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Hi, everyone. I'm Van Dean, the Chair of UCL Neurology and neurosurgery. And I'm delighted to see so many of you here today at the launch of our National Preclinical Neuroscience Teaching series. Our first session today focuses on brain and the spinal cord and will be led by me that we have selected the best tutors amongst ourselves to deliver each individual session moving forwards. Today's session is a part and a first of our eight part tutorial series which has been carefully designed to signpost you to the most important topics out there, provide clear and concise information on various topics across Neurosciences that you will be learning as well as provide guidance about exam relevant content, which altogether are very important for building your core learning and foundation in Neurosciences. As you engage with our material over the next couple of weeks and beyond, you will follow the logical comprehension of our tutorial series, which has been carefully structured by me and my team in a way that it makes most sense when learning about various systems and various topics across this broad field of neuroscience. Now, I'd like to invite our in Aurora fourth year medical student and incoming phd student who is the preclinical lead from our society to share a few words about our tutorial series and tell you a bit more about how it's structured. We're going to be starting with an introduction to the brain and spinal cord should be led by PH um The session is configured uh in, in, in such a way that we will be learning some content at the very beginning for the 1st 45 minutes and then we'll break out into small group tutorials. We've prepared a set of um, of, of questions SBA S short answer questions and C PSA stations which are faithful to the sort of difficulty in depth you'll be required to er, sort of understand from your exams. You, you'll probably recognize from your question banks already that, that the question depth and difficulty can be quite variable. It's hard to know what you need to know. And so hopefully we can try and communicate that um that sort of stuff to you. We'll be working every Tuesday, Monday and Tuesday. Um And so I know this is the beginning of the week and the last thing you want to do is stay late in university, but I hope we can offer a, a great deal of value to you. Um And overall make your experience uh learning neuroscience much, much better because it is a beautiful discipline. Um and it is profound, it is interesting, it is confusing and II think that's what makes it so enticing and so, um, fun. Would you look clear now? Yeah, just to talk a little bit about a tutorial s already mentioned everything. Just to mention that this is actually the first time all the academic societies at UCL have come together to produce this series and we've gone through the syllabus across, not just UCL but across the country to see how it aligns with all the pre the curriculum. And it's designed in a way that it actually is meant to make sense rather than the way the medical school offer and teachers. So I guess all of you will find a value in it. We start with brain and spinal cord and then we move on to looking at sensory systems, followed by motor systems and then looking at common pathologies before we move into looking at some special sensors at some other things. Um The tutorial schedules are already um out there. I think it will be out on social media. So all of you guys will get to know about it a bit more as well. Uh But yeah, just bear with us. I think for today's session. Um The goal of this session is particularly one second. I hope we can. Yeah. OK. I don't have a pointer. That's a shame. But anyway, so the ovary of the session is all about learning the basics of the nervous system trying to get a bit of a feel about neuranatomy. It's vast, it's very big, but I hope you'll get the basics after today. Understand a bit about the intracranial region, how we um kind of know about the structures and what they actually do followed by a little bit about uh the growth brain anatomy that we want to introduce you guys, which we've followed up upon different sessions that we have upcoming. And then, and the part two, I'll talk a little bit about cranial nerves, um the cranial fossa and all the different uh foramina that you probably have to know about for the exams and for the long run as well. And I'll go a little bit into the brainstem and the spinal cord just to end it. And hopefully after today, you'll have a very broad intro introduction, which will be supplemented by all our future sessions. So don't worry if you don't understand anything, things will be repeated in the future sessions and you'll come across these in your other lectures as well just to move on. So the basics of nervous system, we all know about starting from a level, starting from G CSE S and everywhere. And it's always been taught as a fundamental principle of the nervous system. Firstly, we know that we have got the central nervous system which consists of the brain or the spinal cord followed by, we've got the peripheral nervous system which contains different sorts of neurons. Now, that is where it gets a little bit complicated because in the peripheral nerve system, imagine if you were to toss something hot, you can feel it. Well, that's because you've got sensory neurons in the peripheral nervous system that can somehow communicate with the brain and tell you that you're feeling hot. Now, if you want to move your hand, your brain somehow signals that out to the muscles, the responsibility contractions, excitation relaxations as a result of all of that, you get a contraction. So we know that we've got motor and sensory norms. But the interesting thing about that is all about the integration, which is the fundamental principle in preclinical Neurosciences. So if you look at the diagram on the right, it's not just the central nerve system on its own or the peripheral nerve system which contains all the nerves, but it all comes together and brings about those actions and those sensations which are most important for us. Now, the building block of the nervous system is all about neurons. If you look in the left here, you'll see lots of different kinds of neurons that are present in the mammalian body. Many of them you might know or may have seen and many of them you don't. Let's take an example right in the middle of here where I show the different parts of the neurons. The couple of things I want you to know about is if we consider this as a nerve cell, then we've got a cell body and these things you could consider as origins. And this concept is very important. So you have an origin that consists of the cell nucleus, all the organelles that are reported for the homeostatic function of the neurons. And then you've got these outgrowths or processes that come out of your cell body or the origin. And these, we call us exons. And when they all bundle up together, for example, if you take a section of the spinal cord, and if I consider this particular nerve as a single um neuron or a cell, and we've got the cell body right in the middle here, in the dorsal root ganglia, the details of which we will get to later, what we can say that when it all comes together, you get your bundle of nerves and these concepts such as for example, you've got an origin and an outgrowth and all of it coming together to form your nerve. These concepts are fundamental in the building blocks of Neurosciences. Now, obviously, there are many other types of cells that you'll probably have heard about astrocytes, glial cells, satellite cells, loads of other ones, immune cells like microglia. But all these things will slowly fall into place. You learn about more