Neuroanatomy | Neurology | Neuroscience | Dr Najeeb

Estimated read time: 1:20

Summary

Join Dr. Najeeb as he delves into the basics of neuroanatomy. In this introductory lecture, you'll learn about the fundamental components of the nervous system, including the central and peripheral systems. Dr. Najeeb breaks down the roles and functions of the brain and spinal cord within the central nervous system, as well as the sensory and motor functions within the peripheral system. He also touches on the differences between special and general senses and explains critical concepts like gray and white matter, neuronal signaling, and the autonomic nervous system's components. Prepare for an engaging exploration of the nervous system's intricacies, perfect for newcomers to neuroscience.

Highlights

Dr. Najeeb introduces the basic building blocks of the nervous system, making complex concepts accessible 💡.
Understanding the roles of CNS and PNS is key as Dr. Najeeb explains their distinct functions with clarity 🤓.
Discover how the brain processes information and how past and present experiences influence neural responses 🔄.
Explore how sensory inputs lead to motor outputs, unraveling the brain's decision-making processes 🕹️.
Distinguish between gray and white matter and their significance in the central nervous system 🎨.
Learn about the fascinating structure and function of the hindbrain, midbrain, and forebrain 📖.
Dr. Najeeb makes neurology engaging with his explanations of cortical structures and neuronal pathways 🚀.

Key Takeaways

The nervous system is divided into central and peripheral components, each with specific roles and functions 🧠.
Central nervous system includes brain and spinal cord, responsible for processing sensory input and generating motor responses 🚦.
Peripheral nervous system deals with transmitting information between the body and central system through sensory and motor pathways 🔄.
Gray matter consists of neuronal cell bodies while white matter is made of axons, both playing unique roles within the CNS 🌈.
Dr. Najeeb elucidates how general senses differ from special senses, highlighting their origins and specificity 👀.
Learn about essential functions of motor responses, both voluntary and involuntary, managed by different nervous system pathways 🎮.
The lecture provides foundational knowledge crucial for understanding more complex aspects of neuroscience and neurology 📚.

Overview

In his engaging and accessible lecture, Dr. Najeeb takes us on a journey through the fundamental aspects of neuroanatomy, breaking down the components of the central and peripheral nervous systems. With his thorough explanations, he helps demystify how the brain and spinal cord operate within the central system, and how motor and sensory functions are carried out in the peripheral system.

Dr. Najeeb elaborates on the significance of gray and white matter in the central nervous system, clarifying how they contribute to neural functions. He further distinguishes between special and general senses, illustrating how these senses arise from different parts of the body and serve varied purposes.

By the end of this session, learners gain a concrete understanding of how the brain processes sensory inputs to generate motor outputs, the role of autonomic and somatic responses, and the overall fascinating design of our nervous system, preparing them for more advanced studies in neural science.

Chapters

00:00 - 00:30: Introduction to Neuron Anatomy The chapter titled 'Introduction to Neuron Anatomy' covers fundamental concepts related to neuron anatomy. It explains the basic concepts of the central nervous system and the peripheral nervous system, as well as gray matter and white matter. The chapter aims to provide a foundational understanding of these components as part of the nervous system.
00:30 - 01:00: Central and Peripheral Nervous Systems This chapter delves into the fundamental division of the nervous system into two primary components: the Central Nervous System (CNS) and the Peripheral Nervous System (PNS). It emphasizes the structural and functional distinctions between these two systems. The importance of understanding this division lies in how each system contributes to overall neurological function, with the CNS being responsible for processing information and the PNS playing a crucial role in transmitting signals between the CNS and the rest of the body.
01:00 - 01:30: Components of Central Nervous System The chapter titled "Components of Central Nervous System" focuses on the main elements that make up the central nervous system, specifically the brain and spinal cord. It emphasizes that the CNS is primarily composed of the brain and the spinal cord. An illustration or description likely indicates the location or structure of the spinal cord.
01:30 - 02:00: Functions of Central Nervous System The chapter 'Functions of Central Nervous System' provides an overview of the central nervous system (CNS), which includes the brain and spinal cord. It covers the basic concepts and functions of the CNS, highlighting the key structures such as the brain depicted in red, and explaining their roles in the body's control mechanisms.
02:00 - 02:30: Sensory Input and Motor Output The chapter titled 'Sensory Input and Motor Output' delves into the fundamental roles of the central nervous system (CNS). It poses a question about the primary function of the CNS and emphasizes its role in regulating various processes. The text suggests a deeper exploration of the central nervous system in subsequent discussions, with an educational focus on understanding its core functions.
02:30 - 03:30: Division of Peripheral Nervous System The chapter discusses the function of the peripheral nervous system, emphasizing its role in thermo-regulation and its ability to send signals. It highlights the primary function of the central nervous system, which is to collect information from the environment and throughout the body.
03:30 - 04:00: Special and General Senses The chapter discusses the sensory system's role in collecting information for the central nervous system (CNS). It highlights that a primary function of the CNS is to receive sensory information. The simplification of this process is illustrated with a basic diagram emphasizing the CNS's fundamental function.
04:00 - 05:00: Visceral and Somatic Sensations The chapter discusses the central nervous system's role in receiving sensory input from the self and the environment, highlighting that sensory nerves are part of the peripheral nervous system.
05:00 - 06:00: Proprioception and Sensory Systems The chapter titled 'Proprioception and Sensory Systems' discusses how the sensory system collects information and then compares and contrasts it with past information. An example given is of someone collecting sensory information of people present in a room, highlighting how the brain identifies different people based on past and present sensory input.
06:00 - 07:00: Conscious and Unconscious Sensory Information The chapter explores the process by which sensory information is processed in the central nervous system. It highlights the role of the sensory system, using the example of the visual pathway. Additionally, it discusses how new sensory information, such as the visual appearance of a person entering a room, is compared against previously stored information to determine recognition or unfamiliarity.
07:00 - 08:00: Voluntary and Involuntary Motor Responses The chapter titled 'Voluntary and Involuntary Motor Responses' discusses how the central nervous system processes new information. It emphasizes the role of comparing and contrasting incoming sensory input with stored information to integrate new data effectively. This integration helps in processing sensory input by leveraging both present and past information.
08:00 - 09:30: Autonomic Nervous System The chapter discusses the role of the autonomic nervous system in processing sensory input and deciding on appropriate motor responses. It highlights the example of recognizing a friend visually and smiling in response, or smelling good food and reacting to the pleasant aroma as illustrations of this process.
09:30 - 11:30: Introduction to Brain Structures The chapter titled 'Introduction to Brain Structures' discusses the basic functions of the central nervous system (CNS) in processing sensory inputs and generating motor outputs. It begins with an example of seeing good food as sensory input, leading to motor outputs such as the secretion of saliva or gastric juices. This highlights the CNS's fundamental role in receiving information through sensory nerves and processing it.
11:30 - 12:30: Neurons and Glial Cells The chapter discusses the functions of neurons and glial cells in processing sensory information. It explains how sensory experiences are compared between the present and the past, and how new information is integrated with previously stored data. The central nervous system then makes decisions based on this information and generates motor responses, which can include movement through muscle or locomotor systems.
12:30 - 15:00: Gray Matter and White Matter This chapter discusses the roles of gray matter and white matter in the brain, focusing on their functions in receiving, integrating, processing information, making decisions, and sending motor outputs. It emphasizes the central nervous system's pivotal role in these processes.
15:00 - 17:30: Tracks and Nerves This chapter focuses on the peripheral nervous system (PNS), explaining its role in the larger context of the nervous system. The PNS is responsible for transmitting sensory information from peripheral body parts to the central nervous system (CNS) and conveying motor commands from the CNS back to these peripheral areas. The chapter emphasizes the simplicity of this function: bidirectional communication between the body's periphery and its center.
17:30 - 20:30: Reticular Formation and Brainstem The chapter begins with the discussion of the central nervous system, emphasizing that more detailed information will be covered later. It then transitions to the peripheral nervous system, noting its division into two parts: the motor peripheral nervous system and another unstated part.

