ATI TEAS Complete Nervous System Review I HESI A2

hey everyone welcome today we're going to be reviewing the nervous system for those of you that are studying for the atits or the sca2 exam the information regarding the nervous system for both these exams is going to be the same so everything that we learn here about the nervous system today is going to be relevant to both of those exams the only difference is that the questions are worded differently the questions are going to be different for atits and Hesse so practice questions you want to look at something that if you're studying for Ati look at ATI practice questions if you're studying for hessi look at hessy practice questions okay so with that being said let's go ahead and get started with the nervous system so the nervous system breaks off into different divisions two major divisions are the CNS and the pns central nervous system and per referral nervous system so CNS is your central nervous system I'm going to shorten it now with NS okay and then we've got your peripheral nervous system central nervous system is going to include your brain and your spinal cord brain and your spinal cord the way you can remember this is CNS Central what is at the center of your body your brain and your spinal cord area are in the center of your body so remember Center Central Central Nervous System brain and spinal cord and of course this includes all of the nerves that are in the brain and spinal cord like your cranial nerves and like your spinal nerves everything else that is not within the brain and the spinal cord are going to be your peripheral nervous system this is all of your nerves in the rest of your body in your arms and your legs coming off branching off of your CNS these are all your peripheral nervous system now the pns breaks apart into two other subdivisions the somatic and the autonomic autonomic your somatic system is under voluntary control voluntary control meaning that we have conscious control over the somatic system meaning we can think of a movement and the somatic system will take care of it right we can think to let's say catch a ball or pick up our groceries or throw a ball or jump all of these things are going to be under voluntary control we voluntarily consciously thought about doing them so they're going to fall under somatic system okay now somatic system is going to affect your skeletal muscles so you can think of it like this if you voluntarily consciously think I want to jump I want to skip I want to run I want to throw a ball well all of these movements really involve mainly your skeletal system right your skeletal to move you so it's going to affect your skeletal muscles now autonomic is quite the opposite autonomic is involuntary control involuntary control is you have no conscious control over any of these movements this is going to affect your smooth muscle generally which includes your your heart muscle and your glands autonomic involuntary control you have no conscious control over it's going to happen whether you wanted to or not things like respiratory rate heart rate those are probably the two most important things they happen without our conscious control right for example to breathe our diaphragm is under autonomic control our diaphragm is just going to contract and relax throughout the day without us thinking about it and this is going to help us breathe our heart is also going to be all day without us even thinking hey hey heart can you beat no it does it automatically automatically autonomic okay somatic these are the ones that you're going to use usually when you're like doing some kind of exercise if you need to lift some weight you need to play some basketball you know shoot that's going to be under somatic control okay so autonomic involuntary control further subdivides into two other categories sympathetic and parasympathetic your sympathetic system is known as your fight or flight okay fight or flight the reason it's called Fight or Flight is because it's activated when we are in a situation where we feel like we need to fight or take flight these situations might be stimulated by the ease the four e's remember these okay exercise emergency excitement and embarrassment okay so sympathetic system as y for system is triggered by these four e's exercise emergency excitement or embarrassment all of these are going to trigger this this this sort of excitement in us that's that's going to say do we want to stay and do we want to fight or do we want to run and we want to take flight for example say you are on a safari and a lion freaking comes up to you and it starts to chase you you have two options am I gonna stay and I'm I'm gonna fight this line or am I going to take flight okay that is your fight or flight system now certain things are going to happen in your body to help you to survive these things are going to be these two that I'm going to point out first these are probably the most important for you to remember and one of them is increased heart rate and force of contraption so increased heart rate and increase force of contraction well this is going to help because it's going to put more blood circulating around your body especially your muscles which are going to need it to run next you're going to have an increase in respiratory rates okay you're also going to have an increase in the dilation of the bronchi in the lungs so you see how these are going to help you with survival or one other one you're going to have increase in pupil dilation increase pupil dilation how is this going to help you it's going to help so that you can see better right so all of these things that are going to happen in your body during fight or flight are going to help you to survive okay now these are not the only things that happen in your body there is a huge list it almost affects every single organ in your body but I would say for the teas exam hesi remember these These are definitely the most important okay a good way to remember what triggers your fight or flight are the four e's exercise emergency excitement and