hey there this is concept one notes on the nervous system and these are gonna be a little bit longer in class we're gonna separate them into lots of small chunks but for the sake of the video we're gonna truck through all the slides and just know none of the other concepts are this long so just this one is gonna be a good bit of background so we cannot have a unit on control and coordination without talking about the nervous system it is our body's ultimate control center it oversees all communication among all the other systems the endocrine system also plays a huge role in control which we're going to talk about in concept 3 it's totally dedicated to that system but the nervous system is ultimately king it's ultimately in charge so in general how does it work essentially your system is specialized and designed to take in sensory input to receive stimuli via millions of sensory receptors you have throughout your body to integrate those stimuli so to process the input what's being input into your body and decide what should be done and then figure out how to respond a motor output output it's gonna activate some effector organs or some structures in your body that will then cause some sort of response and these kind of words like effector organ and response and stimuli are all terms we talked about in unit 1 concept 2 when we reviewed homeostasis and feedback loops from biology 1 so if those are terms you don't remember go back and watch the unit 1 concept 2 video just to refresh your memory so what do I mean by all this these are kind of maybe some fancy terms for something that's really simple so let's say you're driving and you see a red light so what you're seeing that's a sensory input that light is a visual stimuli or stimulus excuse me your nervous system then processes what you saw that's the integration portion and then tells your foot the effector organ to do this motor output to hit the brake pedal and now it's obviously a bit more complicated than that but this is the general 3-step process that your nervous system uses in order to control and coordinate everything going down in your body so structurally what's the foundation here your nervous system is made of your nervous tissue which we talked about in unit 1 concept 3 which you can go back and review but well God will dive into a bit now and your nervous tissue is densely packed with two types of cells we have your neurons which are also known as your nerve cells and these are excitable cells they respond to stimuli by conducting impulses in order to transmit signals so these are our communication cells they're so important but our nerve cells are actually only 10% of our nervous tissue the other 90% are the neuroglia or the glial cells so these are supportive cells they're providing nutrition insulation and they're just helping with the overall signal transmission process and you can see some of them picture here so one of the things we're gonna pause and do in class is this research and report activity where we're gonna learn about all these different neuroglia or these glia cells that support the neurons and that make up 90% of our nervous tissue but we're gonna keep trucking through so let's talk more about neurons other than that research and report about the neuroglia the rest of our all the rest of our energy is focused on the neuron even though it's only 10% of nervous tissue this is our conduction structure so we need to know how it works so all neurons these are their parts they have a soma or the cell body that's kind of this oval structure here this is the life-support of the neuron it has the nucleus in it and then most of the other organelles like a lot of mitochondria so think why would it make sense that we a lot of mitochondria well we need a lot of energy to conduct these nerve impulses another term to tell you is ganglion this is just a collection of cell bodies from multiple neurons that can be located in the body not just in the brain or say this spinal cord so anytime there's a group of cell bodies we refer to that as a ganglion all right then extending from the cell body are processes so they're just these extensions and there's different types of processes we have the dendrites which we see here these are the receptors of signals this is what we would refer to as our input region and this is different from the axon which is what's actually generating and transmitting the nerve impulse this is our conducting region of the neuron or the sending region it's also can be referred to a long axon can be referred to as a nerve fiber um nerves in general are just when we can't talk about your nerves we're just talking about bundles of axons that extend from the brain in the spinal cord to the rest of the body and we'll talk about them a little bit more at the end of this concept a couple of fun of facts about neurons they are some of the longest-lived meaning the oldest cells in your body so it's important that you have proper nutrition in care because your neurons can last your entire lifetime because of this though that also means that they're irreplaceable they're labeled as amniotic which means that that once they've specialized and become the nerve cell they can no longer do mitosis and divide so nerve cells don't replicate and make more nerve cells so if one gets damaged it's damaged for good they're not constantly regenerating like say your bone cells do and so this is really important it's when we said we talked about brain damage or nerve cell damage it's significant because it's not something that can easily be repaired or regenerated and then another interesting thing is how much energy your neurons require they have a very high metabolic rate so they need a car in supply of glucose and oxygen and that's why cells like your neuroglia are so important because