Neuroanatomy | Neurology | Neuroscience | Dr Najeeb Transcription

00:00 - 00:30 right today we are starting with the neuron atomy very very basic concept extremely basic concept right that what is Central nous system what is peripheral nervous system what is gray matter what is white matter so and so forth right so first of all we start with that nervous system consist of two important components
00:30 - 01:00 number one is central nervous system right and number two is peripheral nervous system right so nervous system is basically divided into central part and the peripheral part right now in the central n systems central nervous system
01:00 - 01:30 consist of brain and the spinal cord central nervous system consist of brain brain and spinal cord now this area this all shaded area this is your spinal
01:30 - 02:00 card right and this upper structure all the you can see red area this is considered yes please brain so central nervous system consists of brain and the spinal cord right now what is the basic function of central nervous system a very basic concept
02:00 - 02:30 we'll study detail later on what is the basic function of the central number system anyone uh your definition of functions of central number system is no no no no what is the very basic function of central nervous system what central no system is doing yes please it is regulating
02:30 - 03:00 one of the function is Thermo regulation what okay he also send signals what else okay let me tell you very basic function of central number system it collect the information from environment in the whole body this is the number one function what is the function of number one function of central number system is it should take the information from the environment and from the
03:00 - 03:30 all body it collects the information through the sensory system so whole sensory system is giving the information to the central number system and Central number system function number one is it should receive the sensory information is that right let me make it a very simple diagram that if we say that this is your central nervous system right what is the function of this first very basic function of
03:30 - 04:00 central number system is that it should receive the information right this information about the self and the environment should go to the central nervous system this is sensory input this is sensory input and this sensory system sensory nerves which are taking information to the central nervous system they are part of the peripheral nervous system
04:00 - 04:30 number one it collect the sensory information number two once the information come here it Compares and contrast the recent information with the past information let me give you an example I'm standing in this room giving a lecture anyone who is present in the room right my sensory system is collecting the information here's Irene here is Carlos here's Amal here is zza here's Ronald how I know that my central nous system knows that because
04:30 - 05:00 Sensations are being collected in central no system through the sensory system for example my visual pathway is that right number one number two if someone knew enter through the door again that information is taken to the central no system but as soon as information will go to the central no system about the new person I will compare the new image with the past image and see that can I recognize the person is he totally strange for me or
05:00 - 05:30 is a familiar phase so what central system is doing whatever new information is coming it should compare and contrast with the past information because Central no system has stored lot of information already so Central no system receives the sensory input it stores the sensory input it compare and contrast and process the sensory input integrate the present and past
05:30 - 06:00 experiences and then it decides about the motor response that what should be your response to incoming sensory input right then Central of a system we generate the decision what should be done now for example friend of your come sensory input is you see the person motor maybe you give a smile or a very good food come with a very good smell sensory input is smell is going
06:00 - 06:30 sensory input is you see the good food and motor output will come from Central of system maybe it will start passing saliva or gastric juices so what is happening if someone ask you what is the very basic fundamental function of central number system you must say Central number system has Duty number one that clect that it should receive all the information which is coming to it through the sensory nerves is that right once it receive the sensory information it should process the
06:30 - 07:00 sensory information compare and contrast the present and the past sensory experiences then it should integrate the new information with previously stored information then Central n system should make a decision what to do right and then it should it should generate some motor response motor response right which may be movement through a muscle or locomotor system or
07:00 - 07:30 which may be secretion by a gland or maybe change in the smooth muscle activity like G motility change after the food right now this part which receives the information which integrates the information which processes the information makes the decisions and sends the motor output this system is central unit of the brain this is the central nervous system and all this system which is taking the information
07:30 - 08:00 to the central n system and taking the motor information from the central of system to the peripheral tissue these two together are called peripheral nervous system so what is the duty of peripheral nervous system duty of peripheral nervous system is to take the information from the periphery to the center plus to take the motor decisions from the center to the peripheral that's so simple is it right we will discuss
08:00 - 08:30 the functions of central nous system in big detail later on right but this was just the beginning right now we go to the peripheral n system and see what is there peripheral L system is naturally divided into two part yes there is motor peripheral nervous system motor peripheral nervous system
08:30 - 09:00 and yes there is sensory peripheral nervous system so peripheral no system has two part one part is working as motor part other part is working as sensory part is it clear now
09:00 - 09:30 okay so we were talking about the central sensory of system is taking the information from the periphery so we say information will flow in this direction right and information is going to Central number system through the sensory now and of course you know that according to this diagram motor system
09:30 - 10:00 will generate the response so direction of response in our sketch will go like this so here is a motor response am I clear so this is our central unit that is information input and then information output now sensory nervous system is further divided into yes there are special
10:00 - 10:30 Senses there are special Senses senses yes and there are yes general senses General Sensations there are special Sensations and there are there are special Sensations and there are General sensation is that right now
10:30 - 11:00 now what is the real difference between the special senses and general senses what is the difference between the special Sensations and general Sensations which are going to the central nous system anyone yeah don't tell me special Senses of special senses and general senses are general senses uh what is the real difference specificity you mean special senses are specific and general senses are non-specific you have to be more
11:00 - 11:30 specific in your answer yes what is the difference between special senses and general senses there are many differences the most important difference is special senses are generated only from a specific part of the body and general sens Sensations can be elicited or initiated from any part many parts of the body many parts of the body for example touch you can feel from
11:30 - 12:00 multiple part of the body touch so it's a general sense is that right but you can see only through your eyes can your ear see or can you see with your lips you cannot right there's one specific part of the body which is concerned with the sensation of Vian is that right so that should be considered a special sense we can say special senses are senses which cannot be elicited or sensed through multiple part
12:00 - 12:30 of the body or from most part of the body special Senses can be elicited by specialized designed you can say receptor system which are present in only some specific part of the body for example VN sense of V is only from eyes is that right then another special sense is altion the smell you can smell with your nose can you smell with your eyes or with your fingers
