Brain Part 2

Added: 2026-05-30

[00:00:00]so this is the introduction of the plain trout's and its function so we have four major parts of the brain starting with its cerebrum as you can see it in here this is a cerebrum which occupies majorly about 99% of the brain structure then comes the diencephalon the diencephalon consists of three parts of which one is not shown in here one is the epithalamus which is mainly responsible for production of a hormone called melatonin then there is thalamus there is hypothalamus so three parts in diencephalon epithalamus thalamus and hypothalamus and then comes the brainstem which is around here so as you can see the entire middle portion has been brought out and this part in here is the brainstem which consists of midbrain we call it midbrain here it is written as mesencephalon which was an older nomenclature then we have a pons and then medulla oblongata which continues into the spinal cord the fourth region in here is cerebellum so four major parts number one is cerebrum number two is diencephalon number three is brain stem and number four is cerebellum so within diencephalon there are three parts number one is epithalamus thalamus and hypothalamus within mid membrane stem there are three major parts one is midbrain pons and medulla oblongata so let's understand a little bit introduction of the functions of these vein parts we learn in details as we go along but the main functions of the cerebrum is it is for conscious thought processing it actually it is an intellectual function is where the command or all decisions are made of the brain for the different parts of the body okay all skeletal motor movements skeletal muscle movements are all orchestrated or you know directed from this region which is called a cerebrum diencephalon first part is epithalamus as I said we learn about that as before now here is listed autonomous it is a relay and processing center for sensory information so we have done this before right sensory information are those that pass from and the different muscle from its receptors or maybe the visceral organs through the receptors to the central nervous system these take in the information to the central nervous system which in here we are talking about drain so those are sensory information and this is where the sensory information is processed okay third is the one that is shown in here is hypothalamus the word itself hypo means lower so it's just below calamus and that's the reason it's known as hypothalamus it is a center controlling emotions okay it is a center where several hormone production takes place so we this glad is our this part of the brain is also call a neuro endocrine part because it is part of the in your nervous system it's part of the endocrine system so it's called a neuro endocrine gland because it controls the production and function of several hormones it is also as it's written here is a center of many emotions like a crystal behavior or your love loving someone all those emotional factors are governed through this region then comes the brainstem which consists of three major parts as I said is midbrain pons and my mid rate it is a center of two major processing center one is the visual data is processed there and number two is the auditory so what you see and you can interpret that object is processed in this region and what you hear and you can process it is also mainly controlled in this region then comes pons the word pants means bridge it is actually a really a center between the thalamus and the cerebrum so it helps to move information to the to the cerebellum which is around here and to the thalamus which is above it okay it is also it also will learn subsequently it is also Center when it helps a lot for medulla oblongata to do its function okay so next comes the medulla oblongata it is a relay Center for sensory information as we just learned what is sensory information it takes up the sensory information and then transmits it basically gives it to the cerebrum you know this this part in here where mainly all the the control is going on the other one of the major functions of melanin gotta it is a center of many activities which means that it is a regulatory system there it regulates a cardiovascular respiratory and digestive system activities what it means is it keeps the rhythm a city it keeps it causes the heart pumping with a rhythm and that rhythmicity is controlled by the medulla oblongata we learn this more in details when we learned the autonomic nervous system on ANS and see the role of medulla lon in there but right now just remember it is a Center for the regulation of which visceral function for example cardiovascular respiratory and digestive system activities cerebellum which is the posterior end of the brain is mainly for balance okay it coordinates complex motor pattern it adjusts its the balancing you can walk in a straight line because of cerebellum in addition to that it is also responsible for fine motor function and we learn all of it as we go along okay so we are going to start visually with cerebrum which covers a major part of the brain and as you can see it in here there are a several ups and downs which are these elevations and depressions in here right these elevations are called gyri and these depressions are known as sulci okay so very important to remember that these are elevations are GI or gyrus depressions are sulci or sulcus now when these depressions or sulcus becomes little deep they form what is known as a fissure okay so fissure is a deeper groove and we know of a very very large fissure that is present in the in the brain which is a largest which is known as the longitudinal fissure which actually divides the brain into two equal halves okay so it's called the right hemisphere and the left hemisphere and the longitudinal