they're providing that for your neurons actually about 1/4 of your daily food intake goes to the activity of your neurons and their signal transmission so that's pretty cool so they're kind of important all right let's talk more about some of these structures so the end of the axon we have these axon terminals this is where neurotransmitters are released in synapses when a nerve impulse is received and this is called the secretory region so this is where we actually send out the signal now something that helps with conducting the impulse or conducting the signal is something called the myelin sheath so myelin actually wraps around our axon here and it protects and electrically insulates them and that helps in increasing the speed of nerve impulse transmission now these their communities little unmyelinated gaps between the myelin sheath and these also increase the velocity of nerve signal conduction something called saltatory conduction is where net nerve impulses jump between the nodes of ranvier and then that can increase the speed of the impulse so this might sound a little bit confusing but it's gonna make more sense as we dive more into the details of how this structure actually allows the nerve impulse to be conducted and what a synapse is and all these things we will get to it for now we're still just talking about our neurons and let's now talk about how we can classify them so neurons can be classified first by their structural differences and basically that's just looking at the number of processes or extensions that are coming out of the cell body so a multipolar neuron means it has more than three processes so it has one accent on and then two or more dendrites as we can see in this picture here 99% of our neurons are Molter multipolar and why does that make sense that we would want most of our neurons to be multipolar well what do you know you remember structure dictates function neurons are communication cells so the more processes we have the more sensory input we can take in and then send out so we want to be able to take in a lot of info and then output a lot of info and so that's why the majority of neurons are multi polar but there are other types too for instance bipolar these only have two processes so one axon and one dendrite and they're on opposite ends of the cell as we can see here so here are dendrites the arrows showing the direction that the nerve signal would be traveling so inputting information through these dendrites going through the cell body down the axon and then through the axon terminals and then these are rare well there's only a few special sense organs that tend to be bipolar which we'll talk about and concept to and then last is unipolar there's just one process it's dividing from the cell body like a teen and so that's what we see here information would come in and then go out that's a unipolar neuron we find this in the ganglia which is just a group of sensory neurons their cell bodies in the peripheral nervous system which we'll talk about and so again think about sensory receptors why would we only need unipolar while they're taking in sensory stimuli and just sending it one direction straight to your central nervous system meaning your brain in your spinal cord to be processed so we don't need to take in information and send it to a bunch of different from multiple sent into multiple places because we're just trying to direct it one way so that's usually why a unipolar one would make sense now we can also classify neurons functionally meaning based on what they're doing the way the impulse travels through the neuron with regards to the brain and spine so this picture is gonna help us see the difference between these three classifications of that so first we have sensory neurons which we see here these are also known as afferent neurons they transmit info from sensory receptors to our central nervous system that's what CNS stands for so to our brain and spinal cord so that's what we can see in this picture so for instance you ever scepters sensory receptors in your fingers that if you touch something sharp they're gonna send that signal that's that's from that stimuli through a sensory neuron to your brain and spinal cord that's where we're trying to go I always think afferent for arriving so or taking in information most of these are structurally unipolar because they're just taking in going one way that's it another type are our motor neurons so these are the efferent neurons I think II for exiting so they're sending something out we're transporting info then that's been processed from the central nervous system meaning your brain and spinal cord just to the rest of the body to get that motor output we talked about in the first slide so most of these are structurally molt's structurally multipolar so they can send that impulse to multiple places maybe to get multiple effector organs working together for some response now between the sensory neurons and the motor neurons there can be these inter neurons or these Association neurons these are in your central nervous system so in your brain and spinal cord and they transport in fro from the sensory neurons to motor neurons so they're just kind of working in between here like we can see most of these are structurally multipolar because they're gonna be taking in from multiple places and sending out multiple places alright that was a good bit of background info on the structure and all of that of a neuron now we're going to stop and do one the most important to these of this entire unit and we're gonna look at neurons and how they actually communicate and transmit signals so this is super important in order to shorten the notes I put this more in an activity form so this is this doing this activity is in replace and replacement of notes and it's super