenacity
39:25 depended upon osmosis. All right, you have someone who's dehydrated right in
39:32 , in a hospital setting, you want to give them 100% water.
39:37 ? Well, because what's gonna happen you put too much water into the
39:41 , the cells are gonna see that , the water is gonna go oh
39:45 , you're dehydrated. There's less water your cells right now. So it
39:48 rushing into the cells and causes the to lie sort of pop, which
39:52 general terms is kind of a bad for you when your blood cells start
39:55 like that. Right? So, what you're gonna be doing in your
40:01 is like, oh, we have patient who's dehydrated or a person who's
40:04 dehydrated, we're gonna give them but we're gonna give them water with
40:08 in it. So that the water much, much more slowly and it
40:13 cause the cells to burst. So is tonicity, it's tonicity is the
40:18 a solution to cut a cell again lose water. All right. And
40:22 again, it's by osmosis. The that you should know are these terms
40:27 here. And it's again, the is hypo, iso and hyper,
40:30 is less iso is same. Hyper more. The thing that's weird about
40:36 term is that it doesn't refer to water refers to the solute in the
40:42 . That's what the tonic portion All right. So this is less
40:48 , same solute, more solute. this is why I say you gotta
40:55 about those words carefully because if you more solute, what does that mean
40:59 water? You have less water. you have less solute, that means
41:06 have more water. And so if trying to remember which direction are things
41:14 , this is in reference to the that you're putting into the solution.
41:20 a hypotonic solution has less solute than cells and that, that are being
41:26 into it, which means it has water. So water flows from the
41:33 solution into the cells and that causes cells to swell up and if you
41:41 too much cause them to burst. right, if you have an isotonic
41:47 , anyone here ever use Visine or clear or any other stuff to drip
41:51 your eyes. If you go and the side of it, it says
41:53 isotonic solution. Does it have the same stuff that's found in tears?
41:58 , but it has the same number solutes. Notice when you see these
42:02 , it doesn't say the same number uh same types of things. It's
42:06 same number of things and you put drip that stuff in your eyes and
42:10 moistens your eyes. It's like putting tears and making your eyes feel better
42:15 the same number of solutes. So no movement of water in or out
42:19 the cells in a hypertonic solution. means you have more solute outside the
42:24 than you have inside the cell that's to draw water out of the cell
42:28 try to create equilibrium. So the actually shrink. All right. And
42:32 what this is trying to show you . All right. So if you
42:40 what osmosis is and you understand where terms come from, it will help
42:45 understand the behavior of a solution and on its tenacity, does that help
42:55 little bit or have I just made a whole lot worse? I
43:04 I got a double thumbs up, take the double thumbs up. How
43:08 I got thumbs up in the I like that. Ok. That
43:11 three thumbs up. Each of you 200 students. So that's like 600
43:15 you. I'm just making stuff All right. And remember you're always
43:25 to stop me and ask a I don't presume that if you didn't
43:29 it the first time that you just to figure it out on your own
43:33 . All right. That's not the of education, you're not. And
43:38 you're gonna experience things that are more than this. But I know osmosis
43:42 in and of itself as a confusing , you know. So don't ever
43:46 afraid to just say, look, don't get it because you're not the
43:49 one. And I told you I get this and keep in mind how
43:54 times did I see osmosis over the of my undergraduate career? Probably every
43:58 . Right. Well, I was poly science major. So not every
44:01 but all the science classes I Right. And I was like grad
44:06 is fine, like, oh now makes sense. It's all right.
44:09 , it's OK. So again, going to be focused here in the
44:15 . And what I want to do I want to just kind of deal
44:17 how are cells talking to each How do they use these structures to
44:22 communicate and regulate the materials that are back and forth? So these
44:28 these carriers, they are trans membrane . As we describe typically, whether
44:33 a channel or I mean, when a channel, you actually exist in
44:37 different states, you can be an channel or you can be a closed
44:41 . Some channels we look at, just refer to them as always being
44:45 or you just may say it's, just an open channel without considering that
44:49 is a possibility for a closed These doors are like channels. I'm
44:59 , raccoons, dogs, nothing can in right, open the door.
45:09 of these used to stay open, open it. Now things can move
45:12 and forth. All right, we already that channels are there to create
45:17 water filled uh channel or cavity or some materials can pass through.
45:23 there is specificity to this. All . So while we look at these
45:28 and say, well, anything can through when you're dealing with a
45:32 they aren't just like a, a , they're actually a lot of uh
45:37 they're proteins. So they have amino with those side chains, those side
45:40 have positive negative charges. They have , they have uh uh hydrolic,
45:47 guess they, they, they like that, you know, so,
45:50 they actually attract specific things and repel things. And so they create this
45:56 to them. We're gonna learn a bit about uh potassium and sodium
46:01 And if you go and look at um make sure it's not up
46:04 Uh If you go look at the the uh what's it called chemistry?
46:12 chart, the periodic table got, to be faster than me. I'm
46:17 and I got more trivia in my that gets in the way of that
46:20 . I think that, all but the periodic table go look sodium
46:24 a smaller molecule than potassium, but in the same column. So they
46:27 the same charge one valence electron, ? So you'd think OK,
46:31 if I have a potassium channel, elements are bigger or ions are
46:36 So surely sodium can just go through same channel. The answer is
46:40 because of that size, they have attractions uh to the uh the inner
46:47 of these channels. So a potassium excludes sodium, just like sodium would
46:52 potassium. So the channels have these of specificities to them. All right
46:58 carry proteins. Like I said, kind of serve as a chaperone,
47:01 have a fixed number of solutes that can carry. There are binding sites
47:06 there. Just like when we looked the enzyme being able to bind to
47:09 substrate, that's what they do. have this active site, the molecule
47:13 to it. That is what causes change in shape. And it can't
47:16 like a million things. It will carry one or two or three items
47:20 a time. So it, it limits the rate at which materials can
47:26 across the membrane. When we look these channels, remember we said they
47:32 exist in an open closed state. we're referring to is a gate.
47:36 what they call them. It could , I don't know why they didn't
47:39 doors or something else. But basically you have is you have a
47:42 this is like a gate. And right now our channel is closed.