systems and how they all integrate together and moving on. I'd like to start today with the skull, the skull, as we all know is there for the protection of your brain because brain is particularly inside this bony structure out there is formed of many different bones. And if we divide the skull, for example, if you took a skull and divide it into half or approximately half in a lateral way, what we could say is it's divided into two parts. One of it forms part of your face, which we call as your viscera or the skull hold which you can call us neurocranial. Now, there are different bones out there which then join together to form each of these cavities. The important one we focused today is our neurocranium, which is you could call as a cranial cavity. It consists of the brain each side. And importantly, if you look at the lateral part, which is the interesting bit, lots of different bony structures come together to form this and that is something with practice and with learning, you will get to know, for example, there is a frontal bone, there is an occipital bone at the back. You've got the sphenoid bones, lots of different bones that come together and that is something you would know and how these eight cranial bones come together to give you this neurocranium. Now, obviously, we need to take a step back and understand how did actually all of this start when you go to development? We understand that at birth, we have these bones present, but these bones are not fully grown or fully formed in that, that it leaves this membranous gaps in the middle, what we call as fontanelles and as you age and as development occurs, these bones close together and then you have the closure of these fontanels giving us sutures. Now, what are sutures? If I go back one slide, you will see that these different bones are joined together in a midline sort of ridge that they form. These are known as, which are kind of immobile joints. If you have seen sort of any sort of dissections or uh pro sections being done, you will see these sutures very clearly that DEMAR the borders between these different bones. So if you have to label different bones out there, you will know them by these different sutures. Now, importantly, there are different places in our skull that are particularly weak. And as medics, you would want to know the clinical relevance. The one big part is known as the Terry. It is where you've got the union of different bones that come together. For example, the frontal bone, you've got the uh temporal bones, the parietal bones, the sphenoid bones and the union of this forms a very weak point in your skull known as Ater. Importantly, there is an artery underlying this, known as the middle meningeal artery that supplies your meninges. And let's say, for example, if you had a skull fracture, then you could have a potential risk of having a rupture of this middle meningeal artery, the leading to bleed and that bleed is known as hematoma, which we will cover in a bit. Now, now that we have talked about the skull, if we go a little bit inside, we come to other structures that are present there. For example, if we go right to the skin and obviously, the skin has different layers as well. And there's a nice mnemonic to remember this, but we won't get too much into it. But the important bit here is once you've traversed through the skin and the skull, you reach a layered unit of different membranes which are quite specialized to protect your brain once again and also serve homeostatic functions, regulating the CSF et cetera. There are particularly three layers of these membranous units which come together and are known as the men meninges and the three parts are the dura mater, the arachnoid mater and the pia mater. And they're all sequential. For example, the dura mater is uh double layed, whereas the ma and the pia mater are single layed. The important thing about that are these concepts that if you've got different layers, you must have spaces between each and these spaces are fundamentally important for clinical scenarios. For example, you've got an epidural space. Now, out of this talk today, I want you to get a few concepts that are very integral to neuroscience, epidural, that means extradural outside the dura. So that's between your skull bone and the external part of your dura mat. And that is potential space, that potential space means that they're all very close together. And unless there is a trauma, there is a pathology, you will never see that space or that space will never come into existence. Similarly, we've got a subdural space which is just below the dura. And what happens in this case is again, in case of a trauma, you might see a bleed or any sort of pathology or intracranial pressure rises between these regions of the arachnoid matter as well as the um innermost layer of your dura mat. The third one is an interesting one, which is your arachnoid, a subarachnoid space. And in this case, what you would see is an actual space which exists and that is where you've got freely flowing CSF right now, why am I talking about meninges? The important thing is always you have to remember the clinical relevance because not only these are tested because actually likely to come across patients will have certain diseases. Now, meningitis is one of the most common ones, which is particularly inflammation of your meninges from a bacterial viral or fungal infections. You've got meningiomas, particularly benign tumors that can happen in the meninges and cause intracranial pressure to increase. And lastly, we've got hematomas that we have just discussed, which is essentially but a pool of blood, you know, it collects in a specific region and then leads to different sort of pathologies. Now to focus a little bit on hematomas because these are interesting pathologies that you might come across. Now, epidural as we've already discussed is outside the dura. It's between the skull and the external part of your dura. And that can lead to the pooling of blood in that region, typically due to rupture of middle meningeal artery. And that is something that you probably have to remember if you see ever epidural is most likely to middle meningeal artery on the upper right. I've got a diagram right here which kind of shows how that bleed would potentially look like. If we look at a CT scan down here, an epidural hematoma is likely to be lent shaped and has a nice demarcation to tell you what kind of pathology this might indicate. On the other hand, we've got subdural hematoma, which comes across as a more flatter crescent shape under a CT scan. And in that case, what happens is you've got venous bleeds, which can happen very quickly or in some cases, very slowly can lead to that pooling of blood. So to be able to say these differences are quite interesting when you see, look at CT scans and kind of try to understand what might have happened. In this case, I've put down a table right here. When you guys get the slides, you can look into the individual differences to give you a better understanding if you're interested. But for now, we'll just leave it there to understand the basic principles of how these things differ. Now, once we have discussed about the meninges, let's look into the intracranial cavity. Obviously, we've got the brain the most interesting part, I guess for everyone. But if we take a step back again and think, how does this brain develop? I know development is sometimes regarded as one of the most daunting subjects ever. But if we think about it, we start off by having a neural tube in the fetus, that neural tube in this case shown here will sort of differentiate into different sort of vesicles. And these different vesicles will then go on to form specialized structure. So we start off