important that you get everything from it so pay good attention to that for now we're gonna move on so let's look big picture how is our nervous system organized well it's actually kind of complicated first we divide it and we can basically divide into two broad categories you your central nervous system your CNS which I've been referring to a lot that's your brain in spinal cord and then your peripheral nervous system or pns which is everything else now this can get divided up in just so many smaller sections we have the sensory division or the afferent division of that and then we have the motor or the efferent division of that so what's taking in and then what's basically spitting out that motor division can be divided into the somatic and autonomic nervous systems based on if we're causing voluntary or involuntary movements responses and then that autonomic can be further divided into parasympathetic and sympathetic so we're gonna kind of go through each one of these and talk about the characteristics that define each one all right so two main divisions of the overall nervous system like we said the central and the peripheral nervous systems central nervous system is your brain and your spinal cord this is our integration and control center peripheral nervous system The Pianist is your spinal and your cranial nerves that are all throughout your body and this is really the communication sister system between the CNS and the rest of the body so this is what's doing you know transmitting that information from our what we are taking in through sensory organs and then we're out putting through effector organs alright let's talk a bit more about the CNS let's kind of break down the important structures of the CNS well we have the brain in the spinal cord we're gonna spend most of our conversation talking about the brain so how is this delicate and very important brain that is your control center protected while younger skull which we talked about in the skeletal system and unit 2 but then you also have these tissues that's which I mentioned in unit 1 when we first learned about histology that's around the brain and these layers of tissue our meninges and then there's also this cerebrospinal fluid that the brain floats in that cushions the brain from injury you have these ventricles in your brain which we'll look at when we dissect sheep brains which are holla'd fluid fill hollow fluid filled cavities that contain choroid plexus which makes this cerebrospinal fluid that the brain is floating in some fun facts about your brain it's actually the best way to describe its consistency would be to compare it to tofu which is a little gross if you ever had to tofu you may never look at it the same again another thing that's pretty interesting is your brain isn't fully developed until we've gone through puberty especially your frontal lobe which is critical for our ability to make decisions and judgment and so if anyone's ever told you as a high schooler that you're a terrible decision maker or you have poor judgment just blame it on you're not fully developed frontal lobe yet it's not your fault you can't help that your brains not fully developed other fun fact your brain ease is 20% of the oxygen in our bodies and like I said earlier a fourth of the glucose that your body's taking in because it requires it has a really high metabolic rate it needs a lot of fuel and also an adult brain weighs about three pounds so that's pretty heavy that's pretty pretty intense and pretty fascinating alright if we were gonna look at the brain as a whole we would divide it basically into three main parts the cerebrum the cerebellum and the brain stem the cerebrum is the largest part of your brain it's all of these colored sections I have here so one way of looking at your cerebrum is um as left and right hemispheres each hemisphere controls the opposite side of the body so your right hemisphere is actually controlling your left side and vice versa your left hemisphere is more known for regulating things like speech and logic and sequence comprehension math and writing whereas your right hemisphere is associated with creativity in or being artistic in your imagination and your intuition and musical abilities so if anyone's ever said I'm more left brain or more right brain that's kind of what they're referring to there but another way we divide the brain is how we see pictured here excuse me how we do the cerebrum is always see here which is looking at the four lobes so the frontal the period all the occiput all in the temporal lobes and we can even further subdivide these into smaller sections based on their individual functions which we're not going to get into here are some of the things this part of your brain does it's a bunch and then the surface is referred to as the cerebral cortex and we see these different folds at the brain and those are there to increase the surface area of the brain and then we can also subdivide the cerebral cortex in just three functional areas the motor areas the sensory areas and the association area so there's a bunch of different ways we can subdivide the brain and look at all the intricacies of it but we're gonna really look at the four lobes mainly when we do our little project on this our group project which I'll talk about later alright so that's 80% of your brain right there is a cerebrum now let's talk about the cerebellum this is under your cerebrum you can see it there it has roles related to maintaining posture and balance coordinating timing and pattern so that all of your subconscious movements are smooth and agile you're not having to think too much about them this is about 11% of your brains mass and then the rest is your brain stem so this is that the base of your cerebrum and anterior to the cerebellum has three parts the