47:47 gonna open this? Well, in the case of these doors,
47:51 mechanically gated. I have to come and I have to manipulate the door
47:55 open it up. But you go a grocery store and you step on
47:59 pad, right? And I guess also mechanically, but just pretend for
48:04 it's electrically gated, right? It up because you create a pressure that
48:08 on electricity to open the gate, . So there are different modalities that
48:14 up these types of channels depending upon type of channel, it is.
48:18 the most common type are here listed the side, voltage gated channels are
48:23 to open up to changes in membrane . Now, that's a word you
48:28 seen yet. All right membrane we're not going to get to that
48:33 I think the next unit. But this means, it's actually the build
48:36 of ions on either side of the , the potential refers to the difference
48:41 charge from one side to the that's the potential energy and it refers
48:47 that build up itself. So when change the concentration of ions on either
48:52 , the electrical charge around that uh changes. And so that's going to
48:56 the channel to open and close, ? So that's voltage gated ligand gated
49:01 is a fancy word for saying it a key ligands are things that bind
49:05 molecules, right. So ligand is chemical that binds to the protein.
49:10 so what we have here is a that goes in and unlocks the door
49:15 the channel opens up right now, gated channels can have the key that
49:22 on the outside or it can be key that appears on the inside either
49:27 mechanically g or mechanosensory. That's what described something comes along and manipulates usually
49:33 you're doing is you're manipulating the surrounding . So you might be manipulating the
49:39 , right. And when you manipulate membrane, the membrane protein in there
49:43 gonna be and bent as well. that's gonna be what causes the channel
49:46 open up. It is an easy to remember. Right. Have you
49:50 pinched yourself or got stepped on attack something poked you? And it
49:55 right? That physical manipulation of the activated a mechanoreceptor so that you could
50:04 the pain is basically warning you something you. You know, the mechanical
50:10 that you're receiving is letting you stop doing that. And then the
50:17 type that's not demonstrated here is thermally . And here this is just a
50:22 in the temperature causes a change in shape of the molecule which causes it
50:25 open or close, right. So to the mechanical gated. Now,
50:32 promise we were going to come back these two things, primary and secondary
50:36 transport. So here's primary active transport here, we're dealing with the
50:44 And what that carrier is doing is it changes shape in the presence of
50:50 T P A T P being the carrying molecule in the body. This
50:55 here is the example that we use every single solitary class. It's the
51:00 potassium A T P A pump. right, when you see primary active
51:06 , typically, what you're going to is something that is moving a molecule
51:12 its gradient. It's acting like a , it's pumping from an area of
51:16 low concentration to an area of high , right? If you have water
51:21 the boat, you have to pump water out of the boat,
51:26 So you're pumping water from a small to an area of large, you're
51:31 against the direction it wants to So you need to use energy.
51:34 so that's what happens here in this example. All right, this particular
51:40 , what happens is, is you to pump sodium out of the cell
51:45 you want to bring potassium into the , you want to create this odd
51:52 because what you're doing is you're creating energy that you can use at a
51:57 date. All right. So remember couple of days ago, I think
52:01 was where we talked about there being concentrations of solute inside and outside the
52:06 . And I said, remember sodium potassium, do you remember me saying
52:09 you probably didn't re you probably haven't it yet. But I said this
52:13 something that kind of is important. reason you have those different concentrations is
52:18 of this without this pump, you imagine sodium on the inside and the
52:23 of the cell would be about the sodium potassium on the inside and outside
52:27 be about the same because they would a point of equilibrium because of
52:31 But what this pump does, it no, no, no, I
52:34 want that. I want lots of outside. I want very, I
52:37 very little sodium inside. I want of potassium on the inside, very
52:40 potassium on the outside. So what gonna do is I'm going to be
52:45 to the inside and be attractive to . And so when I get three
52:50 to bind on the inside of this pump A T P can come
52:56 I can break A T P release which is going to change the shape
52:59 the cell so that the, the that I picked up will then be
53:04 to the outside. What happens is the binding site is no longer
53:10 to sodium and it has no nothing do but leave. It has no
53:14 because it's only open now in that . So they can't just hang out
53:18 say, well, I'm just gonna out here. I've gotta leave.
53:20 they're pushing things to the outside where doesn't want to go simultaneously. When
53:27 release those sodiums, I've created binding now for potassium. So potassium binds
53:34 when those two potassium binds, that's signal to say, hey, flip
53:38 around the other direction. So it back the other direction. Potassium no
53:42 is attracted. So it gets So at the cost of one A
53:46 P, I'm moving sodium out and moving potassium in and I'm creating these
53:52 . So the outside of the cell looking like this relative to the inside
53:56 sodium and the inside of the cell like this potassium versus potassium.
54:06 No, no sodium moves out And the idea here is just because
54:10 not gonna ask you the mechanics. mean, this is, this is
54:13 diehard biology, right? But the here is I'm moving things where they
54:18 want to go. Why? Because gonna take advantage of that. I'm
54:23 use this for other purposes. I'm up energy. This is in essence
54:29 body behaving like a battery. Which is really cool if you think
54:35 it because all the electrical activity you're upon is dependent upon this really weird
54:41 gradient that you're creating. And we're go into more detail in a couple
54:46 lectures, but this is where it starts. And this is the example
54:51 primary active transport. Why is it active? I'm moving something at the
54:56 of energy directly applied to the Energy is being used to power this
55:03 ? You see the A T P , another example of this um that's
55:08 to understand even. So I show this because it's, it's what we're
55:11 to spend a lot of time But this is just an example.
55:14 easy, easy to understand. This a proton pump. All right,
55:19 is what's working in your stomach. is how we move protons around the
55:25 . All right. So again, is primary active transport. Here is
55:30 A T P, I'm breaking the and I'm using the energy to move
55:34 from inside the cell to outside the . Right. So that's kind of
55:40 easy one to see. I'm only one thing that's pretty straightforward. But
55:44 have calcium pumps, we have all of different types of pumps. In
55:48 , these pumps right here, when talking about the lysosomes, the lysosome
55:52 this really acidic environment. They have pumps pointing into that lysosome so that
55:59 can pump in tons and tons of to create a really, really acidic
56:04 . All right, that's an easy to visualize relative to the other
56:10 But the other one is where we're to spend more time. So if
56:13 kind of get lost, it's OK, this, I can see
56:16 using the energy directly to move that outside the cell. So far.
