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BIOL 2301 Human Anatomy & Physiology I - 2301_lecture15_1021
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00:03 All right. Mhm. Yeah. , today, what we're doing is
00:09 are now beginning our journey into the system. Uh Yeah, there was
00:16 rejoicing. So, today, what gonna do is we're just going to
00:19 of introduce ourselves to the idea of does the nervous system, how is
00:22 nervous system protected? All right. know, generally speaking, what is
00:26 nervous system responsible for? No Control control is now Yes, movement
00:33 be. But that's control of It's the muscles themselves are directly involved
00:38 movement. So, what we're gonna , we're gonna kind of do this
00:40 of like, here's a general overview how we kind of divide up the
00:44 . Because remember we're all about When we deal with anatomy, then
00:48 gonna go and look at the different that are responsible for protecting, then
00:53 gonna look at a couple of arteries veins and then I think we're kind
00:56 done for the day there. So lots and lots of fun.
01:00 . No, no. It's going be you know, me I talk
01:03 little bit. All right. to start off, we're start off
01:10 when you think about the nervous you need to think that there are
01:13 basic parts to it. All Now, I'm gonna preface all this
01:16 with this. Is that remember anonymous organization. So when we organize things
01:22 kind of throwing things in the box to help us better understand how things
01:28 . All right. But remember when dealing with the nervous system, everything
01:31 integrated. So it's like you're talking one thing, but understand that it's
01:35 working by itself. It's working with the other parts as well.
01:39 And so our starting point here, principal parts. We have the central
01:42 system and we have the peripheral nervous . This is a real easy,
01:48 division, understand the central nervous system your brain and your spinal cord.
01:53 right, we're going to break down the brain is over the next couple
01:57 lectures. All right. But that's . It's brain and spinal cord.
02:01 job for the most part is to information and process that information to create
02:08 . All right? So this is control center portion. So, your
02:13 cord, for example, if you on a tack, it doesn't have
02:16 go up to the brain to oh, I've stepped on a
02:19 I need to lift my foot at level of the spinal cord. There's
02:22 reflex that will occur to cause you lift your foot up, granted you
02:26 send the information up to the brain make you go al to perceive the
02:31 that there is pain, but you not have to process the idea of
02:35 , there's attack on my foot in foot to make me lift my
02:41 So the spinal cord does stuff is I'm trying to get up. If
02:46 not in the brain and you're not the spinal cord, that means you're
02:50 else. You're in the periphery. , periphery is basically broken down as
02:55 the nerves and the ganglia. I'm going to give you a big
02:59 star know this because it's one of trick questions that shows up. Maybe
03:03 in my class, but someplace are there nerves in the central nervous
03:09 ? No nerves are the periphery? , nerves. Are the structures found
03:17 the peripheral nervous system? Alright. jobs or at least the peripheral nervous
03:22 job is to receive information and then that information up to the central nervous
03:28 . Central nervous system processes. And the peripheral nervous system is how the
03:33 from the central nervous system gets back to where it needs to go.
03:37 right, so the in and the the nerve parts. Alright. The
03:42 are basically exchange pathways. When you the term ganglia. All right
03:47 that's just kind of a loose We're gonna go into a little deeper
03:51 over the course of the of the . But if you understand those two
03:55 , Central nervous system, brain, spinal cord, peripheral nervous system,
03:59 else, which is primarily nerves. good to go and then everything
04:03 Just kind of falls into those two . Now there are some simple organizing
04:11 . Alright. I've kind of highlighted first. There's a hierarchy of
04:16 We should be familiar with this. are people above us and people below
04:19 . Right. Little brothers and little are below us. Right? Parents
04:26 above us, right? Teachers and and instructors and bosses are above
04:33 Trainees at work are below us. we're training in which case you are
04:38 below. All right. So we information from lower levels up to the
04:45 levels. Information is being processed in higher level, relative to a lower
04:51 . Now I said thanks to be in the spinal cord and that is
04:55 true. But when we're dealing with . So like I said, I
04:59 step on a tack and lift my up. Right? That's being done
05:03 the at the lower level. But order for me to perceive what's going
05:08 , it has to be processed in upper level in the cortex, for
05:12 . All right. There are patterns structural and functional when it comes to
05:19 and basically what this means is when have neurons, neurons are similar functions
05:23 are located in the same location. we're going to see this when we
05:26 into the special senses and so I'm going to use an example there.
