[MUSIC] Okay. So let's look, let's think about what happens when there are bleeds. We've got all these blood vessels coming into the brain. Things happen. Just like we get bruised on our, on our, the surface of our skin, there can be bleeds within the cranium. Unfortunately because there's a very limited space inside the cranium the consequences of bleeds that are within the cranium are much more serious then, then getting a bruise on your arm, say. So what we're going to do is we're going to look at where these bleeds can happen. And this just shows you the, the various parts that, of the of the cranium. This is the skull. And right inside the skull is this tough dura. And then underneath the dura, what we're looking down on is the piarachnoid. And if we go over to the board. I've expanded the space between the skull and the brain. Another name for brain is parenchyma. So, the skull, the dura adjoins the skull. The, these, there is no space here. No space. And there's no space between the dura and the arachnoid. And then there's this arachnoid to pia in this area the part underneath the arachnoid is called the sub arachnoid space. And in that space is cerebral sp, spinal fluid, also known as CSF. So here's an area where there's a lot of fluid. This is basically what makes, prevent, or protects your brain from sloshing around, or from bumping into the skull. You're in this protected balloon formed by the dura that is fluid filled. Fluid filled with CSF. And so as the brain moves around, it's, it can't really bump into the skull until you get to a very high acceleration, because there's this there's, there's this fluid protection from preventing it from doing so. And then we have the brain itself. And when we talked about last time were, were strokes that happened in the parenchyma and so this would be say if there's a bleed into the parenchyma that would be a h, hemorrhagic stroke. But what happens, these blood vessels are coming in from outside, so what happens if they bleed in, in one of these other areas? Well, in, in between the skull and the dura, this is called an epidural bleed. And these are epidural, dermal actually hematomas. These are extremely dangerous. They are typically fatal. If not treated very quickly. This is what killed unfortunately Natasha Richardson as you, as you may be aware. For a moment there, for a space of time there a person can be completely lucid. They call that the lucid interval. But eventually these bleeds will be fatal if not treated very quickly. Then there's another potential space, at potential, but not actual space between the dura and the arachnoid. And if there are bleeds into here, that's called a subdural hematoma. Now, in that case these can be asymptomatic. These can be, these have a range of severity. They can be either asymptomatic or they can actually be lethal. And, and in fact you'll, you'll find for instance older people will have some hematomas that are existing some small ones and not particularly giving them any symptoms. Then there are bleeds that go, that happen in the subarachnoid space, the CSF filled space. Now you may have heard that the brain does not have any pain receptors, does not have the ability, we do not have the ability to sense pain when the brain itself is injured. But we do have very sensitive we're very sensitive to injury in the meninges. And when blood comes into this subarachnoid space the pain associated with it will be the worst headache of your life. And this is an extremely dangerous bleed, the sumarac, the subarachnoid hemorrhages and they can kill. And it unfortunately very recently there was a a really unfortunate accident where an indivi, Philip Hughes was a, is a, or was a cricket player. And he was wearing a batting helmet but the, the cricket ball actually bounced up and hit him right here. And what it did, was it actually. It compressed one of these vertebral arteries so much, that the vertebral artery actually split, and it just bled right into the bla, brain. So that would be a subarachnoid hemorrhage. And, he very quickly, lost consciousness. And, despite, heroic efforts, the du, physicians, on the field and then later at the hospital were unable to save his life. So, that's a subarachnoid hemorrhage. And finally there are these parenchymal, parenchymal hemorrhages, that, that are the strokes of, of last time. So, in a final segment we're going to wrap up by comparing. What, what various parts of the nervous system do, and, and how injuries or diseases that affect various parts of the nervous system differ in terms of impact and in terms of improvement. [MUSIC]