medulla oblongata the midbrain and the pons which we'll be able to see pretty clearly when we do our sheep brain dissection and it's basically relaying info between the rest of the brain and the spinal cord so that's kind of the brain stones role there because that would be connecting to the spinal cord which is the other main component of the central nervous system and it's coordinating a lot of our automatic functions like breathing circulation your body temperature your sleep weight cycle digestion swallowing all of that stuff alright so we're gonna stop it in class and do a project where we're gonna dive into each of these parts closer and we're going to do a sheep dissection all that but again for now we're gonna keep powering through so we talked about the central nervous system now we're gonna focus our attention on the peripheral nervous system so functionally we subdivide the peripheral nervous system into its sensory or afferent division which consists of its sensory nerve fibers remember I told you earlier afferent I think of arriving with the a but really it means afferent means to carry towards so think it's taking in information it's the sensory input division we're receiving sensory stimuli and we're sending that back to our CNS aka the brain in our CNS essentially in order to integrate it you have somatic sensory fibers that carry in fro from your skin your skeletal muscles and your joints and then you also have visceral sensory fibers that are carrying in fro from the visceral organs then we have the motor or the efferent division these consists mainly a motor nerve fibers that are sending out information effort means to carry away I think II for exiting so it's sending out information for that motor output so it's say key information from your brain and it's sending it to affect your organs like your muscles so that they'll contract or your glands so that they'll secrete a hormone or something like that we're gonna come back to the sensory division we're actually going to talk about it at the end of the notes as a way to kind of transition into concept to which we're going to talk about your organs that are specifically specialized for your senses and taking in sensory stimuli but for now we're going to keep subdividing the motor division so two parts of your peripheral nervous systems motor or efferent division the somatic which are consists of somatic motor nerve fibers these are conducting impulses from your central nervous system to your skeletal muscles specifically we talked about these in unit 2 we talked about movement and muscle contractions because they control our voluntary movements the autonomic nervous system your visceral motor nerve fibers these are conducting impulses from your central nervous system to your smooth muscles your cardiac muscles and your glands so they're controlling our involuntary movements like your heart beating or your lungs taking in oxygen or your stomach digesting basically just the places where your cardiac and smooth muscles are so now we're going to talk a bit more about that somatic nervous system this should be a review a lot of this from unit 2 we talked about the muscular system and muscular contractions so again we're in the peripheral nervous system we're in the motor efferent division we're talking about the somatic nervous system within that so your somatic motor nerve fibers they innervate skeletal muscles and that's how they control voluntary movements so the neurons cell body this part is starting in the central nervous system and then the axon is extending all the way to the skeletal muscle it affects so these can be some of your longest axons in your entire body now we utilize a neurotransmitter called acetylcholine which is ACH that's what's released from the axon terminals into the synapse and a neuromuscular Junction in order to stimulate muscle contractions so this is a diagram we looked at in unit 2 just I pulled it up again just to refresh our memories so nerve impulses gets it sent down the neurons axon into a neuromuscular Junction which we have zoomed in on here you can see acetylcholine being released into the synaptic cleft in order to stimulate the receptors basically to receive it and then cause a muscle contraction the acetylcholine binds receptors on the skeletal muscle cell which then transmits the AP the action potential that's a term we learned in our inquiry activity to then initiate the muscle contraction which we can see zoomed out here going on at the muscle cell all right now other side of this so those are our voluntary movements moving controlling the skeletal muscles that do voluntary movements now I want to talk about the involuntary the subconscious thing that's your autonomic nervous system so we're in the peripheral if we're still doing motor output but we're talking about the involuntary motor output that's the autonomic nervous system your muscle fibers are innervating cardiac and smooth muscles as well as glands to control involuntary movements and instead of just having one really long neuron these actually they're this system utilizes a two neuron chain to connect the central nervous system to the effector organs all over the body so the first neuron cell body starts in the CNS and then it's gonna synapse with a second neuron that's going to extend into whatever effector organ that we're having an effect on now so that we would refer to the first neuron as its axon as the preganglionic axon and then this one is the postganglionic axon and what neurotransmitters are released in this synapse well nono reppin Efrain is you or any is released by the sympathetic nervous system and then acetylcholine is released in the parasympathetic and both of these neurotransmitters can be stimulatory or excitatory or inhibitory and so we'll talk about both of