Neurology | Hypothalamus Anatomy & Function – Transcript

00:14hi ninja nerds in this video today we're going to talk about the hypothalamus we're going to cover the basic anatomy first then the basic function of the hypothalamus then what we'll do is we'll dig into the nitty-gritty talk about the different nuclei really expand on the overall functions of the hypothalamus and then have a tid little bit of a conversation on the pathways or connections between the hypothalamus and other structures and their relevance all right so let's go and get started all right engineers so let's start talking about the basic anatomy of the

00:42hypothalamus really what i want you more to understand rather than going into all the details on the neural anatomy is to know that the hypothalamus is a part of a structure in the brain deep within the cerebrum a gray matter structure called the diencephalon that's the big thing i want you to know so it's a component of what's called the diencephalon now that leads us to the question that the diencephalon it's a it's kind of a cluster of gray matter

01:09deep within the cerebrum right well there's a bunch of different structures that actually make up the diencephalon and that's what i want you guys to really focus on so the epicenter of the diencephalon is actually this blue structure here you see this blue egg-like structure here this blue egg-like structure here is called the thalamus this thalamus is kind of the center of the diencephalon and all the other names of the components of the diencephalon are named based upon the position

01:38related to it so one of the components of the diencephalon here is the thalamus that's the big one right the second one what we're going to do is is we're going to take the thalamus and we're going to move posterior right so if you go post so this is the anterior portion of this diencephalon this is the posterior portion of the diencephalon so here in the posterior portion you have this pink like gland on the back of it you know what i'm sorry purple gland i'm going colorblind the purple gland on the

02:07back here this is called the pineal gland and the pineal gland with a couple other structures what other structures well really if we wanted to there's kind of like i can draw like a little asterisk there there's what's called the habenula right and then you have the another structure called the habenular commissure and then you have this other structure back here called the posterior commissure but really the posterior commissure the habenula and the pineal gland make up what's

02:35called the epithalamus so let's write that down epi thalamus is another component of the diencephalon and what are the things that makes it it is the pineal gland and it is the habenula and it is the posterior commissure

03:01beautiful so we understand two parts of the niencephalon thalamus epithalamus okay now let's move a little bit just kind of inferior just a little bit inferior maybe even a little bit posterior to the thalamus you see this red structure this kind of maroon colored structure here just kind of inferior to the thalamus this right here is called the sub thalamus this is called the subthalamus this is another important

03:30component of the diencephalon the last component which is actually what we're going to be talking about primarily here i'm going to shade it in here in green all of this area here that i'm shading in that's anterior and inferior to the thalamus what is this called the hypothalamus so this is the hypo

03:55thalamus and these are the main components of our diencephalon now a couple other just anatomical things that you should know because it's clinically relevant here you have your hypothalamus right there's these little things that are kind of it's a part of the hypothalamus but it's a little nucleus a little nugget hanging off of it you see this thing here this kind of like little boob structure here hanging off that's called germamillary bodies we'll talk about this in more detail but it's

04:21actually a part of the hypothalamus the other thing that's really important here you see these things here these hanging off of the hypothalamus this is your pituitary gland so this is called your pituitary gland this is another important structure that's associated with the hypothalamus one more that's really important you see this structure here that's kind of cross it actually crosses you have your optic nerves they're moving backwards as they move backwards they cross called the optic

04:50chiasma that happens just around the area of the hypothalamus so this right here is called the optic chiasma so it's kind of important here to understand some of these things one other thing just to kind of define the borders here you see you have this thing here coming down from the corpus callosum here's your corpus callosum right you have this structure coming down here this here is actually important it's called the lamina

05:17terminalis it's called the lamina terminology just kind of gives you what the border of this hypothalamus and then really this little nugget here is called the anterior commissure okay but the basic thing i want you to know taking away from the anatomy is that the hypothalamus is one of the four components of the diencephalon now what i want to do is is to take this portion of the hypothalamus cut it out and zoom on it a little bit more

05:43so we can talk about the zones of the hypothalamus and the nuclei that occupy it all right so the next thing that we need to do here is that we're going to zoom in on the hypothalamus okay so you kind of have again that anterior border that's why i kind of mentioned it was that lamina terminalis and the anterior commissure and then here you have your optic chiasma right the other thing here is that we have this kind of remember how i told you this is coming into the pituitary gland well this here imagine this is like a large funnel

06:11right here's this kind of like large funnel shaped portion here this actually has a special name sometimes they like to ask this on exam it's called the tuber cyanerium and what happens is the tuber sinerium will start narrowing is going to be called the infundibulum okay and then it obviously extends downwards into your pituitary gland

06:38all right good now the next part here is that we have four zones that i need us to know because there's nuclei in each one of these zones the first one here the first zone okay this first zone is called the pre-optic zone this is called the pre-optic zone there's one nucleus present within the pre-optic zone we're going to abbreviate it for now but we'll actually write it out in more detail later but this is called the

