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So let's get started. Hello, everyone. Welcome to our, uh, final back to school Siris. Um, Gracia with pretty nisi today I bring your own preclinical, um, lectures. If you already don't know. Police follow us on our social Czarsky. Easy. I'll mention it again. And, uh, our social will be put into the chat. Um, just a quick, quick word from us ones is medical protection society Are a Corgan ization that provide defense against medical lawsuits or anything legal related. Did they do a weekly 183 lbs? It's free for medical students on DA junior healthcare professionals. So if you are keen on winning 183 lbs on a weekly basis, sign up and you'd be entered into a drawing M D u r Another defense organization Medical difference. A union on they specialize in, uh against it. It's, um it's similar to MPs, um and ah deals off a free membership, and I think it's 10 lbs to renew your membership when you go from F one to F two. 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Hopefully, everyone can see that. So Hi, everyone. So, today I'm in this presentation. I'm going to be going through some urology with you. So for those of you that don't know me, I'm Megan on one of the pre clinical teachers in the pre clinical teaching team are squeezy a savant sent. This is our last session on the back to school Siris. I hope these sessions have been really useful. Two guys that preparing you for returning to medical school again. This has been part of the pre Clinique's e Siris, which will be running sessions throughout the academic year. Um, we aim to make your pre clinical years of medical school ah, lot easier. Here's a list of our upcoming sessions. The's will be going up on Facebook a sev ent shortly. So make sure you click going on those events on Facebook to get the date, the times and the zoom links. Sorry, man. And just add on if you just go to the previous slide. Um, the basic clinical sciences we have, uh, because we wear going for a big, bigger audience. Ah, not only call if we have renamed it from platform for clinical sciences, So that is your BCS sessions, and we will put K sessions at the bottom, but we will name it like embryology, it Chantix and congenital abnormalities bracket K seven. So just a heads up? Yep. And those sessions, they're open to everybody. But as advanced will label them for the card of students as well. So, for neurology, here's what I'm going to be covering with you today, but let's get straight into it. So I'm going to begin with an overview of the structure of the nervous system just so we can orientate Selves. So the nervous system is that into the central nervous system, which contains the brain and the spinal cord on the peripheral nervous system, which includes the spinal nerves, their roots and the branches prefer nose near muscular junctions on the cranial nerves, except two of them. So just to get some interaction going, does anyone know which two of the cranial nerves aren't in the central nervous system on the powerful nervous system? Sorry, you just type it in the child. Yep, one and two. Well done. Who said that? That's correct. So your your factor in your optic on these are extensions of the brain, so that technically crosses the central nervous system. So then the peripheral nervous system then spits on. It separates itself into sensory neurons carrying Afrin signals on motor neurons, which occurring if rinse signals on. I don't like to remember that as it's being in our for best quarter, so you receive a sensation first. So Afrin begins with the first letter of the alphabet. A on. Do you have a motor neuron to move in response to that signal? So it's an inference signal where the letter years later that day and the after that, Then, within the motor portion of the nervous system, we have autonomic nerve fibers, which control the actions that we do not consciously think about or control, such as our breathing, our heart beating, digestion, things like that. And you have these somatic nerve fibers which control the actions, which we do have concerts conscious control over on such a zar scalito muscles, for example. Finally, the autonomic nervous system is broken down into sympathetic. So you're fighting flight system. Your parasympathetic called Rest and Digest on the Internet nervous system, which is a mesh like system off neurons that live within the walls of the GI tract, and they control the smooth muscles here. So in this CNS and the Penis, there are nerve fibers, which helped to conduct impulses. Between are sensory organs are brain or spinal cord on our effect organs, but the CNS and the Penis also comprised of many other non your own or cells that do not produce that electrical impulses, but instead maintain home your Stasis, promote electrical conduction on provide support protection for neurons on these supportive cells called Vioxx that was a clear cells Andre within the CNS. There are three types of yourselves. Can anyone type in the chat for me? What? Those three types of cells are in the central nervous system. No worries. No worries until we're going to go for it. So the fast one that I'm going to tell you about is, um oligodendrocyte. So so oligodendrocyte They mile in a accidents in the central nervous system on the A move that is, to increase the speed of salt. A Tariq undock shin from gaps in the myelin sheath. So you have your oligodendrocyte sites, which is kind of creating little Mile