Bozeman science: The brain

hi it's mr. Andersen and in this video I'm going to talk about the brain structure and function remember structure is what it's made up of and function is what does it do we sometimes refer to this as the anatomy or structure and the physiology or the function and so the cool thing is that we're going to go through 17 different structures in the brain kind of lay out the basic plan of the brain but you're using your brain to process it if you do a good job when we get to the end and I review all the parts you should be able to tell me what their structure is and what their function is and so what type of organisms have brains it's the animals animals use nerves they have muscles to move around and so they have to organize that movement and so they use a brain and so if we look at the two basic body plans of animals some are radially symmetrical in other words they're built around almost a tire and then some are bilaterally symmetrical in other words a tiger you could draw a line right down the middle there's going to be a clear right side and a left side there's going to be a clear front and end and as we became bilaterally symmetrical we had to organize that movement so this is a simple animal body plan and so this animal is going to move towards the right and as it does so it has to take in information we call that sensory information using neurons and so right now you're taking in sensory information from your eyes from your ears and then inside your brain you're going to integrate that information you're going to make sense of it and then you're going to figure out what you want to do how you're going to act dependent upon that and so then we have this loop of motor neurons out or motor nerves and so this loop in simple animals is also important in understanding how our brain works but if we look at these real primitive brain we find that they have a real common structure they have these four humps and we call those the well the first one is not a hump but the spinal cord we then have the hindbrain the midbrain and then we finally have the forebrain and we find this consistent throughout all animals and if we look at something like a shark it pretty much looks just like that primitive brain you can see down here we've got the spinal cord that's bringing information in we then have the hindbrain the midbrain and the forebrain and so one thing you should remember is that the closer we are to that spinal cord the more basic the functions are and so we're right down in this brain it's going to be basically keeping the heart beating keep the circulation going digestion in the shark but when a shark decides to attack you or it has some kind of an emotional response that's going to be way up here in the forebrain now if we look at you when you were really little when you were an embryo you had a brain that looked very similar you had a spinal cord you then had a hindbrain you had a midbrain and then you had a forebrain but during development that that brain changes radically and so this is what an adult brain looks like so we still Steve see that spinal cord we then have the hindbrain we have the midbrain but look how large that for brain is going to be and so that's where all of those emotions and memories and all of that thinking we generally attribute to the brain is going to be in the forebrain and so let's get to the actual anatomy and so they're going to be 17 parts that we're going to go through so you should always be thinking what's the name of the structure where is it and then what's the function what does it do so if we look at a basic brain plan we find these four things jump out right away we're going to see the brainstem we then see a cerebellum on the back of the brain so again to get yourself oriented right the eyes are going to be right up here and so this would be joy to the back of the head so that's going to be the cerebellum we then have the area of the thalamus hypothalamus and then finally we have the cerebrum which is going to be that dominant upper portion of the brain and so let's begin with the brainstem the brain stem is broken down into three individual structures before you start at the bottom we've got the medulla oblongata the ponds and then we finally have the midbrain and so those three things medulla oblongata ponds and midbrain make up what we call the brainstem so that's the structure what's the function well it really does two things the first thing it's going to do are these more basic needs it's going to keep your self breathing keep circulation going digestion swallowing all of that is going to be controlled by the brain stem if there's any damage to the brain stem it's going to be catastrophic what else does it do then we have information coming in so we have sensory information just like that worm did coming up to the brain and then we have motor nerves going out and so the brainstem is important in routing that information and filtering that information sending it where needs to go what's behind that we have the cerebellum the cerebellum and the function of that is motor control so as you do sports for example it's the cerebellum that's giving you that coordination and it also gives you motor memory so as you learn to ride a bicycle and you remember how to ride a bicycle that's going to be thanks to your cerebellum if we keep moving up we now have the thalamus the thalamus again sits right on top of the brain stem and so the best analogy I could come up with is a router it's basically sorting data and sending it where it needs to go if we were to look below that there's a little structure here that's incredibly important it's called the hypothalamus that's going to be really right above the roof of your mouth what is that accountable for its homeostasis so it's maintaining body temperature it's maintaining osmolarity all of that stuff is contained right up in the hypothalamus also important in circadian rhythms and then if we look right below that you can see a little gland hanging out and one half of that pituitary gland the posterior pituitary is technically part of the brain and it's important in basically sending off hormones and so there are nerves that flow into that pituitary and it's sending out things like and a diuretic hormone that keeps your water balance the same oxytocin it'd be another important hormone that comes out of there if we keep moving up then we get to the level of the cerebrum what's the function of the cerebrum that's integration so what we're doing is making sense of all that data that comes in now what makes up that cerebrum are going to be all these neurons there's tons of neurons that are connected together billions of neurons and billions and billions of synapses or connections between these neurons and that's where we're making sense of information as it comes in now if you were to look at this image right here so of that brick wall so take a moment to look at that and I'm going to show you some other images now focus on this and then that and then that and what we find is as you look at those images your brain is integrating it's making sense of all that information and it used to be a black box we didn't know really what was going on but now we can use technology like a functional MRI functional magnetic resonance imaging and what we're looking at here is a brain in action so the same study was done on females and what they would show them is something neutral like a brick wall and then a kitten and