let's start this morning with our classification of [Music] neurons we have a structural classification a functional classification and a chemical classification you can use any of them when you're talking about neurons so let's begin with our structural classification we can have unipolar cells and these you'll find primarily in the embryo we'll have just a Soma and a process then we can have the pseudo unipolar which you've already had but we'll put it in for completion sake pseudo unipolar and it will be found in the dorsal root ganglia you'll see later that that's your spinal ganglia the dorsal root gangling and that as we showed previously you'll have two processes but one stem to the cell to the Soma so we come up with a single cell we had a peripheral [Music] process why don't we just call it a dendrite because it's myelinated so this is a rare exception this peripheral process is myelinated though it serves the function of a dendrite by bringing the information into the Soma and we call the process that's on its way to the CNS a central process then we have bipolar cells bipolar which just tells you then we're going to have two processes a single Soma so here we'll have a dendrite and an axon taking the impulse away taking the impulse in where do we find bipolar cells we find them in the retina in your eye eye receptor your retina we've already had one group of them we had them in the old factory epithelium so a bipolar cell in the old factory the old factory nerve and and we'll find them in the auditory ganglion auditory gangion and then by far the most of the nerve cells will be multipolar so multi-polar these are most numerous so you only have really two in the adult to worry about bipolar pseudo unipolar and then everything else is multipolar example we'll give the anterior horn cell again it's got its many poles our anterior horn cell we'll use all of these as we're developing the functional aspects of the nervous system so we're just Gathering up our building blocks now then we have our functional classification again very simplistic but basic to get us started we'll have most we'll have sensory and what's the third inter neuron yes the inter [Music] neurons so example of a motor cell we'll keep using it because I hope 10 years from now you'll remember the anterior horn cell it's a motor cell it's what's allowing me to ride on the Blackboard the anterior horn cell it's in the spinal cord sensory example of sensory once again I'll use the same one your dorsal root gangion everything coming into your spinal cord passes through the dorsal root gangion these are also called spinal ganglia collectively and then we have the interneuron so most neurons are interneurons they will connect the motor and the sensory so let's just say there're between motor and sensory sensory will be bringing things into the CNS and then it goes over to interneurons until you want a a function and then the motor will take it out and carry out the function so then we have chemical classification and there's so many chemicals associated with the nervous system system now we can't begin to take a couple of hours to give them to you so we'll just give you three examples we have what are called coleric neurons this will be chemical Co [Music] leric neurons so those who've had this before what's the transmitter acetyl choline right acetyl Coline we have adrenergic neurons what's the transmitter adrenaline yes then let's just put in one more let's put in a gabaergic gab argic what's the neurotransmitter Gaba what's it stand for gamma Amino what's the next word buic last word acid so it gives you examples as we said there are many many more of these now so just a few more basic terms we've been using them but we haven't defined them what we call groups of neurons so groups of [Music] neurons of like function inside the CNS are called what nuclei plural a nucleus singular or nule [Music] I plural so example since we've talked about it before talked about the vagus nerve when we go to see where it's originating from part of it's originating from the dorsal motor nucleus of 10 dorsal motor nucleus of the 10th cranial nerve and what's the name of the 10th cranial nerve the Vegas right so we review and review right constantly get it from different perspectives now a group of nerve cell bodies outside the CNS group of nerve cell bodies outside CNS what do we come gangon ganglion singular and ganglia plural so with this very simplistic introduction we have some tools to begin to work with let's go now to the development of the nervous system I give the development because it will give you the terminology basically for the whole nervous system at the beginning so that we could use it for more advanced functions so let's look at the development of nervous system and we all started with a simple neural tube with our nervous system starts as a simple tube this is called the neural tube and it will have a central canal that's our Central Canal this is the headend tail end this end is going to form your brain so what's the rest of all of this going to form spinal cord sure your whole CNS so the neural tube develops the CNS now let's take a section through this cranial end crosssection of neural tube and our Central Canal is changing not just a simple elongated tube it's taking on some shape here this now is our Central canal and the central canal now in the head end will form the ventricles of the brain form ventricles of brain so you have these Chambers inside the brain coming from the original Central Canal we have a landmark here the SoCal called