Transcript for:
Understanding the Brain and Nerves

so chapter 14 the brain and the cranial nerves these are the outcomes we will get into the details of the brain regions uh spaces inside ventricles the different cranial nerves anatomical and functional classifications and the function of each part of the brain and generally speaking the brain is the largest part obviously of the central nervous system remember we did the spinal cord which is the other part and the brain consists of cerebrum's rebellum the encephalum brain stem we will get into the details of each part but cerebrum cerebellum diencephalon brain stem cerebrum cerebellum the encephalum brainstem cerebrum is this big two hemispheres cerebellum diencephalon and brain stem are smaller parts but we will get into the details so here is the first part or these are all the parts here cerebrum is this big the largest one and this is there is a cover outside we call this cover cortex and there is an inside um filling which is uh white matter we will get into the details but what you see here this big one here this is the cerebrum this blue one in the back here is the cerebellum the tiny brain and then within this cerebrum there is a diencephalon and the brain stem is this part right here the green starting from here this this and this these parts right here this is called the brain stem so cerebrum's rebellum the encephalon and green step cerebrum is the high mental function others are less if you guys still remember when I started I said that the whole central nervous system is managing the body but the the spinal cord is more like a supervisor a low level management and then you go up to the next level like the brain stem the the diencephalum the cerebellum and then the higher is the cerebrum the highest of all is the cortex of that cerebrum the cover that's outside here this is your awareness this is your Consciousness this is the highest of all so we go to go in that sequence so we start with the cerebrum spinal cords what's above the spinal cords those three what Above This those three cerebrum this is what we're talking about the heist of which the cortex so this cerebrum is doing the highest functions highest functions means basically thoughts in intellectual functions memory decision making planning all these high function it's not like you touch something and you move away it's not something like your your uh viscera are moving or something like that these are all basics but for this one this is the highest function there are two hemispheres half spherical structures and there is one right and one left the cover of that cerebrum is called the cerebral cortex and this is gray matter the filling inside is white matter if you guys are following and you have an exam coming tomorrow you should remember that the spinal cord is gray insides and white outside do you remember that the gray inside with all these horns and it's right outside this is the opposite the cortex outside is gray and the inside is white there is some gray in that white but generally speaking cortex is gray and the inside is white the surface of this cover or cortex is not flat there are some depressions or grooves and some elevations elevation depression elevation depression it's waving like this the elevation is called gyri or or the single is gyrus the depression are called sulcus but some of them are deeper and we call it fissures so elevations is just gyrus depression shallow depression is sulcus which is the vast majority and the deeper one are called facial it's like this if I get this and just cut a little bit like this we call this sulcus if I cut all the way deep in we call it fissure cerebellum is the second largest of after the cerebrum and this is basically to coordinate body movements we will discuss the details this is just an introduction just like the cerebrum It's also two hemispheres and it is also covered by a cortex that's gray matter as well then the diencephalon the diencephalon is located somewhere in between those two in between the cerebrum and cerebellum basically there is a thalamus under the thalamus above the thalamus that's basically what it is Thalamus above it and under it okay thalamus is sensory and for information stop at the thalamus before going further before going up she should stop at the thalamus there is part above the thalamus we will talk about it and part under the thalamus which is called hypo EPI and hypo hypo is under the thalamus hypothalamus it has a lot of functions uh emotions autonomic functions hormone production this is just an introduction again and these are the broad lines we will discuss the details uh other parts of the diencephalon pituitary glands this is under the influence or under the control of the hypothalamus that I just mentioned okay so what's connecting the hypothetic I will show you guys the picture coming but what's connecting the hypothalamus to this pituitary gland the other name for this gland is hypophysial glands you will see it coming but when you see hypothesis or hypophysial gland it is pituitary gland it's the more scientific name or the other name for it so there is a pituitary gland and what's connecting it to its manager the hypothalamus something called infant nebulum or stalk and we have a lot of models in the lab that we will discuss this part um next part or the last part here is called the brain stem and the brain stem is a stem that's connecting what's above to what's under above it and and behind it and under it it's something in the middle a stem in the middle above it the encephalon and cerebra behind it cerebellum under spinal cord and there are three parts for this from above going down midbrain ponds medulla oblongata midbrain ponds medulla oblongata this is the sequence from above going down midbrain generally speaking it process site sounds reflexes maintaining Consciousness this is just randomly speaking again we will discuss the details it's it's for processing um vision and sound and so on underneath the midbrain the response and this is basically the pawns is connecting the cerebellum to the brainstem it's behind it is the cerebellum what do we have in napans we have some tracts relay centers and some nuclei nuclei for what nucleus and generally speaking do you guys remember the ganglion or the ganglia which is a collection of cell bodies the ganglia is a collection of cell bodies outside the central nervous system so what do you call a collection of cell bodies inside the central nervous system we call it nucleus clear collection of cell bodies outside we call it ganglion collection of cell bodies inside we call it nucleus so there are nuclei for both somatic and visceral motor control last part is the medulla oblongata and this is connecting anything above it to the spinal cord inside of which there will be part of the central Canal that we talked about in the spinal cord if you guys still remember do you remember this canal in the middle of the spinal cord in which the CSF is circulating it will start here and this is basically the regulation of autonomic functions heart controlling the heart heart rate and blood pressure and digestion okay look at this picture right here this part up here is the diencephalon and then look at those three green blue and Lake havan green blue havan right here those three together or the brainstem top the top one is midbrain followed by pawns and the lower one is the medulla oblongata okay um what is this diencephalon this is the thalamus and underneath it is hypothalamus and look what's connected to it down here you see this what's the diencephalon thalamus hypothalamus and then connected to the hypothalamus is this gland here you will see it in the lab this is called the pituitary gland or hypophysial gland or hypothesis pituitary hypothesis hypophysical same thing and you