hey everyone welcome to professor long's lectures in anatomy and physiology you're going to hear my voice but not see me because i'm zoomed in on these two models today what we're going to be covering is the ventricles of the brain which are some fluid filled chambers and the meninges the coverings of the brain now if you're following along on the list of things to know first and foremost if you're watching these videos you know that they're intended for use by students who are enrolled in my anatomy and physiology class excuse me at del mar college if you're not in my class your instructor may use different models they may use dissections they may use different structures different names so learn the material the way that your instructor wants you to learn it if you find my videos helpful please hit like please hit um subscribe if you want to subscribe but at least hit like now if you're following along for my class we're going to be on the list of things to know we're going to be at the bottom of page 32 and the top of page 33 i'm actually going to start on page 33 and then work backwards okay we're going to cover the ventricles on page 33 then we're going to cover the meninges on page 32. so if i look at the outside of the brain it doesn't appear to have much empty space inside of it but it does and i did some drawings of this and of the meninges hopefully you've watched that video first and then you can come back and see this and see how i'm going to test you on the models those empty chambers if i could pour if i could break the top of the brain open there would be some empty chambers on either side of the corpus callosum and they're filled in with this plastic fluid if i can dump water in there somewhere in the in the thalamus there's two little holes that come together and form another ventricle and there's another hole that runs down and forms a fourth ventricle and so they're all buried inside the brain if i open the brain up and i start to take it apart let me pull this model aside for a second push that out of the way i can see here on either side of the corpus callosum this is front this is back these two big plastic pieces here would be some fluid if i poured fluid in there stuck this in a freezer and froze it i would have ice cubes in the shape of the container so to speak so that represents where the space was the chamber called a lateral ventricle there's a right lateral ventricle and a left lateral ventricle or you can just say lateral ventricles now i'm going to pop off the corpus callosum there would be a septum pollution here we don't see it on this model and then on either side of the fornix here there's a little hole and we can't see it but there's a little hole that drains into the thalamus so if i poured fluid in those empty spaces it would drain right into the middle of the thalamus so if i continue to take this model apart what i get down to is the brain stem and i can see how the lateral ventricles run here and here straight back to these points but then they run underneath on either side that's all lateral ventricle here there would be a septum fellucine there and then i have another lateral ventricle that runs underneath here it's kind of hard to see when i'm manipulating it but if i pop this part of the diencephalon off i can see how this lateral ventricle wraps around where the thalamus is and underneath there's another one on the other side they're going to drain right about here through to to a little hole inside the thalamus so if i pop this part off i can see how it sits three dimensionally here's the lateral ventricle this little connector right here is called the interventricular foramen people look for a hole but the whole thing is a space so that's your interventricular foramen and then this little structure down here would represent the third ventricle sitting inside the thalamus and the hypothalamus we have the cerebral aqueduct and we have the fourth ventricle here okay so if i pop this off you can see how it would fit inside there and sit around this structure so if i look here lateral ventricle interventricular foramen the two little connectors there here's the third ventricle kind of looks like a little moose head with an eyeball and then that's the interventricular i'm sorry the cerebral aqueduct and the fourth ventricle here now the fluid that is filtered out of our blood at and into these chambers is filtered by a series of specialized capillaries called the choroid plexus that's why there's red on here we're not going to worry about that on this model now we also have this other model that has the ventricles on a stand so this is still your lateral ventricle if i twist it around i can see another lateral ventricle here i can see if i look at it this way those two little connectors you see how it looks like the letter y and then these are sitting on top those two little connectors there and there would be the interventricular foramen it's not much but it's that little connection this would be the third ventricle here looks like a little moosa's head and we rotate it this way so lateral ventricle interventricular foramen third ventricle the fluid would flow down here through the cerebral aqueduct into the fourth ventricle on this model if it's painted pink and all four ventricles their pink stuff represents what we call the choroid plexus the the vessels that filter out the cerebrospinal fluid and that cerebral spinal fluid would flow up here through the interventricular foramen to the third ventricle where the thalamus and hypothalamus are through the cerebral aqueduct down here to the fourth ventricle i hope you can see how that fits together okay so this is one of the more difficult things to get across to students when you're teaching brain anatomy now i'm moving out the way and i'm going to bring in two other models and these two models are going to show us what we call the meninges i call this one the meninges model we call this one the handle head model because it looks like his head has a little handle they're going to show us a lot of the same structures now if you watch the videos that i talked about earlier where i drew out the meninges and i drew out the ventricles the meninges are pretty tightly wrapped around the brain and those meninges have some gaps between them we have one called the dura mater the outermost layers then there's the arachnoid mater separating those as a space called the subdural space underneath the arachnoid motor is one that's right up against the surface of the brain called the pia mater and separating those is in a space called the subarachnoid