by having three plain vesicles, the prosencephalon, mesencephalon and rho cephalon. And then we will go on to having five vesicles which will finally give us our forebrain midbrain and the hindbrain. The important thing about that is sometimes you will get questions about the origins of different structures of the brain. So try and relate the individual um sort of origins of these vesicles and what they finally lead to. And that is important. But if you actually look in adult brain, for example, the diagram is shown below here, you see how it all makes sense. You've got the forebrain, the midbrain and the hindbrain. And slowly you develop and differentiate at different cell types and reorganization into giving you your sort of cortex, the midbrain cerebellum, the spinal cord and things that we already know about. There are many mnemonics out there that can help you remember it. But I would suggest remembering it uh because this is sometimes um asked in terms of questions. But also it is interesting to know if you want to specialize in neurology elsewhere. Now, let's start with an introduction to neuroanatomy because we're talking about the brain very simple as you've learned possibly in other subjects or come across, we just have to define different planes to understand where are we looking at? For example, if we look at the front, this is your anterior side. If you look at the back, this is your posterior side. But this could also be called as a rostral and EENT or your cranial and your CAD. And in that way helps you orientate structure. And obviously simple terms, the superior inferior, these also help define different plants moving on from that brain dissections, imaging. All of these have relevance to clinicopathology or research, whichever one you might be interested in. The important thing about that is to know what are the orientations that we are looking at. Because in that way, you'll see different structures. For example, if you were to take a coronal plane, you will see the brain as though you were looking at the person straight off. For example, a person lying down as a corona will look at the person, for example, um doing a dissection or if they have the post mortem, you would see great flap straight on. If you were to divide it in a vertical manner from the top, you would see a seal view and you can also see transverse axial or horizontal plane if you were to cut the brain in horizontal um uh manner. Now, these structures help you to orientate different parts of the brain. And for example, if you have a difficult case to diagnose and you were looking at a brain tumor, obviously were to do surgery, you have to know what are the landmarks, what a what is around it. And you look at different planes to understand what these structures are. So it's good to get into a practice of knowing what plane we're looking at and also what other structures we're expecting. Now, once we've talked about the skull, here is the brain nicely sitting inside the cranial cavity. And I've got lots of terms out there which you guys might have learned about already, but it's a little bit about knowing these terms and what they actually mean. I've got lots of terms there. Let's start with the basic ones. So we've got the gyri, which essentially means the elevated ridges around the brain over the hi there will be lots of gyri when you look at the brain, the sulci um over here are these grooves between these jars and we can look at fissures which are essentially the deeper grooves that you can see here moving on. You can also see if we divide the brain into two halves. You see the longitudinal fissure here. And then if you divide it from the lateral side between your different lobes, which we will come across in a bit, then you can also see that there's a deeper grooves dividing your brain. Now, importantly, when we divide the brain into different parts, we give them different names and try to understand the different functions. But this particular talk, I leave it to introducing the different parts. And the next coming talks, you can get introduced to individual parts as you go across those systems. So we've got the frontal lobe very simple. They've got the parietal lobe. Now, how do you divide it? You divide it by the central circus, once you go around and look at the other part, say from the side, you can divide your temporal lobe as well as your frontal and parietal lobes to look at your temporal lobe as well as occipital lobe, which lies at the back. Now, then we've also got the other structures such as the cerebellum, the spinal cord and the brainstem. Now, all of these particular parts of the brain have different functions. For example, the frontal brain, uh frontal part, very important for your personality, decision making thought process, et cetera. Occipital part is particularly of vision. You've got the temporal parts which have got a lot to do with memory and recognition. And then you've got the brainstem that connects all of these parts on the top with the parts that are below, for example, your spinal cord and your peripheral nerves. So again, if I come back to the example I gave before, if you wanted to move your hand, the thought process could be occurring in your front below going to your motor cortex, which is another specialized part and then going down in different tracks and different structures to finally signal to your muscle. OK. That is how you need to act and we'll get to that um details and coming lectures. But for today, the basic principles of how it comes together is very important. Now, once we have looked at this brain nicely sitting inside the skull, what we can do is then, for example, take a section through the middle and then look at the deeper structures here. We've got, for example, we've got the cortex right here. We've got specialized structures. Now, coming into view, for example, you've got the pituitary gland important for growth, um hormonal regulations, you've got your hypothalamus, like sitting here very important for homeostatic functions that you might have come across in other subjects. Then you've got your midbrain, the pons, the medulla, which together forms your brainstem. And you've also got other structures like the cerebellum, all of them leading down to the spinal cord. But what's interesting are these structures right in the middle, which which sit deep inside the brain known as ventricles. Now, these ventricles are usually hollow spaces, but in a real human, these would be fluid thick. Now, what are these ventricles? Now, these are a set of interconnected cavities. And as I mentioned, the brain is B in A CSF. Um So it's a solution which is similar to your plasma. But in a way BS the brain to maintain its buoyancy and also for homeostatic functions, nutrients, et cetera. And these ventricles are responsible for the production mainly of the CSF as well as the transporter removal. Now, within each brain, within each uh ventricle, sorry, you've got a set of specialized vessels called the choroid plexus. And they help produce this in a nice diagram over here. It's actually not a diagram, but in animation over here, you can kind of see how these ventricles sit together. Now, there are four main ones, the right and the left ventricle, for example, shown here and then it leads onto your third ventricle to the foramen of Munro and then it leads all the way to the cerebral aqueduct which is a very thin um or a narrow duct leading all the way to your fourth ventricle. And these have pathological consequences. If in any case, if for example, overproduce CSF or if there are blockages at any point, you get conditions such as hydrocephalus, which will come across in other lectures. But just to give you a heads up that these things are possibly