um, pockets. But there's gaps between them on Do the nerve conduction almost jumped between those gaps on that speeds up the conduction rather than just going straight through. Also, after there's nerve damage, your oligodendrocyte prevent the growth of neurons in the CNS because they expressed some angle growth inhibitory proteins on that, make sure that the neurons don't go back in correctly. The central nervous system is a very delicate structure. You don't want things growing back in correctly and messing things up, so it suppresses that great on Do the one oligodendrocyte. As you can see here come out a mile and a multiple urines that time. So can anyone type in the chapel? Me. What the equivalent cell is in the peripheral nervous system? Brilliant. Yep, especially guys were done yet. So it's one cells correct. So there are two types of one cell. There are myelinating time cells, which wrapped around the neurons and allow Lapid's. So take three conduction between the nodes of Rome. Be a and you must have known myelinating germ cells, where, this one says, do not contain my island to wrap around the axle. No more than eight inch one cells conduct action potentials a lot more slowly because you don't have that on salt a tree conduction. So that usually found, um, in the Neurontin that controlling all I'm kind of nociceptive dull pain. Do you have, like, a dull ache? They go through bigger for the normal in 18 shown cells. Does anyone know what the type of fiber is in the peripheral nervous system that controls a dull pain? Brilliant. Yeah, well done yet. See? Brilliant. That's great, guys. Yep. C five c o c. If I was control your door pain on does they won't know what controls your sharp pain? A daughter yet mastered guys yet, So you're a delta. Fibers carry that sharp pain on their conduct a lot more quickly, so there'll be more myelinating. So then, I think in the chat a little bit later, some other people mentioned some other central nervous system for yourselves. The next one, I'm going to talk about the Astrocyte. So so. These are starship cells, which have lots of different functions. These cells maintain the integrity and the structure of the blood brain barrier. They regulate the concentration of potassium around your arms, which is obviously really important for action potentials. We know that's to do with the movement of irons. You need really carefully control the amount of potassium around those neurons. They also help with a glutamate neuro transmit of re uptake into nuances. Once on action, potential was made in a neurotransmitters been released from the sign Active class. Then they need to be taken back up again. Is the Astros that's gonna help with that? And they also surprised the neurons with energy for molecules such as cholesterol on lactate to make ATP, as well as helping to regulate blood flow to the brain via mechanisms controlling vasodilation and vasoconstriction of the vessels. So astrocyte do lots and lots of different things. Then we have all my quickly, uh, on. Bees are basically the white blood cells of the central nervous system. So what they will do is they will Facusse I toes or they will eat up any damaged or infected cells. So can anyone taking the chapped? Why do we need Mike there in the central nervous system? Why can't all normal white blood cells do the job My country function here? Yeah, you guys have got it yet so they can't cross the blood brain barrier. So that's why we need a completely sip a separate set of like, white blood cells start cells in order to make sure that the brain can be equally protected from damaged or infected cells. So in the peripheral nervous system, there are two types of legal cells one being this one cell that we've already mentioned. Andre, Other type of side that we have is called satellite. So what's that slight cells do is they cover the surface of the cell bodies of neurons in the peripheral nervous system. On what they do is they act like a cushion. Azizullah's providing nutrients to supply energy to that you're on. So that's kind of an overview of the cells and the structure of the nervous system. I'm going to now start with the spinal cord and talk about it's interactions with the peripheral nervous system on. Then I'll go on to talk about the brain itself. So these final tracks are the neuronal pathways that run between the brain through the spinal cord on out to operate Freeze. And there are three main tracks that you need to know really, really well on your pre clinical years. So you have two sensory or a sending tracks, which carry sensory information on run from our sensory organs through the spinal cord and up to the brain. And you also need to know one motor or descending tract, which ones from the brain done spinal cord to your affected opens so we'll go through those now. So let's start with the sensory tracks, a sending since retracts made up of three neurons. You have a fast ordinary on a second order in your own, and a third or dinner says, illustrate what each of those nose do. Let's take a Nexium pulse. So let's say you reach out with your hand and you touching object. Your first ordinarily is going to carry that sensory input from the peripheral pressure receptor from where you've made contact with the objects through a peripheral, never to a structure called the spinal or the dorsal root ganglion, which you can see on this image. Now a ganglion is just a fancy word for just saying a collection of cells bodies in