those in a second so now we're gonna further subdivide our autonomic nervous system into that sympathetic and the parasympathetic so the parasympathetic division in the sympathetic division so parasympathetic these are your cranial sacral nerves meaning if you are gonna look at your vertebral or your spinal column which is part of the skeletal system we talked funny unit two we're talking about nerves that are extending from the base of your brain or just above your tailbone okay so that's kind of the two locations they are if I go back to this picture you can see them here so they're coming out from this area or this area of your spinal cord the ganglia are far from the spinal cord they're actually right next to or inside your effector organs and this division specializes in calming you down it's going to do the opposite of everything that our sympathetic division does so look at the sympathetic division these are our thoracolumbar nurse oh they start between our thoracic and lumbar vertebrae so if we go back to this picture they're all in the middle here those are some of that in herbs and the ganglia are in the spinal cord and then they send signals far distances to effector organs and VistaVision is responsible for exciting you are amping you up so these work in opposition to one another when one's working usually the other ones not working there or they're opposing each other and vice versa alright so let's talk about that parasympathetic division first so this is your rest in your die just division some people refer to it as the d division think digestant gen defecation and in diuresis which is just your urination this is the second that's just maintaining your body's involuntary functions and conserving energy for later the way this is set up is to communicate to one effector or again at a time so if we look at some of the nerves we're just gonna constrict the airway or we're just gonna slow the heartbeat or just gonna stimulate activity of the stomach that kind of thing the preganglionic acts all our cells are longer than the postganglionic so we remember we went back here we said the autonomic division has these two neurons that work together so this one would be longer than the other the autonomic our excuse me the parasympathetic division uses no repin Efrain that's any and hormones in order to stimulate and inhibit whatever signals were trying to pass along just a reminder neurotransmitters are just chemicals released from neurons to cross synapses neurotransmitters and hormones can be actually the same chemical a neurotransmitter is just being released from a neuron and a hormones being released from a gland so that's kind of the difference there there we go didn't forgot I had that typed in there so an example note RepA nephron is a chemical that can act as a neurotransmitter when it's released from a neuron but it can also act as a hormone when is released from a gland into our blood again we'll talk more about hormones and concept three okay so a lot of info in class we're gonna stop now and talk more about neurotransmitters and drugs and the process of addiction but again we got to keep powering through these myths for a get closer yell okay last subdivision of the motor efferent division is a sympathetic this is known for your fight-or-flight some people refer to this as the e division because it controls exercise excitement emergency and embarrassment so all these things that would maybe send your body into fight-or-flight it is set up in a way that one stress signal when we send a response out to multiple effector organs at once so we're not just gonna signal your heart to beat faster we're gonna signal your heart to beat faster and your eyes to dilate and your saliva to you know to stop and your sweat to increase that kind of thing all at once it's focusing on what your body needs to do right now to survive not long term maintenance and energy conservation like the parasympathetic those preganglionic cells are shorter than the postganglionic and it's going to use norepinephrine and hormones for stimulation and inhibition as well and again it works antagonistically to the sympathetic division so it's usually doing the opposite but they can actually work together cooperatively so an example of how they work together cooperatively cooperatively is during sex so your parasympathetic division stimulate the dilation of blood vessels during sexual assignment in external genitalia so in females that's the clitoris and then males that's an erection in the penis while the sympathetic this division is stimulating and causing the ejaculation of semen and reflex contractions in the vagina so they're working together to do that process all at once now what I really want to talk to you about though is stress we're gonna do a pilot class and learn a bit more about how your body responds stress both short-term stressors things that might just excite your body in a fight-or-flight real quick and then also like the long-term impact of continual stress on the body kind of what that looks like but again gotta keep truckin so we've done the central nervous system we've done all the motor afferent division of the peripheral now we're going back to that sensory afferent division all right where we're taking in stimuli so this division has sensory nerve receptors that take in stimuli from our physical environments and then send those to the brain to interpret and respond to or to do that integration part that we talked about in the very first slide receptors can be classified by the type of stimulus that's going to activate the receptor so here's a picture of a pictures of a bunch of different kinds we have mechanoreceptors these are ones that respond to mechanical force like vibrations which we'll see in the ear pressure stretching touching that kind