important and how you can relate a structure function relationship for each of them. Now, moving on, we've also got between the two layers of the dura, something called a dural venous sinus. Now, obviously, brain is an organ and a very important organ needs a high amount of blood perfusion. And you've got arterial blood, obviously, you will have venous blood as well. Now, these dual venous sinuses help to drain the venous blood. I'm coming to circulation here for a bit so that you can understand how this whole structure fits together. So let's assume the brain was sitting right inside the skull and between the skull or between the two parts of the brain. Over here, we will have the fold of the dura called a fork cerebri and on the top of the top margin over here, we have one of those dual sinuses which are between, for example, if you have the meninges between the two layers of the dura, you've got this dual venous sinus, the one at the right at the border on the top. Here, we call a spiro sagittal sinus which collects all the venous blood uh from, let's say, cerebral veins, your cranial bones, the meninges, et cetera and to drain it all down to form different structures known as your transverse sinus leading on to forming your sigmoid sinus and then draining into internal ju when you have a closer look at these structures. So you'll possibly be able to understand a bit better. But the only thing I want to point out here is the superior sagittal sinus, usually at the confluence, takes a right turn to then form your right transverse sinus and then go inside to become your right sigmoid sinus. And then finally drain you into your right check lymphs. And these are important concepts because these, when you look at different sort of cases or try to understand things better. That makes sense. For example, if we go on now to look at the inferior sagittal sinus, what you see here is that the inferior sagittal sinus at the lower border of eal cerebri, it drains the left now and then goes on to become um the other structures which he just describes, describes such as the left transverse sinus, as well as the left sigmoid sinus and finally draining the left stroke a little bit. Now, there are lots of other different types of dual venous sinuses as I've listed here. The only one that I would want you to know is the cavernous sinus. Now, the cavernous sinus sits right in the middle where you can see your sphenoid bone right here, which we haven't discussed um today, but it will come across in other parts of the toe. So it sits right over here and we will get to that in a bit. Now, we've talked about the venous drainage. What about the arterial supply? Now, for the brain, in particular, we've got arterial supply for two main vessels. First of all, you've got the internal carotid artery, which supplies the major part of the brain as well as we've got the vertebral artery. But they have got an interesting anatomy over here, which is very important to learn at your stage. Imagine if we've got the skull and all of these arteries are ascending to go inside your skull. What would happen at the neck? You would see that there must be different openings that allow these vessels to go all the way from the neck to the base of the skull to to then supply your brain. So you see something like this. And interestingly, I just pointed out here, you can see the middle meningeal artery here as well, which is a branch of your external carotid kind of going inside the skull as well. And you can relate it back to the pathology that we discussed, for example, epidural bleeds. But what we also see is internal carotid going in here. And also in this diagram, the vertebral arteries are not shown, but they will also go inside the skull. And at the end, what you get is a skull with a formation like this sitting at the base and that we will come across described as a circle of Willis. It's very hard to describe the circle of Willis unless you've seen it in person. And the reason for that being that it's a 3d structure, which is often portrayed in a very two D manner. But all you need to understand. And I think this is a very good diagram is to understand that the brain stem would sit right here and you would have the temporal lobes sit right there and all the other parts of the brain kind of sit on the top. And when you take that off, this is the sort of information you get. And I think this photo over here that was taken from a simulation does a little bit of justice to that. For example, you can see your basilar artery, which we'll get to the details here in a bit. You see the carotids coming through here and then forming this sort of circle right in the middle that supplies your brain. Now, this is something unfortunately, you'll have to learn, but there are ways of actually getting around it. For example, I've said two internal carotids go in. So you can see the internal carotids right here and they go into your skull. And what they will do in this case is join the other parts of the other arteries that are there. For example, two vertebral arteries entering through here and they will form this basilar artery which will then join your internal carotid right here. The important branches that you possibly have to know about are these basilar artery, the pontine arteries that supply the pons as we have seen in a sort of nice schematic diagram of the brain before and then the anterior cerebral artery, the middle cerebral artery and the community communicating arteries right there. And these vessels supply the major structures of your brain. And you will essentially, as you practice more and more you will get to it. Another simple way is to think about it. You start off at the base and you start by thinking, I've got two vertebral arteries coming together for my basilar artery. That's a bit of your learning. Then you add onto it. OK, let's say the internal carotids come up and they firstly, they become your middle cerebral artery. Then you learn a little bit more and then you kind of join the other structures there and try to learn um the main structures that you have to know the main arteries that you have to know. The smaller ones you wouldn't possibly have to know. But in this case, I'll just um say, know the major ones. There are these pathologies like locked in syndrome, lateral pontine syndrome, et cetera. That will all we will come across in subsequent lectures. This is just there to show you how these vessels relate um to different pathologies that can occur. Now, we've talked about the top of the brain, we've taken it off and we've looked at the underside to see the circle of Willis, but it doesn't end there. If you look at the brain just from the underside, you get all of these structures coming out and what are these structures and we call them cranial nerves. Now, when I teach students, the first question I always get is what are cranial nerves? Very good question. If you match it, when you feel senses, for example, someone poking you with something or you touch something hot, you feel things. Now what happens to your face and the neck region? They need to feel things, they need to see things. You've got special senses, touch, pain, et cetera. To feel the cranial nerves are there to facilitate the sensory and motor information from parts of your face and your neck region. It's just as simple as that. And we've got 12 different pairs and these pairs are there because you need to feel different senses. For example, vision, taste, smell, hearing, et cetera. Now we sequence them and you can see in the previous diagram, it wasn't labeled, but now it's labeled into different parts of different nerves. As we can see here, you've got olfactory optic oculomotor, all these different nerves that you will have to know