the peripheral nervous system. So I said before that the spinal nerves and their branches that part the perfume nervous system. So this ganglion is just a collection of cells, but he's here, so the cell body off the first or general is in the ganglion. But then it the nerve kind of continues round, and it projects into the posterior or the dorsal grey horned of the spinal cord, which is the yellow area on this diagram. As you can see, it's kind of making a V shape where it's about to sign up Now. The one big role for sensory tracks, which I hope will make things easier, is just remember that first for gyn you're on's always remain. It's electoral, the same side to the side where they end the spinal cord on so they don't cross over to the other side of the spinal cord. They cite when they sign ups with the second order in your own, which is our next type of you're on. They do this just before the pathway Dex eight, or crosses over to the other side. So as soon as you get that switched from the first order to a second order in your own, and that's when the pathway will deficit. Eight. So the first order in the second order neurons consign. Act in to place one of two places, depending on what pathway they're in. So they can either sign up in the tip of the posterior great horn of the spinal cord in an area called the substantia gelatin osa, which is where they sign up for the second order. Neuron that second or ordinary on more than Dex A. And ascend the spinal cord in something called the spinal thalamic White Matter tract, on which I'll explain more in a sec. But that is what's being shown it in this image here, so It's sign up singing in the dorsal horn deca, stating, once you get to second order urine and then heading up alternatively, the first organ your own. Consider a it see natural travel up the dorsal column track. Um, and it conduct a say further up, um, in the medulla, um, and then the when it dexa disappoint. Deck straight is where the second order in your list. So then, when that second order neuron reaches a sub cortical areas, so just an area meaning just below the cortex somewhere so the thalamus, the medulla, anything like that, this second order in your arm or then sign ups with Third or General and these third order neurons pick up that neuro impulse and they carry on to the cerebral cortex. Um, specifically for your sense, retracts your somatosensory cortex so that you can begin to proceed that stimulus. So let's go through the tracks more individually. My biggest tip for learning the spinal tracks because I know that could be sometimes a bit hard to remember, is using the name of the track to work out where it's going. So let's start with the dorsal column ascending sensory pathway. So start off by using the names. The dorsal column That means it's going to be traveling in the back or the posterior or dorsal part of the spinal cord. Now this tracks carries information about flying touch, vibration and proprioception, and proprioception is just known where your joints are in space know incredible angles. There are without having to look at them with your eyes. So that's worked for on your arms again. So the first organ you're on is going to carry those sensations of fine touch vibration appropriate section from your peripheral nerve to the spinal cord. It will enter the spinal cord, and it will remain. It's electoral and travel up The dorsal column pathway, which is the said, is on the posterior part of the spinal cord, and it does this in the same side of enters, and it travels up all the way to the medulla. Um, then when it gets the medulla, um, the first surgeon, your own sign up says of the second order neuron at one of two notes Nuclear in the medulla, depending on where the sensory signal has come from, so either within the nuclear scrutiny, ISF for any signals coming from the upper limb or from the nucleus Priscilla's, which is for any signals coming from the love him. And once, as I said before, when you've had that sign ups between the 1st and 2nd or general assumed you've done that, it will. Then next eight on it travels to the Kalamazoo, which is our sub cortical area for this pathway. The third and Order Your on, once signed up in the thalamus, travels from the thalamus through a white matter area called the internal capsule up to the primary somatic sensory quarter. So next onto the spinal thalamic pathway, so once again use the name Spinothalamic. It's going from the spine to the thalamus, so it's going from the spinal called to a part of the brain's. It's going from somewhere peripherally to summer century, so it must be a sensory pathway. Now the spinal thalamic track is composed of to kind of subtracts. You have the anterior pathway, which carries crew touch, which is basically just touch where you can't precisely discriminate its location and where it's coming from on pressure as well. And you also have the natural pathway, which carries pain in temperature and I like to remember that as pain and temperature P and t spine know fill Amit. I've highlighted it on the side. It's got the pee in the tea and it, so hopefully that will help you remember it. So let's work for on your arms again. I've put little stars is to wear each of them all on the image. So your first or gyn you're on it's gonna carry those sensations of pain. Temperature, crew touch etcetera from a peripheral nerve to the spinal cord. Once it reaches the spinal cord, it might ascend one or descend one