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Current time:0:00Total duration:10:23

Video transcript

your brain is the most complicated structure in your body it sits inside your head and it's protected it's housed by your skull and it's made up of these these billions and billions and billions of neurons or brain cells and all these brain cells these neurons are interconnected in this really intricate way that allow you to do things like like sing and they allow you to dance and they allow you to to hear things and to smell things and to think and learn so on this side view here let me just show you the the major components of the brain the major three sections of the brain so we have our cerebrum here this big pink part that really is the the majority of what you see when you look at a brain that's the cerebrum the outer part and then in this sort of light purpley pink down here underneath the cerebrum we have our cerebellum and then in purple here at the very bottom we have our brainstem and the brain stem will eventually sort of turn into the spinal cord so that's what it looks like from a side view but let's look at what it looks like when it's sort of sitting in your head in your skull it looks kind of like that so this is what we call an anterior view we're looking at it from the front anterior so just to correlate the anterior view at the side view that we have over here everything that I'm outlining now in pink that's the cerebrum and then this light purple this is a cerebellum down here and then in proper purple this is the brainstem here and you can see it sort of turns into the spinal cord nicely down below so now that we're all acquainted with the major three components of the of the brain let's further subdivide the cerebrum into its component lobes so we have our frontal lobe here and in this light blue color and your frontal lobe is the main lobe involved in consciousness and thinking we have our temporal lobe here in this this green color and your temporal lobe helps you with your sense of smell and and your sense of sound you have your parietal lobe here in red and your parietal lobe is really important in helping you feel stimuli like pain and and touch and vibration and you can't really see your parietal lobe from the front view so I'll just draw it on the the side view here and you have your occipital lobe in yellow here and your occipital lobe is really important for your sense of sight so let me just make it really clear that all the lobes of the brain have to work together to get their functions done but having said that the functions that I sort of listed earlier for each lobe that's what that lobe sort of specializes in so that's some really basic brain anatomy so by now it's really clear that the brain is really metabolically active so it's going to need a lot of fuel it's going to need a lot of glucose and a lot of oxygen and it gets that by having a really rich blood supply so here is sort of a glimpse at the major arteries of the cerebral vascular system and it looks really complicated right I mean wow there's so many blood vessels there it's kind of a lot to take in and it is a bit of a handful so I find that it's easiest to to look at them from the underside to learn about the different blood vessels that supply the brain so let's look at that now and I appreciate that it doesn't seem any easier from the underside but we can we can go through it together so let me just reiterate that that the image on the right over here we're looking at an underside view right so we're looking up from underneath at a brain and looking at the blood supply from underneath and this will all sort of start to come together and make sense soon so you just have to sort of bear with me now so let me start by saying that although it looks really really complicated up top up here all of the blood that gets to the brain is essentially coming from four major arteries initially okay so you've got one here so this is the right internal carotid artery is on the right side and then you've got an internal carotid I'll just abbreviate it ica on the left side so that's two out of our for me your arteries then you have this one here which is the right vertebral artery and then you have the left one over here and by the way they're called the left and right vertebral arteries because they sort of run up on either side of your spinal column so within your vertebrae bones and and the internal carotid they run on sort of the anterior on the front part of your neck alright so these are the four main arteries so two vertebral arteries and the two internal carotid arteries right left and right of each and actually notice that the two vertebral arteries they sort of come together right they come together and they form this one artery here that almost looks like a little centipede and that artery is called the basilar artery basilar artery so we'll actually include that as one of our major vessels as well basal er so let's find those same arteries over on the other view the inferior view here so here's your right vertebral artery here's your left vertebral artery here's your basilar artery so that's already three out of our five major arteries and then your internal carotid they're actually a bit funny to find on this one they actually end right about here and you can see that you can see that I've sort of snipped the arteries here and in fact this is right about where the internal carotid arteries end and we'll find out what they sort of turn into in a few minutes here so those are the ends of the two internal carotid all right now we can sort of get stuck into figuring out what all the rest of the arteries are and you know it is a really complicated sort of area so I've always found that the easiest way to do it is to think about which arteries serve the cerebrum which arteries serve the cerebellum and which arteries serve the brainstem so let's take a look here let's first look at the cerebrum so coming off what used to be the ICA the internal carotid we have the creation of our new vessel called the middle cerebral artery the MCA so I'll draw that in here and solid I'll color it and install but then notice how it sort of dives underneath this lobe here so we'll we'll just do that in almost a cross hatch pattern okay so this is the middle cerebral artery and this is going to serve and remember there's one on the other side too so I'll do in solid here then when it sort of dives a bit deeper into the brains lobes will show that it's not superficial anymore and on the anterior view it's a little bit tougher to see of course but we'll do our best to draw it in so there it is there and it sort of heads out laterally okay and it does the outside part of the brain here now what else serves the cerebrum let's actually do them all in blue here we'll just use a different shade of blue all the cerebral ones will do in blue so the next thing that we have are the anterior cerebral arteries and the anterior cerebral artery supply blood to the inner parts of the frontal lobes right so you can really see how the anterior cerebral artery supplies blood to the the inside part of the frontal lobes now we have a middle cerebral and an anterior cerebral the only thing we're missing is a posterior cerebral and we're actually not missing it because we're about to find it so our posterior cerebral artery is right here and you can see that it sort of dives deep sort of above the cerebellum here so I'll just put that in and dotted in sort of hatched lines here and it's really tough to see on the anterior drawing but it's about right there so we're almost done all the blood vessels of this cerebrum the one thing I want to point out is that notice how the anterior cerebral vessels are connected by this little bridge here and this bridge is called the anterior communicating artery and notice how the middle cerebral artery and the posterior cerebral artery er are joined by this bridging artery here right and there's one on each side here and this is called the posterior communicating artery so one thing that might become really apparent to you is now these arteries that serve the cerebrum have taken on almost a year ring shape right there's a really obvious circle right here and this is really important in terms of brain circulation this circle is called the cerebral arterial circle or the Circle of Willis if you want to use the eponymous name and why is that really important well just think about this let's say you get a little blockage in internal carotid here on this side well you can imagine that now we're sort of restricting blood from getting up this internal carotid remember we said it was a major artery the internal carotid blood can't enter the Circle of Willis and cat enter the middle cerebral artery from this internal carotid anymore but because we have this collateral circulation provided by the Circle of Willis where blood can sort of go around the circle blood can still come up from this internal carotid and get around the circle and go into the middle cerebral artery from there right from the other side and blood can still continue to come up these vertebral arteries and up the basilar artery and still perfuse or fill up the entire circle and thus it really minimizes the the chances of you having some type of brain injury due to lack of blood flow to a part of your brain because there's this collateral circulation the Circle of Willis really important good so those are the three major arteries of the cerebrum the middle the anterior and the posterior cerebral artery