56:23 you with me, secondary active All right, secondary active transport,
56:31 can see has different names. You see coupled transport or co transport
56:36 All right, here you're still moving against the gradient that it's that it's
56:42 know that it has. But here not going to use energy directly.
56:47 right energy directly means I'm the molecule receive the A T P I break
56:51 A T P I use the A P I do the movement indirectly means
56:55 else is doing the A T And now because there's potential energy,
57:00 going to take advantage of the potential that was created by that first
57:04 So over here on this side, that sodium potassium A T P
57:09 right? Potassium is coming in, is coming out. I'm using energy
57:12 do that. So that means there's of sodium over here, there's
57:15 there's less sodium over there. So direction does sodium want to go if
57:19 have lots of sodium up here and little sodium here, where does it
57:22 to go down? It wants to into the cell, right? It's
57:27 for an opportunity. How do I back into the cell? That's where
57:30 my, that's where all the space . I'm stuck with all this other
57:33 around here and I have no comfortable , everyone wants to talk to
57:37 right? So what I'm gonna do I'm gonna look for a way to
57:43 back inside the cell. Secondary active takes advantage of that gradient,
57:50 So this is an example of this of secondary active transport. It's not
57:54 only one. It's, there's many them glucose is one of the sugars
58:00 body wants inside cells to power the of the cell. All right.
58:05 you don't find a lot of glucose floating around your body. It's inside
58:09 of your cells. So in terms the concentration, little glucose, lots
58:14 glucose. So where does glucose want go if it had a choice,
58:19 would it want to go? You to go out of the cell,
58:22 that doesn't do you any good? cells are saying uh uh you don't
58:26 to go out of the cell. want you inside the cell. So
58:28 glucose that's outside the cell is trying be pumped into cells. But glucose
58:34 all intents and purposes is energy, ? You've learned at some point you
58:38 a glucose molecule, you go through a billion different steps. You're gonna
58:41 a T P out of it, ? You guys remember learning that at
58:44 point, oxidative phosphorylation. That horrible . Do you remember that horrible
58:48 Right. So you go through you go through the crab cycle,
58:52 go to oxidative phosphorylation. I left the pyro over there. But you
58:56 through all those steps, you're gonna energy. Do you want to spend
58:59 to move energy? What do you that sound efficient to you?
59:05 it's like I don't want to invest to make money, just give me
59:08 money, right? Let me find way to make the money. So
59:12 we're really doing here is a way efficiently move energy without expending it.
59:18 , we're still spending energy, but can use that energy for all sorts
59:22 different things, right? And what done is we've created potential energy out
59:28 . Sodium wants to come in glucose want to come in, but it
59:33 to come in because the cell wants . And so what it does is
59:36 going to come in together using this , the potential energy of the sodium
59:42 the movement of glucose against its concentration into the cell. All right,
59:49 think I've lost some of you or just getting tired, but I'm gonna
59:52 you an example that I think works well. But I'm finding the more
59:56 give this because I've been teaching for years, the more I give this
60:01 , the less you guys understand it you are becoming a boring generation.
60:06 , man, I just offended every of you. When I was in
60:11 . I went to Two Lane University lanes in New Orleans if you didn't
60:14 . And we used to go out the time, literally every single solitary
60:19 , you could literally step off And there were four bars. I
60:23 actually go to a bar during the of the day before one of my
60:29 because it was so bad. It a medical ethics course and we made
60:34 fun. Me and this other guy meet before class, we would have
60:37 couple of drinks. We'd say Who Pro Who wants? We'd go into
60:41 , we would then debate. It the best ever. All right.
60:46 you kind of understand the behavior around lane it was not a party
60:52 but it was a party school, ? You worked your butt off,
60:56 know, but you also played There wasn't a bar around campus that
61:03 have a ladies night. And this where my story begins. All
61:07 ladies night, all these bars would covers. Ladies could get in free
61:11 drink, but they didn't want to for drinks. But if you went
61:15 with a girl, they would let in free as well. So really
61:20 idea was is we want to get money from the guys because they know
61:23 all the girls are, but the don't want to pay for their
61:26 So the best thing to do is get them coupled in together. So
61:30 you do is you go to one these bars and you'd hang out in
61:32 and a bunch of guys would be there a bunch of freshmen or sophomores
61:35 we didn't have girlfriends at the time a bunch of girls would show up
61:39 you'd kind of say, hey, , can I go in with
61:41 If I, if you help me get in, I will pay for
61:45 drink and they'd be like sure. then you'd go in and I didn't
61:49 to pay a cover charge and all had to do was buy a
61:52 The girl got her drink for free then we got to either hang out
61:55 we'd go and find someone else that wanted to go hang out with.
62:01 here I am, I want to in the bar, but I
62:05 don't want to pay the $10 cover . They can get in just
62:09 but they can't get in because they want to pay for the drink.
62:13 so do you see what we got is, hey, let's make a
62:16 . We got this passage way that we both go in at the same
62:20 , we can both get what we . That's an example of secondary active
62:27 transport. Does that kind of make ? Is it the dumbest example ever
62:34 ? Yeah. No. Yeah. . Now there are different types of
62:40 active transport. Um Typically you'll see some books, they'll just refer to
62:44 as cot transporters. But typically what talking about here are SIM porters and
62:48 porters and the prefix should tell you is same direction, anti is opposite
62:52 . So here we're moving two or substances in the same direction.
62:56 we're using two or more substances in directions. So again, you're using
63:00 concentration gradient which is potential energy to something in a direction that it doesn't
63:07 to go. In other words, against its concentration gradient, that's what
63:12 active transport is. Yes, Hm. Right. So, so
63:18 terms of potential energy, remember the example I gave you like you pick
63:22 a ball, you put it on shelf, it now has potential
63:24 The potential energy is that if it , it's releasing the energy,
63:30 So by moving it up and out the cell, we now have more
63:33 or less here. So it has to move back into the cell,
63:39 ? That's, that's, that's its , it wants to move down the
63:42 gradient. So the potential energy is because there is no equilibrium the two
63:54 correct. So here again, this the same thing. So I've got
63:58 of sodium here, very little sodium . So there's my potential energy.
64:03 glucose on the other hand is moving its concentration gradient. So I'm using
64:09 potential energy of the sodium gradient to the glucose against its gradient. The
64:16 things are working together to uh to the movement of the glucose because sodium
64:21 come in through this channel without glucose can't come through this channel.