or two spinal levels. Or it might just stay at that level. Would center. That depends where it is in the spine. So then enters the spinal cord via the posterior spinal room. And it's signed actors with second order neuron in the substantial gelatin. No, sir, which, as you can see from the images just in the tip of the dorsal horn. So now we have our second order Neuron. Remember of roll? It says we get our second order, neuron. It's gonna dexa straight straight away on the second or general is gonna dex a travel across over to this side on, then travel from and then travel out the spinal cord. You know the natural or the anterior spinal thalamic track, and it goes up those tracks until it reaches the pollen this on at the thalamus. That's where our second order neuron sign that says, without third ordinary on on the third order in your entree, Val's from the problem. It's through the internal capsule again to the primary somatic sensory cortex. So that's the two main sense retracts that you need to know. So now let's go back to Let's Go to motor tracks now. So these are our descending tracks. So instead of having a 1st 2nd 3rd order in your in your motor tracks, have their signals carried by two neurons. Pacific Lee, an upper motor neuron and a low amount in your own. Now, once again, that's using example to help make sense of this. So let's say I want to move my arm, for example, using my scaly two muscles so an upper motor neuron is going to start in the cortex in out of grey matter of the brain on gray, matter is just a it contains in your own cell bodies. So the cell bodies of the upper motor neuron we're going to start there. Then the axon of that motive you're on is gonna come down the cortex down the spinal cord in the White Matter tract. Remember what matters just made up of accidents. You're gray. Matter is somebody's, um, are your white matter is your accent's that travels down the white mass track on it goes into the horns of the spinal cord. Then, um, it goes into once it's in the horns of the spinal cord. It Sinuses with the lower motor neuron at an area called the anterior horn Cell. On this is found in the anterior part of the one of the spinal cord on That's the start of your lower motor neuron. And that's where the cell bodies of the emergency one hours. Well, then what? That After that, the lower motor neuron comes out of the anterior or ventral route through the spinal nerves to the nerves of the periphery to then innovate the muscle. So in this case, two mile, So let's go through the one motor track. We really need to remember on dots the corticospinal track. So once again used the name Corticospinal, so it's going from the cortex to the spine, so it must be going down. So therefore, it must be a motor track. Now, the court respond. Attract nerve fibers begin in the street because Texas, I said, um, and they they receive a range of input. So they receive input from the primary motor cortex, the pre motor cortex on the supplementary motor area, while we go through the different areas of the brain shortly. So hopefully that will make more sense. So all of the neurons from those different part motor areas of the brain converge on. They descend through that internal capsule, which is a said, is a white matter pathway, which is located between the thalamus and the basal ganglia on. This is really important critically to know, because the internal capture is particularly susceptible to compression from a hemorrhagic bleed. So where there's a bleed bleed in the brain on this is only is a capsule a stroke, Um, and if you have a captain of stroke that come there for cause issues with this descending tract and cause lots of motor problems in the rest of the body, so going back to the pathway after the internal capsule, the neurons passed through the mid brain through the palms and into the medulla on in the most inferior part, the medulla. The track divides into two, which each takes different paths. So first you have the lateral corticospinal track. This decade, states of switches sides in the medulla descends through the spinal cord in terminates in the Ventura allow anterior home and then from that interior horn on the lower motor neuron Sinuses with the upper motor neuron on the low mood, motor neuron goes on to supply the muscles of the body, whereas the other tracks the anterior corticospinal track remains. It's a natural descends in the spinal cord on deck A states the level of the spinal cord that wishes to exit up, and then from the eventual horn below, a motor neuron once again goes off. Just apply the muscles of the body. So hopefully that those that's made the tracks of it easier to understand. I'm now going to go into the brain itself, starting with its anatomy, so I'm going to start off by just talking about the lobes of the cerebrum or the brain So the cerebrum has two main hemispheres, the left on the right, and they're separated by an extension of the jury. Mata off the meninges called the folks Serebrier within the long Detroit No official um, basically, the longer treating a fissure is just the gap between the two hemispheres of the brain. So each hemisphere has five loads. Teo, as you can see from this side, it has frontal, parietal, temporal, occipital and insur, and you can't really see the insulin here. It's not seen from the electro services, but if you separated along the line, which I've labeled the lateral focus, you would then be able to see the insulin low. But