embarrassment when you're in these situations these things are going to happen to your heart your lungs your pupils okay now your parasympathetic system is going to do the opposite of sympathetic it's actually called the rest and Digest rest and Digest okay so everything that happens here is actually going to be counteracted here for example instead of your heart rate increasing well you just want to rest now so your heart rate is going to decrease what else is going to decrease if you're resting what else is going to decrease your respiratory rate right you don't need to have a high respiratory rate if you're just resting right what else instead of having your in your pupil dilate they're not going to dilate they're going to constrict instead of having an increase in dilation of the bronchi in the lungs well you're going to have a relaxation I'm not going to write it down because I don't really have enough room but just know that here here you're going to have an opposite effect okay it's going to decrease so over here remember we have our four e's and these trigger sympathetic system right into fight or flight well over here the parasympathetic system is triggered by rest it's just triggered by rest okay when you're at rest these things are going to help you relax also when you're at rest what happens in your body is maintenance to keep and maintain homeostasis okay so think of this also maintains homeostasis rest and digest but it wants to also maintain homeostasis now over here we have the four e's over here we're going to have something called the 3D so I am gonna write it up here okay these are diuresis the second one is digestion and the third one is defecation diuresis means to pee digestion just means peristalsis right all your food is moving through your digestive system defecation is to poo Okay so these three three these three things are gonna happen during rest right because that is part of maintaining homeostasis in your body that is maintenance right to secrete and to defecate all of this waste product that's all maintenance in your body so just remember in parasympathetic system this is going to be your time to go pee to go poo and to rest okay but sympathetic why would it not benefit us to you know need to go poo or pee during fight or flight you really want to focus on things that are going to help you survive at that moment and going poor p is not going to help you survive at that very moment okay okay I hope this makes sense to you just remember nervous system goes into CNS and PM says the pns is going to be the one that subdivides into a bunch a bunch of other subdivisions right so pns divides into your somatic and autonomic autonomic like automatically automatically it's going to control smooth muscle okay somatic voluntarily you consciously think about moving skeletal muscles right okay you're involuntary autonomic system is going to further divide into your sympathetic fight or flight or your parasympathetic rest and digest okay so we're gonna go ahead and move on to our CNS alrighty guys so again the nervous system breaks down into your CNS and your pns I've written down here the sub sections of the pns just in case you need for reference but we are moving on to the CNS the central nervous system which includes your brain and your spinal cord your brain and your spinal cord are center right center Central Central Nervous System all right let's go ahead and get started okay so here we have two major sections of the brain the cerebrum which includes four lobes it includes the frontal lobe which is at like the front part of the brain here you see the eyes the mouth and the nose that would be in the front part of you know your face so this is the front part of the brain so this is frontal lobe your parietal lobe is right over here your occipital is in the back and your temporal is right here by your ear and then snug down right back here you have your little brain which is the cerebellum okay so your two major parts your cerebrum which includes your four lobes and then your cerebellum your little brain way back here and then attached to this is of course your spinal cord that goes down the back so your temporal lobe is going to interpret sound and that's generally okay and what I feel is most importantly because all of these lobes interpret so many different things and some things are overlapping and it can be a lot and especially if you're studying for the teas exam you really don't want to fill up your head with every single little thing that each of these interprets or is related to just focus on the high yield things which in my opinion temporal sound is where it's at sound is what you really need to focus on that happens here in the temporal lobe for occipital lobe it's going to be vision so anytime you see something it's going to be interpreted in the occipital lobe parietal you're going to interpret any type of touch like pain like pressure for some reason on exam questions they like to focus on the frontal lobe and cerebellum and I'm not sure if it's because frontal lobe there is frontal lobe dementia which I believe is pretty common and I'm not really sure if that's why they you know exams tend to focus on frontal lobe but um it affects a lot of important things so let's go ahead and write those down one of those things is memory the other thing is behavior judgment problem solving of course and written and motor speech I'm going to write it up here okay written and motor is is meaning the ability to physically move your mouth to make a sound of speech right so written in motor speech so your frontal lobe some of the major things that it interprets is memory Behavior judgment problem solving written and motor speech I do suggest that frontal love you remember all of these okay lastly we've got cerebellum so your cerebellum helps coordinate voluntary muscle movement some examples are of course generally your posture your balance and generally your coordination okay so let's go over this little part here now you might want to think this um this is your spinal cord but this