05:30 all the neurons responsible for processing sound located in the temporal lobe. They're
05:36 going to be scattered around the All right. There is a high
05:39 of organization here. All right. not basically a bunch of wires that
05:44 been jammed into your brain. You to make things work. There are
05:50 areas you can point to and say is for that. This is for
05:53 . This is for that. It's to be complicated. And in
05:56 the truth is is we don't understand completely. Alright. Our knowledge of
06:01 the brain works and all the networks stuff like that is fairly limited.
06:06 there's a pattern that we are recognizing is structural and functional organization. All
06:12 . There's topographical organization. And what means is that it's gin, not
06:18 just jammed in there and it's not similarity. It actually matches your body's
06:25 . So, if you look at example where the neurons are that are
06:31 for receiving sensory input from the So, obviously my toe is lower
06:35 my hand. Would you all agree that? Yeah. All right.
06:39 , if you look at the organization where sensory input is organized within the
06:44 central gyrus, you will see that is a point where the feet are
06:48 there's a point where the head or the hand is and all the points
06:52 between relatively match that location in the central gyrus. So there's a positional
07:00 topographical organization. Now there's also That would be kind of called tona
07:07 or visual and it depends on what of special sense you're talking about a
07:11 would be sound visual would be I on and so forth. So,
07:15 idea here is that there is organization is clearly demarcated in the brain so
07:22 the brain knows where information is coming . 10 last the brain is plastic
07:29 the central nervous system is plastic. the word plastic means mountain.
42:45 Excellent. All right. So hopefully we're recording it. All right.
42:49 , again, highest pressure up So, one of the ways we
42:52 how does fluid move? Well we we have pressure gradient. So we
42:56 the highest pressure where it's being made it's pushing fluid down to the place
43:00 the lowest pressure is which would be those villa or granule ations.
43:05 But there's other things that cause movement their cilia in there. Remember the
43:10 on the cells the sillier sit there like this. Go away, go
43:13 , go away, go away. it's pushing the fluid so all on
43:17 epidermal cells, that's where you're gonna the cilia. And it's pushing the
43:21 away from where it's being made. that's another factor. And the third
43:25 your postural factor is a postural Alright. And basically what it says
43:29 because we sit up and stuff like man, we move around that causes
43:33 to move in our bodies. It's just generally speaking. So your blood
43:37 in your legs and stuff. Have ever noticed that you kind of move
43:40 legs around when you sit. Some you watch them and start wiggling
43:44 That's just helping the fluid move around body. All right. It's not
43:47 not just a nervous tick. And your postural asked uh postural uh I'm
43:56 as your posture is a consideration. have two that has an effect on
44:02 cerebral spinal fluid. All right. made in the corporate plex is inside
44:07 ventricles, exit back to the blood their work annoyed villa. And we're
44:15 . Final structure. So, we've through. We know it's bone.
44:19 don't even talk about the bone because already learned it. We looked at
44:22 meninges. Then we looked at the spinal fluid. And now we're in
44:28 fourth structure. The fourth structure is blood brain barrier. All right.
44:33 , what the blood brain barrier is both an anatomical and physiological barrier between
44:39 blood inside the capillaries and the interstitial surrounding the nervous tissue. All
44:46 So, these are blood vessels that penetrated through the pia and are now
44:51 the nervous tissue. All right. , what do we have here?
44:56 basically watching what is moving through Okay, um in essence, I'm
45:02 to tell you the story here in , in essence, what we wanna
45:05 is any small change in the interstitial can affect how the neurons interact.
45:10 I'm going to tell you this fun . You can google this. This
45:12 about the second or third year I teaching here. Um It was when
45:18 we came out All right. Remember we All right. I guess now
45:23 got the switch but it was the because Nintendo. All right. So
45:27 the we came out it was like freak of nature. Everyone was looking
45:32 the xbox, everyone thought the PS or whatever was out at the
45:36 I can't remember. We're like the Systems of the Century and the Nintendo
45:42 the we know was expecting this and wanted and there was a short
45:47 All right. And so you couldn't it at christmas time. So there
45:52 contests, you know, it was the radio shows a tv show.