sequence or 12 of them, which can be numbered or you can classify them in terms of how they work. For example, which one is predominantly sense, which one is predominantly associated with movement and some nerves will be mixed and I'll work through the most important ones um for this lecture today and we will leave the specialized ones for the individual ones later. Now, one other thing I wanted to point out is to go back to the first slide I explained is a core concept of neuroscience to understand the origin and to understand what's happening after that. And a lot of the times when we introduce cranial nerves, we talk about different types of nuclei and that's where the confusion arises. So the fundamental principle is if we look at the brainstem here, and if we were to take a cross section, we would see an origin, which is basically consisting of all your cell bodies, like the nucleus, all your organelles that supply that neuron. And what is coming out of it are these individual cranial nerves. So the nuclei in these contexts essentially means your cell bodies or groups of cell bodies within your brainstem. So now you know where the origins are. And obviously, as I mentioned that these cranial nerves come from brainstem. And if you look at the brainstem, in particular, they've got three different parts, the midbrain, the pons and the medulla. And then these give rise to all your different cranial nerves. The different locations of the cranial nerves are shown in this table here. For example, the nerves, one and two come off your anterior brain, you both three and four coming off your midbrain and the different one comes off your ponsa, et cetera. Um Unfortunately, again, or fortunately, whichever way if you're interested in it, you'd have to know this just so that you have a bit of an idea. But the good thing is it follows a sequence and whenever in the slides you see something written in italics or asterisk, just remember that these are some interesting facts which are not really very, um, sort of easy to teach, but some things that if you know, will possibly help you with some of those niche, niche questions in the exa in the exams. No, the cranial nerves. This is sort of like a very functional overview and we will cover the main ones in bits that it actually makes senses for the first bit. What we will do is cover the interesting sensors. So the olfactory and the optic are very interesting in the sense, they're actually not part of the brainstem or they do not arise from the brainstem, but they arise from the brain tissue itself. So if you were to take a brain and um sort of look at the underside of it, you will see that they actually originate from parts of the brain and not exactly the brainstem. And hence, they're interesting the olfactory particularly for smell, the uptake of vision. And here we've also got another one, the vestibular cochlear nerve, which we'll get through in the Audi audition literature. But it's about two nerves coming together, the vestibular part associated with your balance as well as the cochlear part associated with your hearing. And there are lots of details to how it actually works. And um here it's just about introducing the nerve out there. So when you get to those sort of talks, you understand it much better. Next, we have a group of nerves. In this case, what we call as the oculomotor trochlear and abducens. So the best way to remember this is that they're associated with the eye function. Importantly, if you look at, I like to start actually from the bottom to the tropia and the abducens because they, each of them supply one muscle. Each here is the diagram of the eye. And you can see different muscles associated with it. The superior rectus, inferior rectus, lateral rectus, medial rectus. These are the very easy ones to remember. You've got two others, the superior oblique as well as inferior oblique right here. And to remember it very easily, the tropia nerve tr means a pully. So if you look at this over here, it essentially looks like it's in a pulley system. And in that way, you can remember that's a trochlea nerve which innervates your superior oblique. And you've got the abusive nerve over here which supplies your lateral rectus muscle. And these individually supplies one eye muscle. But when you look at oculomotor nerve, the easiest way to remember is to supply all of the other muscles other than these two, they're also important for parasympathetic component, which is associated with your pupil dilation, both in terms of light reflex. If you were to shine a light in someone's eye the people would immediately uh constrict and that is mediated by your oculomotor response. And also when you were looking at, let's say different distances, far versus close your eyes will accommodate to look for those changes. And that is also mediated by a no um interesting bit over there is that when you do the eye talk, you will get into the details of it and then it becomes much easier. But for today, it's just about introducing this. So when it comes to you, uh next time it's not new. Now, what can also happen is that you can get lesions of these nerves. For example, one of the nerves can stop working. You might have a certain pathology in your brain, for example, a stroke that has affected a particular nerve nuclei. And in that case, you can get different sort of eye signs and in that way, you can judge, OK, which nerve has it actually affected. Now, moving on to the trigeminal nerve, one of the most important nerve. And when people ask about the sort of sensations of the face and how to feel things. The first thing we think about is the facial nerve because that is more intuitive. But interestingly, the trigeminal nerve is actually the one that supplies the main part of your face. Here we start off with a motor nucleus, the motor nucleus is there to supply muscles of mastication. So to do with eating and chewing on the other hand, we've got a range of different sensory nucleus. Now, the reason why I have different forms of sensory nucleus is because we've got different parts. For example, proprioception, pain, touch different things to feel and hence your different forms of nucleus help facilitate the origin of different nerve fibers which help you to feel that. And again, we've got different sorts of nucleus over here, the mesencephalic trigeminal nucleus for proprioception on trigeminal nucleus for proprioception. So it's for tactile information. And you've got spinal trigeminal nucleus for sort of um getting your nop information, not just from your face and related structures but from other structures as well. But the important thing to hear, remember is that different sorts of modalities like proprioception, touch and pain are felt by different nuclei or the fibers arising from different nuclei and moving on. We've also got the facial nerve. And once you learn the trigeminal nerve in comparison to the facial nerve, then a lot of these things make sense. The facial nerve particularly arises from cerebellopontine angle. And once you start looking at the inferior structure of the brain, quite a lot, you will be able to tell apart which nerves these are. Um now when we once I just put the picture over here, just to point out that once you look at the pons right here in the middle or right here and the cerebellum right here. When you look at the cerebellar pontine angle, the first nerve that rises out here is a facial nerve. So it just makes it easier to know where your landmarks are. So if you ever get a question about sort of pointing out which nerve is a facial nerve or the other way around, you will know where to look at all. Now, the facial nerve particularly consists of two roots and the important thing here to remember is they've