64:26 this carrier carrier without sodium present, two things have to be there.
64:32 right. So what I want to is I want to show you this
64:34 I don't want you to panic, not memorize anything. On this
64:37 I've just described some really basic systems carriers and channels, voltage gated
64:44 thermal gated channel, mechanically gated I've talked about two different types of
64:48 . And once you learn those basic , right So this is all about
64:54 a pattern, something basic. You'll these things all over the place.
64:58 this is these next two slides are examples of this, right? So
65:03 your pump that sodium potassium pump. sodium, you know, pumps do
65:08 they use energy directly to move And so we saw that do we
65:12 any other pumps on? Here's here's a calcium hydrogen pump, here's
65:16 calcium pump. They all behave the same way, right? They use
65:23 T P to move one thing in direction or the other. We looked
65:26 the proton pump which I don't think on either of these two slides.
65:30 right, potassium channel, sodium channel channel. But this is a voltage
65:38 . This is not all right, is probably a li gated channel in
65:42 particular case. So, but a is a channel is a channel.
65:46 just have to figure out how you it. So once you see a
65:49 , you know how it behaves it or closes depending upon what type of
65:53 , voltage gated calcium channel, you the really horrible dude. There are
66:01 of sodium channels. I think the I heard it was like 250 different
66:07 of sodium channels in the human Well, why do we need so
66:14 ? Because there's different forms of regulation stuff along those lines. But they
66:21 . Here is a sodium solute we just looked at the sodium glucose
66:27 . So what we're doing here is , look, there are different types
66:31 sodium, whatever transporters you could be , it could be amino acids,
66:35 20 amino acids. So each of amino acids use some sort of mechanism
66:39 this. So you've learned a you can apply it. Now when
66:43 see it over and over again and we get over to the next
66:46 you'll see there are different types of right here. We got a cot
66:51 . There are two things are moving the same direction. What kind of
66:54 would this be SIM port or Antiport right here. This is a weird
66:58 . We got one going this two going that way and one coming
67:03 . Uh Well, this is antiport we have two things moving in opposite
67:07 . Here, we have an exchanger an anti port system. Here,
67:11 got a channel here. We got channel here. We got a code
67:14 that's import here. We got a porter here. We got a,
67:18 exchanger. So that's antiport. You I'm not even looking at what they're
67:22 . I'm just telling you, you know behavior based on those simple things
67:26 we've already learned. This is N C C, you know. So
67:32 , it's nomenclature and sodium K potassium C two chlorine. You know,
67:40 , you don't need to know this just showing you you've already learned stuff
67:44 you don't even know that you've So when you come across it,
67:47 next time you're gonna be like, , this is nothing different than I've
67:50 learned already. So we move things and forth across the membrane through channels
67:59 carriers, things can move through the if they're lipid soluble, but most
68:04 aren't lipid soluble and some things are big to be moved through a channel
68:08 a carrier. If I want to a piano through those doors, I
68:13 do it. Well, let's make bigger than a piano or make the
68:18 smaller. Right. These doors don't not particularly helpful because I could move
68:22 piano through there. Right. But things are really, really big and
68:26 already seen this, we use vesicles move things that are really big like
68:32 and the process of moving a protein material out of the cell. We're
68:36 , we're using a vesicle is referred as exo there's the out exit
68:42 exocytosis to move these things. We're to have those snares and those SNPs
68:49 all those other little things that we go into a lot of detail
68:52 But because we're moving things along tracks because they have specific docking places and
68:58 , there's going to be energy that's to move and manipulate these vesicles.
69:02 any sort of movement through a vesical is going to be energy dependent,
69:06 going to require energy of some But exocytosis is outward, but we
69:11 move things into cells. We use process of endocytosis. Now, endocytosis
69:16 kind of a generic term that just things move inward. And again,
69:20 we're going to do is we're going form a vesicle. So instead of
69:24 the vesicle and moving it to the , what we're going to do is
69:27 going to gather things up and then going to pinch off and create the
69:30 . And that vesicle then contains the that we're trying to move. And
69:34 different forms, the more we study , the more we realize that there's
69:38 unique methodologies that take place. The thing that we ever discovered was something
69:42 I showed you yesterday when we looked LYS, it's phagocytosis, right?
69:47 literally means eating cells. So it's eating, it's a process of engulfing
69:53 phagocytosis is specific to certain types of . And what they do is they
69:58 take their cytoplasm and their plasma membrane they reach out and they engulf the
70:04 that they're doing. So they create vesical by reaching out and, and
70:09 , right? So when we looked that picture of that bacteria, and
70:12 saw that faga site actually consuming, at how the picture looks like it's
70:16 going up and around that bacterium to the vesicle. All right. So
70:22 is a very unique methodology that's specific consuming these large pathogens. Pinocytosis was
70:31 second one discovered. It was oh look, you know, the
70:34 looks like it's pinching portions of the off. And so in other
70:38 it was kind of like this where membrane was flat and then it kind
70:41 invaginated and then it pinched off and was like, oh well, this
70:44 dainty and cute. So if this the reaching out is the eating,
70:48 must be the drinking. It's pino drinking, cytosis cell drinking. All
70:56 . And what we're doing here is actually just grabbing what happens to be
71:01 the cell, there's no specificity to . Whereas phagocytosis like I'm hunting you
71:06 and I'm, I'm consuming you. like, oh, well, whatever
71:08 grab, I grab and whatever happens be in that solution is I'll,
71:12 work with whatever I got. All . So it's very nonspecific. But
71:18 another type that has actually kind of been well described and it's like,
71:23 , sometimes I want something very specific I'm gonna use the same sort of
71:27 where I have this pinching off. basically, I'm gonna have receptors and
71:32 receptors get bound up and then they into a specific location. And once
71:37 get enough of them, then there these molecules that cause the pit to
71:42 of iag like this with the receptors the surface. And now I've caught
71:47 those receptors have bound up and I off and that would be that last
71:52 this is receptor mediated. So it's you the receptors are involved. And
71:56 there's some communication that's taking place. , when we do this, the
72:02 that we're forming down here, this has a special name. It's an
72:06 zone. If I'm going outward, do you think it's called Z?