45:55 know, they would have contests. was this contest that was going on
45:58 California. It was the P for week contest, that's what I call
46:04 . All right. If you guys Mr Beast. I know there are
46:09 in here. Every show is a , right? And it's like we
46:13 in the boat for 37 hours to who would win the boat. We
46:15 in the Lamborghini for 48 hours to who would win the Lamborghini. Gotta
46:19 Gotta Gotta Alright, same sort of . We're going to give you all
46:23 bunch of water to drink and then can hold it the longest gets the
46:29 do you see the P for the contest? All right. And so
46:33 they did is they just everyone shut whole bunch of water with a fixed
46:36 , But everybody there is different So we had big people and small
46:39 . And there was a young woman was trying to win her Nintendo for
46:44 kids, right? And she was four ft eight or something. And
46:48 had to drink the same amount of as everybody else. That water goes
46:51 your mouth, down in the digestive from the digestive system to the
46:54 And it has to disperse to the . And what it did was one
46:58 places it goes, it goes to brain. All right. That's just
47:01 space and water can move back and across these barriers fairly easily. And
47:06 trying to do is just trying to the water in such a way so
47:10 you get uh proper osmotic balance is word I'm looking for. All
47:16 So, she's small amount of blood have in your body about 5.5 liters
47:22 fluid, total fluid in your body eight liters. You throw in a
47:25 of water and you're that itsy bitsy tiny. And it goes to your
47:28 that disperses through the brain uh basically out all the ions and then all
47:34 a sudden your neurons can't fire Mhm. All right. This is
47:40 example of why you want to maintain keep the brain kind of separated from
47:45 . And this is an example of much water is a bad thing.
47:49 so, what happened was the areas are responsible respiration and heart regulation stopped
47:54 . So she basically drowned in her fluids, right? She died.
48:00 know it's a horrible story. You it was gonna be a happy
48:02 No, not happy ending. All . But I use this as an
48:06 to help us understand why slight changes the interstitial fluid of the brain are
48:12 and important. I could sit there point about alcohol and all this stuff
48:16 you're like, yeah, yeah, get it. Right. But this
48:19 an example of something that you think okay for your body. And if
48:23 put way too much in, it's to cause you harm because there's no
48:28 to regulate how much water goes into brain right now. I'm not saying
48:34 going to drink too much water. . A tiny girl drank way too
48:38 water for her body and didn't have way to process it fast enough.
48:43 right. So, what we're gonna is we're regulating what goes in and
48:48 of the blood. All right, the structure of the blood brain
48:51 So, let's talk about the anatomical because there's an anatomical says this is
48:57 barrier between here and here. we're going to prevent things from going
49:01 and forth. So, the first is we have these tight junctions between
49:07 endothelial iem? Or the capillary epithelium the is what the name is called
49:12 Ethiopia. But it's the capillary Alright. I want you to imagine
49:16 a moment picking up a bunch of out of a bucket of water or
49:22 , Right? And you take your , you scoop them in and you
49:25 out the marbles are going to stay your hand but the water's going to
49:27 between your fingers. Right? That's how the capillaries in your body
49:33 . They're fairly leaky. All They don't have these tight junctions.