12:30 - 13:00 you cannot right again altion is from special area altion smell then there's taste you can taste with your tongue but can you taste with your finger no now your tongue your tongue has special Sensations as well as general Sensations special sense in the tongue is taste the general sense in the tongue is touch temperature now touch and temperature you can feel with maybe
13:00 - 13:30 fingers as well as with your tongue but taste you can only feel with your tongue but not with your fingers so taste sensation become a general sense or special sense special sense okay then can you tell me some other special sense hearing yes you can hear with your ears you cannot hear with your tongue or you cannot hear with your foot try it someday you'll be frustrated right so we can say sense of hearing that is also special sense then sense of
13:30 - 14:00 balance you know in innerer has two part here has two part one is concerned with the hearing which is called Cocker system another is concerned with the balance which is called vestibular system right vestibular system right there's a specialized you can say functional unit which can very accurately determine the sense and generates and sends the sense of about
14:00 - 14:30 position to the central number system so sense of yes please position right equilibrium equilibrium and position sense of position which is mainly generated by vestibular operators of the innerer right so these are some examples of special Senses again let me repeat it what is whole nervous system about n system is having number one to collect
14:30 - 15:00 the information from the periphery take the information to the center integrate the information Pro process the information make a decision and bring the motor response is that right information is going to the central of a system through sensory system information is coming from the central of a system through motor system Sensations which are going to the central of system some sensation are special Sensations right
15:00 - 15:30 which are elicited from some specialized areas in the body and there are other General Sensations which can be initiated or elicited from multiple parts of the body these are called General Sensations the general Sensations can be further divided into yes sotic Sensations and somatic Sensations and visceral
15:30 - 16:00 Sensations visceral Sensations can you tell me some example of visceral sensation sensation which is coming from within the from the visra to the central nervous system classical example of that is when you develop abdominal cramps in diarrhea those Sensations are coming from
16:00 - 16:30 G right but visceral Sensations are usually from the visra which may be dull pain pain from the VIS is usually dull but pain from skin is very sharp so dull pain may be coming from the VRA or there may be discomfort due to distension of VRA distension of VRA may lead to discomfort for related with the
16:30 - 17:00 visceral right or sometimes visceral abnormal movement give a sensation to you right so there's certain Sensations which are coming from the visra right or from deeper part of the body right then there are some Sensations which are called somatic Sensations who will Define somatic Sensations for me what are somatic
17:00 - 17:30 Sensations anyone have you heard of this word or never heard of it what is really meant by somatic Sensations anyone have you heard of the word somatic Sensations which usually include pain temperature touch vibration proception so what is how do you def find sematic Sensations sematic
17:30 - 18:00 Sensations are Sensations from the yes from the skin right subcutaneous tissue superficial areas of the body you can say most of the sematic sensations are coming from superficial part of the body as visceral Sensations are from the deep part of the body so sematic Sensations are coming from superficial part of the body and sematic Sensations are
18:00 - 18:30 also coming from locco motor system loc motor system what is loc motor system yesal local motor system sotic Sensations are for example from the skin right also from the facias and also coming from locco motor system what is locom motor system the system in the body which is
18:30 - 19:00 which is used for Locomotion Locomotion mean movement it means skeletal muscles it means joints like capsules ligaments tendons all the sensations from there are also considered somatic Sensations and of course somatic Sensations are general senses sematic Sensations may be coming from The Temper joint or may be coming from the knee joint is that right so they're generally
19:00 - 19:30 elicited in the body right so somatic Sensations are like touch pain temperature and proprioception first I told you the origin of sematic sensation main origin of sutic sensation is skin and related inment and sutic Sensations come from locomotive system mainly these two areas and some other areas what are the types of somatic Sensations that may be
19:30 - 20:00 pain temperature touch and proprioception have you heard of the word proprioception all of you have heard it okay who is going to impress me by telling the this very personal concept of prop reception Irene okay this is one component of proception she is talking about the sense of position right so yes Ronald what is
20:00 - 20:30 your concept of proper reception okay this is yeah this is partly right the same definition you are giving what irin give that you say proception is concerned with the how the body parts are oriented in the space right any more simple concept all the sensations coming from
20:30 - 21:00 the locomot system all the sensations which are coming from locomotive system and going to the central of the system as a group they are called propioception plus especially sense of position which these two people are telling right so it means that if with my closed eyes if I'm moving my hand for example this my hand is here okay I move in the air and now I'm not seeing my hand it is here I can still bring this
21:00 - 21:30 finger there how much Central no system knew that where is my right finger right hand and how my cent of system could generate the motor response so that left hand can come accurately that point and sensory information was going through this area sensory information from the joints ligaments skeletal muscles attension in them all of that were computed by the cerebellum to generate the image position of this part and then it then what happened center of
21:30 - 22:00 a system ordered the left hand to go and touch it and then even corrected it when it overshoot do you think if this information was not going to the central number system could Central number system bring this in right position no property ortion is very important all the time Central of system is Computing all the sensory input which is coming from joints ligaments skeletal muscles capsules right even from scan
22:00 - 22:30 and from computation of that all information from constantly incoming information Central Nal system is making its position of the S sense of the position of the body part thank God there is proception that when you walking do you sometimes you while you are walking by mistake do you lift your both legs off the ground you ever did and all AR why you didn't do it
22:30 - 23:00 because when you walking center of a system is Computing all the information coming from your limbs and it knows when one limb is lifted off and other should be grounded is that right for example another concept of proper reception for example you want to scratch your ear Central system already knows where is the ear even with closed eyes and Central system really knows where is my finger and it knows I should scratch in
23:00 - 23:30 this B so all this information trillions and trillions of action potentials are moving from different sensory systems to the center of a system and it will compute like a computer and every moment it is deciding how the different parts of the body are oriented in the space for example with your close eyes right now you can tell what is the position of your legs you are with open legs she has crossed her legs he's with open legs
23:30 - 24:00 right if I asked you to touch your nose even with closed eyes can you do that or not how you know that that you are knowing the limb is approaching position of the limb you know it very well prop perception is going on so this is very important to know that somatic Sensations which are going to the central nervous system right they are having a very important component called proprioception why I'm concentrating on this because