72:13 again, you're starting to learn the . It's like, oh, it's
72:16 34 X dimethyl blah, blah, , blah, you know, it's
72:20 . It's, it goes in, in, if it goes out,
72:22 X O. All right. Zoom just like fancy word to make it
72:26 like you're smart, right? So use these different methodologies depending upon the
72:34 of the molecule. Now, cells talk to each other. This is
72:39 process of cell signaling. That's, the generic term. And there are
72:46 ways to, to determine how a is going to talk to each
72:50 So how close are you? How do you need the message? And
72:53 is your intended target? All So if I'm a cell that's next
72:58 another cell, I'm going to use specific methodology where I'm talking either directly
73:04 this or I'm actually, if I'm to them, I might send materials
73:07 and forth between the two cells via junctions. All right. So what
73:13 do is we kind of divide up signaling into two different categories. We
73:16 is membrane potential is involved. is it electrical in nature?
73:22 So am I using ions to move to create signals? But the majority
73:28 the signaling in the body is done chemical. And while we talk about
73:32 and muscles being electrical in nature, is true. They use a lot
73:36 electrical signals, but ultimately, those signals result in a chemical signal.
73:41 I'll distinguish that when we get right? So when we're talking about
73:45 signaling, what we're talking about is being released into the environment to communicate
73:50 cells that are both nearby and far . And we have different types of
73:53 for this type of signaling depending upon you're looking at. So, have
73:57 ever written yourself a note to remind about to do something? Right?
74:02 you actually are self communicating. This be autocrine signaling. Now, you're
74:08 on, why would a cell have tell itself what to do?
74:10 maybe you have a process that needs be regulated, right? So remember
74:13 we talked about negative feedback. This be an example of negative feedback.
74:16 releasing a signal that signal comes binds the receptor that slows down the
74:21 process. And so here you can that you have to have the right
74:24 any time you're doing any sort of signaling, you have to have the
74:27 receptor on the cell that's receiving the . And here what you're doing is
74:32 cells producing some sort of response, it's releasing the chemical to regulate that
74:38 . All right. So that would autocrine. Whenever you see auto,
74:41 think self, we have two words that are gonna be, you have
74:46 be very careful about, especially on exam when you're reading fast, you
74:49 have to slow down. When you these, we have this term paracrine
74:53 we have another term on the next . It's Jurin right. Paracrine signaling
74:58 when a cell is releasing factors to that are surrounding it and are
75:04 All right, that doesn't mean that directly connected to each other. They're
75:07 nearby cells. It'd be like me a note to you, right?
75:13 nearby, I'm handing it off to , but you're not actually touching
75:16 It's in the neighborhood. All So the molecule itself is going to
75:20 into the surrounding area, but it go too far away because that signal
75:25 be destroyed because uh unregulated signals are things. As we mentioned, the
75:31 has to have the right target So the pink cells up there don't
75:35 the right receptors. So they're not . Only the cells with the right
75:39 are going to respond. So typically think of this, but here is
75:43 example of a neuron. The neuron an electrical signal to cause the release
75:47 a chemical. This would be an of paracrine signaling as well. So
75:52 cell to which it's communicating has there's the chemical. All right.
75:59 paracrine Jurin, on the other which is very similar to paracrine is
76:05 there is direct contact between the right? You can do one or
76:10 things. So here we have a receptor uh relationship. So cell over
76:16 has the ligo, there's the When the two cells come together and
76:19 lion, the receptor touch each right? They're not, not,
76:23 a release into the environment. It's the two cells are touching each
76:26 You'll get a response in the cell the receptor. This is typically called
76:31 to cell recognition. And you use that are called cell adhesion molecules.
76:36 see them usually abbreviated as CAMS. other type is through gap junctions.
76:41 can also be considered a form of signaling. Um in some cases,
76:45 here you have the two cells, have gap junctions. What you're doing
76:49 you're moving very, very small chemicals the two cells. So whatever this
76:54 is doing, this cell is doing well because it's sending a signal through
76:59 gap junctions. I don't know why don't walk around with this endocrine signaling
77:10 sometimes called long distance signaling. Here have our cell releasing the chemical that
77:16 goes out into the blood travels around body. And then when it travels
77:21 the body, it will kind of out of the bloodstream and kind of
77:25 into the interstitium, the interstitial And when it comes across cells with
77:29 right reel receptors, the cells respond that don't have the right receptor,
77:33 do anything. All right, this the type of signaling when you think
77:37 cell signaling is probably what you think . All right, this is what
77:40 do. So this would be an cell. It's releasing a hormone out
77:44 the blood, it travels some point the body and this is the target
77:49 some distance away. All right, vary in size and structure and we'll
77:55 to it in a MP two for most part. Now, both the
77:59 system and the endocrine system use this of signaling. Now, what
78:03 What are we talking about when these are arriving? All right.
78:07 there's different types of signals that So these hormones, these signaling molecules
78:12 do one of two things. You work through a receptor through a process
78:16 metabotropic uh signaling. All right, tells you meta is from metabolism,
78:25 ? Tropic just tells you to start to activate. All right. So
78:30 what we're gonna do is we're gonna through three steps first, a signaling
78:34 finds its receptor so far. So . That's pretty simple, right?
78:38 receptor already exists and inside the you already have chemicals that are part
78:44 a pathway that just need to be . Did you guys, when your
78:47 ever play the game mouse trap, you didn't play the game mouse
78:50 maybe you own the game mouse trap you just built the mouse trap to
78:52 what would happen. It's like a Goldberg machine. You know, the
78:57 machine A turns on B which turns C which turns on D which turns
79:00 E which turns on F which makes cool happen, right? So that's
79:05 of what's going on here is I'm activating the system. So when
79:09 get the receptor, that external signal an internal pathway, an internal
79:16 This is what is referred to as , I'm turning outside and the inside
79:22 then that signal grows and amplifies and results in some sort of change or
79:28 in that cell. All right. would be an example of metabotropic.
79:33 we didn't talk specifically about any a , we didn't talk about the
79:37 Uh It can be activation or inactivation certain uh uh you know, catalytic
79:44 or gene expression or any sort of thing. It just changes what the
79:48 is doing. All right. So works through a, a receptor that's
79:54 on the cell's surface activates a pathway already exists causes change in the
80:03 This would be an example of And again, being very nonspecific.