is actually your brain stem this little part right here okay your brain stem and your brain stem includes three parts all right the first part up here this part actually it kind of goes in in here okay just imagine it's it's actually right here this is your midbrain next you have your Pawns and lastly you have your medulla obligata so medulla so your brain stem is composed of your midbrain your pawns and your medulla oblongata remember your midbrain is not so much where I drew it here crunched up here it's actually pushed up into the brain a little bit more if you were looking here at my my face it kind of looks here like it would be here right but it's kind of up here more okay this is your midbrain your Pawns and then your medulla obligata and then it extends into your spinal cord right here spinal cord because I haven't really seen any emphasis on this on the exam I'm not going to go through what really they interpret um I think it's just more important that you know that these three are part of the brain stem and they're located right here one more thing I want to show you is this meninges that cover the brain and the spinal cord okay so you've got this stuff called meninges okay meninges are a protective layer that cushion the brain and the spinal cord brain okay there are three layers the first layer let me show you right here the first layer is the innermost layer and it's called your Pia matter okay your p in matter is going to be attached to your brain tissue so it's going to surround the entire brain like this and your spinal cord like this okay so that's your inner layer your Pia matter is your inner most layer your Pia matter contains blood vessels and of course if you have blood vessels anywhere what is it going to do it's going to supply oxygen and nutrients but it's also going to trans transport out waste product okay so that's your PM matter and that's its function the second layer is your arachnoid layer a rack annoyed okay so that's gonna go right on top of your Pia matter arachnoid has something special it has CSF in it CSF CSF is your cerebral spinal fluid I'm gonna write it up here okay CSF cerebro spinal fluid and this stuff has this does the same thing that the meninges do they protect and cushion the spinal cord in the brain okay so uh protect I'm gonna I'm gonna write protect and act as a shock absorber okay your outermost layer is your Dura matter Dura so this is gonna go right outside your arachnoid just like this okay this is your outermost layer your Dura matter now what is out here you've got your brain tissue on the inside you've got your PM matter you've got your arachnoid you've got your Dura matter and then what is out here well this is your skull so you understand how your Dura is your outermost layer and how your p is your innermost layer so CSF and your meninges work together to protect the brain and the spinal cord they act as a shock absorber just in case you have any impact if you get punched or if you get smacked or whatever happens you get in a car crash these things are there to help cushion the impact so that you don't put have any damage to this internal tissue right this soft tissue right here okay guys before I erase this let's just go ahead and review it again we've got the cerebrum which is the largest part of the brain we've got the cerebellum the little brain we've got the brain stem that comes right off of the brain it includes the midbrain the pons and the medulla obligata then comes your spinal cord you don't need to worry about any interpretations here but you do have to worry about the interpre interpretations of the lobes specifically focus on frontal lobe okay we've got memory Behavior judgment problem solving written and motor speech that's all frontal lobe parietal is touch occipital interprets Vision temporal interprets sound generally okay generally so cerebellum is going to help coordinate voluntary muscle movement in other words it's going to help with your posture your balance coordination okay we've got two protective things going on here one are your meninges there's three layers your innermost layers your Pia which has blood vessels your your second layer is your arachnoid which has CSF fluid what is CSF fluid it protects the fluid that protects and acts as a shock absorber and then you've got your Dura your Dura matter is the the external layer and it's a hard layer okay and then after your Dura what do you have your skull okay and your CSF meninges again what do they do what's the whole purpose generally of them they help protect your brain or your spinal cord from shock impact so let's go ahead and move we're going to go ahead and look at the structure of a neuron so here we have an entire Neuron a neuron is a specialized cell inside of the nervous system now there are a few key structures that you need to memorize let's start with here this is the cell body okay so the cell body interprets incoming signals or messages and generates the appropriate outgoing signal or message okay now these incoming signals these signals or messages that are coming into this particular neuron come in from the dendrites the dendrites are these these that Branch off of the cell body and a dendrite receives incoming signals so the dendrite is going to receive incoming signals so messages are going to come in to this cell they're going to come in through the dendrite they're going to come into the cell body the cell body is going to read that signal or message and it's going to generate the appropriate outgoing signal or message now that outgoing message that is leaving the cell is going to leave through here this is called the Axon to hear this is your Axon your axon is signals that are leaving the cell axon is the pathway that signals used to leave in neuron so here signals are coming in they're getting interpreted by the cell body the cell body is like okay this is the appropriate message let me send it out this way and it travels out the axon and once it gets here these are your axon terminals at the axon terminal there's a communication between