see the connection here this connection connecting the hypothalamus to the pituitary this is called the the stalk or the infantibular okay so the so what you're seeing and and we have a model like this in the lab what you're seeing here is just two structures these two structures are diencephalon on top brain stem at the bottom foreign so this was all everything so far is just an introduction to the main parts one more time the brain we finish the spinal cord now we're doing the brain what are the main parts of the brain cerebrum the two hemispheres cerebellum in the back diencephalon underneath it brain stem cerebrum cerebellum diencephalon brain stem these are the main parts we will start with the cerebrum the two hemispheres right and left first thing is where do they come from the embryonic developments and we're not going to go too deep but you need to know where do they come from generally speaking so the in in embryo there used to be three vesicles from which all the parts that I talked about will come you will notice that all of them end with syphilan syphila means brain there is bras or brazi means front or four braid mesin is metal it's even some kind of similar a little bit missing metal mesen metal or Med brain rambi means behind or the back hind brain these are the three from which you will have five secondary tele andynencephalon methanephalon is the same thing it didn't change and then methanecephalon and myelencephalon at the end diencephalon and mesencephalon they will stay as it is so that's two till encephalon will make the cerebrum methanecephalon will make cerebellum and ponds and myelin cephalon will make the medulla oblongata and here it is so this is what you need to know here this slide right here primary Frozen mezin rambi mezin doesn't change at all so this is the easy one mesencephalon become what become mesencephalon secondary and then it would become still mesencephalon which is a midbrain midbrain so this doesn't change what change are the other two prozi Pro front this is the one that will give you till encephalon that will become cerebrum diencephalon that will stay as it is and then the Rumbi the back one or the hind brain will become methanecephalon and myelencephalon methanecephalon give you cerebellum ponds and myelin cephalon give you the medulla oblongata this is the origin that you need to know is this slide that I just talked about now inside the the the cerebrum inside those two hemispheres we have spaces it's not like it's compacts there are spaces inside and these spaces are lines to include them there are different spaces why do we have spaces because inside the brain the blood does not enter all the way into the brain it doesn't happen like this because the brain is too important and too sensitive to allow the blood to enter inside the brain there is a filter there is a barrier the blood should stop and you should allow only part of it to pass and this part is called cerebrospinal fluid cerebro brain spinal spinal cord this is the fluid inside the central nervous system are we following so far so this is what why do we have spaces called ventricles CSF cerebrospinal fluid this fluids why do you have this fluid because I can't allow the blood to enter into the brain too sensitive too important there can be harmful things in the blood so you have to stop it there is a barrier this barrier will allow part of it water and certain things including the nutrients and oxygen certain things are allowed to go in and these parts that are allowed to go in CSF so we make it in the ventricles every ventricle will have a part that will filter out and make the CSF so these are called ventricles and these ventricles we have four different ventricles two of them are called laterals and then thirds and fourth foreign look at this picture here we have a model like this and there is another one that will show you more but look at this this is left and this is also another lift so this is like right and left laterals and then this one that have an opening here this is the third and last one here is the fourth and the question that I always hear is why lateral lateral third fourth where is first and second we don't use first and second anymore we just say right and left laterals instead of first and second third and fourth is as is we didn't change it so lateral lateral third fourth right lateral left lateral third and fourth now what's happening I just told you that this is where we make the CSF so where do we make the psf in the laterals first and then this CSF is going to go to the Third the third will also add its own cerebral spinal fluid but how the CSF move from laterals to the third what's the connection there there is an opening called interventricular foramen everything that I'm saying is important as you guys know by now I'm not focusing on anything that's not important so this is how it circulates this is how we make it and how it circulates where do we make it lateral Ventures called ventricles first and then what it moved down something called interventricular foramen the opening that between the ventricles which ventricles lateral and third that's where the name came from enter ventricular enter means in between the opening that in between the ventricles so moving to the Third does the third make its own CSF as well yes it will add its own CSF and from the third it go to the fourth through what through a duct that's called cerebral aqueduct from the third to the fourth cerebral aqueduct why did you call it this name acqui means water or watery fluids it's a duct that connects or conduct the CSF which is watery fluid from the third to the fourth and it passed through the cerebrum going into the fourth ventricle and then what and then it go to the central Canal starting from the medulla oblongata and this Central canal is the one that will follow all the way down in the spinal cord we talked about this you guys remember this cross-section of the spinal cord exactly in the middle there is an opening it's not an opening it's a canal which is called the central Canal of the spinal cord so this is how it works look at this picture here same thing but you're looking from the back here is Right lateral left lateral interventricular foramina to the Third from the third cerebral Aqueduct to the fourth then through the central canal okay how the brain is protected physically of course we have the skull bones this part specifically not without the facial box this part is called the cranial bones so cranial bones and then cranial meningese do you guys remember the spinal meningese what's the innermost one of these covers Pia followed by arachnoids and the outermost is the durable one the one that faced the bone durable same thing here it's the same thing same Arrangement same everything but we call it cranial because this is a brain cover and also the cerebral spinal fluid how the silver spinal fluid is protected because it acts as a cushion right if something happened and you're moving like a vigorous movement sudden movements if you have fluid inside it will act as a cushion right like you're falling in a water Matrix that will absorb shock right so it is in the ventricles and also around the brain do you guys remember the subarachnoid space what was the importance of the subarachnoid space if you have a question like this what does it have no the subarachnoid not the epidural subarachnoid what's the importance I told you one thing important about each one of those subarachnoid what do you have no what's importance what if this is a question which will be a question of course this is something important cerebrospinal fluid this is where the cerebral spinal fluid circulates you guys should remember this remember when I told you about the spinal tap we get a sample you get it from there from from the subarachnoid