fissure basically divides it into two halves and we learn that more as we go along what you see in here is shown in beautiful colors in blue green red and you know pink the different loads of the cerebrum so what are these lobes these are four in number number one there is frontal lobe there is parietal lobe his temper alone and there is a saboteur so if you so basically if you look in here the frontal lobe is in the front part of your of the brain the occipital lobe is behind and the back the parietal lobe is near the top in the central region and the temporal lobe is near your ears so let's learn a little bit of these lobes the frontal lobe likes deep into the frontal bone you learn that in skeletal system and basically forms the anterior part of the cerebral Hemisphere there are several circuses and gyrus is within the frontal lobe and the main function is voluntary motor functions it is responsible for verbal communication decision-making planning and personality okay so it is a very very important lobe because all your decisions and intellect is centered in here next comes the parietal lobe the parietal lobe is lies deep into the parietal bone and forms a superior posterior part of each of the cerebral Hemisphere its main function is involved with the general sensory function such as evaluating a shape or texture of an object being touched so if you touch an object you find it silky you touch an object you can say that it is rough all of these basically evaluating the shape and texture is determined by the parietal lobe the temporal lobe is internal to the temporal bone and it is involved in hearing and smell okay the last which is behind on the posterior end is the occipital lobe lies internal to the but alone and it is mainly responsible for processing incoming visual information and storing visual memories very important law it takes in visual information and stores the visual memories in the form of visual plays so these are the four major lobes of the cerebrum but deep inside the cerebrum there is another law which is known as insula okay the insula is the word insula means island and it's a very small law and it is really deep into the lateral sulcus it is apparently it is not very well studied but we know that it is involved in memory and interpretation of taste okay so this actually whatever I've said so far is written in horse so you can read through them this is the frontal lobe how it is involved in the motor function in concentration verbal communication decision-making planning and personality parietal lobe is mainly responsible for evaluating shape and size and texture of the object temporal lobe which is involved in hearing and smell and occipital lobe is responsible for visually in information processing of the visual information and also it stores visual memories okay and insula which lies deep inside it is mainly responsible for memory and interpretation of taste so basically just a recap there are mainly for visible lobes and one inside which the fifth float insula the four loops are prattle frontal Hospital parietal and temporal okay so the four of them so let's now understand some other a little bit of the cerebrum in little more details because it is highly important and we know that it consists of two major parts it is divided into two major halves left and the right cerebral hemispheres by efficient so it's a deep fissure it's a deep cleft which divides the brain into two halves which is known as the left hemisphere and is known as the right hemisphere I want you to understand that these two hemispheres apparently look the same but their functions are very different okay so you have to understand that and these hemispheres do talk to each other they are connected with each other either by bundles of axons that go across from left and right or sometimes they can go from top to bottom okay so the largest tract that connects the left and right hemisphere is known as corpus callosum and it is a method by which they can be these two hemispheres communicate with each other it has been seen that and the carpus color width of the carpus callosum is different between males and females or between gay individuals lesbians and straight individuals so this actually shows you we just learned about the different lobes of the cerebral and different functions apart from that the several cerebrum also can be divided functionally into motor areas sensory areas and association areas we do not go into depth with the functional areas and dividing the brain and further according to their function which is done in you know advanced classes so we are going to stick with the major three categories of functional areas will you remember them as these are motor areas that set in information from the brain to the different parts of the body in order for it to control and there are certain motor areas designated in the brain for that then there are sensory in areas that receive information in to the brain for its function from the different from the different sectors it can be from the muscles it can be from the visceral organs and then there are association areas which is basically like the overlap between the sensory and the motor areas and they coordinate amongst themselves okay so we are going to go ahead with the next part of the brain we learned about cerebrum and we learned about how important cerebrum is for this decision-making now we are learning about the next part of the brain so this is cerebrum as you can see and right now this is what we are learning right now is the diencephalon so diencephalon as I said consists of three major parts epithalamus thalamus and hypothalamus so mainly the epithalamus consists of the pineal body so if you look in here let me see yes so this is the region where the pineal body is and pineal body is basically an