it's just underneath. So an important thing to know is that each hemisphere controls the other side of your body. So, for example, if the left side of your brain was compromised, the right side of the body couldn't trolls would be affected. The surface of the cerebrum is called the cortex, which is really highly involved. Did infolded unfolding? The sheet helps to increase the surface area of the cortex and packs more gray matter, more cell bodies into that small volume available inside our school Onda Gym. As a general rule, the more advanced in animal is, the greater the degree of involving there is in the cortex. Now, this unfolding creates both dry right and so okay, which you can see in the in the image in the bottom. Right. So the soul kind of the groups in the cortex on the gyre a of the ridges these groups create. And the way I like to remember this is a so quiet sounds a little bit like soak on down. So it means, like to be sad or to be depressed. Therefore, the so chi are the depression's in the cortex. And what I've done on this slide is I've labeled the main cell kind gyro, the brain that you need to know on these are really important for your briefing nucleus. And then in terms of the lows, it's important to know what separates each load. So this I'm just gonna point out a few other important areas on the external surface of the brain. So the pre, except to not, is on indentation around about five centimeters in front of the occipital pole, which is kind of the most posterior part of the occipital lobe. Um, and that pre exception notch is found on the inferior lateral border of the temporal lobes of the bottom kind of lateral outside. And it's a really significant landmark, as the occipital lobe is defined as line between something called the lateral prior to Temple Line, which is a theoretical line joining the pre occipital not on the prior to accept It was so close, Um, another way s. O that separates the occipital, open the other lobes of the brain. And then, if we want to separate the temporal from the front on the prior two lobes, that's done by the lateral so close to the point of which the Sylvian fissure the electric sockets turns upwards, defines the border between the temple on the prior two lobes on the lateral surface now on the side Here included some of the key functions of each of the lobes. But I'm going to go into that in more detail my next flight. So let's go through the functional anatomy of the brain, so the cortex, immediately anterior to the central soakers, is known as the primary motive cortex on um, the function department medical text is generating your impulses that passed down the spine Spinal cord through the descending pathway is on, but we were talking about earlier and control our muscle movements are motor function. In contrast, the cortex immediately posterior to the central focus is the primary somatosensory cortex, and this has a map of the body and let representing move on. Sensations are talking about pressure. Vibration are paying in different parts of our body. On the function of this area is to receive the sensory information from ascending pathway is when it first enters the cortex and it kind of process is those then some other important areas that you need to know are broken area. So this is located in the left hemisphere, um, in the frontal lobe, and it's associated with speech production on the articulation, more ideas through growth spoken and written language on. This is really important clinically, and you'll be tested on it quite often. Is damage to this area can cause an inability to produce speech. In contrast, very case area is found in the Left Hemisphere in the posterior superior temporal lobe. Um, and this is another critical language area, um, which is primarily involved in the comprehension and the processing of written and spoken language. So damage to this area causes an inability to comprehend speech. So I'll repeat that again. So Broca's area is your ability to produce speech. So if that's damage, you're not going to be able. Teo. Articulate yourself and produce speech. Raise your Veronica's area is more about comprehending speech. I apologize. That's slightly wrong on the slide. I will change that before they go up on metal. I've also included some other areas here, which I'll let you read through in your own time, which are the areas that you should know if you're preclinical years. So then onto the cerebellum. So the cerebellum is found in the posterior inferior part of the skull just below the brain. Um, and it's responsible for fine tuning on movements and know, initiating them more fine tuning them, specifically planning them, coordinating your movements, controlling their timing's on how precisely movements are a swell. The cerebellum has many other roles as well, so it plays role in most learning balance posture, muscle tone, regulating our fear and pleasure emotions as well as attention and language. Now, if you have a dysfunction in the cerebellum. It produces six main symptoms. Does anyone know any of the symptoms is produces or the acronym that's used puppy in the charity Do If not, I'm worry. Danish Well done yet. Does anyone know any of the any of the parts that make up the Danish acronym? No worries. If not, we're gonna go through them now. So as sets, if you have cerebellum dysfunction on the way to remember, what goes wrong is by the afternoon Danish. So the first, um, dysfunctional function that you