49:37 right. And this is what allows to exchange back and forth. But
49:41 the brain the astra sites which are type of glial cells surround the
49:48 And they tell those capillaries we need to make tight junctions. So
49:53 you can picture the same thing, take super glue and put it between
49:56 fingers. Right? So your fingers separate. And then go and scoop
50:00 then put superglue between your two And when you pull out the water
50:04 won't leak out. It will stay there with those marbles. So that's
50:09 first barrier. That's part of the brain barrier. Is this tight junction
50:14 capillary cells? All right? The barrier is what is a thick basil
50:22 . Now, what basil amina is is the connective tissue that lies between
50:28 . Sorry epithelial cell and and the group of tissues underneath it. All
50:33 . So, it's kind of like screen door, Right? It's basically
50:37 network or mesh work of proteins. so if something can sneak between the
50:42 cells or even travel through the capillary , there's still this mesh work that
50:48 hinders the movement of large proteins. right. So, it limits what
50:52 actually pass beyond the capillary. and it's not actually showing in this
50:59 . But you can imagine just on other side. And then what we
51:03 is we mentioned the astrocytes and the , the glial cells which we'll talk
51:06 on Tuesday and in essence what they is they maintain structure in the
51:11 And so what they have is they these extensions. Right? And that's
51:15 these the structure they're called. Um , foot processes. And there's another
51:22 I'm not even remember. But what foot processes do is they come up
51:25 the capillaries and they basically jam up them. And they also have tight
51:30 . So what you now have is have a layer of cells you have
51:35 layer of connective tissue and then you another layer of cells and there's tight
51:39 . So the only way you can on the other side out here where
51:43 light is That would be the interstitial is you have to pass through the
51:49 and the helium and you have to through the astra site, you can't
51:52 in between them because there's no path between them. So that means the
51:55 of the capillaries in the cells of astrocytes have to have the right receptors
51:59 the right channels and the right carriers allow things to pass through. That's
52:04 it's an anatomical barrier. There are cells called parasites, not parasites,
52:11 , parasites means cells that are next and these basically helped coordinate information and
52:17 things move back and forth. But the key ones are this part right
52:22 here. Now, we've already mentioned and I'm just going to reiterate
52:27 And with regard to physiological restrictions, your water soluble, in other
52:32 you carry a charge or you are in any sort of way. In
52:37 words, you like to be around and that's where you're going to
52:41 You can't pass through these cells, need something to grab you and move
52:47 along to the other side. If fat soluble on the other hand,
52:52 lipid soluble, no plasma membrane is to keep you from getting away from
52:57 water. So that's why you'll be to pass through the cells fairly
53:04 Now, where do we find these blood vessels basically all over the
53:09 All right. So, whenever you a blood vessel in the brain,
53:13 going to have this and this is it's the blood brain barrier. Now
53:17 the core. Oid plexus where the cells are. If there was a
53:22 brain barrier, I wouldn't be able get the materials out of the
53:25 So what we've done is we don't the same sort of blood brain
53:30 There's a tight junctions exists between the cells but they don't exist between the
53:35 cells. That means I can move from the blood into the interstitial fluid
53:40 that area. The epidermal cells can up stuff but it can't leak into
53:44 ventricles. Okay. And then there other places in the brain that lack
53:52 blood brain barrier and the reason for is because they need to know what's
53:56 on inside the blood. The hypothalamus one of these areas. And what
53:59 doing there is we're looking to see in the blood so we can send
54:04 control information to other parts of the , The hormones the hypothalamus releases
54:10 So it needs to have access to blood. So no blood brain barrier
54:14 the hypothalamus, pineal gland sort of same thing, vomiting center.
54:21 What is the most likely way to something toxic into your body? Come
54:26 ingestion, right. We put everything our mouth, right? We touch
54:32 face in our mouth all the The most likely thing. I
54:36 come on you've done this before. mean I did this this week.
54:39 a couple of days ago I went the fridge. I pulled out something
54:42 looked at it smelled. I'm I can't really tell. Right?
54:48 then I just cook with it and just like, you know, I'm
54:51 going to win or I'm going to . Right? I've got a body
54:55 knows how to fight bad things. not going to kill me.
55:02 So, we get it. I . It didn't actually make me
55:07 All right. But the idea is the likelihood is I'm going to put
55:10 toxic. All right. You're not bad as I am. Do you
55:15 live by the 5 2nd rule? , Yeah, cookie drops the
55:21 Right. Well, so yeah, not gonna do the five seconds in
55:24 bathroom. All right. But if drop an oreo on the floor,
55:28 gonna be like, pick it blow on it because that makes all
55:32 better. And then you're going to it. All right. Five second
55:37 . So, if you get bit something poisonous or sorry, excuse
55:41 Something venomous. You gotta use the term. One of the things that
55:46 is we vomit. Right? And ? It's again because the brain just
55:53 sitting there going the likely point of of this toxin is through consumption.