space and what's that what's the significance or importance of the Pia what runs on its surface anybody blood vessels yes and what's the significance of the epidural space fat for anesthesia yes you guys should remember this um now this is a physical protection how about biochemical protection meaning or isolation meaning how chemicals the the harmful chemicals are not allowed in blood brain barrier BBB blood brain barrier there is a barrier between the blood and the Brain starting with this protection bones we talked about it but how about the meninges same thing like the spinal cord they are continuous with the spinal cord ones the dura matter which is the outermost one is two layers it is two layers here okay it is two layers there is an outer one that's actually adherent to the Bone and there is an inner one which which is adherent to the or or Not address I'm sorry which is part of the meninges two Jewelers one is the inner one that's part of the meningese we call it meningeal layer and the outer one we call it the periosteal because it is uh connected fused to the periosteum so what you have in between those two does anybody know is that the case payer arachnoid giora Jura what's in between those two parts of the Jura what's the space Epi epidural this is the epidural outside of the Jura epidural space epidural space yes because it's outside one of them so we call it epidural Epi means outside it's outside one of the two layers of the Jura now this Dura matter specifically the dura matter here is different it's not exactly like what the one on the spinal cord the spinal cord we just said there is a Dura matter and the space outside of it and inside of it that's it right but here the situation is different the geodometer surrounding the brain remember the brain is not really uh like a ball it's not really like spherical structure it is two halves right and these two halves there are spaces in between otherwise how is it two halves right there is a right Hemisphere and left hemisphere and in between there is a space and underneath there is the speed there are spaces what what do I mean by that I mean when the dura matter is covering the brain like this above it and then it will find the space it's going to dig into that space making a hold clear it's going like this and there is a space yes make a fold and then continue got it anytime you see a space you're going to make a fold and we call those dioral folds the folds of the juror why do we need these faults because this is how uh uh the the CSF is going to circulate we will talk about the rest of the circulation but it's making a Space just like this if this is a Dura matter and this is the brain the brain is two parts when I find the space it will make a fold like this can you see this this is a fault and it is not like two layers are not entered it's exactly like this can you see this where you're living like a canal here so there is a canal like this this is the Dural folds so it can allow CSF to circulate inside of this so why again are we making these fault because these folds are will be called the part of of which that's going to collect uh the the CSF at the end we are going to call them venous sinuses what I showed you this space in the fold or this canal in the fold are called venous sinuses Dural venous sinuses what are these faults exactly I told you that when you see a space you make a fold right what are these faults and what are the spaces containing these folds and this can make a good question lab and lecture where exactly like you're going like this you found the space what's the name of the face and what's the name of the fold inside of which this can make again lab and lecture both of them so the first one is called Fox cerebri this will go in the space in between the two hemispheres this space or Fisher is called longitudinal fissure next is called Tim thorium cerebelli what does it mean what did you get that name from folk celebrate the first one fox means the separator means cerebrum this is a separator of the two hemispheres of the cerebrum does that make sense if it doesn't make sense just let me know to say it doesn't make sense I will explain it again that's the cerebrum the big one two hemispheres right and there is a space in between so when you go into that space and make a fold you're separating the two hemispheres so we call it false the separator of the two halves of the cerebrum yes this is their separator it's separate them false cerebral the separator of the two hemispheres hello no no not the ventricles these are Dural sinuses this is completely different the Dural sinuses are deep inside the brain this is surrounding the brain so we're talking about two different things okay are you guys following the space the first spaces that I talked about The ventricle are deep inside the brain all the way inside but what I'm talking about now is the cover outside these are the meninges surrounding the whole brain from outside this has this is the space and this is a space but we're talking about two different things next is called tintorium cerebelli what does it mean let me explain it easily cerebral hemispheres are up here all right cerebellum is in the back here so these are two different parts isn't it cerebrum and cerebellum there is a space in between those two so if you make a fold in that space this is called a transverse Fisher so if you make a fold in that space aren't you covering the cerebellum do you guys get what I mean this is cerebrum and this is cerebellum clear cerebrum and cerebellum is underneath like this if you put a fold in between those two this fold will be covering the cerebellum right that's why we call it in thorium cerebral light what does it mean the tent of the cerebellum isn't it above it like this like a tent right tentorium cerebelli I will show you pictures but this is generally speaking so this is very important here Fox cerebri where is it in between the two cerebral hemispheres what do you call it longitudinal fissure you will see it and since it's a fold it will allow fluids to move in it making the sinuses what are these sinuses Superior and inferior sectional sinus you will see the picture how about the tintorium in a transverse fissure between the cerebellum and cerebrum what is says sinus inside of this transverse sinus because it's transverse fissure last one folks cerebelli what's the fox cerebral cerebellum did I explain the false cerebri are you guys following the difference cerebrum cerebellum cerebrum no else cerebellum cerebrum the two hemispheres the big hemispheres cerebellum with two L's this is a tiny brain in the back are we clear remember I told you fox cerebri is that separator between the two hemispheres right of what of the cerebrum the big one how about the separator in between the small one same name but instead of folks cerebral separator of the two cerebral hemispheres this is a separator of the two cerebellar hemispheres okay meningese same thing we have Pia arachnoid giora Pia is attached to the brain just like uh what we what we mentioned in the spinal cord and then arachnoid is a metal one under which you have the subarachnoid space for the CSF and then there is a subdural space between uh that Europe and the arachnoids it's exactly the same as we mentioned in the spinal in the spinal cord so look at this look at this picture right here and look at this section this is the cortex covering the brain it's part of the brain this is the cover of the brain and then you have Pia advertent can we see it here it's even the same color the brown here and then this layer right here the blue this is arachnoid so what is this part here between arachnoids and Pierre sub arachnoid space for what for CSF subarachnoid space so Pia followed by arachnoids and then you see those two layers both of them have the