24:00 - 24:30 later on in advanced lectures we will study that there are many diseases which disrupt the proper reception and then you cannot walk well can you walk well or you can coordinate your movement not is that right so this was something about somatic Sensations we'll do every part in detail later on visceral Sensations okay so this is all sensory system information going to that another concept all the s sensory information which is
24:30 - 25:00 going to the center of a system are you aware of all the information or not no some information you are aware and that sensory information which is going towards the central of our system and you are aware of that information we say these are the sensations which are going up to the Consciousness level you are conscious of those sensory experiences but there are some sensory experiences you may not be aware of there's some sensory information which
25:00 - 25:30 is going to central nervous system and central nervous system is processing that information but those informations do not reach to your conscious level and you are not aware of that information can you give me some examples of that information that is called as a unconscious Oh yes most of the time you are not aware of your peristalsis until really something terrible goes with your git right excellent example is blood pressure you know blood pressure is measured by the special sensory systems
25:30 - 26:00 for example coted sinus from the coted sinus there are nerves coted sinus right with changing blood pressure coted sinus has special nerve endings of the ninth nerve glossop frenal ner and information goes to the center nerval system about the changing blood pressure you are not aware of that is that right then okay this was one classical example so all the sensations which are going to the centrer of system some do go to the conscious level then
26:00 - 26:30 most of them many of them do not go to the conscious level okay just by the way there's a question which part of the which part of the central of system determines the level of Consciousness I mean I say that sensory input has come to the central L system if it goes to a specific part you will become conscious of the sensation if it does not reach to specific part you will not be conscious of the information for example I will tell you
26:30 - 27:00 while you are sitting one minute back you were not thinking about your sense of position so sense of position was going only to a level which was not processing the information at a conscious level but if I say concentrate on your sense of position then you suddenly know what is the position of your feet what is the position of your legs what is the position of your hand you're doing like this right so then suddenly it go jump information jump and it is escalated up to the level of conscious
27:00 - 27:30 seat so what is the part of the central of a system which really processes the information and make you the conscious of the information who will tell me the answer yeah limic system is more concerned with the memory with the emotions and with some visceral activity and mood we'll talk that later which part of the central n system is concerned with the conscious Talus has very little conscious
27:30 - 28:00 appreciation of pain but not the everything for example um you may be very or I'm very conscious that I'm giving the lecture what is the temperature here I know who are the people sitting here I'm conscious about my activity that I'm delivering the lecture right I should not really reveal my true self in front of the camera right so I'm conscious of so many things and you are also conscious very careful about answering even though your answers are not coming into audio because our cameras system is not taking only my audio it is so adjusted in uh you can
28:00 - 28:30 say way that it's not uh recording your answers but your are conscious so which part of the center of a system processes the information at conscious level that if information does not go there Sensations are there but you don't know but if Sensations go there to that part of the center of the system you become aware of the senses yes excellent Irene has given a very good answer that is cerebral cortex so
28:30 - 29:00 this is the cerebral cortex right which is concerned with the Consciousness that whatever information comes right it will take it up to the conscious bring to your conscious level if some sensory input is going to the central of the system but that sensory input does not reach to cerebral cortex right then you will not appreciate that sensation in the conscious way you will not be conscious of those Sensations for example sensation of blood pressure are you aware of that no because that does
29:00 - 29:30 not go to the cerebral cortex but if someone touches me information is going to the cerebral cortex so I become aware of that am I clear that's very good answer right the seat of Consciousness is cerebral cortex okay let's go to the motor responses that once the sensations go to the central n system central n system will decide make some decision about decision may be not to respond or
29:30 - 30:00 decision maybe to respond and if Central n system is going to generate a response then through the motor system motor neurons and nerves information will come to the peripheral part right there are two types of motor responses some of the motor responses can be voluntarily controlled some of the motor responses can be under your will for example you want to shake a hand with your friend or you do
30:00 - 30:30 not want to shake your hand is it under your will or not right you want to take cup of uh tea or you do not want to uh touch the cup of tea this is under your control so some motor responses are under your control right and there are other motor responses which are not under your control for example there's a chicken piece in a plate now to hold that chicken piece and to put in your mouth and chew that is under your cons control
30:30 - 31:00 but once chicken piece has gone to your stomach can you tell the stomach don't digest today I will digest it after two weeks G will work as it wants it is not under your control is that right if there's some lemon here or if there are two three cut lemons here in the plate right to take those lemons and taste them is your conscious but if I being produced is it under your will under
31:00 - 31:30 your control no no so it means M responses that you will take the lemon and taste it this is under your will but if even if lemon remain there and you start salivating that salivation is not under your control so we can say all the motor responses which are generated by the central of a system some of them are under your willpower and under your voluntary control and some Sensations are not under your voluntary control the sensations which
31:30 - 32:00 are motor responses which are under your voluntary control these are called somatic motor responses somatic motor responses or voluntary motor responses is that right opposite to that those motor responses which cannot be controlled like secretions of L they cannot be controlled voluntarily or movement of
32:00 - 32:30 the smooth muscles cannot be controlled voluntarily or heart rate can you change your heart rate willfully until you're not very specifically trained in some certain type of special trainings we cannot control our heart rate you cannot decide to tell your girlfriend that you are very angry but you show her that my pulse is going up is it right heart rate is not under your control so it is voluntary or involuntary involuntary
32:30 - 33:00 so voluntary responses are somatic motor responses and involuntary responses involuntary responses are automatic responses or we simply call them autonomic auto nomic motor responses so what did we learn here that all the motor responses can be categorized as has voluntary motor responses and
33:00 - 33:30 involuntary motor responses voluntary motor responses are also called somatic motor responses and involuntary motor responses are also called autonomic motor responses is that right can you give me example of somatic motor response for example when I move my hand this is somatic motor response is that right voluntary motor response right but if my git is right now digesting the grains which I eat in the morning that is
33:30 - 34:00 involuntary J is producing secretions it is producing peristalsis right another example if you see a dog and you see dog size is really big and dog looks very unfriendly you decide to run away now running maybe voluntary but with that your heart rate goes up that is envel so autonomic nervous system is in at without your control right so
34:00 - 34:30 involuntary system automatic system again the motor output in autonomic nervous system is divided into two sympathetic nervous system yes and parasympathetic parasympathetic nervous system right usually right now when you're comfortably sitting there's some
