Introduction to the Central Nervous System - Video Tutorials & Practice Problems
On a tight schedule?
Get a 10 bullets summary of the topic
1
concept
The Central Nervous System
Video duration:
1m
Play a video:
Hey everyone and welcome to the central nervous system. Now, you may recall, we did touch upon this briefly in our chapter on the nervous system and nervous tissue, but just to give you a quick refresher before we're diving into a lot more detail, the central nervous system or the CNS consists of two components and those are the brain and the spinal cord. So if we look at our figure here, we have just the CNS represented. So we have the brain up in the skull and our spinal cord extending down into the body. And we often think of these as two separate structures, our brain and our spinal cord, but these really are one continuous structure and we'll have a whole video talking about that coming up soon. So stay tuned for that. Now, the CNS basically functions as the control center for the human body. So it is responsible for pretty much everything that makes you you what makes you unique as a human being and what makes human beings unique as a species. So it's going to be controlling some of the more basic, not simple by any means but basic functions like you know, keeping you alive, motor regulation, all that fun stuff, but also things that are very uniquely human. So our capacity for complex cognitive processing, language, skills, memory skills, creativity, all that fun stuff all starts in our central nervous system. So our next video will be talking about our brain in a bit more detail and I will see you there.
2
Problem
Problem
Which of the following actions does the central nervous system play a role in?
A
Trying to remember the answer to an anatomy and physiology question.
B
Coordinating your skeletal muscles to catch and throw a ball.
C
Deciding what you want to have for dinner.
D
All of the above.
3
concept
Major Regions of the Brain
Video duration:
3m
Play a video:
So in this video, we're gonna be talking about the major regions of the brain and there are four of these regions. So the first is the cerebrum and I would bet if I asked you to close your eyes and just picture a brain, this is probably what you're going to be imagining. So the cerebrum is the largest, most anterior part of the brain. So everything that you see here in green, it's really the bulk of the brain and it contains the cerebral cortex, which is what has that incredibly distinctive wrinkly kind of tree bark appearance to it that we all know as a brain. So that is the cerebrum. Now, the next structure is the diencephalon. So the diencephalon is the central part of the forebrain. And when I say forebrain, I just mean if we draw a line in the brain right about there, everything above that is the forebrain. So the cerebrum and diencephalon are part of the forebrain. So the diencephalon is the center or the middle of the brain. It's an internal structure. So the brain that we're looking at here is see-through and that pink part is right in the middle of it. And the diencephalon consists of a few subdivisions. It has the thalamus, the hypothalamus and the epithalamus. All right now, don't worry too much about what you know, where those are or what those look like. We're gonna cover that in a future video. So just know what the diencephalon is for. Now, moving downward a little bit, we have the brain stem. Ok. So the brain stem is the structure here And it has the very important job of connecting the cerebrum to the spinal cord. And it consists of three major subdivisions. So we have the midbrain right there in the middle of the brain, the ponds and the medulla lingo. OK. Again, don't worry too much about what those do yet. We'll cover all of that in future videos, just kind of know where the brain stem is for now. And finally, we have the cerebellum. Now, cerebellum actually means little brain and that's what it looks like. It looks like a teeny tiny brain kind of tucked right into the back of your brain right there. And the cerebellum coordinates our motor activity. You know, quite often when we think about the brain, we kind of think of the cerebrum as being like what's in charge. But when it comes to anything motor related coordinations, smooth movement, regulating motor activity, the cerebellum is really who controls all of that stuff. So that is quite a bit of terminology to cover all at once. But again, you don't have to know the details and the functions of all of these um subregions or anything like that. What I want you to be able to do right now is to be able to look at a diagram just like this and be able to label where the cerebrum brainstem, diencephalon and cerebellum are. And we're gonna go over function and detail in future videos. So I'll see you there.