got different sensory and motor functions. For example, they come off of two nucleus, nucleus solitus also as well as a superior salivatory nucleus. Now, they've got different function. For example, the fibers arising for a nuclear solitarius, they will supply taste to the anterior two thirds of the tongue floor of the mouth, the palate et cetera. Whereas the superior salivation nucleus particularly goes into submandibular glands to supply your parasympathetic to allow more production of your saliva. On the other hand, we spoke about muscles of ification in your trigeminal um nerve. But in this case, when you look at your facial nerve, it actually controls the muscles of facial expression. So not the muscles that help you with chewing or sort of um making uh jaw movements. But the ones that you actually use to make sort of talk um or close your eyelids, for example, open eyelids, smile, et cetera. Now I put here an interesting thing is innovation of the tongue and that is something very important to know because that is possibly one of the most important things that he will come across. Now, the innovation of the tongue is kind of complex and goes back to developmental origins. But the interesting part to note over here is if we consider taste in general, the anterior two thirds are controlled by your facial nerve. Whereas the posterior one third is controlled by a glossopharyngeal nerve. On the other hand, if we look at sensation, for example, the bulk majority of the anterior two thirds is by the lingual nerve, which is part of your trigeminal nerve. And the part of the posterior one third is bio glossopharyngeal nerve. On the other hand, you've got the motor component, which is particularly mainly by the hypoglossal nerve, which will get you in a bit. But this diagram is put out there so that you can understand how again different fibers come together to control different structures and, and different modalities. Now to quickly go over hyperlocal nerve, this is one of the nerves that controls your tongue and is particularly responsible almost all muscles of your tongue, both intrinsic and extrinsic intrinsic, meaning the to the muscles that actually make up the tongue and extrinsic, meaning the ones that actually help move the tongue and the ones that are just adjacent to the tongue. Now, the clinical relevance of that is if you've got a hypoglossal nerve lesion, you will essentially see the tongue deviate to the side of the lesion. For example, if you've got a lesion on the right side of the right nerve, you will see the tongue deviate uh towards the side of the lesion because of weakening of one of the muscles that is very important for maintaining that. And to know this sort of slight clinical relevance helps you because if you're given an excerpt of a patient in a certain case, you will remember, OK, which side of the lesion can it be? And that goes across different sorts of cranial nerves that you have just trying to know what the clinical relevance of that are. And sometimes it's just very self explanatory. For example, if you've got a optic nerve damage, what might happen? You lose your vision. If you've got an olfactory nerve damage, what might happen, you might not be able to smell what we call a s, but it's just about knowing that how, how they function and kind of trying to relate it back to what clinical pathology might see. Now, here we've got uh possibly the last nerve that I will talk about today, which is about accessory nerve, uh predominantly a motor nerve or purely a motor nerve actually, which um supplies your sterno cleidomastoid uh muscle, which helps you to move your neck and also supplies part of your trapezius. Again, the interesting thing of there is to remember the clinical significance. For example, if you've got a lesion of your um accessory nerve, then you get problems on the side of the lesion in your ster apply a mastoid. But what you get is a partial sort of weakening of your trapezius. And the reason for that is trapezius is supplied by the other parts of your cervical plexus so that your C three C four and C five. So, although you might have an accessory nerve lesion, you will get a partial change, a partial change of strength in your trapezius. If you were to shrug someone, you'd see a partial change only. So these are some sort of some important clinical relevance to think about. And we've talked about the brain and the brain nicely sits on this cavity. Well, the cranial base is also very important because as we mentioned, it kind of goes on from the bottom part of the brain and kind of leads on to different openings to which different structures uh go from the neck all the way to the brain and vice versa. And that we call is a cranial fay. So now there are three, the anterior, the middle and the posterior. And these have sort of indentations that indicate which part of the brain sits on them and the right, you can see the different bones and make it all up. And when you revise anatomy overall, looking at the facial pos I can describe the neurocranium, the viscerocranium, you can kind of see how this all comes together to form the base of the skull. But the most important part of the foramen, which are the openings that are present in your skull. And there are about 21 parameter in the skull. Um But the most important ones that you possibly have to remember are in the next couple of slides. But the important one I wanted to raise here is we're often um given these sort of structures to view, for example, if you were to take the brain off and look at the structure underneath, but we also have to remember that we can see the structures from underneath as well. For example, if you were looking at the skull from below and to be able to relate these two together are particularly important. And you might get questions as to finding out which parameter is this one from both sides. So it's just about knowing how you orientate yourself to look at both structures. But the important one I want to point out here and just some tips on how to remember. For example, the first one, the cribiform plate looks like a baby's crib. And that is why it's named after that. Um That is where you get your olfactory. Similarly, you have your optic canal, superior orbital fissure, which are kind of self explanatory. Important ones that are um kind of interesting to remember are the foramen rotundum, which are kind of round structures right here. The ovale which are oval, you've got the carotid canal here, the Foramen Lacerum because it looks lacerated right over here and you've got all sorts of other structures. But what's important to know is that sort of working through what goes inside each structure every time. But the important thing again is it follows a very nice structure and once you revise it, it sort of makes sense. For example, the first one could be form is just one, the next one is only two, the third one superior orbital fissure, which comes third in terms of uh its location has your 34 1st part of your trigeminal and sixth. So in that way, you can kind of see how they all follow a sequential pattern and you'll have to remember it. I've labeled here three different ones which are wasn't labeled in this diagram, but I think are quite important as well as the different arteries and veins that also go through it. But just knowing the nerve is possibly not enough because you might get questions about the arteries in particular. Um Try to remember the foramen spinosum because we've already discussed meningeal vein, the meningeal arteries, et cetera. One thing which I touched upon briefly was the cavernous sinus. Now, the cavernous sinus sits right in the middle of your sphenoid bone and interestingly harbors a lot of important structures. For example, starting