34:30 - 35:00 sympathetic activity in the body as well as some parasympathetic activity but if you undergo some stress sympathetic activity will go up and if you are very comfortable and relaxed parasympathetic activity will dominate in your body yeah so you only have voluntary to have a yeah actually all the skeleton muscles we say the skeletal muscles are
35:00 - 35:30 under your will right you can control them as you want if you wish to right but smooth muscles and cardiac muscles you cannot control glandular activities you cannot control right so they are set to be controlled by autonomic nervous system and skeletal muscles which are under your control they they are by the somatic motor system is it right for example there's a muscle biceps here right this is under voluntary control thank God if your
35:30 - 36:00 limbs are under involuntary control it will be a terrible situation you are sitting with Irene and some very beautiful girl pass and you have involuntary legs you will be in a terrible embarrassing situation and maybe for other people disappointing situation so thank God most of the many many muscles and Locomotion is under voluntary control is that right and what goes with your poor heart when someone beautiful passes thank God it is not revealed usually to your
36:00 - 36:30 girlfriend that is going inside is that right so you just imagine that your limbs are having all inv involuntary control do you think life will be good problem will be especially with the kids you cannot take them past the sweet shop if they have involuntary movement of the limbs all the kids sticking to the Sweet Shop you get it but there are other things like G activi or heart activity or many glandular activities
36:30 - 37:00 they are under what is that involuntary control or autonomic control now this autonomic control which is mainly visceral control again that is adjusted autonomic motor output has two part one is sympathetic output other is parasympathetic output you can say that motor output which is coming to the involuntary muscle either some of it is going to sympathetic output other is
37:00 - 37:30 parasympathetic right sympathetic output become dominant in the body or increased in the body when you are under stress fear respon response to fear you know when you are afraid your sympathetic activity increases is that right and what sympathetic activity does It prepares you for the Fright flight response right when you want want to run away it depends on what kind of threat is there if you have a small dog
37:30 - 38:00 very small dog biting at you will your sympathetic nervous system go up no maybe dog sympathetic nervous system go up when you respond to dog if dog is very small but dog is Big then your sympathetic nous system goes up you get me now this is automatically for example if a very big dog is chasing you right one thing is you run away that is
38:00 - 38:30 voluntary skeletal muscles and you know where to run towards the doger away away but sympathetic nervous system increases its activity and automatically heart rate goes up automatically the blood vessels to the skeletal muscle dilate blood vessels to other visra construct so that blood should be diverted to the skeletal muscles right when dog is after you and you are really afraid and trying to fly away what about your git activity it
38:30 - 39:00 should go up or down it go down you don't uh want to digest at that very moment the chicken piece you eat otherwise dog may take your leg piece is that right so what really happens that sympathetic nervous system knows which organ activity should be enhanced in the stress and which organs activity should be reduced for example cardiac activity will go up in stress but G activity will go down opposite to that when you are not in stress you're very
39:00 - 39:30 comfortable there's no threat in environment you're in a cozy you can say bed temperature is good no memories coming which are disturbing you you have eaten a very good food do you think you are under stress or you are with less stress less stress so then sympathetic activity will go down and Paras atic activity will go up is that right that will take the
39:30 - 40:00 heart rate down that will parasympathetic activity when it increases heart rate becomes less but git activity becomes more is that right so this was very briefly an introduction that what is central nervous system and what is peripheral nervous system we already know that peripheral nervous system has sensory nerves which are taking information to CNS and peripheral nervous system is motor nerves which are taking information from CN to the periphery right and then we discuss that
40:00 - 40:30 central nervous system has a brain and spinal cord and important part of the brain okay let's discuss what is this part of the brain yeah this part of the brain this is forbrain this is called for brain in the forbrain this superficial area right this is
40:30 - 41:00 called cerebral yes please cerebral Hemisphere okay let me make a diagram from the frontal view as you see that will make it more clear if I'm standing like this and you make a section of the brain right
41:00 - 41:30 now this is forb brain here it is midbrain here these structures hind
41:30 - 42:00 brain and this structure is spinal cord now cereal cortex is the gray matter which is present on the surface of this right that I will discuss later now first of all this is spinal cord what is this this structure medula what is this structure pawns and
42:00 - 42:30 what is this on the back Cala now pawns Meda and Calum this is as a group called hind brain H brain or other name for this is other name for the hind brain is ranyon Roman sephon is that right then this is the hind
42:30 - 43:00 brain here is the forbrain in between the hind brain and forebrain we are having this structure and this structure should be called midbrain what is it called mid brain or other name for the midbrain is Misan seon that's very good mean
43:00 - 43:30 sephon so brain has Roman seyon and Misan seyon after that this top area is called forbrain this top area and this four brain is four brain is also called proen sephon [Music] pren sealon again please listen Central nous system consists of brain
43:30 - 44:00 and the spinal cord brain has hind brain midbrain and for brain H brain is called also Ranon mid brain is called also meanon and for brain is called proen seon right then out of this proen seon right this outer part outer part right this is called for example this
44:00 - 44:30 outer part has a different name and this part and deeper structure has a different name who will tell me the name out of proen sephon there's outer part superficial area of pren sephon and there deep structures of fren sephon The Superficial structure of the fren spons are also called cerebral hemispheres these are the deepest structures of cerebral
44:30 - 45:00 hemisphere now these outer structures what are they called ton sephon they are called ton sephon and what is this Dion sephon how you can remember that Dion sephon is in and ton seon is out you have seen the video that is why you answering so well okay I will ask Carlos Mr Carlos how you remember that Elan sefon is outside and Dian sefon is
45:00 - 45:30 inside you remember there was some princess beautiful Charming Diana she was there Rose of England you remember her right you just imagine what was happening with Diana wherever she was she was the center of attention and there were many many telescopes from everywhere trying to not into detail so what happened here also in central of system here is Diana and what are
45:30 - 46:00 here what are these telescopes from every direction do you think this image this a bit emotionally loaded image can you remember it for a long time so Diana has to be in the center and telescopes has to be from everywhere beautiful princess our brain is also designed like that Dion sephon is in the center and telescopes Thon
46:00 - 46:30 sephon is from every direction so cerebral hemisphere the deepest part has which structur dianon and on outer part what are the structures tanon dlon am I clear any question up to this now again let me repeat it that Dion seon is the deepest part of cerebral Hemisphere and what is this tons are out part of cerebral hemispheres but both of them together are called
46:30 - 47:00 Frozen sephon am I clear to everyone right after this now before we really go into detail of neuron Anatomy I want to introduce some very basic concept and basic terms related with the nervous system right now nervous system is made of two types
47:00 - 47:30 of cells basically right nervous system is made of two types of cells one type of cells are called neurons and others are what are the neurons neurons are the real true functional cells of the central nous system neurons are basically the cells which conduct the information the electrochemical information that is called the action potentials so action