notice, um, is distorted. Oh, cocaine easier. Which is an inability to form that rapid alternating muscle movements. So, for example, for those of you that have done any concern any of our oscal sessions or a ski sessions or definitely clinical teaching yourself when you do an upper limb neurological examination, you sometimes also patient too rapidly turn over their hands like this. That is to test the dysdiadochokinesia because you have seen whether they rapidly alternate in the muscle movements. And then there's a taxi. Uh, this is a lack of muscle control or coordination off voluntary movements. So, for example, walking and picking up objects, then you have a nystagmus, which is on involuntary, rapid and repetitive, repetitive movement of the eye on. These are often in like a beating pattern, so you might ask the patient to look out inside and you see their eyes kind of beat and they can beat side to side, up and down that can also go secular as well. It's just that involuntary, repetitive record movement of the eye. Then you have an intention tremor. This is where a part of the body starts to tremble when it's attempting to do a really precise movement. So, classically, you see someone trying to touch on examiners finger or touch their pen on as they get close. They they're fine on the way there, since they such it close to it, they start to shake on. That's your intention tremor. You then got slurred speech, which is pretty self explanatory and hope Otomi is. That's a lack of muscle tone, so someone will appear quite floppy then. Our last kind of bit of structures in our brain and our skull are the brain stem, so this is composed of the mid brain, the ponds and the medulla oblongata from superior interest in mid brain, most superior Lee, then the palms and then the medulla. The brainstem connects the brain to the spinal cord, and hence that's where our ascending and descending tracks passed through. A Z, I explained earlier on the brain stem has lots of different functions for which is really important. So it's the origin of 10 of the cranial nerves. Specifically, numbers 33 12, which allows get a surprise sensory motor innovation to the face and neck on the brain stem also plays an important role in our autonomic functions, so the midbrain is associate it with control of our vision or motor control, our sleep and wake cycles, alertness and temperature regulation. The ponds contains nuclei that controls sleep, swallowing, bladder control, hearing taste I movements, facial expressions, facial sensations and posture on the medulla contains the cardiac. They were spiritually vomiting on the vasomotor centers, which regulate really important autonomic involuntary functions that just breathing our heart rate and BP. Now I'm going to be talking for the alter ease that supply blood to the brain. So I think the main structure that you need to know for this is the circle of Willis On the circle of this is the main structure, which surprised, but the brain on it sits on the anterior surface of the brain stem on the inferior surface of the lobes. So you kind of a brain up here. It's sitting just below it, and the important thing about the circle of Willis is that it gives rise to three main report arteries, so I'm not sure if you could see my mouth. But it gives rise to the anterior cerebral artery, the middle cerebral artery, over here by sides on the posterior cerebral artery. So the anterior middle and posterior cerebral arteries are no no's endarteritis is, so they're terminal branches are no interconnected, so there's no collateral circulation between them. And so if one of these three broad trees is blocked, for example, by a clot or anything like that, the tissue cannot that these arteries supply can't be supplied by other blood vessels and other arteries, which is what happens sometimes in his game. Extra oaks where o'clock will get stuck on. There's no other blood supply so that part of the brain will become a ski make and sometimes die. But the base of these arteries. There's this collateral circulation known as the Circle with this, but even though is really important, it's quite interesting to note that only about 20 to 25% of people have a complete circle of Willis, even though is emphasized a lot. A lot of people don't have a full circle full ring here. So even though not everyone has it, why is it important? Why have we evolved that collateral circulation? Well, if a ninja vigil does have a complete circle, this on a part of that circle becomes blocked to say one of the vessels has a clot or there's a narrowing, um, cerebral profusion. So profusion and blood flow to the brain. Consider car in the other arteries on blood, or it either brain will still remain perfused. And so that's the circle with his acts as a fail safe, safe mechanism. In that way, because if one part the soap gets blocked, the blood can just reroute around the other way. However, if we didn't have this or even individual has an incomplete circle of Willis, um, one of the vessels becomes blocked. There's no other vessel roots available. Eso there will be no cerebral profusion to the areas affected on dance. As I said before, this can lead to strokes. Now there's quite a lot the cycle of words which I don't have a lot of time to go through. I just wanted to go in point out the key points. So starting from the top, your antirougeurs immunity kating arteries on they collect. Connect the right in the left anterior cerebral tree. Then