sulcus limons because we can use it for functional considerations so we'll put our Landmark here these lateral projections of the central Canal we call them the sulkus limons sulcus limitans limiting sulcus then we can draw an arbitrary line across to the periphery of our tube and everything dorsal to our line will go into What's called the AER plate AER PL plate the AER plate is sensory ventral to our arbitrary line will have the basil plate so what's everything in the basil plate motor what do they call the gene that stimulates this Arrangement no Sonic Hedgehog I didn't name it is the gene that affects the protein that affects the AER and basil sensory and motor plates so we're always learning things new it's never always the same so now with this we want to introduce a few more terms here we need to have a roof plate and as you would anticipate the roof plate is going to be up here so this gives us just some basic divisions that we'll work with as we go along if we take a section through the area of the brain this will be essentially the same in the spinal cord initially and then the brain takes off and becomes so much more elaborate so now let's look at the divisions of our neural tube so I've said before the liver only weighs seven pound seven pounds Li the liver weighs three pounds and the Brain weighs three pounds and yet the liver every single cell is the same as every other cell so if I take some of my liver here or liver here or liver here or liver here they all look the same they're phenomenal factories but the brain only weighs three pounds if I take some here it'll look entirely different from some here some here everything's different that's the beauty of it that's the contrast that's the challenge so now let's look at our uh divisions of the neural tube start very simple again three main divisions and down to our chord use simple terms to start with forbrain midbrain and hind brain now we change the terminology put it into our old languages because the literature does that so that you're familiar with what they are we had lots of fun in an office hour the other day turning on things in the web and working it out and explaining all the terminology because students are beginning to get it now they can begin to talk about it so what's our forbrain it's the pros in sephylon so enlon means brain Pros means before so this is our forbrain then we have the MZ enlon mes enlon which is our midbrain heard of entis haven't you en sephtis inflammation of the brain and the hind brain will now be the romin sephylon and the ROM just deals with the shape AR rhombus so that's a shape arhus in Greek we'll see when the look at The ventricle how it changes now then these continue to divide and give us more divisions and then we'll look at the derivatives of each of these divisions now the pros and sephylon is going to change into the telen sephylon and the dlon and the Dylon it's worth the investment of time to get familiar with these to begin with then you can handle things from now on anywhere in the brain the mesen sephylon stays the same the ROM benon divides in two just as did the pros in sephylon so we have the Met enlon met enlon and the which was the last last one you know my enlon my enlon how do I remember their order alphabetically s t and Y so you can think this is head end tail end so s te just as it is in the alphabet so it'll help you because en sephylon is common to all so now what we're going to do is take each one and say a few words about it so you get your orientation of the total brain because we'll be bringing things in to part of it then take it on to another part to another part modifying the impulses so we need the basics Basics Basics first let's start now with our my and sephylon what are the derivatives of the my and sephylon simple because it's a very basic part of your brain just adjacent to the spinal cord I mean this brain elaborates for early animals just had a spinal cord information coming in going out sort of reflex then they add some more cells to modify that so you put in a my enlon then we go on and we're going to see the cerebral cortex is going to be way up here the highest to modify everything so our myen sephylon the structure we're going to form will be the Medela I'll give you the F full name just so you've heard it magala a blong soon as I spell it right long got there we go we seldom use that but the kidneys have a medulla the adrenals have a Medela and people talk about the medulla they have to say of the brain which structure they dealing with your Medela is only one inch long so it's a very small part of your total brain when you picture it just one inch it's one inch in a chimpanzee too so it hasn't evolved that far up to the human so it has lots of functions in that one inch very dynamic as we said before it's essential to life but deals primarily it's got a center for cardiovascular and respiratory functions where did I say the frenic nerve gets its control for its rhythmic firing ponds and medulla this is this will be going down for your frenic nerve to keep you breathing respir respiration Center so there are lots of cranial nerves that all of a sudden I lost it no it's there the um cranial nerves associated with the Medela will be 8 through 12 the name of the ventricle in the DOA will be the fourth ventricle you have four ventricles we're starting at the bottom this is going to have the fourth ventricle soon as you start reading your MRI scans you'll be alluding to these all the time because they're major landmarks so how does let me just do this how does your