space so if i could peel all them off or actually if i can show you this model let me move this one for a second if i look at it from the front this side of the model looks nice and clear and clean this side of the model is very vascular with this white film covering it that white film or white membrane represents the arachnoid mater if i ask you for this white covering that's the arachnoid mater they've peeled it off the other side these little white dots right here are called arachnoid granulations and they're like little pieces that stick up if you were looking at the tips of my fingers and i twisted them then we're seeing the tips of the fingers by looking down at this but they would be holding up this piece right here which would be called the dura mater now i'm going to grab a sheet of paper to illustrate something and i'm going to show you on a different model if i took this braid on the half shell okay and i take this piece of paper and fold it i can slide it all the way down into where it hits the corpus callosum and then i can wrap the paper out around this i wrote some notes on there and it would i could completely cover the brain that covering would be called the dura mater now they've taken some scissors and they cut most of the dura mater off and peeled it off so we can see the arachnoid mater and the arachnoid granulations and then it leaves us this little fold right here that fits inside the cerebral hemispheres like that let me show you this way so this little flap on either side here represents a piece of the dura mater at the top edge of the dura model there's a big blue blood vessel running through here that's called the superior sagittal sinus it's a long blood vessel that runs all the way through here it collects a lot of blood and um this the arachnoid granulations collect cerebrospinal fluid and drain it back into that vein now watch if i pull the two pieces of dura mater up you see this flat piece right here that fits in between the hemispheres that's called the falx cerebri falx pronounced falx and cerebri meaning cerebrum it is a fold falx means fold of this of dura mater that fits between the cerebral hemispheres it actually has arachnoid and pia mater in it too so these two pieces here would be your dura mater of course they cut most of it and removed it falx cerebri this blood vessel on top is called the superior sagittal sinus we saw it from this view but there we see it again this is called the inferior sagittal sinus and that would be falx cerebri okay so on this model i can see dura mater superior sagittal sinus arachnoid mater and the arachnoid granulations the clear membrane that would be covering this like if i put saran wrap over it would be pia mater if i pull this up i see the falx cerebri and the superior sagittal sinus there now the reason we have the handlehead model is because it represents the exact same stuff only missing the brain and we have the bone tissue here you see the coronal and sagittal suture of the skull so this structure here that flat spot is this one that's your fault cerebral only this one has a piece this one has the bone on top you can see some spongy bone and some bone marrow there now if i lift it out and tilt it you can see the superior sagittal sinus and the folk cerebral the little flaps that would have been up against the skull would be dura mater here also if i look inside the skull you can see the dura mater is this white lining it's almost like the lining of the helmet okay it lines all the inside of your skull now if i do this and it's a little bit tricky to see but when i have the dural monitor going over the um over the cerebrum the dura mater actually tucks into the the folds of the cerebrum the cerebral hemispheres and it tucks into any other nook or cranny or crevice that it can fit so when i put this other brain back together for a moment give me just a second i wasn't prepared i should probably reshoot the video but i'm not going to at this point you guys can follow along for a second so when i'm looking at the brain like this the cerebellum is not actually attached to the cerebrum the cerebellum is attached to the brain stem and they can be separated and i can actually fit a fold of dura mater inside of there and because of the shape of the cerebellum now let me move that because it has this little point on top it makes a little tint over the cerebellum so these two little flaps represent a piece of that meningeal structure this would be our fault cerebri it comes down and flattens out and forms these two little wings that are called the tentorium cerebelli or cerebelli that's the tentorium cerebelli like a little tent over the top of the cerebellum now if i take this model where i see the dura mater inside and i stick the cerebellum in there i can see how the tentorium cerebelli separates the cerebellum from the cerebral hemispheres it would all be in there something like that okay so on this model i can see dura mater and dura mater i see the falx cerebri and superior sagittal sinus and i see the tentorium cerebelli finally if i look at the cerebellum underneath it kind of dips in and comes back out and it creates a little little a little nook there spot where the dura monitor can fold up this little fold right here this would be your superior sagittal sinus this is where the tentorium cerebelli was attached but we cut it with a scalpel and removed it this little fold that goes down to the spinal cord would fit right inside that little groove of the cerebellum and that is called the falx cerebelli fox cerebelli so one last run through i'm gonna go through both models for you without me moving a lot of stuff or making you wait these two flaps are dura mater the dark line is the superior sagittal sinus the clear covering on this side would be the white covering on this side would be arachnoid mater and these little white bumps are called or dots are called arachnoid granulations if i pull the dura mater up this flat piece here is called the folk cerebri the big blue blood vessel would be the superior sagittal sinus if i take this model i still have underneath here dura mater i have the falx cerebri and superior sagittal sinus i have the two flaps of the tentorium cerebelli and then in here i have the falx cerebelli and this is all dura mater all right look i hope you learned something i hope you had as much fun as i did pick three or four structures repeat them in the same order till you can't stand it learn the ventricles learn the meninges we'll talk about them in lecture again hope you had as much fun as i did i'll see you on the next video