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  • Okay, so this is a tutorial on the parts of the brain. So, this is a basic tutorial and

  • I want to give you an overview of the different parts that make up the brain. So there's not

  • going to be huge amounts of detail here, but this is just a tutorial to sort of orientate

  • yourself with regard to structures of the brain.

  • So we'll start off by looking at the brain stem. So, first of all, I'll just point out

  • what we're looking at here. We're looking at a side view of the brain. Anterior is this

  • side, posterior is this side, and obviously superior and inferior. So, you can sort of

  • see the veins and how it sits there.

  • So I'm just going to rotate it around and we'll take a look at the brain stem. So I've

  • just removed some of the nerves to make it a bit more clearer. So, the brain stem is

  • this bit here and it consists of three parts. You've got the medulla oblongata, the pons,

  • and the midbrain. So the medulla oblongata is this bit here, which is most distal or

  • most inferior, and it starts at the end of the pons and it ends where the spinal cord

  • begins. So the spinal cord begins at the opening of the skull at the foramen magnum, and this

  • is where the medulla oblongata ends.

  • So, just above it you've got the pons, which is this bit here. And above the pons, you've

  • got the midbrain. So, what I'm going to do is just isolate the brain stem. So I've just

  • removed all the other structures. We're looking at the exact same view. You've got the medulla

  • at the bottom; the pons and the midbrain above it. So the midbrain is this region here and

  • it consists of -- so, at the front, you've got these bits, which are called cerebral

  • peduncles and, at the back, you've got these little sort of hills, and these are called

  • the corpora quadrigemina, and this is Latin for quadruplet bodies because obviously there's

  • four little bumps.

  • So, the top ones are called superior colliculi and the bottom two are called inferior colliculi.

  • And the word colliculi is Latin for lower hills, because of their appearance. So, these

  • colliculi sit on the tectum, so the tectum is sort of the roof of the midbrain. So, tectum

  • means roof in Latin, so here corpora quadrigemina sit on the tectum of the midbrain.

  • So the midbrain is this structure here. You've got the cerebral peduncles and you've got

  • the tectum with the four colliculi. So, in the midbrain, you've got loads of nuclei.

  • So, nuclei are collections of cell bodies, which are contained in the nervous system.

  • Sorry, in the central nervous system, whereas ganglia are collections of cell bodies in

  • the peripheral nervous system. So, in the brain stem, there's lots of nuclei, which

  • are important for controlling functions like heart rate and blood pressure and respiration

  • as well as things like the level of consciousness and wakefulness and arousal. And then you've

  • got lots of cranial nerve nuclei and nuclei related to the cerebellum, which I'm just

  • about to show you.

  • So I've just switch back to this model and I'll just show the cerebellum. So, the cerebellum

  • is this part of the brain, which sits behind the brain stem. So you can see it here, sitting

  • directly behind the brain stem, and you can see it has these two lobes. So the cerebellum

  • means little brain in Latin, and this has loads of connections with the brain stem and

  • it's important in motor control and coordination and balance and muscle tone, and that sort

  • of thing.

  • So, if I remove the cerebellum, and I'll just remove the hemispheres as well. So, we can

  • see the midbrain here, so you can identify them by the colliculi. So that's the midbrain

  • sitting. Well, this is the dorsal surface of the brain stem.

  • So, the next part of the brain that we need to talk about is called the diencephalon,

  • and this is the part of the brain that sits on top of the midbrain and it consists of

  • the thalamus, the hypothalamus, and the pineal body or the pineal gland, which is what it's

  • also called. So, I've just removed the cerebral hemispheres and the cerebellum, and we're

  • looking at the back of the brain stem. So, remember, you can see the midbrain here, which

  • is easy to notice, and then, below, you've got the pons and the medulla oblongata. So

  • the midbrain is sitting just above this.

  • So, you can see this paired structure. These paired sort of oval roundish structures. These

  • are called the thalami, and you've got two thalami. So, one on each side, and they're

  • joined at the middle via the interthalamic adhesion. So, just below the thalamus you've

  • got the hypothalamus, which is a little bit smaller. So the hypothalamus sits here. So

  • I just got rid of a few of these structures so you could see the oval-shaped thalamus

  • and the hypothalamus below it. And at the back, just here, you've got the pineal gland.

  • So the thalamus is a really important structure to know about because it essentially acts

  • as a switchboard or gateway to the cerebral hemisphere, so it relays connections to the

  • cerebral hemisphere - to the cerebral cortex of the cerebral hemispheres. And it contains

  • lots of nuclei. So, the thalamus sends and receives fibers from the cortex and it's got

  • thalamo-cortical loops and lots of reciprocal connections. So, it's important for many things

  • such as sleep and wakefulness. It's important in coordinating information from the various

  • sensory systems and it also has links to the basal ganglia, which I'll come to talk about,

  • and also the cerebellum.