4
example
Introduction to the Central Nervous System Example 1
Video duration:
50s
Play a video:
All right. So this example tells us George just found out that he has a small glioma on his midbrain. In other words, he has a glioma on his blank. And we have those four words that we just learned. So right away, I know that it's not gonna be cerebrum or cerebellum because neither of those had anatomical subdivisions that we learned, right? And this can be a little tricky because the diencephalon is in the middle, you may think like middle midbrain. Um but the diencephalon consists of the thalamus, hypothalamus and epithalamus, not the midbrain. So diencephalon is out and we are left with brain stem. So the midbrain is the uppermost portion of the brain stem right underneath that is the pond and then we have the medulla abling. So our answer here is c brain stem. So I'll see you guys in our next one. Bye bye.
5
Problem
Problem
The diencephalon is ________________ to the brainstem and ________________ to the cerebellum.
A
Superior, posterior.
B
Superior, anterior.
C
Inferior, anterior.
D
Anterior, posterior.
6
concept
CNS Development
Video duration:
3m
Play a video:
All right. So in this video, we're gonna be talking about the development of our central nervous system and CNS development really begins with the neural tube. And that is the embryonic structure that eventually becomes the CNS. So this literally starts off as just one tube. And what happens is the anterior end will eventually kind of form, um it'll begin to grow and it'll form three constrictions. And those three constrictions are going to mark off these three primary brain vesicles and then the caudal end of that tube where the inferior end will eventually become our spinal cord. So for the remainder of the video, we're gonna go over those three primary brain vesicles and we'll talk about what structures they eventually mature into in the adult brain. So the first primary brain vesicle is the prosencephalon. And this is also called the forebrain directly below that we have the mesencephalon, which is also called the midbrain. And then below that, we have the rhombencephalon and that's also called the hind brain. So if we look at our little embryo here, the one labeled early embryo, this is what it's going to look like between the 3rd and 4th week of development. So you can see we already kind of have these little constrictions, kind of bubbling out and we have our forebrain, midbrain and hindbrain beginning to form and then right inferior to that, we have the part of the neural tube that will become our spinal cord. And you can see this one labeled late embryo here. This is what it looks like by about the fifth or sixth week of development. So you can see it's already beginning to really kind of grow and expand out. And we're seeing that very characteristic folding that allows our brain to fit into our skull. So that's already happening by about week five of development. Now, in terms of what structures these are going to mature into. What we see is that the prosencephalon or the forebrain is going to mature into the cerebrum as well as the diencephalon, the mesencephalon or the midbrain will mature into the midbrain, which is one of our brain stem structures. So that one's kind of easy to remember. And then the rhombencephalon or the hind brain will develop into two brain stem structures. We have our ponds and our medulla aada and it also matures into the cerebellum. So if we are looking at our mature brain down here, to kind of give you a better sense of where these delineations are. If we draw a line right about here, like we did in the previous video, everything above that the cerebellum and the diencephalon is our forebrain and then right smack in the middle of the brain. Again, this one's kind of easy. That's our midbrain. And then everything below that line is our hind brain. So we have our ponds, our medulla aada and our cerebellum there. So you can see, even though we often think about and talk about the brain and spinal record as being these separate structures, you can see how they really are just one continuous structure. And that's how they start in embryonic development. And even as they grow and mature and become much more complex, that's really how they stay, they are one continuous structure. And that is of course our central nervous system. So I'll see you guys in our next video to talk even more about the CNS and talk more about the cerebrum. See you there.
7
example
Introduction to the Central Nervous System Example 2
Video duration:
1m
Play a video:
All right. So this example asks us throughout fetal development, the prosencephalon becomes the blank and the blank. So if we're thinking about a neural tube, the prosencephalon is at the top and it's at the top of the neural tube and it's going to grow into the structure that creates the top of the brain, which is the forebrain. Right. So right away, I can eliminate A and D because they both include the midbrain and we are dealing with the forebrain. And we remember that the forebrain consists of the cerebrum and the diencephalon. Those are the upper brain structures. So our answer is c it can't be b either because remember the cerebellum is a hind brain structure. The part of the neural tube that makes the cerebellum is way down here and these are gonna kind of grow opposite from each other. The prosencephalon will be moving up, the part that makes the hind brain will be moving down and kind of back. So our answer here is c the cerebrum and the diencephalon. I'll see you in our next one.
