[MUSIC]. Ok, so now what we're going to do is we're going to look at the ventricular system. Now we really didn't emphasize this in the, in the course, but inside of the brain, there is a, there are these spaces that contain cerebrospinal fluid or CSF. And they are within the telencephalon. There's a piece of ventricle in every section. So, within the telencephalon is called these lateral ventricles. That's this c-shape. And then in the diencephalon, it's the third ventricle in the mid brain. It's the cerebral aqueduct. In the hind brain, it's the fourth ventricle. And from the fourth ventricle, CSF leaks out, this is, this is really cool. It's really cool. Okay. So here's the, here's the the brain and front, there's a leaking point right here called the Foramen of Magendie, and then there's these two leaking points over here on either side, the foram, the two foramen of Luschkas. Well, no, one frame in a Luschka, two foramen of Luschka. The fluid, the CSF flows back from the lateral of ventricles of the fore brain, of the telencephalon back through this third ventricle. Which is in a diencephalon through the cerebral aqueduct through the fourth ventricle, and when it gets to the fourth ventricle, it comes out through three holes. This is one of them, foramen of Magendie and then on either side, one and two, there is the foramen of Luschka. So there are three holes. Foramen of Luschka on the left, Foramen of Luschka on the right and Magendie. And, these three holes, CSF comes out and then it covers the convexity of the, the outside of the brain. So, the CSF is then between the brain and the dural. It's in the subarachnoid space. That's where the CSF is. It's the fluid with in the dural sac. And it surrounds both the brain and actually the central the spinal cord. So it surrounds the entire central nervous system, brain and spinal cord. So that's where the CSF is going to come from. it's, it's the same deal on the human. Although, unfortunately, this specimen doesn't have a great medulla, but it's coming out from this middle section and then also out from on either side. >> What happens to the CSF after? >> So at, so the [LAUGH]. So what happens to the CSF? There has to be a drain. If we didn't have a drain, we would have a problem. And what happens, actually, is that it gets taken up by the arachnoid. The arachnoid takes it up and puts it into these things called dural sinuses. So there are things called arachnoid granulations that are going to scoop up CSF, used CSF, put it into the sinuses. The sinuses drain into the veins of the body and back to the heart, through the vein vena cava. Okay. So, in the next section, we're going to look at all the ventricles. [MUSIC]