then something like dirt and then something like puppies and so what we're seeing is as those images are switching back and forth we can start to see where blood is flowing around in the brain and we can start to figure out what the different parts of the brain actually do we're able to figure out their function so when we're looking at the cerebrum every picture that I've showed you is from the side so the eyes up here but if we were to rotate that 90 degrees now we're looking at it head on we'll find that there are two hemispheres there's going to be a right and a left hemisphere now they're connected in the middle using something called the corpus callosum so that's a connection of nerves in between the two hemispheres and we do tend to show lateralization there are going to be certain things that we put kind of on the left side of our brain like mathematical reasoning and logic and things that we put on the right side like facial recognition now this is plastic in other words we can move these functions back and forth and you can even have a radical hemispherectomy were you cutting one of these out and you still have a functioning brain now if we were to go right below the corpus callosum we get into this area called the basal ganglia and it's made up of a bunch of nuclei what are nuclei or what is a nucleus in a brain it's basically a bunch of neurons that are right next to each other that have the same function and so all of these nuclei together make up what's called the basal ganglia you can see this would be the corpus callosum connecting it together as well so this is below the cerebral cortex what's the function of that well scientists have been able to figure out this is this complex interaction of inhibition and excitatory response between these neurons and basically it controls a lot of our motor control and if you have somebody owes Parkinson's disease then we're having problems in this big basal ganglia area as we move farther up the brain we eventually get to the cerebral cortex and that's going to make up about eighty percent of the brain so it's most of the brain itself and its broken apart into these four lobes and so if we start in the front of the brain we have what's called the frontal lobe what's the function of that it's mostly executive function so it's kind of like the us of your brain it's emotional control up there and if we have people who have damage to that frontal lobe they have really huge emotional swings as we move back towards the back of the brain we get to the parietal lobe what's the function of that it basically is sensation it's you dealing with and reacting to your environment so we have a lot of neurons coming in here from a sensory input as we move to the back we have the occipital lobe the function of that is vision primarily vision and then we moved on to the side we have what are called the temporal lobe temporal lobe is going to be important in language it's important and hearing it's also important in memory we have a lot of memories in there and so each of these lobes have different functions that are associated with it and hopefully those little icons help you remember those functions now if we're to go inside the parietal zone we'd find a really important part here it's called the somatosensory cortex and that's where sensory information is coming into the brain and then on the other side of the lobe we have what's called the motor cortex and so going way back to that worm we have information coming in sensory information and then we have motor output coming out and so that's going to be a point of integration where we get information in decide what we want to do with it and then send that message back out now for you to look at that somatosensory cortex and map it along the cerebral cortex we would find that we dedicate huge amounts of that brain surface area to things like your fingers your tongue your lips in other words we have way more neurons and way more sensory information and coming in from your fingers as opposed to for example your back we don't have as much of a dedicated to that on the back side we could also use functional MRIs and then even an operation to figure out where a lot of these things are located like speech and smell and hearing but over the future we're going to get really really good at figuring out specifically what are all the different parts of the brain what are the nuclei what do they do and even mapping it down to the level of the neuron so how did you do do you remember those 17 different structures and their functions well it's time to review so let's go through it what's this one at the bottom overall we call that the brainstem hopefully you got that um what are the three parts of the brain stem though do remember that could you pause the video and then say what they are while starting from the bottom remember we have the medulla oblongata we then have the ponds and then we have the midbrain so that's going to be the structure and where it's found can you remember the two functions of the brain stem two big things were number one is to maintain breathing heart rate digestion swallowing so these fundamental properties of life but what's the second one remember it's to sort information going up and down what's behind that what's that structure column that is the cerebellum and so what's the cerebellum do remember that's coordination motor control and also motor memory do you remember what sits right up above the brainstem that is the thalamus what's the thalamus do remember it's sorts information as it moves up to the upper parts of the cerebrum what's below that that is the hypothalamus underneath that what's that do remember that's homeostasis it's maintaining that internal body state do you remember what hangs off the bottom of that that is the posterior pituitary hopefully you're doing well so far if we keep going then what is this upper portion of the brain called we call that the cerebrum okay let's keep going into the cerebrum then so do you remember what's that connection between the two hemispheres of the brain we call that the corpus callosum and do you remember what we call those little nuclei that are found below that cerebrum those are called the basal ganglia and they're really important in motor control and remember the corpus callosum allows our hemispheres to connect if we were to go up to the upper portion what do we call this you know highly folded upper portion of the cerebrum that's called the cerebral cortex do you remember what the front lobe is called that was pretty easy that's called the frontal lobe what about the yellow lobe right here that's called the parietal lobe do you remember what they do frontal lobe remembers executive or boss like functions and then parietal is going to be sensation of the environment what about at the end you remember that that's called the occipital and then what about at the bottom that's the temporal occipital remember is a location where we have vision and then temper role is going to be more language hearing memories are there now there are two other parts in our lobe so what called this area right here and then this area right here those are called the somatosensory cortex remember that takes in information make sense of it and then we have the motor cortex which is sending information out so those are those 17 structures if you don't remember them you may want to watch the video again maybe make some flash cards but that's the brain and I hope that was helpful