neural tube change as it forms the Medela you can say just put your two hands together The Palms represent the basil right and the finger the AER here's my sulcus limitans in between when I come to the medulla it opens out like this so out here will be my AER my basil will still be my ponds but what is important is what happened to that roof plate we extended it tremendous SL so if we do this or our roof plate I guess was pink wasn't it sorry so that's our roof plate so this is now AER plate basil plate basil plate AER plate and this is our roof plate when you study narrow in detail you'll see how important this is and this is our fourth ventricle so look at how it has changed I've seen people fail a PhD exam for not being able to work out what nuclei are in various areas because they didn't have their fundamental development of this area of the brain so this will give us then very fundamental picture of our Medela let's move on up to the methan sephylon two major derivatives from the metan seylon who knows those pardon yes what are we coming up from cerebellum and ponds right derivatives will be the cerebellum and the ponds cerebellum will be on the dorsal side ponds on the ventral side so briefly what is these so here's our Medela down here our spinal cord and we've put in our cerebellum and on the ventral side we'll have the ponds so now what in the world are those the ponds is a bridge that's what ponds means we'll just expand it here's our ponds here's our cerebellum what's it bridging it's a bridge of fibers connecting the cerebral cortex which is up here the most highly developed part of your brain from cerebral cortex down to cerebellar Cortex so I'll have paramal cells way up here in my cerebral cortex that'll have axons that are going to go all the way down down down down to my ponds masses of fibers coming down and then they will synapse and send fibers into the cerebellar cortex so major tracks for the cerebral cortex to talk to the cerebellar cortex from cerebral cortex paranal cells to cerebellar Cortex and the connecting link is the ponds so that essentially gives you pontine function tremendous amount of fibers coming in people are still trying to learn why actually this whole cortex should have fibers going in so what then is our cerebellum doing for us cerebellar [Music] functions will you learn this early we'd have learned it too balance and coordination and now as we're beginning to understand the connections with cerebral cortex it plays a role in learning fine movement give an example of a [Music] Pianist see those hands without a cerebellum that wouldn't be Pro possible so with a panis cerebellum's affecting both hands and feet you've got those pedals going as well right terribly important we've tested what it means before so that gives us just a basic introduction to our method sephylon let's move on to the mesen sephylon move it over here we need to take the mes enlon maybe if I give it some Dynamics for you the bullet that shot President Kennedy was lodged in his mesen sephylon why they couldn't go in for it because you'll see how it's not on the surface it wasn't any place they could go for it was deep so the mezan seyon we're F first let's look on a dorsal view see no part of the you have to have all these views we'll look at you'll see these four rounded structures looking down I'll show pictures of these so you'll see them let's just get the basic Arrangement now I think I'll take this off since there are four of them they're called the quadr geminal bodies quad Reginal for bodies quad reinal bodies and the two Superior ones are called the what Superior calculi Superior calculi is just little Hill because they look like little bumps here Superior culi what do they do for you visual motion pick up that little fly out there you hit your tennis ball you're watching it visual motion the two inferior ones what are you going to call them inferior C sure you can begin to name some things that Mak sense right inferior calculi they're part of your auditory pathway you hear a loud bang and you jump an auditory reflex response through your inferior calculi very simplistic here any one of these you could spend hours talking about all right let's take now a um what kind of section do I want let's take a ventral View ventral View and here we'll have our Dian sephylon up here we'll see these fiber tracks coming down like this and down here we have fibers going in this direction and they're going out to a structure that looks like this so we've just left our mean sephylon and we developed these two structures so what are they these two structures we just developed in our met and sephylon pardon ponds and cerebellum sure this is ponds and cellum from a ventral view pond and cerebellum just letting you know where we are because we this was all met enlon now these fibers here are the ventral surface of our mezen sephylon so these are called cerebral pedones it'll come together it just takes time we getting the parts we'll show how they're connected and now we're going to take a coronal section of the mesan seylon and we'll see the calculi this way I'll take it on down this way and our Central Canal has changed completely I'm sorry oh I'm sorry Dian sephylon that was just abbreviation for dianon please ask all right now this is our Central Canal what do we call the central canal in the mezan sephylon no that will be between the dianon this is between the fourth and the third pardon cereal cerebral Aqueduct good for you this is a cerebral aqueduct and this is where the central Canal is smallest in the