this neuron and another cell so this is a Communication Center at the axon terminals so communicates with other cells so again receiving information comes in through the dendrites it gets interpreted at the cell body and here the cell decides what is the appropriate message to send out whatever the message is it sends it out through the axon and it eventually re is received at the axon terminal here at the axon terminal there's going to be some communication that we're going to talk about in a little bit but first there's something going on on the axon called the myelin sheath that we need to talk about first so what I've drawn here in brown extending down the axon is the myelin sheath the myelin sheath wraps around the axon kind of like a Band-Aid and it leaves these spaces these spaces are called the nodes of ranveer so each one of these little spaces is like a little Junction here and the reason why these nodes and the myelin sheath is so important is because it allows the electrical impulse let's just say this is the electrical impulse coming out this way okay this electrical impulse instead of going straight down down the axon what it does is it jumps from myelin sheath to myelin sheath to myelin sheep doing so helps speed up the conduction so the myelin sheath and the nodes of ranvir helps speed up electrical impulse down the axon nodes of ranvir and myelin sheath speed up so action potential is the most appropriate word for electrical impulse so you might not see the word electrical impulse on your exam you might actually see the word action potential so make sure you write that down action potential is electrical impulse so nodes around here myelin sheath helps speed up action potential by allowing it to skip okay so there is a difference in the myelin sheath between the CNS and the pns okay so in your CNS your oligodendrocytes are going to produce myelin in your central nervous system but in your pns your Schwann cells are going to produce myelin okay remember that CNS oligodendrocytes produce myelin pns Schwann cells produce myelin both myelin do the same thing they're going to help increase electrical conduction Okay so we've gone over all the parts of a neuron now let's go over the synapse the synapse is this area that where the communication from one neuron to another or one cell to another happens so let's zoom into this area here okay so we're moving on to our synapse our synapse is our communication Junction in short it can happen three ways that the synapses involved it can happen between one neuron and another neuron like this example that I'm going to show you right here we've got neuron number one and we've got neuron number two here if an action potential happens between two neurons what's going to happen well that action potential is just going to travel past to the next cell a neuron can also communicate with a muscle in which case what's going to happen is a contraction a muscle contraction a neuron Canal a neuron can also communicate with a gland and what's going to happen here is there's going to be hormone release from the gland right okay so synapse is the communication Junction like I said we're going to be looking at communication between a neuron and another neuron the synapse involves this terminals right here these axon Terminals and it involves the tip of these dendrites of the second cell right here so this whole thing is what we're pretty much looking at here so I'm actually going to make this Axon terminal a little bigger Axon terminal make it look a little bit bigger okay and I'm going to make this dendrite of this second cell look a little bit bigger too let's see what's going on here okay so this is the dendrite so the interaction is between one cell's axon terminal and the dendrite of the other of the other neuron so why are we why is the dendrite communicating here because remember the dendrite is receiving incoming information so since number two neuron is receiving information from number one it's going to receive it through the dendrites and why is the axon terminal involved here when neuron number one wants to give out or send out a signal it's going to do so through the axon and the axon terminal okay so let's look inside of the axon terminal inside of this terminal there are vesicles and remember vesicles are just like little sacs that hold special little packages and in this case that special little package are going to be neurotransmitters so these blue things are neurotransmitters neuro transmitter and what do neurotransmitters do they send messages so our messages are inside of these little vesicles well those vesicles need a signal to let them release the neurotransmitter so that the neurotransmitter can travel to the next cell so here's what's going to happen action potential action potential which really is just an Impulse right action potential is gonna travel down the axon it's going to travel down to the axon terminal when it hits the axon terminal it is going to open these little channels on the terminal this opening here right these openings here are going to let calcium ions calcium anions flood in to the terminal bulb so calcium is going to go in it's going to flood the terminal once calcium goes in it is going to Signal these little vesicles to move towards the dendrite and open up and release those neurotransmitters so they're going to open up and those neurotransmitters are going to go across the synapse and they're going to be received by the second cell specifically there's going to be these little tiny receptors right receiving the neurotransmitter so there's going to be these low receptors and the neurotransmitter is going to go in there and it's going to go in here and be received so that is basically how one neuron communicates with another basically action potential eventually hits the axon terminal step one step two calcium channels open step three as the calcium floods into the terminal it's going to tell the vesicles to release the neurotransmitters step four neurotransmitters are going to be received by the receptor in the