47:30 - 48:00 potentials are passing through the neurons from one area of the nervous system to the next area of the nervous system so we can say one group of cells in the central nervous system collectively called neurons have very long long processes called exons now basically neurons are those cells of the nervous system which is concerned with the communication signals is that right
48:00 - 48:30 they're taking the action potentials then there are other cells which are not neuronal cells but they are present in nervous system the other group of cells are sporting cell to the neurons the true functional cells of the central nervous system are neurons and the other cells which sport the neurons right they act as a connective tissue for the neuronal
48:30 - 49:00 cells now what those cells are called as a group again let me repeat central nervous system is made of primarily two types of cells one type of cells which are conducting the information which are the true central nervous system cell right which are doing the true function of nervous system taking the Action Potential from one area to another area is that right releasing the neurotransmitter generating the action potentials is that right those cells are called neurons then there are many other cells
49:00 - 49:30 which sport the neurons we call them connective we call them connective tissue cells of the nervous system these connective tissue cells of the nervous system as a group they are called gal cells neurog gal cells what are they called neuro gal cells is that right neurog gal cells so Central liver nervous system has two types of cells
49:30 - 50:00 there are neuronal cells and neurog gal cells neuronal cells are the true functional cells of the central nervous system which are generating Action potentials and conducting Action potentials and neurog glal cells are the sporting cells of the nervous system about the neurog glal cells I will go into detail later but I will now introduce some very basic terms about the center of a system in relation to the neurons for example when you study
50:00 - 50:30 neuron anatomy and neurophysiology you come across two terms very frequently one term is gray matter and another is white matter everyone who is studying neuron anatomy And neurophysiology even neuropathology he comes across again and again the terms of gray matter and white matter so Ronald is going to tell us what is gray
50:30 - 51:00 matter these are the cell bodies of the neuron let's suppose cell bodies of the neurons are connect present in the ganglion also autonomic ganglia do you think autonomic gangli are graay matter no no by your definition it is but it is they are not agreed by other doctors he says that cell bodies of the neurons are called gray matter mostly he's right but I put an
51:00 - 51:30 objection to him that cell bodies are collected in the autonomic ganglion also cell bodies of neuron but autonomic gangli are not called gray matter because gray matter is only in central nervous system and autonomic gangli are part of peripheral nervous system his definition need a little refinement actually collections of cell bodies within the central nervous system are called gray matter let me tell you cell bodies of what cell bodies of neurons
51:30 - 52:00 neurons are like Mouse rats so this is one neuron and what is this long tail what is this tail Exxon what is this tail Exon now in some part of the central nervous system if there are many rats together and these are the Tails right now these cell
52:00 - 52:30 bodies because they have the nuclei right they look gray now this collection of the cell bodies within the central nervous system within the central nervous system this collection of cell body is called gray matter when we say there is cerebral gray matter it which means in the cerebral hemisphere in some area lot of
52:30 - 53:00 cell bodies of neurons are collected together so when all these body of the rats together this is gray matter and all the Tails put together are called white matter so when in the central of system we are talking about here's gray matter and there is white matter what really should come to your mind gray matter means that in that area there are lot of cell bodies of neurons and white matter means that that is the area where there are lot of
53:00 - 53:30 axons together because axons have some milein sheet and they look somewhat white color and cell bodies when they're collected in one area cell bodies have you know nucleus DNA RNA all those structures impart darker color to the brain substance right so now again I will repeat in central of a system a lot of cell bodies are of the neurons are put together that is called gray matter and if lot of axons are put
53:30 - 54:00 together that is called white matter is that right now we can say now that nervous system again we'll divide into central nervous system and yes please peripheral nervous system but now we are talking not functionally we are talking structurally in the central ofous system where a lot of cell b are collected these are the cell bodies right collection of cell bodies what is
54:00 - 54:30 it what is that gray matter right so we divide it like gray matter and plus Central system has yes white matter is that right gray matter we can show by many many cells there neuronal cells right this is the G matter and what is this going yes white matter I hope you'll
54:30 - 55:00 remember this now whenever someone say there's a disease of white matter it means this is concerned with axons if we say there's damage to gray matter it means lot of cell bodies are damaged is that right then gray matter is further divided into two types in the central of system gray matter is divided into two specialized type some are called
55:00 - 55:30 cortex and others are called nucleus have you heard of like third nerve nucleus veus nerve nucleus have you heard of it veal nucleus in central no system right now some of the gray matter is called cortex and some of the gray matter in central no system is called nucleus what is the difference between cortex and nucleus question goes to to Ventura you heard of it there is cortex
55:30 - 56:00 in the brain and there are some nuclei in the brain what is your real concept Jessica please she's going to impress all of us yes we have a new friend there do you have any idea the difference between the cortex and nucleus when we study neuron atomy we say there is cerebral cortex there is cereal cortex many diseases related with that we talk about third n nucleus six n nucleus do we talk or not we talk about nucleus for salivation nucleus for
56:00 - 56:30 lacrimation women are very much special you know nucleus for lacrimation nucleus for Taste we call it nucleus of tractus solitarius vus nucleus so what are these nuclei or and what are these uh G what is this cortex should I tell you or you can guess yourself Amal try to guess something because very big basic of central neur yeah that's very good he
56:30 - 57:00 come up with some good idea let me tell you here is suppose I draw the central number system side view right now listen the gray matter the gray matter which is applied on the surface of the central of system is called cortex sometimes actually there are lot of cell bodies you know which are collect CED which are collected on the surface
57:00 - 57:30 of what is this four brain cerebral Hemi sphere so what is this area there are a lot of neurons with there yes cell bodies and these neurons with their cell bodies right all the structure where the neuronal cell bodies are abundantly present this this is a gray matter of course but because this is applied on the surface of the cerebral hemisphere it is exposed on the
57:30 - 58:00 surface of the cerebral hemisphere this is called cerebral cortex what is it called cerebral cortex opposite to that you know that here is Calum what is here Calum and there's also a lot of neuronal cell bodies here and they are making this gray area and this gray area which
58:00 - 58:30 is also Exposed on the surface of C balum this is called cereal cortex so this is cerebral cortex this is cereal cortex what is cortex cortex is just a gray matter Exposed on the surface of the brain what is gray matter gray matter is the collection of neuronal cell bodies is a difficult concept it's so easy isn't it
58:30 - 59:00 now this is cerebral cortex this is cereal cortex now from here let's suppose that from these neurons there's what is this there exons suppose the exons are going down now what this all collection of axons which are going down what is this white matter what is this white matter many exons connecting like this here so what is this white matter many