brain so you get a tumor in the midbrain and you can block your cerebral Aqueduct and you block all the flow of CSF cerebral spinal fluid that's in your ventricles so it's a crucial part we had a professor who blocked it he'd come to class to show us they put a shunt in to let the CSF run and they ran it under his skin and took it down and it went into his abdominal cavity the kids would just come touch it they love to touch his shunt but he won't I mean he had sort of retired and everybody had forgotten him but once he got that shunt he became a star in class so that was nice all right but it tells you how important each one of these things is if one stops to tell you the Dynamics of them and there we are and we didn't get very far did we we have lots to go but I think what I will do while I have have this just to make these Dynamic for you here are your cerebral peduncles in this view they're down here this is coronal this is ventril right this is ventril this was a ventral view but you took them across this way so they look this way what are these then generic term for them because we don't know what level we are corpor quadr gemina right they're on the dorsal surface so these are your corpa quadr gemina and we're going to put in here I will go to my slides very important structure here we know more about it function just about any place in the brain what's it called substan the black substance we'll come back to that next time but let's have our slides substantia if you see me sitting here doing this it means I'm losing cells in my substanti Parkinson's disease we'll pick that up next time let's let's review all right here's our main character all fully formed just so you can see what we're developing we take it through development so you get the stages here's our 1-in Medela there's our cerebellum our ponds is going to be tucked in here we haven't developed our cerebral hemispheres but we'll come to them next one this gives you a chance to introspect how many times have you introspected into your own body when you brush your teeth tonight open your mouth look back you'll see your uula then you'll have your tal column and then imagine you could go straight through and you'd be at your spinal cord but then start to climb this is Medela this is cerebellum this is ponds this is fourth ventricle here are calculi Superior inferior here's our cerebral peduncle we only got that far we have all this yet to develop next one this just shows our tube for our prosen seylon Mees and seylon ROM and sephylon and we're going to see it change so that the prosen sephylon is going to form our cerebral hemispheres here's our dlon here the eyes will come out from there the retina then this is our future Aqueduct it's big still here's our fourth ventricle and we can see how the how it's beginning to curve and change in the next one and this shows what it's this is hindbrain midbrain forbrain what happens if this does not close one month in the embryo you don't form a brain you have what's called anony without a brain we've seen those when I take my small class over to UCSF to pathology where the brain this did not close obviously your is closed at one month in utero so we go over here here's our medulla here's our ponds the cerebellum is going to develop here here's midbrain we got this far here's our Medela here's our pond here's our cerebellum here the calculi and here the cerebral ped dunal next one and this is just putting it in the head so you can see cerebrum is going to come from the telen sephylon the Dian sephylon here the midbrain the cerebellum and beginning to develop now cerebellum ponds Medela already you're getting tired of hearing them there's Superior calculus inferior cicus and there are your ped Dunes on the ventral surface this was dorsal surface next one and this is to show the brain of an embryo at four months you see none of the fissures people say Well when does it begin to fold well you could say at least you know you don't have folds at four months so roughly around five months in utero do you begin to fold because if you didn't fold you'd have a brain that's 2 and 1/2 ft Square so it's got a fit in this skull to get through this birth canal so it folds right but see this just shows pawns so cabel and Medela midbrains in here next one now we're looking at a dorsal view here's why it's called a romen sephylon this looks like a romboid figure this is a roof of the fourth ventricle medullas down here we've taken off the cerebellum so we can look down and see Superior calculi inferior calculi we're going to go up into Thalamus basil ganglia and the hemispheres in the next one and this shows the ponds from A ventrol View here's the pond you can see it's a real bridge going into the cerebellum but it's connecting all the areas of the cerebral cortex sending them all in because we know now that cerebellum deals with learning we used to think it was all of these muscle things it's very definitely involved in our learning here's your Medela and if we went deep in here we go on to our ding next time but this is Meson next one and this just shows the fibers coming from the cerebral cortex they've got to all come in funnel down when they pass through here this would be your cerebral ped dunal coming in these fiber tracks have to go clear down to my spinal cord so I can be playing with this pointer in the next one next one please this one just shows the development of an area of the insul it's by some people will be speaking in 131 a it's in a very important area for a speech in the next one is that it that's it enjoy