off with pituitary gland, very important for hormonal regulation as well as lots of different other functions. Now, clinical pathology you might get is in a pituitary tumor or a pituitary sort of expansion. For whatever reason it might be. What happens is, as we can see, the optic canal is just above your cabinet sinus. In that case, it can compress your optic nerve and get optic symptoms. And that is a very common clinical sign you would get in these conditions. Other than that, you've also got your ocular motor nerve, internal carotid arteries, ophthalmic, uh nerve, abducent nerve trochlear nerve, all going through your cavernous sinus. And there are different pneumonics that you can use. But particularly you do try to remember the cavernous sinus quite well. It's a very important part. Now, when we spoke about the cranial cavity as we come down through here, what we get are parts of your brain stem. The important parts of your brain stem are looking at, for example, these structures, you finish the brain right over here is your midbrain. You look at the palms, the medulla together becoming your brain stem all the way into your spinal cord, spinal cord. And what we talk about here are just individual structures such as the midbrain and all of it will come to you. Again, I just want to introduce a couple of anatomical terms so that you know what you're looking at. So if we end the brain of the midbrain, right about sort of here, the start of the midbrain is where the blue region is demarcated here. And here you have important structures called the tectum and the tegmentum. The tectum in this case, harvests two important structures, the super colliculus and the inferior colliculus, which look like these bulges out here. And when you look at different scans of the brain, different sections of the brain, you will always be using these as different landmarks, you know where you are. So whenever you see a collicus, you know you're in the midbrain, the why is it there, The superior colliculus is important for having sort of maps of your vision. For example, if you hear someone talking, how do you know they're there? Obviously your uh your ears play a function. But on the other hand, you need to sort of uh comply your understanding of your visual map or where you are in space to understand where it is. And when you kind of come to audition and understand a bit more that it becomes a lot clearer, then we've got the empirical which is very important. But in this case, in uh particularly in humans, for uh purchasing of what you hear and sort of integrating it with other sensory modalities to get a full spectrum of what you're actually hearing and trying to understand what it all means. Then we've got the tegmentum. In fact, the tegmentum is actually the whole part of it. But in the top bit of the tegmentum here, you've got different uh structures called the retin. It's very important for movement, giving rise to rubrospinal tract, which you will come across. Um the per to gray again, very important for pain processing and controlling um descending pain inhibition. For example, you can, in different scenarios or different contexts, you will have felt different sorts of pain, waking up in the morning, you feel a different pain threshold as you would do at night. And all of that has got different forms of regulation. It's very complicated, in fact, but then peria upgrade pain is an important part. Also, you've got connections with something called a reticular system called a reticular formation. Now, the reticular formation is a very diffuse form of network that is present in your midbrain just about showing here. And what I really wanted to point out here are the major parts of it. For example, you've got the median reticular formation, also consistent of your RFA nucleus. Then you've got your lateral reticular formation as well as your paramedian reticular formation as well as some of the nuclei. But the important of that to remember is the central one, the lateral one and the median one and all of this have different function, but it's a very diffuse form of uh network of neurons that it has importantly, it consists of in many vital functions. For example, breathing consciousness, BP, heart rate, sleep, bladder control, um generation of your motor control. For example, how you walk, how does it start off the pattern of walking? Um That all is these structures and circuitry that control that is located within your particular formation. And importantly, how do they actually do this? Well, obviously, they need to be able to do this via different mechanisms and those mechanisms are known as your neuromodulatory nuclei. And what that very simply means is that you've got different forms of neurotransmitters and those systems in specialized circuits, which helped, helped do these sort of functions. For example, I'm gonna focus on four different ones. Firstly, the no adrenergic. Secondly, sera third anergic and fourth cholinergic systems and all of these might have some sort of integration at some level. But then again, also have specific functions or specific things that they're associated with, which helps you understand and kind of formulate what these functions are associated with and what the neurotransmitters are involved. And when you look at pharmacology or how we treat different pathologies, all these systems that come into place. Um First of all, we got the serotonin, no adrenaline neurons as shown here, Serotonin and noradrenaline. And when we look at that, you can see how these circuit tree kind of go around in the brain and what structures they innovate. And I've just labeled here all the different nucleus um that are actually the ones of the origin from which this uh fibers actually um come out from. And when you go through neuroscience quite a lot, you will come across these structures and try to kind of integrate how they work, for example, in many different pathologies like psychiatry, um et cetera. Um The other thing that I wanted to mention particularly here is dopamine. Again, one of the most important ones that you'll come across and possibly a third lecture from now in motor cortex and movement, you'll come across that quite a bit and that dopamine associated with movement at the same time associated with struct um sort of circuitry that is with addiction, reward, um emotions, et cetera, decision making, et cetera. So it's all about getting a feel of what is out there and how the systems come together to give you all these different functions. Now, once we've looked at starting from the top of the brain, the midbrain. So the brainstem, we come across the spinal cord, which is perhaps second last structure that you need to possibly do a sort of movement or any other simple task. Now, the spinal cord is a central nervous system structure which runs all the way from your brainstem to your um lumbar region or just for the sim simplicity, you could say low back. Interesting fact to know is actually the spinal cord in adult humans ends at the L1 level or when you are sort of more younger person or just at birth is at the L3 level. But because of the elongation of the way in your um rostro cordal axis, you get this uh movement of the tip of the spinal cord, which is known as a medullary cone. And you can see that when you look at an adult, it will end at an L1 level. And that is an important factor. Not there are 31 pairs of spinal nerves that basically come outside. And here's a diagram to show where they actually between the intervertebral foramina, how these nerves actually come out from. And the other bit I wanted to focus on here is to look at a cross section and getting used to knowing the cross sections of the spinal cord. You have got, I guess a part of your