second neuron okay guys I'm going to erase this so this is basically how one cell communicates how neurons communicate with other cells we're gonna go ahead and move on to glial cells glial cells are another type of cell found in the nervous system okay like I said cells in the nervous system include our neurons but they also include glial cells we also call them neuroglia now the CNS and the pns central nervous system of a peripheral nervous system they have different glial cells so let's take a look at CNS okay so the glial cells in the central nervous system one you have astrocytes astrocytes function is metabolic and structural support you have microglia these are going to re remove debris you have oligodendrocytes remember these make your myelin in the CNAs in your pns you're going to have Schwann cells you're not going to have these but you'll see that in a bit and number four epidermal cells you're going to have these the cover and line cavities these are kind of like a skin okay in your pns peripheral nervous system you have satellite cells which are support cells and you have Schwann cells that make your myelin instead of the oligodendrocytes you have Schwann cells now I know this is a lot to remember in my opinion there are four that are really important to remember first oligodendrocytes you have to know this that it makes myelin and the CNS and Schwann cells you absolutely have to know that this makes myelin in your pns secondly maybe remember astrocytes and satellite cell cells um and then lastly I really haven't seen this on exam but I just thought I would add it in here just in case if you want to take the time to memorize it but um these two right here okay so I have one more thing to review with you guys let me go ahead and take this down Okay so let's look at this this is the reflex arc and basically the reflex arc is from the moment that you have a sensation on your body how does it transmit an Impulse to your CNS and then how does your CNS respond to your body with the appropriate message okay so this first of all this is a cross-section of the spinal cord within the CNS and then this here is an arm this is a muscle and here this person is touching something hot accidentally touched a candle okay of the fire on the candle the first thing that's going to happen is there is a nerve in here and there are dendrites on this nerve and these dendrites are going to interpret the sensation of pain from this fire touching okay it's going to interpret that pain and it is going to send that signal up here now the end of this dendrite where it where it felt this sensation this is called the receptor receptor and this is the first part of the reflex arc so a receptor is the end of a dendrite where a stimulus is detected so stimulus or stimuli detected first thing stimuli is detected now this signal is going to go up the nerve and it's going to go towards the CNS so this sensory neuron is going to take this message over to the CNS once the sensory neuron is here in the spinal cord it's actually going to meet with a inter neuron remember this interneuron is the connection between the sensory and motor neuron three is the interneuron interneuron so the interneuron is the bridge between sensory and motor neuron okay so you can guess that what comes out of here and comes back to the body specifically the muscle what comes out of here is your motor neurons so number four is your motor neuron okay and this motor neuron is also called what efference different neuron okay this motor neuron is going to reach this muscle right here this muscle is called the effector remember an effector is something that the nerve is affecting so it can either be a muscle or a gland in this case it's your muscle so it's going to tell your muscle hey move out of the fire this thing hurts okay so this is step five the motor neuron is going to reach the effector muscle and Signal it to move so this is your reflex arc from Step One the stimulus some sort of stimulus is detected on the dendrite specifically okay in this case this person has their hand on the fire and they're like oh what's the stimulus that stimulus is going to go up into your sensory or afferent neuron it's going to go into your CNS specifically here we're looking at the spinal cord right within here it's going to reach your interneuron which is a bridge between the sensory and the motor neuron it's going to go past the bridge and then it's going to come out with the motor or efferent neuron when it comes out this motor efferent neuron is carrying a message of what should this muscle do so it's going to tell it hey contract so that you can move your hand out of the way and remember a factor number five a factor is either a muscle or a gland in this case it is a muscle okay so I just want to emphasize that your sensory and afferent neuron you have to know this okay you have to know what it does sensory or afferent neuron is sending a message towards your CNS okay what is the message here the message is that oh I just touched something something feels like fire sending a message towards your CNS your CNS is going to interpret that message and find some kind of appropriate response once it has it it's going to send out that message to your motor neurons or efferent E for exit I know some people like to use exit because it's exiting away from the CNS so your motor efferent exiting away from CNS towards the body okay you have to know that if you're going to know anything from the nervous system you have to know sensory nerves is the same as afro nerves it's sending messages towards CNS motor neurons efference sending a message away from CNS towards the body okay let's do that again sensory nerves sending messages from peripheral nervous system to the CNS motor neurons efferent sending messages from the CNS to the body okay I think that's pretty much it um I hope you learned something new and until next time

Channel: TheTutor_Geek

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Id: OxxUyP1Vw4Y

Length: 43min 34sec (2614 seconds)

Published: Tue Apr 11 2023