you have the posterior communicating artery, which connects the internal carotid artery on the posterior cerebral artery on the same side. Teo internal carotid. Here, your posture is horrible. Has your posterior communicating sky in between the tape? Then you're, um it's starting now. The bottom of the diagram. The two vertebral artery's converged to form the basilica artery in the midline at the level of the inferior border of the palms. On down off of the basilica artery are Ponty and branches, which supply the ponds itself. You also have three sets. Cerebella arteries. They're not your cerebral arteries or cerebella arteries. Specifically your superior, your anterior inferior on your posterity, inferior which, as the name suggests, surprised the cerebellum on the door was still surface of the brain stem. Now. One thing to note clinically that's really important is that clots causing strokes and things are most likely to occur in the middle cerebral artery on. That's because it's the direct continuation of the internal carotid artery, which is the main artery running up the neck that supplies the sack of Willis. So we said that the circle of Willis gives rise. Those three means Rebrov. He's the anterior cerebral artery, the A C a middle cerebral artery, the NCAA on the posterior cerebral artery. The PCA now in terms of whether he's run, uh, the runs in the long do tuna fish ER which, as I said before when we were talking about the anatomy of the brain, is between the two lobes on the supplies, the majority of the medial surface of the brain and also the anterior superior portion of the lateral break. So that kind of makes sense. If it's running between the two brains, the two hemispheres of the brain is going to supply that the internal surfaces and it's a supplies the anterior and superiors of the front and top portions off the sides of the brain. Then you have the middle cerebral artery. This runs through the lateral soakers, which we said was separating the front or in the temporal lobes, and it surprised them, supplies the majority of the lateral brain surface, which makes sense if it's running on the between. Those two lows on the outer lateral side is going to supply the majority of that. The PCA or the posterior cerebral two runs backwards in that long district. Officials that separating the tree hum says supplies the majority of the posterior inferior Saphris of the brain on both median that medially and laterally. So just therapy it surprised the back on the bottom surface is of the brain on, um, is it mainly is supply your occipital lobe now? One thing to know is when there's a blockage in need to each of these arteries, you want to be able to associate that with the different parts of the cortex on be functional road rules they play so that you can see on Diovan work out what patient will present with clinically so on The A C A supplies the prefrontal cortex, which controls are higher cognitive functions, are social skills, are personality as well as the primary motor and promoter areas for the lower limbs. The emcee A supplies the watery auditory cortex, which is responsible for hearing Broca's area in the frontal lobes. Reproducing speech Verdict is a row for understanding speech on the primary motor and promoter areas for the apple in on the reason why, um, the upper limb and the lower limit different even though you're still supplying the primary motor and promoter areas is remember I said that the supplies the medial surface off the of the hemisphere is, and that is where the the sensation on the motor information for the lower limbs is. However, the NCAA is supplying the lateral services, which is where the information for the upper limbs and the trunk is. And finally, we have the PCA, which is a sense of mainly supplies there except to lobe on that's responsible for our vision. So to recap, if you had an anterior cerebral artery ischemic stroke, your lower limbs would be mainly affected if you had a middle cerebral artery stroke, which is the most common because I said it's a direct continuation of the internal carotid artery in your upper limbs and your trunk will be most affected on if you have a posterior cerebral artery stroke than your vision will be most affected. So I'm just gonna go into our final topic of the day, which is the CIA CSF for the cerebrospinal fluid. So cerebral spinal fluid is an ultra filtrate of the blood. So basically that means is it's fluid that's made by filtering the blood through high pressure. Now the cerebrospinal fluid contained within the skull has three main functions. Can anyone type in the chapel? Those functions are protection. Yet that's already good suggestion. Anything else? No. Trey Shin Protect protection. Keeping, coming. Explain. Wait list trends. Stability. Buoyancy, cushion. That's great, guys. Well done. Eso the three main ones I've got of maybe the ones you've listed as a protection. So it's the CSF acts as a cushion for the brain, so it limits neural damage in If you had a head injury, Um, buoyancy is the next one. So when the brain is immersed in the CSF, the net weight the brain is reduced to about 25 g really light. So this prevents excessive pressure on the base of the brain because if you didn't have the CSF, You'd be putting a lot of pressure on those lower structures, like the brain stem and the cerebellum. And we've talked about why they're really important, important things like our breathing and regulating the heart