endocrine gland the size is really small like a piece P sized gland and it produces melatonin melatonin is involved in the sleep sleep-wake cycle so basically what it means is if you are a person who wakes up at 7 a.m. in the morning even if your lights are off and it's dark outside at 7 a.m. you will feel that you know you have your sleep is done and you are awake this biological clock and that means now getting up at 7 a.m. which is kind of your routine and maybe going to sleep at 10 p.m. is in your routine this is going to happen whether there is sunlight whether there is a cloudy region does not matter it will you will feel sleepy at 10 p.m. and you will wake up at 7 a.m. so this biological clock is controlled by the by the pineal gland and the provided production of melatonin okay so so this is for the epithalamus going past that the next one is okay is autonomous the thalamus and this region in here is thalamus and the thalamus has paired oval masses of gray matter which lie on both side of the third ventricles if you remember the third ventricle we had learned about two lateral ventricle third ventricle and the fourth ventricle so this region is near the third ventricle and basically it is a really center for the sensory information to the cortex what does it mean that all the neurons all the sensory neurons actually pass through this vision and go to the cortex region of cortex means we're talking about cerebrum we are talking about the outer part of the cerebrum which is called the cortex you can see this gray region which is basically the cortex of the cerebrum so all the neurons pass through the thalamus these are sensory neurons we are talking about pass through this region and go into the cortex our information is received from these neurons via thalamus to the kardec's and this is mainly responsible for crude perception of sensation so all these sensations how you feel about it is all taken up by the neurons and it passes through the thalamus to the cortex region then comes hypothalamus very very important region this hand the hypothalamus is known as the neuro endocrine gland because it is involved in endocrine function and it is part of the nervous system so is a neuro endocrine gland and it consists of many nuclei so the word nuclei means it's a group of neurons okay so a group of neurons when they do a particular function it's called a nucleus and you can see just like skittles it looks like skittles but it's not so of course these are shown so that you understand that there are several nuclei and each of these nuclei have different functions okay some are involved in the production some are if loneliness defects cycles and so on and so forth so there are many many nuclei and each one have different functions some of the major functions of hypothalamus is it receives somatic and visceral input that means it receives information or a sensory information from the somatic from the skeletal muscles from the different parts of your internal organs into here and this that's the reason it is part of the autonomic nervous system we have a separate lecture on autonomic nervous system and you will see the role of hypothalamus is immense in that in that lecture so it is involved in somatic and visceral input it is involved taste smell hearing and one of the major major function of hypothalamus is temperature it regulates temperature of the blood so it is it acts as a thermostat of your body it is involved in emotional behavior like aggressive behavior or love-hate you know those kind of emotions are also to a certain extent controlled by the hypothalamus so here these are all the different functions that I was just mentioning let's understand that it is a master control of ANS autonomic nervous system so there it can regulate heart rate blood pressure respiration and so on and it is a control center of endocrine system so it produces many many hormones and they are produced they in turn help in the production of several other hormones from the anterior pituitary gland so so it the neuro the hypothalamus produces regulatory hormones they in turn act on the anterior pituitary to produce several other hormones which act on the target cell to produce have an effect so these hormones different kinds of hormones that it produces is all involved in different functions some are involved in stress regulation some are involved in reproduction some are involved in growth so there are many many such hormones that are produced by the hypothalamus which helps in the entire body regulation of endocrine function it is also it produces two major hormones one is called the a da ADH which is antidiuretic hormone ADH and oxytocin antidiuretic hormone is involved in the retention of water and oxytocin is during labor some other functions of hypothalamus is it is involved in body temperature as I said it is it's like it acts as a thermostat it is involved in emotional behavior love-hate aggressive behavior it controls food intake very important yes how much food you will have is also controlled by the hypothalamus it is a society center so it is involved in food intake it is involved in water intake and as I said it produces a hormone which is known as ADH antidiuretic hormone which helps in the retention of water so it can control water intake and it is involved in the sleep/wake cycle so it is involved in the biological clock of your body this takes up to the next part of the brain which is the brain stem so if you look in here you will understand the brain stem consists of three major parts one is this region in here I just give me once again this region in here this is the midbrain okay this is the midbrain this is the region which is known as pons and this region in here is medulla oblongata so again midbrain pons and medulla oblongata and this is the region where you