lumbar spinal cord taken here, the white matter which particularly consists of axons and these axons are coated by myelin, which are lipids and all forms of fats, which is why they look white and in the inside, you've got gray matter which consists of nucleus again, talking about the origins and versus the processes. No, what happens in this case is they've got the white matter on the outside, the gray matter on the inside. And in terms of the brain, it's kind of the reverse. So the brain has got the gray matter on the outside and the white matter on the inside. So that's an important fact to know and hopefully when you get across to seeing different sections, you will see how that actually plays. The interesting bit is as we go down through the spinal cord, the parts of the brain, the white matter changes, which gives you an indication as to which part of the spinal cord you're at. And that gives you an indication as to what structure you might expect. And here, I just wanted to point out that learning to look at different ratios of your white matter to gray matter is important to tell you where you are. And in this case, um if I rightly remember, you might see it's the opposite, the white matter as I said should be on the outside. But in this case, it looks dark. But in this case, I hope that they labeled the myelin basic protein, which is basically labeling all your myelin, which is why it looks black on the outside. But essentially, the idea is you will have all the white matter on the axons on the outside and the cell bodies of the origins of these neurons on the inside here. And again, we talked about the sort of arrangement of the meninges outside of the brain, the pia mater, arno mater, the dura mater on the outside and the spinal cord is exactly the same. And that is also something important to remember. Um sort of kind of trying to correlate your upper anatomical structures with the lower ones. Two of the things I wanted to mention very quickly is that when we look at the spinal cord and we take a section of it, the interesting thing is polarity, you've got sensory nerves, the ones that are helping us to feel versus the motor nerves, which are actually helping us to do different functions or different actions. And in this case, if we focus on the sensory neuron over here, it's a sensory neuron kind of starting sorry. This one starting off with the skin going all the way to the dorsal horn, dorsal. In this case, meaning the one at the back. And in this case, what you see is it goes all the way to the back and then um goes sort of to your ascending structures. On the other hand, the motor neurons getting or receiving the information from ascending structures like the brain, the motor cortex coming all the way down to your ventral root this time of the front of the spinal cord and then exiting to the ventral horn and then supplying your muscle fibers. So very simply put the anterior and the ventral horn important for information out. And the dorsal of the posterior horn is for information going into your spinal cord such as sensation. The other important thing is when we look at the spinal cord in a bit more detail and understand the motor neurons a bit better and characterize how they work. We can look at the muscles that are sort of controlled by the motor neurons sitting close to the central canal. Here are the ones controlling the trunk, whereas the ones on the side are more lateral are the ones controlling your extremities. On the other hand, we ought to see a nice demarcation as to where your motor neurons controlling flexor muscles versus the one's controlling extensor muscles sit. So you can kind of try and see how there is a form of organization even at the spinal cord level, which helps you understand where that neuron might be going and what sort of function it might be having. And that is an important thing to remember. But just for this one, the polarity I would say is the most important concept. And let's imagine if you were at a spinal cord 11, if you're going all the way up, the polarity will be continued all the way through. So this is an important takeaway to understand how they work. Lastly, what I wanted to say here was about a little bit about spinal tracts which will be followed up on motor motor cortex, talk, the one on movement, the one on sensation, et cetera. But essentially we discussed that on the outside, you have your white matter on the inside, you have your gray matter. Now, these white matter are then divided into different columns. For example, the ones sitting in the back or your dorsal columns or your posterior columns, and the ones sitting on the side are your lateral columns and in the front are your anterior columns. Um In this case, what you see is that once they're made into different columns, what are they there for, let's say a sensory nerves enter sensory nerve enters your spinal cord. It obviously has to reach the brain. So it enters all the way through here. And then it follows one of these tracks and it goes all the way up to the brain. So these columns are essentially, if you think about a 3d structure are present to facilitate information in and out of your central nerve system. Now, there are different kinds of ascending tracks, for example, the ascending ones. So you can understand what goes into the brain are your sensory ones and what comes out of your brain are your motor ones. And you will have to learn about all the different ones, but just to point it out there and giving you a brief introduction as to what they are. And in individual talks, you'll get into a lot more detail. For example, in sensation, you'll go into sort of dorsal columns leading to um fine touch, vibration, proprioception sensors. Whereas your lateral spinothalamic tract is important for your crude touch, pain, et cetera. And again, I just put this diagram out here to show you what these tracks essentially mean and what they do. And in this case, just showing one of the uh ones particularly coming from a merge cortex, supplying you go going all the way down through your kind of lateral columns and coming all the way down to give you some sort of instruction to your muscles to contract. So essentially you could call this a sort of uh track that is important for movement. On the other hand, you've got different other information that is going about. For example, the ones supplying a sensation, like fine touch. On the other hand, you can also have the ones supplying your pain temperature, et cetera. But these will we all discussed in subsequent talks. But today I just wanted to introduce you the nervous system. Hopefully, I've been able to do that, giving you fundamental principles to understand what are the basic units and how we understand all of these different um sort of structures that come together to give you the structure function relationship and how we start looking at the brain all the way from the top, starting at the skull, you look at the meninges, you go down, look at the structure of the brain, look at the ones that are on the inside and then follow them all the way down to understand cranial nerves, the midbrain, the brain stem, the spinal cord and the peripheral nerves. Finally, we spoke a little bit about details of the cranial nerves I brought, I think um about seven of them in there and the others to follow as well as we talked about the exit and the entry points, the cranial fosse and how the er foramen and the individual ones allowed different structures to pass through them. And finally ended on a note about sort of spinal cord and the different tracks that allows us to feel or move et cetera and give you a sort of basic understanding of how they work. I think that sort of puts me, uh, to the end and, yeah. Any questions.