56:01 , I'm just going to empty out stomach. So, that's the bombings
56:03 And again, we mentioned the cord up there. So how do we
56:08 things across? Well, we have media transport. All right.
56:13 this is what these pictures are. right. So, basically anything that
56:18 very very small and lipid soluble can just diffuse through. All right.
56:24 doesn't need a receptor or carrier. can basically be carried across. All
56:29 . There's And So, this is examples of things that are lipid
56:34 We have carrie immediately transport. This where we're dealing with things that are
56:38 soluble and have to have something to bind to pick up and move
56:43 All right. And then there's also , receptor mediated transport. These are
56:48 larger things. So, very specific to say I'm looking for the specific
56:54 . I'm gonna put a receptor out , grab the receptor binds to It
56:58 picked up through the process of transito and move to the other side.
57:04 , carrier would be moving into the , then have another channel or carrier
57:09 the other side. All right. , it's You can see it's selective
57:14 terms of how I move stuff. , we're sprinting towards the end.
57:23 , we've talked about the structures of . So, what I wanna do
57:27 I want to talk about blood actual anatomy. Now, the blood
57:33 of the brain can be very very . We're just gonna focus on arteries
57:37 not gonna focus on veins today. right. And what we're gonna do
57:41 I'm gonna point out the important ones , it's very easy to get lost
57:45 all this stuff. And again, you look at the names very
57:49 the names are going to tell you about this. All right.
57:54 you can think about the blood I picked this up to take a
57:57 and then I just walk around with you look at the brain, you
58:02 think of it as blood flow is divided into the front of the
58:06 in the back of the brain. the anterior posterior regions, We're going
58:09 see in the next slide that there's three major arteries in three major areas
58:14 are being served by the blood All right. I want to point
58:19 here in the center, we have circle of Willis will talk about the
58:22 of Willis and a couple of but the circle of Willis, you
58:25 see there is a full circle blood right. In other words, it
58:31 actually go around and around and The example of the circle of Willis
58:36 Houston. Downtown 45 x 1059 basically all the way around the city.
58:44 ? The downtown portion of the All right. So with regard to
58:49 anterior segment, I'm using a little dotted line to break the two
58:53 All right in your neck. You the carotid arteries arteries work up and
58:57 internal critics are responsible for providing all blood to the anterior portion of the
59:04 . It's going to be divided up other smaller artery. But this is
59:07 first place where they go. All . So the branches that you should
59:10 aware of are the anterior cerebral So here that is, there is
59:15 anterior cerebral artery and the middle cerebral . So you can imagine what this
59:20 doing is it's going straight up and upward. All right. So those
59:25 the two big ones for the anterior in the posterior segment. We have
59:31 basilar artery which is this big fat in the middle, right. Those
59:36 being fed by the vertebral artery. this is gonna travel along the length
59:43 the spinal cord. You can see one there's two and they're going up
59:47 and joining together to form the basilar and then the basilar artery is sending
59:53 to different parts of the brain. one is the anterior you love this
59:58 ? The anterior inferior sara, bell artery and then there's the superior cerebellum
60:04 . All right? So here's the inferior, right? So you can
60:08 it goes above and around the back . All right. And then the
60:13 cerebellum artery um is right there. ? So there's the anterior inferior There's
60:22 superior cerebral artery. The pontin These little tiny things. 1,
60:29 , 3, 4 on either side supplying blood to the ponds of the
60:34 stem. Now, not in this is the internal jugular vein. All
60:41 . And so what I want to kind of expresses. So you're sending
60:46 up to the anterior posterior sides goes through all these different arteries. Only
60:51 couple of them are we named and the blood is collected and then it
60:55 back to the towards the heart via internal jugular. This is a nice
61:02 simple picture. You just kind of you All right. Well how are
61:06 sending blood to the different parts of brain? So this is the anti
61:09 the post here. We divide it . You can see here is the
61:13 cerebral artery. So there you go front of the brain. Middle cerebral
61:18 Sorry said cerebellum, cerebral the middle arteries, basically the middle part of
61:23 brain. That was the one that goes up and around. And then
61:26 we haven't talked about is the posterior artery comes off the circle of
61:31 There is the posterior region of the . So you see where the blood
61:35 go based on their names. Is what I'm trying to get at
61:41 anterior, middle posterior and tells you going to the cerebral and most arteries
61:48 hear the term the named artery. right. Not just in the brain
61:52 throughout the body body. The named tells you where it's going where does
61:56 renal artery go kidneys and see it's that. All right. And then
62:02 see when they get smaller and smaller. They have like names based
62:06 shape or structure. Sorry. Circle Willis. Every textbook makes a
62:14 huge deal about the circle of Alright, this stomach. I don't
62:18 how many people we have in the . We have 400 students registered for
62:22 Class eight. Only 80% of you have a circle of Willis.
