# Brain Structures

https://www.youtube.com/watch?v=ej5rONhHy20

[00:00] In this video, we would be covering the brain structures.
[00:04] So to begin, we'll first look at structures that you'll only see present in the embryo.
[00:11] So the first embryonic brain structure we'll look at in detail is the telencephalon.
[00:18] So the telencephalon actually forms the cerebrum in the adult brain.
[00:23] The second embryonic brain structure is the diencephalon.
[00:26] So the diencephalon lies deep within the brain and contains two important adult structures which we'll look at a little bit later, called the thalamus and hypothalamus.
[00:41] The third embryonic brain structure is called the mesencephalon.
[00:44] Mesencephalon is also called the midbrain.
[00:51] The other embryonic brain structure is called the metencephalon.
[00:57] So the posterior portion of the metencephalon becomes...
[01:00] The cerebellum, while the anterior portion of the mesencephalon becomes the pons.
[01:08] The last embryonic brain structure is called the myelin set wall, so the myelin cephalon becomes the medulla mudada in the adult brain.
[01:20] And as you can see here, the myelin Safwan is closest to the spinal cord.
[01:27] So now we'll move on to look at the adult brain structures.
[01:30] So the first adult brain structure we're gonna look at is the cerebrum.
[01:33] So the cerebrum is the largest part of the brain.
[01:38] So you'll see the cerebrum located here in this anterior view, but you also see the cerebrum in the anterior lateral view.
[01:45] And so one thing about the cerebrum is that it's divided into two large paired parts.
[01:51] So you have a right cerebral hemisphere and also you have a left cerebral hemisphere.
[01:56] And each of these cerebral hemispheres are separated from each other by a longitudinal fissure, and you will also...
[02:04] See the launch new fissure here in this anterior lateral view of the brain.
[02:07] Each cerebral hemisphere is divided into four lobes, and the lobes are named after the overlying bones of the skull.
[02:16] So the first lobe we'll look at is the frontal lobe.
[02:20] So you'll see the frontal lobe in the anterior view located here, but also you'll see it in the interior lateral view.
[02:26] And so what's set but structures that separate the frontal lobe from the other lobes of the cerebrum is the central sulcus.
[02:37] So the central sulcus lies posterior to the frontal lobe.
[02:44] Another structure that you'll see present in the anterior lateral view is the lateral sulcus.
[02:49] So the lateral sulcus marks the frontal lobe's inferior importer.
[02:54] So the region inferior to the lateral sulcus is the temporal lobe.
[03:02] And so you'll also see the temporal lobe.
[03:04] Lobe in this anterior view here and here.
[03:08] And so the parietal lobe extends posterior from the central sulcus.
[03:15] So therefore you'll see in this anterior lateral view the parietal lobe located here.
[03:23] Now if you look at the posterior view of the human brain, you'll find the last lobe of the cerebrum, and that is the occipital lobe.
[03:32] So the occipital lobe is located superior to these structures here, which we call the cerebellum.
[03:40] So if you do a cross-section of the cerebrum, you'll see this view here.
[03:47] And so this cross sectional view of the brain allows you to see the cerebral cortex, which is this orange reddish color structure in the cerebrum.
[04:00] And the cerebral cortex is a thick blanket of gray matter that
[04:05] Covers the cerebral hemispheres.
[04:09] And so the internal structure of the cerebrum is made up of what we call white matter, which is this white colored structure here.
[04:21] Now we will look at a midsagittal view of the brain.
[04:24] So the first structure we'll look at is the corpus callosum.
[04:30] And the corpus callosum contains fibers that leave the two cerebral hemispheres together, therefore allowing the two cerebral hemispheres to communicate with each other.
[04:45] And so a structure inferior to the corpus callosum is located here, which we call the thalamus.
[04:50] So thalamus is part of the diencephalon of the brain.
[04:57] And so inferior to the thalamus is this structure here, which we know of as the hypothalamus.
[05:02] And so the hypothalamus.
[05:05] Forms the floor of the third ventricle.
[05:07] And it extends from the area superior to the optic chiasm, which is located here, and extends posteriorly to the mammary body, which is located here.