know the midbrain is midbrain pons and medulla oblongata this is the region where the brainstem is and so the brainstem consists of three major parts and we just said and the most important part is there we have 12 pairs of cranial nerves of which many of them or most of them come out of the brainstem so from 3 to 12 all of those cranial nerves coming out from the brainstem so you can understand it is highly very very important structure again it is it contains autonomic centers means it is involved in autonomic nervous system very similar to that of hypothalamus and it contains reticular formation which is involved in sleep and it serves as a bridge of ascending and descending tract that pass through so from the spinal cord all the tracks that go to the cerebrum for its processing passes through the the brainstem so it is ascending means the ones the neurons that go from the different parts of the body to the central nervous system and descending track means the neurons that come out from the cerebrum or motor neurons that come out from the cerebrum to the different skeletal muscles for its control so very very important to understand the ascending and descending tracts that control that help in in all the functions of the body we are starting from the bottom to the top which is the medulla oblongata in here the medulla oblongata is the most inferior part of the brainstem region okay so it is involved in many many functions and we are going to do some of them so let's understand the individual cranial nerves are there are five different cranial nerves that come out of the medulla oblongata and the medulla groundwater has many nuclei associated with it okay some of the major functions of the medulla oblongata are it's a reflex Center so it's a very very important to understand it is an autonomic and reflects activities are controlled in the medulla oblongata so you can see this reflex activity is controlled in the in la Blanca da and it what does this reflects activity means it means coughing sneezing swallowing all of these are part of the reflex activity there are two major group of reflex centers which is what I'm you know it's so important it has a cardiovascular center and the respiratory center the two major you know these centers are helpful because they are metal obligate actually the cardiovascular center adjust the heart rate so the rhythmicity of the heart is controlled by the medulla oblongata the strengthened of cardiac contraction and the flow of blood through the peripheral tissues to the different parts is all controlled by the medulla oblongata so but their anatomical boundaries you know the the cardiac cardiovascular system actually is divided into cardiac and vassal motor centers and so this this these these the cardiac and the vas emotional system are both controlled by the medulla oblongata it is also a center of respiratory death message which means it sets the pace pace of the rhythmic movements their activity is regulated by inputs from the respiratory centers of on so remember although the respiratory system you can see it is involved in the rhythmicity or how the breathing is going to go on there is involvement of pawns also in the whole process okay sensory and motor nuclei of the cranial nerves the medulla oblongata contains sensory and motor nuclei associated with the five cranial nerves eight nine ten eleven and twelve are the five cranial nerves that are present in the medulla oblongata these cranial nerves provide motor commands to muscles it can be firings you know neck neck region and different visceral organs and different parts of the body okay so that's another very important function of the medulla oblongata again it is a really a center of sensory and motor path so basically what it means is these this is the region we're crossing over our deposition of pediments take place and hope I have a picture yes I do so if you look in here you will understand that it is in the medulla oblongata where the axons actually cross each other tracks leaving these brainstem nucleic cross to the opposite side of the brain before reaching its destination okay so it it can come from here and cross in here and have its effect on the opposite side of the body this process of crossing over is known as deposition okay so neurons can usually have its action on the opposite side of the body as we have learned in in previously so neurons actually cross over the process of deposition happens in the medulla Langara so just going back this one slide that we had started with is medulla oblongata basically is the third part of the brainstem and it continues into the spinal cord it has a five cranial nerves from 8 9 10 11 and 12 are the cranial nerves associated with it and these are involved in several sensory and motor functions it is a center of car it's the Center for cardiovascular and desperation it creates the heart's rhythmicity our breathing Center it sets of the pace for breathing it is involved in you know it's a reflex center for coughing sneezing swallowing etc and in addition to that it also sends in and brings in information from the cerebellum which is very close to it you can see it sends in and out information from the cerebellum so these are the major major functions and of the medulla oblongata going to the next part is some of the medulla oblongata as we just learned the five cranial nerves in the slide is shown 8 to 12 and it has two major nucleus which is involved in the center which aren't sensory neurons and which sends information to the thalamus on the opposite side of the brain this is known as nucleus chrysalis and your nucleus cuny tears and these are very important and I'll show you I'm sorry let's see these two nucleus are very important in in sending information from the medulla oblongata to the thalamus region of the