62:28 So 20% of you do not have full circle of Willis if I
62:34 This is Yeah. Well, you don't need one. It's
62:37 we just we don't know who it . It's random. It's a developmental
62:43 . Some of us have it or should say most of us have
62:47 20% of us do not. I know who it is. What's
62:52 Well, so the question is, the benefit? Well, here it
62:55 basically It serves as a path that that the blood flow goes everywhere.
63:00 , if I blocked that artery right , I'm not going to keel over
63:05 . Right? I can go around and send blood around that circle.
63:10 right. That's the idea is having circle basically. It's like a roundabout
63:15 ways to get to the same All right. Now. Obviously if
63:22 include up there, then your blood travel beyond that point. But at
63:27 circle I can work my way. , I've got a block here where
63:30 blood can then travel around the other . All right. So, we
63:36 the anterior communicating artery. Is this tiny thing right there? That's an
63:39 of that. So you can see the name it communicates between the two
63:43 that uh circumvent it. And then basilar artery again arises from the two
63:49 arteries. In the spinal arteries. a vertebral arteries, and the spinal
63:53 should be right there in the So, I don't know. I
63:57 the popping noise. It just seemed . The guy who discovered it.
64:02 last thing wasn't Willie. That wasn't first name. It was his last
64:07 . All right, good news. almost done. Uh Little bit over
64:15 hour maybe. I can spend 20 talking about this slide. All
64:21 I want All right. This is a weird division. But I decided
64:26 break up so you can see here got two points. And what we're
64:29 is we're moving into the type of that make up the nervous system.
64:32 ? We have neurons And we have cells. We're gonna start with supporting
64:36 on Tuesday. So, we're just up here with neurons. What is
64:40 neuron neuron is simply the excitable cells the nervous system. All right.
64:44 learned about their structure in a general , but predominantly in the central nervous
64:50 where we're gonna be dealing with our cells. All right. The pyramidal
64:55 . This is what we kind of at when we looked at a neuron
64:58 an example. This is the pyramidal multipolar. You can see it has
65:03 going all sorts of directions. It a single acts on just like our
65:08 neuron does. All right. But can see the dendrites kinda go
65:12 And so with this kind of demonstrates you is a cell that is in
65:17 with other neurons that are nearby. it basically works in a network all
65:23 . And these are found all over brain. All right there, primarily
65:27 um um in the prefrontal cortex and the cortical spinal track which we'll talk
65:33 . So they play a very important in cognition. What's cognition, thinking
65:40 understanding. Yeah. Mhm. The So why like that. Okay,
65:51 the question is and you're asking a complex question I'm not gonna be able
65:55 answer if you have the gray matter is primarily cell bodies and you have
65:59 matter which is primarily uh axons. do I have these? And what
66:04 going to see a little bit later think when we talked a little bit
66:07 about the gray matter is that gray has multiple levels. It's actually divided
66:11 into six layers and the layers thickness depends on where you are and what
66:15 looking at here is the interaction between different layers and then those axons,
66:20 ? There are not my eliminated. let's say I need to send information
66:24 this side of my cortex to that . Then what I'm going to have
66:28 have is axons that travel between those points. That's why we have
66:34 All right. All right. We're early. Yeah. It's the
66:38 Wait. You guys have more don't you? All right. You
66:42 have a great weekend. I will you on Tuesday
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