8
concept
White & Gray Matter
Video duration:
2m
Play a video:
Hey, everyone. So in this video, we're gonna be talking about white matter and gray matter. So the nervous tissue that makes up the brain and spinal cord is comprised of two types of matter. So we have our white matter which is made mostly of myelinated axons and the presence of all of that fatty myelin gives them an actual white appearance. So they actually look white and then our gray matter is kind of everything else. So this includes our neuron cell bodies, our dendrites and any non myelinated axons. And these tend to have kind of a tannish gray appearance, which is where we get the term gray matter from. Now, white matter and gray matter aren't just dispersed throughout the brain and spinal cord, all willy nilly, they follow a very distinctive pattern. So what we see is that in the brain, what we have is an outer layer of gray matter called the cortex. So this is the literal outer layer, this is the part of the brain that you can see. So this is what has that kind of wrinkly appearance to it. And then we have so we have this outer layer of gray matter. And then we have an inner layer of white matter. And what we see in the brain is that um we also have these subcortical, so literally under the cortex, kind of little clusters of gray matter that are called basal nuclei. So if you look down at our brain over here on the left, you can see all the way around the edge and you can see it goes all the way around covering the entire surface of the brain. We have our cortical gray matter. And then you can see kind of this inner layer of the white matter, that kind of lighter pink color in our image. And you can see in the white matter, we have these little kind of pockets or clusters of gray matter and those are our basal nuclei. So we have our white matter on the inside there. All right. So that is how they they are kind of laid out in the brain. And what we see is that the spinal cord actually has an opposite pattern. So if we scooch over, let me scooch down, so you can see that spinal cord better. So here we're looking at a cross section of the spinal cord over here on the right. And you can see the outer layer is now white matter and it has this inner layer of gray matter. So we see an opposite pattern where the spinal cord has outer white matter and inner gray matter and the brain has an outer layer of gray matter and an inner layer of white matter with some little subcortical clusters of gray matter. All right. So that is white matter and gray matter in a nutshell. And I will see you guys in our next video. Bye bye.
9
example
Introduction to the Central Nervous System Example 3
Video duration:
1m
Play a video:
OK. So this example reads, given that white matter contains more myelinated axons than gray matter, which of these statements about white matter is true. So let's just kind of think back to what we know about myelinated axons from our last chapter. So we know that axons are where action potentials happen, right? Where they get propagated along. And we know that myelin makes those action potentials go really fast, right? That's where we have our saltatory conduction that really, really rapid signal conduction. So looking at the answer choices here, I see that A is reading white matter is optimized for transferring signals rapidly throughout the CNS. And that is absolutely true. So our answer is a, let's just kind of breeze through BC and D to make sure we understand why those are incorrect. So B is talking about white matter being optimized for processing visual and auditory signals. White matter certainly plays a role, but it's not necessarily optimized for the processing part of that. It's gonna help relay the signals, all right, and then sees reading white matter is responsible for decision making processes in the brain, but it's not responsible for that. Again, it's gonna be helping. But decision making is a super complex process that involves lots of areas of gray matter and white matter working together. And same is for D so D reads that it's responsible for storing information in the brain. Again, it's definitely playing a part, but it is not solely responsible for that. That isn't, that's a whole bunch of networks of gray matter and white matter working together there. So our answer here is a white matter is optimized for transferring signals rapidly throughout the CNS. Thanks to that saltatory conduction, right? So I will see you guys in our next one. Bye bye.
10
Problem
Problem
Neil says that all cortical areas of the brain are found around the outer edge (or surface) of the brain. Is he correct?
A
No; all cortical areas are found in the central area of the brain.
B
No; some cortical areas are found around the outer edges and some are found in the center of the brain.
C
Yes; the cortex is the brain's outermost layer, composed of gray matter.
Do you want more practice?
We have more practice problems on Introduction to the Central Nervous System