[MUSIC] Let's start by understanding the two components of the central nervous system. The two components are the brain, and the spinal cord, and the brain is the part of the central nervous system, that is contained within the cranium, inside the skull, up here, the noggin. And then the spinal cord, is what's contained, here, within the vertebral column. So, the vertebral column is this, you can see it here. The spinal cord is actually right in there. And now let's look at a skull. Here is a skull. We're going to take the top off, and what you can see here. Is the inside where the brain sits. This brain is sitting in here. This is all brain. There's brain in this part too, that continues like that. And then right here, is the join with the, spinal cord. So this, right here, is the foramen magnum. It's the hole, the big hole where the spinal cord comes up, and it joins, its continuous with the brain. Those two components together, the spinal cord and the brain, make up the central nervous system. Let's do one more thing, and try and understand where this foramen magnum exists in us. So, if we take this, it's sitting like this, you can see that here are the teeth, here are my teeth. So, right here, is where the foramen magnum is. Now, if I go like this, I can feel the back of my skull. I can feel this point where my skull starts to indent. And that's exactly, if I go a little bit farther forward, actually. Quite a bit farther forward. I will see or I will come, I would come to my foramen magnum. So my spinal cord is right in there. Okay. In the next segment, what we're going to do is we're going to look at the meninges, the coverings that are within the bone. But outside of the central nervous system. [MUSIC]