[05:25] Now we'll look at two endocrine structures that are present within the brain.
[05:29] So in this mid sagittal view of the brain, you'll find the first endocrine structure, which is located here.
[05:35] And so this endocrine structure is present inferior to the hypothalamus and is called the pituitary gland.
[05:48] The second endocrine organ that's located within the brain is located here.
[05:55] And so this structure is called the pineal gland.
[05:59] And so this endocrine organ is responsible for secretion and
[06:05] Synthesis of melatonin, which is important for regulating the light and day cycles, which was known as the circadian rhythm.
[06:16] Another structure that you see in this cross-sectional view is known as the mesencephalon, which is the midbrain and is located dorsal to the mammoth body.
[06:31] Located inferior to the midbrain is what we call a structure that's more inferior to the pons, which is what we call the medulla oblongata.
[06:43] So the medulla oblongata, which is located here, connects the brainstem to the spinal cord, which is here.
[06:55] So now we'll focus on a structure that's on the dorsal aspect of the mesencephalon, which is this structure here.
[07:05] It is called the corpora quadrigemina.
[07:09] And so the corpora quadrigemina contains two sensory nuclei known as the two inferior and two superior colliculi.
[07:20] Another structure that you'll see present in the mesencephalon is this narrow passageway here, which is known as the cerebral aqueduct of the midbrain, which is another name for the mesencephalon.
[07:36] And so the aqueduct of the midbrain or the cerebral aqueduct, the two lateral ventricles with the third ventricle.
[07:48] Another structure that you'll see is this structure here, which is known as the fourth ventricle.
[07:56] So the fourth ventricle connects the third ventricle with the spinal canal located in your spinal cord.
[08:04] So now we'll focus on.
[08:07] Structures that's present in the cerebellum.
[08:10] So the cerebellum has this internal white matter that is called the arbor that hey.
[08:22] And so as you can see here it resembles a tree with its branches.
[08:28] Now look at a frontal or coronal view of the human brain.
[08:36] And so as you see in this front view of the human brain, you'll see this collection of nuclei called basal ganglion or basal nuclei.
[08:45] And so basal nuclei are masses of gray matter that lie within each hemisphere.
[08:52] And as you see it's very deep to the floor of the lateral ventricles in each cerebral hemisphere.
[09:02] Another structure that you see in this frontal view of the human brain is the internal capsule.
[09:08] Which is located here and here and so.
[09:11] The internal capsule contain fibers that link the cerebrum with the other regions of the brain and the spinal cord.
[09:25] In the brain there are four ventricles in the adult brain, one within each cerebral hemisphere, a third within the diencephalon, and a forth between the pons and cerebellum.
[09:45] So the first bench will you see here is what we call the lateral ventricle.
[09:50] So again you have the latter ventricle here on the left, but you also have a lot of ventricle as you see here on the right.
[09:57] So each cerebral hemisphere contains a lot of ventricle.
[10:00] So the lateral ventricles are connected to the third ventricle which is here via this structure here which we call the interventricular foramen.
[10:07] So one thing I
[10:12] Forgot to mention is that these ventricles are filled with CSF fluid.
[10:17] Therefore the individual interventricular foramen allows the CSF wood to drain from the lateral ventricles into the third venue.
[10:30] So the other structure that connects two ventricles together is what we call the cerebral aqueduct of the midbrain.
[10:40] And so the aqueduct of the midbrain or the cerebral aqueduct connects the third ventricle to the fourth ventricle.
[10:49] And the last structure that you see within this ventricular system are these red colored structures.
[10:54] So these red colored structures are what we call the choroid plexus.
[11:00] And the significance of the choroid plexus is that this is where CSF, the cerebral spinal fluid, is made.
[11:11] So now we'll look at structures present.
[11:13] In the brainstem, so in review we already looked at the thalamus, which is located here.
[11:17] We looked at the pineal gland, which is the smiths Adderley located structure.
[11:25] And we also looked at the kaepora quadrigemina, which are located here.
[11:33] Yep, so nerve fibers located on the ventral lateral surfaces of the mesencephalon, which is located here and here, are what we call the cerebral peduncles.