  • So, I've just switched to this lateral view. I've removed various structures so you can

  • visualize the thalamus right in the center very clearly. So you get a lot of fibers projecting

  • into the thalamus and the thalamus coordinates all this information and it projects fibers

  • into the cortex and it also receives fibers back from the cortex. So you'll often hear

  • the thalamus referred to as a relay or switchboard or a gateway for this reason.

  • So, the cerebral hemispheres are what most people think of when they think of the brain.

  • So, we're looking at these two cerebral hemispheres here. You've got a right and a left cerebral

  • hemisphere. And the cerebral hemisphere is responsible for higher functions. So, thinking,

  • memory, consciousness, language, emotion, movement, and sensory perception - these kinds

  • of things. So, the cerebral hemisphere consists of an outer cortex, which is made up of six

  • layers of gray matter, and you've got the inner portion of the cerebral hemisphere,

  • which is made up of white matter.

  • So, I'm just going to rotate the brain around and I'm going to switch to a diagram to illustrate

  • the cerebral cortex. So if we take a...so imagine just cutting the brain through this

  • axis here. So, directly -- we're going to take a slice of the brain down here.

  • So we're looking at this cross section of the slice we've just taken, so this is a coronal

  • section. And what I wanted to show you on this slice is the cerebral cortex. So, the

  • cortex is the outer part of the cerebrum and it is gray matter. So, you can see this thin

  • bit on the edge of the cerebrum. This is the cerebral cortex and it consists of up to six

  • layers of neural tissue.

  • So, the neocortex is where the cortex has six layers. Any other parts with less than

  • six layers is referred to as the allocortex. And this allocortex can be subdivided into

  • an archicortex and a paleocortex, so these are part of the cortex with less than six

  • layers. The neocortex is the one to remember because this is the newer, sort of evolutionarily

  • newer, part of the cortex and is responsible for higher functions like language and conscious

  • thought. So the neocortex has six layers.

  • So, just looking at the outside of the cerebral hemisphere, you can see that there are these

  • grooves and you've got ridges. So the ridges are called gyri and the grooves are called

  • sulci. And you've got lots of these different grooves and ridges, as you can see, and they

  • all have different names. But two important ones to remember are the central sulcus, which

  • I'm showing you here with the arrow, and the lateral sulcus. And I'll do another tutorial,

  • which goes through all these different grooves and ridges.

  • But the reason I showed you these - the two sulci, the central sulcus and the lateral

  • sulcus - is because these two sulci can be used to separate some functionally important

  • lobes of the brain. So you've got four lobes of the brain, which are separated by various

  • grooves.

  • So, anterior to the central sulcus, which I'm drawing along here, you've got the frontal

  • lobe because it sits behind the frontal bone of the skull. So, this is the frontal lobe

  • that I've outlined in red. Posterior to the central sulcus, you've got the parietal lobe,

  • and this runs like this, so I'm outlining this in yellow. And this is called the parietal

  • lobe because it lies under the parietal bone. And inferior to the lateral sulcus, which

  • I'm drawing on in green, we've got the temporal lobe. So I'm just outlining the temporal lobe

  • here, and it runs like that. And right at the back we've got this lobe here, called

  • the occipital lobe, which I've just outlined in blue.

  • So this is quite a rough illustration of the four lobes, but I wanted to show you how the

  • central sulcus and the lateral sulcus are important and defining these different areas.

  • So, anterior to the central sulcus, you've got the front lobe; posterior to it, you've

  • got the parietal lobe. And then you've got the lateral sulcus, which, inferior to the

  • lateral sulcus, you've got the temporal lobe.

  • So the frontal lobe is important in decision making, problem solving, and planning. The

  • temporal lobe is important in memory, language, emotion, and hearing. And the parietal lobe

  • acts as sort of integrator of sensory information, so it receives and processes sensory information

  • and the occipital lobe, sitting at the back, is responsible for vision.

  • So, that's a very crude overview of their functions, but it gives you an idea that different

  • lobes have different functions.

Okay, so this is a tutorial on the parts of the brain. So, this is a basic tutorial and

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B2 中上級

脳の基本パーツ - パート1 - 3D解剖学チュートリアル (Basic Parts of the Brain - Part 1 - 3D Anatomy Tutorial)

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    wshuang999 に公開 2021 年 01 月 14 日
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