80:07 are different enzymes. So you have square enzyme, the triangle enzyme,
80:13 hexagon enzymes. See all very fancy . And what we've done is we've
80:18 the receptor, the receptor causes activation this enzyme which causes activation of this
80:24 which causes activation of this enzyme. on and so forth. You're sitting
80:27 going well, why would I want have all these crazy steps? Because
80:31 of these things that are being turned aren't just turning on this one
80:36 There might be four different pathways underneath one of these things. So what
80:40 doing is you're amplifying a response It's kind of like when you invite
80:45 friends over to the, the house , right? And your parents are
80:49 of town and they tell two friends they tell two friends and they tell
80:52 friends the next thing, you you're a TV, or you're a
80:56 , right? The cops are All sorts of zany hijinks occur.
81:02 don't know what I'm talking about. generation has the house party movie.
81:09 right. Fine. Everything you turn has to be turned off. So
81:16 system in place actually has a regulator turns everything back off again. So
81:24 is just trying to show you an of that. All right. Um
81:29 here we have this molecule that's getting on and then here it is active
81:34 . It is inactive. So what doing is here's the thing that's making
81:38 active and then there's something over here turned it back off again. So
81:44 though you're turning something on and what seeing is everything being turned on,
81:48 we're not seeing in this picture is thing that turns it back off into
81:51 thing. And so you are self the process so that everything doesn't stay
81:58 forever. Have you gone into one these bathrooms that has the automatic lights
82:03 you walk in the lights turn off if you stand around long enough,
82:06 notice that the lights turn back off . All right, it has a
82:11 in the system to ensure that the is not being wasted. And that's
82:14 of what's going on here. The type of signaling systems is through ionotropic
82:25 . So if metabotropic means I have receptor and I have a whole bunch
82:28 molecules already in place ready to go deals with ions. So, what
82:34 gonna do is I'm going to have ligand that binds to a channel that
82:41 opens or it might close and then flow of ions in and out of
82:46 channel change. Yes, sir. , there is. So let me
82:55 up here. So there's you can um I'm gonna go back one more
82:59 you can actually see where the slide come on. Respond. There you
83:07 . I guess it's a line of , radio wave thing, right?
83:09 what it's showing you here, here's ligand, there's the receptor. So
83:13 ligand binds to the receptor. Um the previous one, here's the
83:17 there's the receptor. So in all cases, just presume the ligand is
83:21 . And in these cases, they're notice we're not even talking about which
83:26 they are, this is just some down on the pathway. So
83:30 this one is showing you here's the , there's the lion and when it
83:33 up, that's gonna allow the free of these particular ions in. All
83:38 , the way you can think about , it says here I am the
83:43 , I bind to the channel, open the door, I get
83:47 But what does the door do? naturally closes on its own,
83:52 So this is why it's short lived the channel has a built in mechanism
83:57 open and then rec close itself. this is why it's a very,
84:01 short lived, very rapid response. when I open that door, that's
84:06 all the raccoons or all the students or whatever it is that you want
84:10 move in and out of the it's just slightly less, right?
84:17 , it's regulated. It's actually everything is very tightly regulated, all of
84:21 things, even though it doesn't kind look like it don't appear to be
84:24 regulated, but it is. um, as an example, let
84:28 think if I can think of like insulin receptor, right? The insulin
84:32 would be an example of a metabotropic is responsible for making sure that your
84:37 uh takes up glucose and starts putting into the cells. Right? Mhm
84:49 . OK. That's that's actually a good question because it can be confusing
84:52 the exam. Paracrine is when I the uh the signaling molecule out into
84:57 interstitial fluid and then it binds to channel with a, with Jurin
85:04 I'm not releasing a signaling molecule. , I may have a ligand on
85:10 surface and I have to handshake with cell that's next to me. So
85:15 means next to pair, means near . So if I'm one cell and
85:20 , the cell that receives the signal next to me, I have to
85:23 come into physical contact with the That would be an example of direct
85:28 uh signaling. The other type is I have two cells that are already
85:33 to each other and one is producing molecule that then travels via a gap
85:38 to the other. OK. So other words, the two cells are
85:43 each other and they're sharing uh signaling back to the question with insulin.
85:49 the insulin receptor causes you to uptake . So what it's doing is when
85:54 receptor binds or the insulin molecule binds insulin receptor, it's activating this cascade
85:59 events to cause changes in the cell say, oh, I want to
86:02 glucose into my cell. That's, how it's working. All right.
86:07 When you're dealing with ionotropic, on other hand, here, the ligand
86:10 on and it opens up a So now what you're doing is you're
86:14 a change in voltage. So you're uh manipulating the cell in terms of
86:19 membrane potential. So remember, muscles in electrical way. So that would
86:24 an example of ionotropic is opening and channels. All right. So it's
86:29 different form of regulation, right? is very, very quick, one
86:33 slower because you have all these things do in the pathway. This other
86:37 of signaling here is nuclear receptor signaling metabotropic signaling. When we describe
86:43 we said that the the receptor was on the surface of the cell.
86:47 can even see in the name nuclear kind of implies that the receptor belongs
86:51 the nucleus. Well, that's kind a misnomer because it can be found
86:56 in the cell, but it's not on the surface of the cell.
87:00 when that ligand comes along. So an example of a hormone that receptor
87:05 bound up and then it becomes translocated the nucleus. And what it does
87:12 is it binds up to DNA and acts as a transcription factor. A
87:17 factor is a molecule that changes gene All right. So let's say
87:24 this cell right here isn't producing the of whatever this gene is. So
87:30 the hormone comes in, binds to nuclear receptor, the nuclear receptor trans
87:35 it now activates the gene. So I'm making whatever that protein is,
87:39 is what it is called DeNovo so New DeNovo protein synthesis now to distinguish
87:46 these two things metabotropic versus uh ion or not metro versus nuclear receptors.
87:52 I come over here and press this , what's going to happen to the
87:56 in the room, they're gonna turn , right? I mean, that's
87:59 simple. So this would be an of metabotropic. Everything that we need
88:04 change the condition of lighting in this is already built into the system.
88:09 the receptor, it has all the wires and the lighting and stuff like
88:13 going to the lights. And so I press the button, the lights
88:16 off, when I press the button , the lights go on,
88:19 Everything that already exist with nuclear I want you to protect. If
88:23 want to change the lighting in the first, I have to build the
88:26 and I have to put the lighting and I have to put the wiring
88:29 and I have to put the bulbs . I have to build everything to
88:32 it happen. That would be de of new, I have to put
88:36 all in. So here, the is much, much slower metabotropic.