same name and there is blue in between this and this both of them are the Duro durameter this is the meningeal one and this is the periosteal one and in between the space is called sinus is that clear when you make a fold or in between the the two parts there is a space in between called uh the subdural space and this part I mean uh the the um sorry uh in between those two we call it sinus so these are one of the sinuses uh basically this is what we have here look at this picture to just to have an idea what are we talking about this is the cerebrum itself what's the outermost cover what's the cover of the cerebrum cortex out outside of the cortex we have three meninges okay one two three here it is arachnoids not adherent so there is a space subarachnoid space for what CSF cerebral spinal fluid and then what what's up outside of the arachnoid giora and subdural species in between it doesn't have significance that we need to know just a name what's the name of the of the space between the Jura and the uh arachnoid subdural space that's it but look at the two layers of the Jura again this is the meningeal one because it's part of the meninges and this is the the periosteal one because it's in contact an advert to the Bone and in between there is a space we call it a sinus remember when I told you this is the cerebrum look at the cerebellum now it will make more sense look at this this is the cerebrum and this is the cerebellum look if you make a fold here can you see this area here or this space here between the cerebrum and cerebellum can we see it in a picture so when you make a fold here inside this what is this transverse fissure and what do you call this fold tentorium cerebelli why don't you see it's making a tent over the cerebellum does it make sense you're making a tent over the cerebellum so tentorium cerebelli inside of which we have the transverse sinus now what is this this is a fox cerebri about this one here Fox cerebelli about this do you see this space right here can you guys see this space this this space should contain the cerebellum you don't see it but it is here so this is the tent above the cerebellum and this is a false in between the two cerebellar hemispheres and this up here is uh the falx cerebri the separator in between the two hemispheres now what are the name of the sinuses running in this and we have a model that looks exactly like this in the lab what are the sinuses here this Falks contain one here on top Superior and one inferior look at this what they call this plane right here if I have a if I'm cutting here what do you call it sagittal so if I have two sinuses here sagittal one above and one under one Superior one inferior what should I call it Superior inferior sagittal sinus make sense like this it's in the sagittal Superior and inferior Surgical Science what else do we have we also have continuation of the inferior it will go straight like this straight sinus and there is one that called goes transversely transverse is like this right these are the basics in the in the very very beginning sagittal and coronal and transverse and longitudinal you guys remember this in the very beginning so if it goes like this It's A sagittal if it goes to the sides it's transverse okay so you do need to know to know these sinuses so Superior sexual sinus inferior session sinus uh straight sinus transverse sinus and this one down here it's not labeled but it looks like Sigma so we call it sigmoid sinus here is a sleeper spinal fluid I was talking about uh where do we make the CSF three percent fluid ventricles inside the ventricles how many ventricles do we have four right so why do we have CSF number one cushion act as a cushion right like a water mattress if you have fluids it will act as a cushion this is one number two it also Supports number three why do we have it in the first place because we cannot allow the blood in right so what was the function of the blood what's the main function of the blood is it into transport the blood is transported what's what else is the function transport oxygen nutrients and carbon dioxide isn't it why do we have blood to give you nutrients and oxygen and to take away waste products and carbon dioxide isn't this is the basic function of the blood same thing but the blood is not allowed in CSF will do that work so it is transport transporting what oxygen and nutrients to the brain tissues and taking away with products and carbon dioxide it also transmits chemical Messengers so I've been saying that we make the tsf and the ventricles we make the CSF and The ventricle yes what exactly make it in the ventricles choroid plexus something called chloride plexus chloride plexus capillaries surrounded by ependymal cells do you guys remember this or not I I told you about these cells and I told you questioning each one ependymal cells remember when I told you CSF here it is Dependable cells surrounding the capillaries we call it chloride plexus this is where we make the CSF about half a liter per day and all these ventricles 500 milliliters per day so Corey Plex is going to make the CSF make it and remove it and adjust its composition now how the CSF circulates uh we know CSF we make it in the ventricles right what what exactly make it in the ventricles choroid plexus right so correct plexus make it in the lateral ventricles it moved from the lateral ventricles to the Third through interventricular foramen from the third it has its own chloride plexus it will add more right now I have more CSF where does it go to the fourth through what Aqueduct the fourth will add its own because it has its own chloride plexuses now we have a lot of CSF in net in the fourth ventricle it will leave through the central Canal of the spinal cord moving all the way sensors at the end it's going to go to the subarachnoid space and come back up are we following like this lateral ventricles to the third to the fourth to the center of canal leaving the central Canal go to the subarachnoid space remember I told you subarachment space where you get sample subarachnoid space subarachment space of what of the spinal cord then it will move up to the subarachnoid space of the brain then we will take it out of there to what to the sinuses and from the sinuses ultimately it will go back to the veins back to the heart can you imagine the whole circulation let me just wrap it up together and help you understand what are we trying to make here we're trying to make CSF fluid inside the brain because blood cannot go in how to solve this issue I cannot allow the blood deep into the brain no so what should we do now arteries going to the brain branching branching branching I'll tell the capillaries but the capillaries contain blood right can you allow the blood to go into the brain no the capillaries with ependymal cells fluoriplexes inside the ventricles we will allow the fluid parts that's filtered what we need only selective to go into the ventricles letter third adding more correct plexus adding more fourth Corey plexus adding more are we following what's after the fourth Central Canal moving all the way down clear what's after the central Canal it will leave the central Canal go to the subarachnoid space right this is the spinal cord surrounded by layers right it will leave and go to the subarachnoid space and then what to the subarachnoid space around the brain following and there is the structure we'll take it from there pour it into the sinuses and the sinuses will take it out back to the veins back to the heart so you started from the heart you ended in the heart clear from the heart to the arteries to the chloride plexus CSF circulating around at the end you take it out of the subarachment space by something called arachnoid granulations or Villa you will see it and pour it into the sinuses in the sinuses it was going