59:00 - 59:30 of the fibers coming from the top and then going to Calum what is this white matter many fibers going from down to top is that right and then going here what is this white matter many connections from here going to the backward what is this B matter many connections from here connecting to the front again what is this white matter is that right now you know the real difference between gray matter and
59:30 - 60:00 the white matter that in central of a system where cell bodies are connected with gray matter and when there's abundance of the aons together they are called white matter and when green matter is applied Exposed on the surface of the central of a system then it is called cortex and there's another term used nucleus please nucleus of the central nervous system should not be confused fused with those nuclei which are present in the cell
60:00 - 60:30 which are called nuclei which have DNA nucleus term is used in two different meaning number one you know within the cell there's a nuclear membrane housing all the chromosomes that is called nucleus but in central nervous system nucleus term is also used in a different different context when we say there third of nucleus what does it really mean yes who will tell me have you heard of this concept this vas nucleus third of
60:30 - 61:00 nucleus fifth n nucleus you never heard of these things anyone heard of you Jessica must have heard when you study Neuroscience you say third of nucleus is damaged and person will develop some problem with the eye movement yeah nuclei are special now let me tell you one thing before you tell me something totally new listen uh sometimes what happen there are some
61:00 - 61:30 cell bodies collected here is that right and this collection of cell bodies of course piece of gray matter but this piece of gray matter from all side is surrounded by what is this is surrounded by what white matter so pieces of gray matter which are embedded within the central of the system and surrounded by white matter are called nuclei they are called nuclei now if from this piece of gray
61:30 - 62:00 matter all the exons are going out and making the seventh cranial nerve let's suppose all these exons going out and making seventh cranial nerve then this nucleus will be called nucleus of the seventh cranial nerve then we say that seventh cranial nerve have a nucleus it means that in the central of a system there's a small piece of gray matter and because and it is surrounded
62:00 - 62:30 by white matter so this must be called nucleus and from this nucleus many fibers are going out these are the rats from here where tail are going out and making seventh nerve so we should say this is a nucleus of seventh so next time when you study the nucleus of third nerve or nucleus of 12th hypoglossal nerve you must get an idea what is meant by the nucleus this is a small P piece of gray matter surrounded by the white
62:30 - 63:00 matter and if it is 12 s nucleus it means 12th nerve aons are connected to that grave matter rather those exons are coming suppose here it is seventh n exons they're coming from the nucleus of the seventh n right so what we can say that gray matter gray matter is divided into cortex and and nucleus right what is cortex cortex is a
63:00 - 63:30 gray metal which is exposed on the surface of the brain what are nuclei nuclei are the gray matter pieces of gray matters in the deeper part of central of system surrounded by yes surrounded by white matter for example there are many many big collections of gray matter in this area in the very deepest part of cerebral hemisphere the multiple pieces of gray matter here surrounded by the white matter so as a group and they are
63:30 - 64:00 controlling many motor functions so these pieces of gray matter in the deepest part of cerebral hemisphere rather these pieces of gray matter in the base of the cerebral hemisphere in the base of cerebral hemisphere these are called basil nuclei what are they called basil nuclei is that right now I will ask a question and you have to answer in the central nous in central central nervous system has two types of cells
64:00 - 64:30 some cells which are doing the true function of conduction what are those neurons other group of cells which are supporting the neurons what are this neuroglia we'll go into detail of neurog later now neurons have a cell body and usually a long process called Exxon those area of central nervous system where cell bodies are put together they are called they are called gray matter they are called gray matter where cell bodies are put together and these gray matter
64:30 - 65:00 if the surface of the some brain this is called cortex if the species of graay matter are embedded with deeper part of the brain and surrounded by the white matter then they are called nuclei am I clear now let's come to the some detail of white matter right you already know that white matal is that part of the brain in which there are a lot of axons put together they are
65:00 - 65:30 not rats but they are tails of the rats is that right that is white matter there are the cables right now white matter can be classified in many ways one of the ways the direction in which directions in which these axons bundle are moving for example some exons of Bund are moving up and down along the neuronal AIS neuro AIS right for example many many sensory
65:30 - 66:00 information fibers come in and then they go upward and lot of motor information is decided from here and motor fibers come down so it means there there is some white matter which is of course group of axons which are taking the information to the upper level and there is some more white matter right or group of exons which are taking the motor responses downward is that right for example someone scratch on your feet so
66:00 - 66:30 what will happen from your foot this information is going like this now what is this this is white matter system taking the information up and then you decide to remove your foot then what will happen that from here information will come down and go to the muscles here so it means in neuronal system there are a lot of fibers which
66:30 - 67:00 are going up and down these are called as a group because some fibers are taking pain information some fibers are taking touch information some fibers are taking vibration information some fibers are taking pressure information in the same way there are fibers coming down which bring somatic motor responses some fibers coming down and bring autonomic responses so all these fibers which are going up and going down as a group they are called yes please who knows excellent they are called
67:00 - 67:30 tracks right so when we say that any fibers which are moving you can say from down to up and Central system or up to down as a collection they are called tracks and those bundles of hexons which are taking information from lower part of the central of system and taking information to the upper part of the central ofel system those those are called ascending tracks what are they called ascending
67:30 - 68:00 tracks so we can say there are some white matter which is taking information yes fically and cly Sally Sally mean upward and cly mean downward and these bundles are called yes tracks so now you know the tracks in the central lers system the tracks are the bundle of axons which are taking information up and down is that right of
68:00 - 68:30 course then tracks which are taking information upward they are called ascending track sending tracks which are taking the information upward and then those tracks we take the motor responses and information from top to down they are called yes descending track
68:30 - 69:00 am I clear so what are tracks tracks are the white matter bundles which take information up and down in the center of the system right fine now there are some more bundles or white matter or exons which connect the right part of the brain with the left and connect the the left part of the brain with the right for example if I
69:00 - 69:30 draw the central of system like this tracks are moving up and down is that right then there are some Pathways which are connecting right to the left and left to the right the spinal cord as well as in cerebral hemispheres and many other areas there are some bundles of white matter which
69:30 - 70:00 are connecting today I have little bit flu my sound is something different now what I'm talking about that there are some white metal connections that which are connecting the central n system components right to left is that right what are those called Corpus Clum is one of the example of that but there are many connections one of that is Corpus colome which is the largest carpus kosom is a very big bundle of white matters which are