88:42 get a response almost immediately here. gonna take a while because I've got
88:46 put everything together. But once I getting the response, it's gonna extend
88:51 be around for a long period of , it's a different form of
88:56 It's changing the characteristic of the cell gene expression. Whereas with metabotropic,
89:01 changing the activity of the cell that doing currently is kind of the way
89:06 think about it. That kind of sense. Hm, to make a
89:17 happen. So this is how steroids . All right. And so
89:21 remember these are lipid soluble molecules but proteins are a protein signaling like
89:29 Um and they're, I'm not gonna through them all. But there's,
89:32 hundreds of thousands of signaling molecule. you guys were listening on the news
89:36 COVID, they're talking about cytokine storms stuff like that. It's how cytokines
89:41 are through metabotropic mechanisms. They're a of signaling molecule, right? So
89:47 of your cells talk to each other these chemical means, very few use
89:53 to do so because there's a very and far between in terms of the
89:57 , but it's just a different form talking causing changes in the cell.
90:02 of all the different ways that you communicate with somebody most common way.
90:06 think of your phone. What are three different ways that you can communicate
90:09 your phone with somebody you can call and what's another one? Email or
90:19 ? See, we got up to , right? And then we got
90:21 those other weird social media things. Anyone here ever use Marco Polo,
90:26 ? That sounds weird. I'm gonna you a voice, a visual voice
90:31 . Now, man, I, gonna just gonna call you up,
90:34 that's another way of communication, And this is just what the cell
90:38 have done. They've come up with ways to communicate with each other to
90:42 different things. If you want to to someone urgently, you're gonna text
90:45 or you're gonna call them call, ? So that's just it, it's
90:51 some depending upon what I want to , I've got different mechanisms. So
90:54 speed at which I want to get done, I'm going to use a
90:57 type of signaling moving on what we're do. We're gonna go into these
91:05 types of junctions between cells. All . And so the example that we're
91:10 here are epithelial cells because they're really to see here. But these are
91:13 for all different types of cells, all these different types of junctions.
91:17 so really what is this is how are connected to each other is what
91:21 trying to get at here. Come , there we go. All
91:25 First type is the desmosome, Desmosome are basically a bunch of cell
91:33 molecules. There's that word, So you have a a plaque of
91:39 , it's not like plaque on your or in your thing. It's basically
91:42 bunch of proteins that creates this hard , then you have a bunch of
91:46 molecules. And so this is cell one, this is cell number
91:49 each cell has its own half. what you do is you bring those
91:52 things together and you create this structure is linked across the two cells and
91:57 associated with those cells is a series intermediate filaments. So this is like
92:02 . And so now what we've done we've created this really, really stable
92:06 so that when one cell is attached the other, it's going to distribute
92:10 tensions, those forces that we described when we were talking about intermediate
92:15 So that's how a desma zone Cads on one side, cads on
92:20 other. They recognize each other, bind to each other. And then
92:23 stabilizes it and this distributes force. right. So each cell has its
92:29 half to the demos. The des is both halves together. A hemi
92:34 . All this is an example of a desmosome looks like. It's a
92:37 , very terrible drawing because cells never like that. But it's trying to
92:40 you see how we're connected to each at these different points. So it
92:43 be where the desmosome is located. right, an desmosome are just half
92:49 desmosome. All right. So when are overlying things like connective tissue,
92:55 this is epithelial cells. So here can see your half of the
92:58 there's your cadences. This is what looks like. You can see there's
93:01 intermediate filaments going off that green That's the plaque that creates that
93:06 And what you're doing is you're attaching proteins that are found within the extracellular
93:12 , that kind of holds it in again. What's there is not particularly
93:17 because it's going to be different depending what type of salts you're looking
93:20 But what we've done now is we've attached the cell. And so when
93:23 pull on the cell or put sheer on those cells, it's actually tugging
93:28 pulling on that hemione, which is to the underlying layer and that force
93:34 distributed once again. So those are desmosome and he desmosome do distributes tension
93:43 force between the cells or underlying If you never saw anything else on
93:52 and you saw it here in the , could you kind of guess what
93:55 does based on the name? it adheres? Yeah. Yeah.
94:01 . That's, that's kind of the thing. So for the longest
94:05 we just had like three different types junctions. But then as we learn
94:09 be able to go in and look the molecules more closely we discovered that
94:13 are more complex things like the adherence . Again, it uses uh
94:19 these uh cell adhesion molecules. But uses instead of having plaques or using
94:25 filaments, it uses micro filaments. so, but it still causes two
94:29 to adhere to each other. So is like cellular velcro and so you
94:33 distribute tension and force between cells. tight junction is kind of like a
94:41 bag. All right. And what does is it allows a series of
94:46 one on cell number 11 on cell two to come together and they kind
94:49 stick together and they create a seal the two cells. So that you
94:55 a space, it's easier to look here if you can imagine. So
94:59 space uh basically seals so nothing can in between the two cells. All
95:07 , movement between cells, not through , but between cells is referred to
95:12 paracellular diffusion. So you'd find these like in your digestive system because you
95:19 things to move through the cell, between the cells as you're trying to
95:23 stuff and you don't want things to out the other direction. So this
95:27 of creates a uh an impermeable barrier from uh within a tube so that
95:34 materials in the lumen can't pass between cells, they have to go through
95:38 cells. So the cell decides which through. Now for the biggest oxymoron
95:45 in biology. There are such things leaky type junctions. I, I'm
95:53 kidding. That's what they're called leaky . Um their purpose, they create
96:03 movement because you now have to pass the cell instead of around the
96:08 This is the same slide just showing a little bit better. So here
96:11 can see the lumen, this is inside your body. So you can
96:16 , I got things I want to through, but I don't want things
96:18 just kind of sneak on through. want them to pass through the
96:22 So I can direct when material is , moving and where it's moving to
96:29 gap junction. We already kind of when we talked about XTA uh um
96:34 signaling. So two cells next to other, what they do is they
96:38 these little tiny molecules called connections. about 20 different types of connections in
96:42 body. One side has its own , the other side has its
96:46 And what they do is those connections together and form a channel through which
96:52 small materials can pass through. And this allows two cells to communicate with
96:57 other as if they were one. right. So your heart beats the
97:07 it beats because ions pass from cell cell to cell very, very
97:12 And so it knows directionally how to those electrical signals to cause the cells
97:18 contract. That would be an example what gap junctions can be used
97:29 Finally, on the outside of I want you to understand that if
97:34 have a plasma membrane, here's your that it's not just this empty environment
97:39 sits around the cell. We refer the interstitial fluid but surrounding each type
97:42 cell is this layer of protein and that kind of is organized around that
97:50 . And this is what is referred as the extracellular matrix. It has
97:54 sorts of materials like collagen and all other small proteins. And this is
97:59 fun little protein right here. It's a proteoglycan. Um It's basically a
98:03 with sugar uh on it. And wa water kind of gets around it
98:08 kind of hangs out around it. what this does is it creates kind
98:13 this protective barrier and this this um that kind of overlays or covers over
98:20 cell. The cell could use it a means to signal other cells or
98:23 communicate with its environment. You can here there's anchoring. So things that
98:28 that occur out here can affect things are occurring inside as well. This
98:32 just cartoon. Um Anyone watched the video that I posted? No.