to move down the sinuses going to the internal jugular vein that will return it back to the right side of the heart so you got oxygenated blood with nutrients and you leave the oxygenated going back to the heart and the heart will do the job and you keep circulating 24 7 just like this okay so um I mentioned that and I will show you the pictures I mentioned that after all the circulation you end up going to the subarachnoid space of the brain is that clear this end part is clear so now I'm in our subarachnoid space now what is this this is the last station the last part we already did everything we delivered what we need to deliver oxygen nutrients and we're taking risk products now it's time to leave how to leave arachnoid will lie arachnoid granulations these are the ones that are going to absorb CSF from the subarachnoid space and send it to the sinuses look at this picture here so lateral ventricles third ventricles moving down fourth ventricles look Central Canal of the spinal cord subarachnoid spaces number four and then it will go to the subarachnoid space of the brain itself which is this green right teeth can you see this the red arrows from which these Grand arachnoids granulations and velai will take it and pour it into this the blue and the blue are the sinuses and look what's Happening Here superstitional sinus fusession sinus straight transverse and then it will leave through the internal jugular vein do you guys remember the jugular foramen in the skull this is where the internal jugular vein leave and go to the heart so this is the correi plexus uh capillaries surrounded by ependymal cells it's going to allow part of it to leave out capillaries surrounded by the ependymal cells and the appendable cells are going to allow certain parts to leave and go to the ventricles look at this these are the sub subarachnoids I'm sorry the arachnoids granulations and Vali we'll take it from here what is this subarachnoid space into the sinuses so we talked about the protection of the brain including the CSF part and the blood supply of the brain blood supply of the brain remember I told you the blood goes to the brain does it leave the capillaries and go into the brain tissues no but how did it reach the brain in the first place like we are here in the heart how does it goes all the way to the brain two routes or two Pathways internal carotid artery and vertebral arteries four antenna crowded here in the front and vertebral in the back do you guys remember the vertebral foramina in which vertebra cervical or thoracic or lumbar cervical do you remember these openings this is where this artery goes It goes in these the transverse foramina if you remember this is where the vertebral artery goes into these foramina until it Go enter into the brain this is one here in the front do you know when we like put our fingers like this to pulsate right to pulsate and feel the pulse here like if we do like this I don't feel something here this this is the the most common location right here okay the radial artery if you wanted to feel the pulse usually we use this three fingers like this and we feel it there is a pulse here but what if somebody is like uh like a comatose or unconscious or something and you don't feel the pulse here we usually feel here if there is no pulse here he's almost dead because this is very close to the heart and it's very big what is this carotid internal one go to the brain so what are the four sources two internal carotid in the front two vertebral in the back and we have models for these so obviously this blood circulation should continue 24 7 if something happened that interfere the those patients will get into stroke and I think we're all familiar with this if you stop the blood going to the brain somehow it will lead to stroke right which is called cerebral vascular accident but does that happen if the blood goes less no shut shut down if the blood shut down even for a few seconds but complete shutdown not partial not less it will lead to cerebrovascular accident also known as stroke and stroke the neurons will actually die not just deprived die three provascular accidents now the blood-brain barrier that I'm that I talked about which is the isolation between the general circulation of the blood from the CNS foreign this barrier is made by a Thai Junction which is a very close Junction the cells come very close to each other between the capillary endothelium the endothelial cells of the capillaries they come very close to each other to the extent of making tight junctions astrocytes are going to regulate this barrier by releasing chemicals to control it it's it's a tilde barrier allow more allowless exercise and what can pass through this is certain things it's selective you have a barrier but certain things are allowed to to uh to go through it these things are selective you select what goes and what doesn't go generally speaking oxygen and carbon dioxide is allowed obviously because you want oxygen to go to the brain and you want carbon dioxide to leave so this easily just passed in and out steroids prostaglandins also can pass this um so just remember certain things including oxygen and carbon dioxide and steroids blood CSF barrier this is another component that's helping out and this is basically the ependymal cells okay so what do we have here we have blood brain barrier and blood CSF barrier blood brain barrier this is the part with the capillaries what's surrounding the capillaries in this area to make the chloride plexus ependymal cells so you have two components here blood brain barrier and blood CSF barrier blood brain barrier endothelial cells connected by Thai Junctions are we following uh how about the blood CSF barrier ependymal cells also connected by Thai Junction and this is the part that's going to together make the chloride plexus that's allow the CSF or making the CSF is that blood brain barrier completely separating uh like a complete spherical structure no you cannot do that you should allow you should allow the brain to communicate with some structures outside so it's not like a complete spherical structure right it's not a complete cover now there are certain breaks to allow communication and you do need to know these breaks one of them is for the hypothalamus the hypothalamus should communicate so how does it release its contents you have to have a break for the hypothalamus another one for the posterior lobe of the pituitary gland posterior pituitary gland because this is where we store the hormones ADH and oxidation so it should allow to communicate you also have a break for the pineal gland so that it release its secretions and the last one is for the choroid plexus this one also have um its break to allow the CSF to maintain the CSF okay uh we are going to go to the different parts of the brain stem but so now we're getting into the different parts of the brain stem the first one is the medulla oblongata which is the lowest one the one at the bottom and this one let me say this way just to make it easy for you listen each one of the three parts of the brain stem the number one function is the same in all of them it's all about location like this is a midbrain where is it located under the diencephalock so what's a function connect the diencephalon to the pants that's it how about the pawns the pants is in the middle what does it do connect those two parts okay so the pawns can connect midbrain to the medulla what's the function of the medulla connecting the the pawns above it to the spinal cord underneath it right so the first function is function by location the function by location if she is sitting down here her function is to connect them that's it this is the first one hair function is to connect them and so on so if you know what is the location connecting that's number one number two