brain ok so next comes pons and as you can see the pons is the word itself the pons the word itself is called means it is a bridge it has its own functions okay and we will learn each one of them one by one so you can see there are white track white fiber crack ascend and descent and they connect the brain and the spinal cord when I say brain it means cerebrum and the spinal cord so there are ascending flags that are descending track where the where pawns actually acts as a bridge to connect both the cell from the spinal cord so there are several cranial nerves that come out of it there are five six seven are the three cranial nerves that are coming out of the pons which is very important to remember there is an important center located in here which is known as P no pneumo tactic center pneumo tactic Center is the pontine a respiratory Center which is helps in keeping the respiratory with Missa tee so if you remember we just learned that medulla oblongata is involved in the respiratory rhythmicity and pons actually or these pontine centers respiratory centers helps in this process of keeping and the redness city which is mainly controlled by the medulla oblongata so this is the region as you can see this bulge region in here is the pons which is mainly in the center between the medulla oblongata midbrain and the cerebrum midbrain the first of all the if you see the pale stem we start with the midbrain so this is the region where the midbrain is and the midbrain actually is consists of the it has three major paths the tectum is on the roof of the midbrain is a region which holds the cerebral aqueduct which we will just learn right now it consists of this region consists of very important two major parts which is known as the core product which eminence I will go to the next slide to me so that you understand so if you see this part this is the entire part is known as tectum and it's it collectively consists of sensory nuclei which are called corpora quadrigemina and the corpora quadrigemina is divided into two major parts one is known as superior colliculi of the corpora quadrigemina and inferior colliculi of the corpora quadrigemina the superior colliculi is involved in eye movements and visuals by the with visual stimuli and the inferior colliculi is involved in the head movement with auditory supplies so the one is involved with vision the other is involved with hearing so it is a very very important part of the brain - there are other parts of the midbrain also which we are not going to go in details like the tech mental and substantia which are also part of the midbrain the last of all is the cerebellum the cerebellum is an automatic processing and coordination centre of four patterns of muscular at and as you can see it is mainly the main function of cerebellum is related with muscle movement we'll do that first let's understand a little bit of anatomy of it it is it has dual hemispheres as you can see one this this is one hemisphere this is another have a sphere and the two hemispheres is divided by formas okay is a central part which is the warmest the if you see a cross section of cerebellum I'm going to the next slide I'll come back to the slide again this is the cross-section of the cerebellum and in here you will see three like processes which are known which are basically white matter so what are white matter white matter are myelinated neurons and these are myelinated neurons form a tree shaped structure and these are called I'm arborvitaes it is absolutely necessary if you you basically remove it you will die so basically it is an absolute necessary part of your body arborvitae the internal white structure matter of the cerebellum these branches resemble like tree like structure okay and that is the reason it connects the cerebral cortex and nucleate tract of the white matter that form in the cerebral peduncles are basically the midbrain and that in this the midbrain and the autumn entire brain stem can be connected with the cerebellum for its activities some of the major functions let's understand some of the major functions of the cerebrum number one it is involved in adjusting the post postural muscle of the body so the cerebellum coordinates rapid autonomic adjustment mmm and it helps to keep balance and equilibrium very very important it makes alteration to the muscle tone and positioning in order to keep the balance in your body in addition it is involved in fine tuning movements controlled by conscious or subconscious level the cerebellum refines loved movement patterns such as riding bicycles if you're riding a bicycle or playing a piano it performs this function of regulating it through the motor pathways the information comes from the cerebral cortex or cerebrum and then it these then pass to the cerebellum and they actually make a precise coordination of your fingers are your muscles of your fingers to perform or play the piano in the right way so fine motor functions are controlled by the cerebellum okay so this is the limbic system we didn't consider that as one or repeat when we discussed the parts of the brain we said that you know it consists of the four major parts and we never mentioned about the limbic system the reason being the limbic system is very very inside the brain and it actually has a very diffused structure as such the limbic system is not considered a separate part of our brain but very much a functional part of the brain which is integrated within the the cerebrum it is has several structures integrated within it as you can see there are several several different parts involved in it and the limbic sub soluble now the limbic system is involved in many of the emotional factors and it is involved in sleep also it is involved in memory also so there it is considered to be a functional brain structure in your body