07:04medial pre-optic nucleus okay so the pre-optic zone is the most anterior portion only made of one nucleus which is the medial pre-optic nucleus the second zone here the second zone here is actually very important lots of nuclei in this one it's called the supra optic zone and in the supraoptic zone there's tons of nuclei one of these nuclei is called the

07:32suprachiasmatic nucleus so the suprachiasmatic nucleus is one you know another one is called the supraoptic nucleus that's another one then above that is the periventricular nucleus and then lastly very important one here is the anterior hypothalamic nucleus okay so we have the pre-optic zone the

08:00supraoptic zone move a little bit posterior you have your third zone here this third zone is called the tuberal zone it's called the tuberal zone so you have pre-optic anterior superoptic and then tuberal zone is the third posterior portion because again we're going anterior to posterior here the nuclein here there's three nuclei here one of them is actually called the arcuate nucleus we're going to put arc

08:27this one's a monster does tons of functions we'll get into detail on that one then you have a nucleus which is actually located more anterior or ventral so we call this the ventral medial nucleus then you have one that's a little bit more dorsally so this is called your dorsal medial nucleus okay so we have the pre-optic superoptic tuberal the last and final zone remember that structure i told you that these little things are hanging off of the hypothalamus towards

08:55the back it's called the mammillary bodies right we told you that that was a part of the hypothalamus well this zone here thankfully is called the mammillary zone and the mammillary zone is actually made up of two primary nuclei one is called the mammillary nuclei right and the last one which is a very important one here is called the

09:22posterior hypothalamic nucleus beautiful now there's one last thing that i have to mention here just really quickly because you can't see this other part of the hypothalamus if you imagine here that we have like this is the third ventricle on both sides of the third ventricle you have kind of these this sheet of gray matter right so here's our third ventricle right with the dots on the sides here is the hypothalamus

09:50well there's actually two parts of the hypothalamus the medial portion and the lateral portion what we're looking at here we're only seeing the medial portion we don't see the lateral portion which is actually kind of if i were to punch my hand through this wall it'd be behind this okay so there's one last nucleus that i need you guys to remember and it's actually so we already talked about all the nuclei here in the medial right and imagine this is anterior to

10:18posterior so you'd have your pre-optic your super optic your tubule your mammillary there's one nucleus all the way lateral and this is very simple thankfully it's called the lateral hypothalamic nucleus and it actually extends almost the entire length of all the zones that we talked about in the medial portion of the hypothalamus which is the pre-optic superoptic tuberal and mammillary beautiful okay now the last thing that we have to talk

10:46about here since we've established the basic anatomy okay and the basic kind of zones and nuclei is the functions what is the basic functions if you had to boil down the functions of the hypothalamus you know what i like to do i like to think about it in three functions so if someone were to ever ask me what's the functions of the hypothalamus i could tell them three things one is it's involved with our autonomic nervous system what does this mean that means it has the ability to either work with the sympathetic

11:14to speed us up fight or flight parasympathetic slow us down rest digest we'll talk about how it also is a part of our endocrine system it's our master endocrine regulator so it's involved with a lot of hormone production okay we'll see about how that how that happens later and the last thing that it's actually really important for is the limbic system it's actually one of the epicenters of the limbic system very important for the limbic system

11:41okay so if someone asks you three basic functions of hypothalamus you say autonomic endocrine limbic let's go ahead and get into the details now all right engineer so now let's go start talking in detail remember i told you that there was three basic functions right limbic autonomic endocrine when we talk about limbic obviously we could just say oh it's involved in the limbic system but we should know a little bit more expand on that a little bit so what is the limbic system responsible for right if i were to ask you what is the limbic system responsible for

12:09i want you to remember it's involved in emotions and when i talk about emotions what am i talking about i'm talking about fear aggression anger right it's also involved with sexual behaviors okay so sexual behaviors preferences it's also involved in feeding behaviors as well so satiety hunger and it's also involved in learning and memory so when we talk about the limbic system i really want you to remember that that it's involved

12:37in memory learning your emotions and sexual and feeding behaviors so now let's talk about how it's involved in that the main one that's really kind of involved with this is these mammillary bodies so you see this part here i'm going to draw a dot there and this little like thing coming off here that's our mammillary bodies now the mammillary bodies we kind of touched on this when we talked about the thalamus the mammillary bodies are important because

13:04they have two primary functions one is again they're involved in this limbic system but one of the big things that it's involved with is memory consolidation so it's involved with our memory particularly the type of memory is episodic memory but it also has an involvement reflex particularly maybe some type of reflex with olfaction what is olfaction smell

13:31so there might be some type of involvement of this structure with this memory behind smells all right so i want you to remember that it's involved with episodic memory and particularly maybe even memory reflexive memories involved with smells okay how we're not going to get into the nitty-gritty here but i want you guys to remember that the the mammillary bodies are connected to a couple structures here do you guys remember there's a structure here called the fornix you guys know this structure this orange