it contained this is the one that that I just mentioned here it's a relay station or communication between the brain and the spinal cord because it's the lowest lowermost one and this goes without saying if you know the location you know the first function but it is controlling the visceral functions containing nuclei for the visceral functions and coordination of the autonomic reflexes visceral functions controlling visual functions and reflexes autonomic reflexes if you look at this picture again we saw this before if you guys remember up here is the diencephalon and these three parts green blue orange or Havoc what is this green on top here this is the midbrain what is this blue in the middle ponds what is the lowest lowest most part this is a medulla after which you have the spinal cord but the three parts are from above going down midbrain ponds medulla oblonger first function is location second function cranial nerves come from this part which cranial nerve come from each one of the three third function nuclei inside one more time what's the brain stem three parts midbrain on top ponds in the metal medulla and at the bottom is that clear three parts what's a function first function location where are you where are you where are you connecting clear this is number one are we are we following number one is location what's number two cranial nerves come from this cranial nerves come from this cranial nerves come from this we will learn it and I will put it together to remind you number three what kind of nuclei do we have I talked about the medulla oblongata reflexes and autonomic functions like respiratory rates like digestive function like cardiovascular function and so on so we will get it one by one but look at this here look at this you will see that three and four coming from the midbrain uh [Music] uh five six seven and eight come from the pawns and the rest come from the medulla oblongata you got one more function here first function is location connecting second function cranial nerves third function which is a harder is the Nuclear So first function is simply what is the function of midbrain here uh where are you I'm in between the the thalamus and hypothalamus above which is a diencephalon and ponds that's it you're connecting the diencephon to The Ponds what's the function of the pawns connecting the midbrain above it to the medulla oblongata underneath it and the cerebellum behind it how about the the medulla connecting the pawns to the spinal cord I think straightforward just location how about the second function second function is three four five six seven eight nine ten eleven twelve three four five six seven eight nine ten eleven twelve two four four so how about the cranial nerve one and two no this is something else it's not related to those so one and two by themselves we will talk about it but the rest the other 10 are arranged in three four five six seven eight nine ten eleven twelve here it is again um oh of course yes for the lecture envelope where is three and four right here three and four midbrain the green five six seven eight it is five six seven eight Pawns and then nine eleven twelve I mean 9 10 11 and 12 is all by itself here where are these located medulla oblongata that's it I think that's easy three four five six seven eight nine ten eleven twelve two four four this is again up here is the thalamus you see you guys see the correct plexuses this is how it looks like you see this red Cori plexus and all locations uh lateral and third and fourth this is where it's located but I want you to look at this here can you see this section what is this part if you guys are following what is this the pawns right you see what's connected to the puns here one two three there are three things connecting here if you can see it these are called cerebellar peduncles cerebellum cerebellum do you remember the cerebellum in the back the small one peduncle means like a bridge like a connection so there are three connections connecting the cerebellum behind to the uh ponds in front of it look at this picture here this is a midbrain this is a pons and this is a medulla at the bottom midbrain ponds medulla oblongata look at the at the pons Superior metal and inferior peduncles this is obviously the fourth ventricle here what are these other reflexes I was talking about reticular formation cardiovascular centers and respiratory prismacity centers you do need to know this so if we talk about the medulla oblongata first function is location connection second function is the last four cranial nerves third function what are your nuclei doing what are you doing here reticular formation sleep wake and controlling the autonomic function cardiovascular the name Give It Away cardiovascular controlling the hearts and the blood vessels ity what does it mean you know what's the Rhythm means you go in fixed interval one two three four like one per second or one every five seconds for example this is called rhythm right so like if you're breathing you go like one two three it should be almost the same sequence like if you're sleeping do you go like a regular if somebody's watching you and you're breathing you're sleeping it's not a regular you do like like this you go and fix intervals these are called rhythmicity you go in a rhythm and this rhythmicity is decided by the medulla oblongata and understand this because the pawns the next one also control there is the the respiratory system but in a different way so let's let me say this way uh if you count your respiratory rate if I count my respiratory rate I'm I'm just resting like this count to count your 20 let's say 20 okay so who who decided that 20 the medulla oblongata does it always stay 20 no what if I'm exercising what if I'm walking running is it going to change this is the parts not the medulla so the medulla is christmasity it said the Rhythm puns control the Rhythm regulate the Rhythm so it changes like its supervisor something like this what kind of nerves do we have here the last four and part of eight eight is in common between those two okay so eight nine ten eleven twelve I usually do it like this the midbrain would be something like this followed by the parts followed by the medulla and then the spinal cord right three four four five six seven eight it's nine ten eleven twelve what do you mean I mean a come from both is this clear you have to know this this will give you a couple of questions just by knowing this uh what else do you have in the medulla oblongata I have two nuclei gracilis and quinitas these are the ones that are are controlling or in which something called pyramids are passing to control the movements there is also solitary nucleus for the visceral sensation inferior Olive this is from the somatic motor commands but what I told you is the most important ones respiratory and cardiovascular system this is the most important ones so here it is look at this these are the pyramids it's part of it this is the inferior Olive right here on the sides pyramids and Olive and right here these different parts here are particular formation Cardiovascular Center solitary nucleus one more time the most important thing that you have to remember respiratory is Misty and cardiovascular system there are other functions but you cannot forget those two most important too about the ponds the ponds will contain some cranial nerves and part of it is for location function number one and two it goes without saying what cranial nerves do you have here it's right here six five six seven eight and location yes between the midbrain and the medulla and behind it is the cerebellum like this one two three and the cerebellum function by location and what else Superior medal and inferior yes and what do we have here the most important the bottom line that you cannot forget respiratory centers