70:00 - 70:30 connecting the right cerebral hemisphere with the left and left with the right of course right but there are many other which are also connecting right and left areas in central of system as a group such fibers are called what type of fibers they are called commissional fibers have you heard of commiss they are called yes commissional fibers so next time when you think there are some fibers in the central ofev system
70:30 - 71:00 which are track you know they're connecting up and down and next time if you read somewhere there are some commissional fibers then these are group of fibers which are connecting the central nous system right and left am I clear commissional fibers is that right Corpus kosom is the largest commiss carpus kosom is a very big heavy information cable between the right Hemisphere and the left hemisphere Corpus kosm
71:00 - 71:30 then not only attention please Central no system not only should be connected up and down not only should be connected right and left it should be connected front and back also for example for frontal lobe information should be connected with occipital lobe and information from ocal Lo must be connected with the frontal L right it means that there should be bundles of white matter which should connect brain
71:30 - 72:00 uh Central of a system components anop posteriorly or postero anteriorly am I right or not so that cable system that neuronal system that Exon system that white metal system that information cable system which connect anteriorly and posteriorly Central LEL system that cable system is called what type of fibers when we say tracks They Are Up and Down connections when we say commissioner they right and
72:00 - 72:30 left connections now we want front and back connections what are those fibers called it's just ABC of neuron atomy we are doing you must be knowing they associate the interior part with the posterior part of the brain and they associate the information from posterior part of the centr of system to the Anor part thank God they have they have no complex name these fibers which associate the information from osterly they're simply called yes Association
72:30 - 73:00 fibers they are called Association fibers right so you can say look here now the fibers which connect from here to here or fibers which connect from here to here these black fibers are Association fibers red fibers are up and down these are the frags and some fibers right and left and these are commissional fibers have you heard of these things oh you know what is gray matter what is white matter gray matter has cortex which is exposed on the
73:00 - 73:30 surface it has nuclei which are embedded within the white matter species of gray matter you have white matter white matter is vertical tracks They are right left commissional fibers they are anop posterior and they are called Association cation fibers they are called Association fibers right then I will tell you
73:30 - 74:00 something interesting have you heard of the term reticular formation have you heard of the term reticular formation neuronet you have heard it isn't it what is the reticular formation you don't want to share your knowledge very secretive about knowledge you know as old hokma was there old time the people who were healers they keep the knowledge to them
74:00 - 74:30 they don't share and tell anyone what is radicular formation let me tell you actually in the spinal cord if I make a section of spinal cord the spinal cord this is the gray matter which is in the center in the spinal cord gray matter column is moving in the center and on the side what is there white matter is it right and in the top part of the
74:30 - 75:00 brain gray matter is outside are you getting me here in the spinal cord G matter is in the center and white matter is outside in Upper levels of the brain gray matter is outside and white matter is inside so when these white metal fibers are going up and down they make here is your brain
75:00 - 75:30 stem this is your brain stem from here to here right now these gray matter column is going centrally gray matter column is going centrally upward this is gray matter column and on the side what it has white matter now what really happens as this fibers are going up as well as fibers are coming down right actually in the brain stem these fibers make major Crossing sensory
75:30 - 76:00 fibers go to the opposite side and go to the opposite hemisphere in the same way fibers which are coming down motor they also makeing the brain stem crosses because fibers from the left hemisphere are coming to the right spinal cord right motor fibers which are descending fibers and from the right hemisphere they're going to the left side it means when motor fibers are coming down they decate they cross in the same way when sensory fibers are
76:00 - 76:30 taking information up right some of the fibers as they enter in spinal cord they cross but some of the fibers they cross in the brain stem it means in the brain stem there are major motor Crossings and the major sensory Crossing so when in the brain stem sensory fibers are crossing and motor fibers are crossing do you think gray matter will remain intact no because Crossings will occur through the gray matter so gray matter will
76:30 - 77:00 break down into small pieces and you will have some area you will have some area in which gray matter and white matter is mixed this is the area in which Central gray matter is there but lot of fibers are crossing motor and sensory so gray matter become into small pieces it become fragmented into small pieces and through this pieces white matter is
77:00 - 77:30 passing axons so we say this area become a network of gray matter and white matter this part of the brain stem become network of gray matter and white matter this network is called reticular formation what is it called reticular formation so what is reticular formation reticle formation is just that part of the deeper part of the brain stem where due to Major sensory and motor Crossings gray matter and white matter mix and
77:30 - 78:00 that is called that is called reticular formation right but during this Crossing some gray matter pieces are intact as large pieces and these large pieces are called nuclei that is why in the brain stem many gray matter when it disintegrate due to Major Crossings Gray matter break down into fragments some fragments are large and these large pieces of gray matter are called nuclei
78:00 - 78:30 so brain stem has lot of nuclei and brain stem has a also reticular formation retic formation gray matter and white matter truly mix and nuclei are that some big pieces of gray matter are surrounded by the white matter within the brain St is that okay okay then one simple question what is
78:30 - 79:00 nerve of course it's peripheral nervous system what is nerve collection of exons outside the central nervous system now listen carefully collection of axons within the center of system is white matter collection of exons within the central L system is white matter and collection of Exxon outside the central nerv system are called nerves that is so
79:00 - 79:30 simple is that right it means when we say there are tracks in the central system tracks are just bundle of exons going up and down but bundle of axon going from C central nervous system to the periphery are motor nerves and bundle of axon collecting information from peripheral part of the body and taking to the center are sensory nerves so what are nerves rather question can be put like this to make a concept very
79:30 - 80:00 clear what is the difference in nerve and track you say there's something common something different what is common tracks are also bundles of exons nerves are also bundles of exons the difference is that nerves are outside Central of system and tracks are inside tracks are also information cables going up and down and nerves are also information cables is that right another very big difference which later on I will tell you that for insulation purpose nerves
80:00 - 80:30 have special cells called Shan cells I will teach you later and for insulation purpose tracks have or white matter has special cells called oligodendroglia so around the neuronal uh exons of the nerves there are Swan cells and around the tracks or white matter in the center of a system there are no Schwan cell rather different type of cells which are called
80:30 - 81:00 olgod dendro why I'm highlighting this point because some diseases attack only Schwan cells so they dealin Dem malonate peripheral nervous system other diseases which attack only olgod dendrite so they Dem malonate Central tracks the some diseases which attack the Schwan cell as well as lioden toite so they produce demalation or conduction problem with the peripheral nervous system as well as
81:00 - 81:30 central nervous system right that's all for today