rate so you don't put pressure and damage them. And finally, if someone's you, some of you mentioned chemical stability. So the CSF creates an environment to allow the proper function of the brain. So, for example, it maintains low, uh, extra cellular potassium levels, which helps with sign up tick transmission between yours and the brain. So now can anyone going onto the generation of CSF Can anyone type in the chat for me? What structure? Generate CSF from where it's located, so replaces part of Texas. Brilliant. Where did you find the cord plexus? Atrovent goes brilliant. Great suggestion, guys. Thank you. That was really good. So yes, you're correct. So the ventricles are the structures that produce the cerebrospinal fluid on. They transport it around the cranial cavity on the two lateral ventricles, which you can see on this image are they're kind of bike handle in shape on there, lined by cells called, and I'm more cells now F and I myself, Sometimes classified ads are for clothes out with CNS, and they are silly ated kilometer cells which produce the CSF on, then help to push the CSF through the ventricular system as they're silly. A beat on the F and I'm cells. Collectively former structure called the core. Oh, plexus So well done that all of you put that you smash it, you got it. So then talk about the flow of CSF. So CSF runs through the four venturers. So I'm either the right of the left lateral ventricles. The third venture, one of four French full. To reach the subject, I'd space surrounding the brain. So the exact part of the CSF is lateral ventricles in through the intervention killer for, um in a order knows the frame and off Monroe. Then it goes into the third ventricle on. That's this is a really important point. Note. The third ventricle was very narrow. It's a very small structure, and it's it's the first structure where both ventricles draining, too. So you got to electroencephalogram they're going into one third ventricle is very narrow, and there's lots of CSF going through there, um, and say it's very narrow because it's right next to the bottom. I the left from my pharmacist. Um, it's right in the center between those. So it's a common point. Two CS have to build up because it is so now them from that it goes into the cerebral aqueduct on Travels Into the fourth ventricle, which lives within the brain stem between the junction between the ponds in the medulla and then, from there goes into this Subbarao annoyed space. So I'm now finally just going to talk about the meninges on as well, the reabsorption of CSF. So we've made the CSF, and it's going through our system. How do we re absorb it and no have a build up? Let's start with them and Indies. So the meninges are member, this coverings of the brain and the spinal cord, and they have two main functions. Firstly, there a supportive framework for the vasculature. So the arteries and veins, specifically the dural venous sciences, which are part of the venous drainage of the brain, and also the meninges at with the CSF to protect the brain from any mechanical drama. So it once again it's it's more tough covering so that you're not going to damage the brain now. The three layers of the meninges are the jury mata, which is the outermost layer on that's closest to the skull on in the spine. It's closest to the vertebral column on the jury. Masa is that in two layers you have the periosteal ear, which lines the inner surface of the skull on that like sticks firmly to the skull on D. But that layer isn't present in the vegetable comic column. So just to repeat the germ, Otto has two layers. The parents doing the men men in June. The Periosteal is the one that lines the inner surface of the skull. It's not present in the vegetable column. Lemon in Julia is the deeper one. Then you have the subject, or spice, and then you have our next, uh, men in July, uh, which is the erection Marta and then the innermost one under the same records. Space is the P, A motto, which is in most on it is closest to the cortex on. It follows a lot the silk I and the dry right off the cortex as well. So he said, CSF is an ultra filtrate a blood problem. Oh, so it's made from blood on the F, and I'm ourselves of the chorioplexus Keep making CSF. They're making about 500 miles a day on. We can't let that build up because they're making that a continuous rate. If we let it build up, then we'd have compression of the brain, which isn't good at all. So the CSF needs to be taken back into the circulatory system. So the space, um, in which the CSF was in, we said, was a separate cabinet space. We said that the jury venous Sinuses on the which is part of the venous drainage of the brain, is found between the periosteal on the men in July. Layers of the jury matter. So what we need to do is we need to get the CSF from the subject. I'd space back in between the two days of the jury matter. So to do that, we need to go through the Iraqi road martyr through the subdural space and threw them in in July of the jury matter. And how it does this is there are small projections of the Iraqi or Balta called arachnoid granulations, which patoot protruding into the jury mata to transport that CSF. This allows the fluid to drain into the jewelry nose Sinuses, which is a set of part of the venous circulation of the brain on. Then once the CSF as crossed back into the drove in a science is it can drain back down into the inferior vena cava. I'm re enter the circulation of the body.