called abnostic and pneumotaxic centers what are these these are the one that modulate medulla is sitting the pace 20 per minute a team per minute 15 per minute and that's it just making the Rhythm pawns above it modified change it go higher go less go up go down breathe more breezeless those two centers otherwise other functions okay but you cannot forget this one midbrain midbrain is two parts itself one of them is called tectum and the other one is called tegmental both of them start with T take time tegment them take mental together midbrain what's a tectum tectum is you have four bodies like this you see this four bodies two and a in the left and two and a right four bodies four means quads right do you know this by try quad so quadriceps I mean quadrigama corpora cuador Gemini quad means four you have the four bodies you will see it in the lab four bodies two Superior right here right and left and two inferior clear this is the part of the mid braid Superior Earth is for vision and the inferior is for auditory function you need to know this the two parts of the midbrain are thick them and pigmentum what's the tectum the four nuclei two Superior two inferior Superior or for vision inferior four auditory or healing how about the tegmentum red nucleus for the blood vessel substantia this is to control its gray matter but its control uh the coordination of the muscles what else is in the midbrain cerebral peduncles uh you mean the cerebellar peduncle the three Superior no these are the cerebellar peduncles are we following cerebellum is in the back connected to the puns by three right Superior Middle inferior how about the midbrain connecting above cerebral peduncles and these are the one that contain the tracts going up and down look at this but can you see this green look in the back here of the of the midbrain can you see this four two Superior and two inferior together all four corpora quadril gemina quad quad-4 the two Superior and the two inferiors two Superior for vision and to inferior four auditory function yeah what do you call each one of those colliculous corpora quad quad what for nuclei what do you call this nuclei colliculus Superior colliculous inferior colliculus Superior is for vision inferior auditory function and then the cerebral bed uncles connecting it to the brain cerebellum just like the cerebrum there is outside cortex and there is inside failing which one is gray and which one is white cortex is that gray or white gray and the inside is white cerebellar cortex is a gray and it also contains folds that are called Folia and there are two Loops only anterior and posterior lobe is it also two hemispheres yes cerebrum is two hemispheres right and left cerebellum is two hemispheres as well connecting them is something called vermic vermis vermis means worm because it looks like it I will I will show you the pictures look like a like a worm inside of it there is a tree like structure called Arborvitae or the Tree of Life Arborvitae and I will show you it actually looks like this most important thing is the nuclei that we have if and I usually do it like this this is what I remember [Music] these three three letters cerebellum if you ask me cerebellum BPM be balanced be positioned M muscle movement enough for the cerebellum if this is the only thing that you remember about the cerebellum I'm talking about physiology Now function enough balance position muscle movements so once you hear cerebellum BPM BPM position balance position muscle movements BPM enough okay anatomy is something else yeah there is a cortex and the vermese and other parts but for the physiology enough said about uncles I talked about it already this is the cerebellum is in the back of the brainstem how is it connected three peduncles Superior metal and inferior peduncles if somebody's having a disorder or an issue with the cerebellum what's going to happen what do you think if if there is an organ responsible for balance position and muscle movement and this is injured what do you think you're losing those that's it right you're losing your balance and your muscle control isn't it if you have a function you lose a function that's it but this is has a name that I want you to remember which is ataxia a means no taxia means like balance Ataxia no balance and no muscle coordination why or details no that's good enough you're responsible for balance and muscle coordination you have an issue you lose those two that's it we call it a taxi yeah so look at this this is the cover outside which is this rebeller cortex anterior low posterior lobe look at this worm-like structure worm in Greek is called vermis so this is the vermese this is what you see here is the cortex same thing look at this inside look at the white matter doesn't it look like a tree look at the inside look at the white inside you see how it's branching like a tree this is how the the three the Arborvitae or the tree of life this is how it looks like so what's the upper body the white matter looking like a tree inside which contain the nuclei next is the diencephalon what's a diencephala thalamus above it and hundreds salamas above it and 100 Thalamus apthalamus hypothalamus AP above hypo is under okay what are the different parts thalamus apthalamus hypothalamus pineal gland is part of of this system above it and the pineal glands you need to know that it secretes melatonin did we hear about melatonin the one that help you sleep well and fight aging and all that stuff yes this is where we make it pineal glands and this is what you need to remember pineal glands melatonin about the thalamus the thalamus I call it I call it the secretary of the brain of course this is not a scientific function we should understand more but just put this in your mind this is my secretary of debris and imagine what do you think if you go to to an office to the manager's office and you see the secretary first are you go just go in into the manager or you have to talk to the secretary first right so you go to the secretary I'm here to bring this information for the manager okay thank you I'll give it to them but I will see what I can do right why are you here I want to know what time you close and open why do you need the manager right we open from nine to five that's it right so not everything bypass nothing bypass the secretary and go to the breed the the secretary will take the information and let me know what you need and I will decide what go to the manager and what does not why would you go to the manager and say somebody's asking what time we open but how that is that important right so the thalamus is the Gateway of the entrance to the bridge to the brain itself it will decide what goes and what should be stopped okay so what's the function here it's a relay station for the sensory information and it decides what's allowed to go to the brain to the cerebrum and cortex and what's not um so basically let me say something like this if you step on a nail or something right isn't that something that you have to take care of right away you have to be aware of it right the thalamus will say of course go go to the manager we have to take care of it right away right immediately you have to do something otherwise you'll be bleeding so this is sharp pain yes the thalamus will allow it to go but compare this to a continuous nagging pain coming from your knee or from your abdomen do you think the thalamus will allow to go to the brain you know what what will happen then you will never fall asleep if you have a little bit of continuous pain in your knee don't you just ignore it and sleep why the thalamus block it the thermos will say what's so important to till the brain the manager about something like this it's not something sharp it's not something that need immediate attention so no it it will be blocked this is