98:38 , it's OK. I'm I'm not if you don't, but you'll see
98:42 in that picture where receptors are actually pushed out above and through the extracellular
98:48 . In that video. So you'll it kind of in reference. So
98:55 not just an empty space around the . It is highly, highly filled
99:00 all sorts of proteins that do How are we doing on time?
99:09 . I got three minutes. I get you guys out, not as
99:11 as yesterday, but like, you , the last little bit I want
99:16 talk about here and I think this everything we need to know with regard
99:19 the cell. I think we move to tissue, all tissue all day
99:22 . All right is how do cells themselves? Well, cells um for
99:28 most part, go through the process the cell cycle. All right.
99:33 so with the cell cycle, we're to have two basic periods, a
99:35 of growth and just doing what you do as a cell. And then
99:40 gonna happen is you enter in this of DNA replication and then division.
99:46 really what mitosis is. All So the the the life span,
99:51 thing that you're living through and doing is really referred to as the
99:55 So this is the metabolic stages, your cells are normally doing. But
99:59 you have actively dividing cell cells, they finish going through that inter
100:03 that's when they go through that mitotic where they divide themselves up and create
100:08 clones of themselves. So your skin constantly doing this. Now there's another
100:13 which we're not going to talk which is meiosis, which is what
100:16 germ cells. These are your cells are going to give rise to your
100:20 . So ladies, at your guys, at your sperm. All
100:24 , we're not going to talk about . It's a little bit different,
100:26 little bit complicated, unnecessary for What I want you to understand is
100:29 basically what's happening here. So what interface, interface has three basic stages
100:35 it? Um You, the first is what is referred to the mebolic
100:38 . This is where you kind of and you kind of just do
100:43 you know, there's no particular activity , that's being directed towards cell
100:48 So you're just doing your thing, cells may even exit out of this
100:53 one this growth phase and go into we call G knot or G
100:57 And this is kind of like, , now I'm not doing anything.
100:59 just being a cell, but you enter back out of G knot and
101:03 can come back in the second Here is the S phase. This
101:08 replication. This is where the cell finally been been told or has
101:12 hey, we're going to divide and gonna make a clone of our
101:15 we're gonna split in two. So they're gonna do is they're gonna go
101:18 and they're gonna replicate their DNA through S phase. And then the G
101:23 phase is getting ready for mitosis. so here, what we're doing is
101:29 checking to make sure, did we our DNA correctly? Do we have
101:33 the machinery in place to make sure when we start mitosis, that we'll
101:37 mitosis? So we are going through process of preparation. So in each
101:44 these phases, there are going to stops to kind of check to see
101:48 make sure that we're ready to go . Drives me nuts. I,
101:54 we go. Did I miss Yes. So, mitosis notice how
101:59 we're going into this stuff. It's really just keep it basic.
102:03 mitosis is division of the nucleus. right. So the division of the
102:08 material. So we're going to go multiple phases, guess what? We
102:12 lots of stuff that happens in But I just want you to understand
102:15 are the phases prophase, meta phase a phase tse. What we're gonna
102:19 is we're going to in prophase, break down our nucleus, we begin
102:25 up our um our DNA, the , the centrals move to the opposite
102:30 of the cell by all those uh chromosomes have aligned. You now have
102:37 intermediate filaments that are moving towards the the chromosomes anaphase, you're starting to
102:43 things apart and then uh by tlas going to start reorganizing the nucleus.
102:48 so those are kind of what's going during the different phases of mitosis.
102:54 right. So if you keep it , really basic in general, just
102:57 of understand breaking things down alignment, , re reforming. I think you're
103:03 be good enough for my class. would not be good enough for a
103:06 biola or an intro bio class. that's good enough for us,
103:10 I want to distinguish here between cytokinesis cytokinesis is now the division of the
103:16 . It really begins around anna phase it continues on through Tilea. And
103:21 is what you're seeing. So you imagine what we have is we have
103:25 filaments that are going to form a furrow that's not being shown in this
103:29 here, right? And it's basically taking a lasso around the middle of
103:33 cell after the, the nuclear material been split to the two sides.
103:36 then what you do is you start the lasso and it kind of squeezes
103:40 eventually pinches off so that your two cells basically are identical to each
103:45 They're not going to be 100% but they're going to have the equal
103:48 of nuclear material, they'll have roughly equal amount of, of, of
103:52 and stuff like that. And they're now able to go on back into
103:57 G ones. So that's all I you to know about the cell
104:03 Is that easier than biology. General or intra bio. Yeah. So
104:07 key thing here is cells divide and a method in which they do
104:10 Ok? 1 45 it was almost cut us out, you
104:17 about 1 40. So when we back, you know, you
104:21 as you're packing up, just remember gonna start talking about tissues tomorrow after
104:25 unit after the test on Monday. again, I will, I will
104:28 out an email to let you hey, um, sign ups are
104:32 , right? But after, um, Monday, we're actually gonna
104:37 get into anatomy because I know you are sitting and going, I took
104:40 anatomy class. Why I haven't. talked about any anatomy yet. All
104:43 , we're gonna get there. Have great day. I'll see you
104:46 Yes, ma'am. I emailed
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