what I mean by sacred Theory it's relay the sensation allow things and prevent things from going and the two thalami there is right one and left one just like everything else these are connected by something called interthalamic adhesion you will see it in the lab how about the nuclei inside the thalamus nuclei we have five nuclei the anterior one is for the limbic system which is uh emotion it's part of the limbic system uh the the medial one is for emotions again but it's awareness the ventral one is the one that we are talking about the most important one which is relay station for the sensory information this is the ventral nucleus dorsal one and then there is geneculate one lateral is for vision medial is for auditory just like the colliculi superior inferior colliculi the corpora quadrigemina remember Superior and inferior vision and auditory here it's lateral and medium this is a location right here of the thalamus these are the different parts but I told you what's the most important of all remember that the ventral one is the one that acts as a relay station and this is the most important one yeah anterior is part of the limbic system medial is for sensation integration and so on but the bottom line is what you cannot forget is the ventral nucleus relaying sensation going up to the series to the uh to the brain also the medial and lateral genicular bodies the medial is for auditory and the lateral for vision more than enough hypothalamus hypothalamus remember we're talking about thalamus under and above right Thalamus we talked about it and more details don't worry much about it unless you are interested but I told you the bottom line this is what you have to know about what's under it the hypothalamus hypothalamus is an extremely important part of the body because it contains different things that are controlling like the whole autonomic nervous system so there is mammillary bodies and this is this is contain the reflex for eating there is infant nebulum connecting it to the pituitary underneath I showed you the picture remember there was a Twitter gland hanging this is what's connecting it infundiblam or the stalk and then the last part is called the tuber scenarium and this is the one that's responsible for the hormones we have a model that looks like this this is the thalamus in the middle and these are the different parts we will talk about it this is called corpus callosum connecting right and left and there are different parts that we will talk about but I just want you to see here thalamus under it look at the hypothalamus and look at this the infant nebulum they cut it here but the pituitary gland should be underneath here it is again look at this hypothalamus is up here you see this hanging pituitary gland and what's the connection inflam or stalk what's the other name for the pituitary gland anybody what's the other name starts with H Ive hypothesis hypothesis so what's what are the nuclei and or the what is the most important thing about uh the hypothalamus I'm giving you the bottom line in each one of those okay cerebellum BPM this is the bottom line right uh thalamus most important most important relay station for sensation plus the genetic bodies there are many other things yes but this is what you cannot forget the bottom line okay so what's the bottom line for the hypothalamus this slide okay number one hypothalamus is literally the manager of the endocrine system do we know the endocrine system endocrine system that that control make the hormones and control the body this is the manager the heads also the heads of the autonomic nervous system it's ahead of two parts two systems endocrine system and autonomic nervous system is that clear this is the manager of both of those being the manager or the head of the endocrine system and being part of the nervous system we're talking about it here right so it's a link between those two it's a link between the nervous system and endocrine system are we good so far hypothalamus the head of those two endocrine and autonomic and being the head of an endocrine being part of the central nervous system it's a link between those two okay so when you say the heads of uh the endocrine system what does it mean it means it manage the whole endocrine system how by releasing hormones factors that go to the different lands and tell them what to do clear I'm the manager I'm the hypothalamus I manage the endocrine system how I make factors orders to tell every gland what to do simply okay all right uh is that it like the hypothalamus is sitting down giving orders to the endocrine glands you secrete this you secrete this no no it set an example it it will say okay I'm gonna make two hormones as well I'm not just giving the endocrine system orders are we following what I mean if you are the head of something yes you're telling everybody you release your hormones you release your hormones you stop you increase more you're the manager right but you should help a little bit so I'm going to do some work by myself what is it secreting two things ADH and oxytocin this is what the hypothalamus itself make ADH will come from a nucleus that's called supraoptic nucleus and you need to remember that oxytocin come from the power of ventricular uh nucleus so what are the secretions and where does it come from important hypothalamus are you only managing the endocrine system no I'm helping as well I secrete those two um the way I remember it if you're interested I call it the said parks I know this is weird this is what I what I use okay Supra optic ADH monumentricular sad box if you wanted to use something else it's up to you but this is how I remember optic ADH paraventricular oxy tooth okay it also regulates body temperature through something called pre-optic area do you remember when we talked about the hype the the homeostasis in the very beginning you guys remember this homeostasis that was like the very first uh chapter one homeostasis remember that when it gets cold we heat up and when it gets hot we cold we cool it down and there is a thermostat here it is it's in a hypothalamus what else circadian rhythm by the suprachiasmatic nucleus circadian rhythm I think we know the Circadian rhythm right if you travel abroad somewhere and you see it's the night and day cycles disrupted we call that circadian rhythm it's controlled by the hypothalamus as well uh uh feed feed hunger thirst and satiety centers hunger and satiety plus thirsty Foods eating and drinking it controls eating and drinking hunger Hunger and uh satiety and thirst limbic system is the next system and the bottom line is here limbic contain m with e motion and memory is that enough yes enough this is what I remember from medical school okay when you tell me a limbic system M click m limbit m memory emotion M memory emotion that's it enough yes just like the BPM okay if you guys want to use my tricks or shortcuts use it if you have your own way use your own way but I'm telling you what I used to do and I still remember it back then until now I still remember it we need to when when you say cerebellum BPM just like this limbic system um memory emotion done good enough uh components of the of the limbic system uh singulate gyrus you will see it uh Dente gyrus another one a para hippocampal gyrus hippocampus uh uh it's okay if you if you remember it but you cannot forget those two amps this is the bottom line and there is another thing that's called Amy De Lloyd body and this is between the limbic system and the cerebrum fornix is also part of the limbic system plus the anterior nucleus and reticular formation all these are parts of the limbic system it is a limbic system with the different components anterior thalamic nucleus uh uh the fornax singular gyrus para hippocampus and so on okay cerebrum and I'm going to stop Eve add the cerebrum