of thing these are gonna eventually take it mechanical force mechanical energy and then convert it to electrical energy those action potentials that'll send it up to the CNS to be processed thermo receptors respond to a change in temperature so they'll take in thermal energy and convert it to electrical photoreceptors respond to light stimuli and they're gonna take in electromagnetic waves and convert that electromagnetic energy into electrical energy those are rods and cones we'll talk about those in concept to chemo receptors are taking in chemicals this is how your taste and your sense of smell work they're gonna convert that chemical energy into that electrical energy to send an action potential and then nociceptors are specific receptors for pain now how does this generally work to summarize it you have some sort of stimulus it gets received by one of those types of receptors and then it's gonna transmit that information through nerves to your spinal cord and then to your brain which is all under this sensory division that we're referring to it can also trigger action potentials that send signals then to your motor division to immediately cause in motor output and this is called a reflex so a reflex is just an automatic reaction to stimuli or one stimuli as a stimulus every flux can be innate or intrinsic meaning it's a rapid and predictable motor response to a startling stimulus such as you step on something sharp you just lift your foot that's an innate thing I have a one-year-old son when he steps on something sharp in our backyard he doesn't he didn't have to learn to lift his foot his foot just automatically lifts off of it because it hurts I can also be a learned or acquired reflex so a response resulting from practice repetition or experience so for instance when you started learning how to drive you learned when you need to start pressing the brake pedal when you see a stop sign ahead that's a learned reflex now you may drive from your house to school and you just school and be like I don't even remember driving here because you had these learned and a reflexes that helped you press the gas pedal when you need to and press the brake pedal when you needed to to get to school so reflexes occur over a highly specific neural pathway and we call these reflex arcs so this automatic response it's not just a simple thing it mean it's a pretty amazing specialized process and every reflex arc has five essential components there has to be the receptor which is the site that the stimulus arrives to there's going to be a sensory neuron there that can then transmit that impulse from your peripheral nervous system to your central so the spinal cord in the brain there's your integration Center which is going to decode the signal out of synapse or at multiple synapses if though if there are multiple so that's integration centers in your CNS then you have your motor neuron and remember there can be Association neurons in here or inter neurons then your motor neuron is going to conduct the impulse to an effector Oregon Oregon that's get then gonna have the effect it's gonna respond by saying doing something like contracting if it's a muscle cell or secreting if it's a gland so let's talk these some examples because this sounds way more complicated than it actually is alright to look at this picture let's see what's going on in this scenario alright let's identify each of the five parts so first we have to have our receptor we have our sensory receptors in your skin they would this that would respond the pain of this thorns they be nociceptors if they're responding to pain alright so that's our first component then we've got this sensory neuron that's gonna send a nerve impulse from the nosey scepter to the spinal cord where it's gonna then be so the here's part of our spinal cord it'll relay that sensation in the brain then this is where the integration is going down right here and our CNS to figure out what do we need to do with this signal then we have a motor neuron that's gonna extend from the central nervous system in our pianist our peripheral nervous system to have a response signal conducted down this motor neuron to whatever our effector organ is so in this case our effector organ is your muscle tissue or the muscle cells and that muscle tissue it's gonna tell that muscle to contract so then you move your hand away from the sharp object alright that's how that reflex is happening fun fact about pain by the way we all actually have the same pain threshold meaning the C point where our stimulus is strong enough to then trigger an action potential in those nociceptors but we all have different tolerances or perceptions for the discomfort that that pain produces so that's kind of an interesting effect alright let's look at one more let's look at another picture and see how if we can interpret it and look for the five components okay so what's our receptor what's receiving the stimulus here well sensory receptors and your patellar ligament right here and your knee are stimulated when they get hit by the reflex hammer so this is going to be a mechanical force this would be some sort of mechanoreceptor then there's going to be a sensory nerve on that is going to senator of impulse from this receptor to your spinal cord that signal gets decoded and your central nervous system that's your integration center then we've got the motor neuron that's going to output that information and send the response signal and it looks like it's in this picture sending that to your quads and your hamstrings and then our those are the effector organs and then what's the effect going to be we can see here right here you contract your leg muscle and to respond to that stimulus all right now these last three slides are just for my honor students if you're not in my honors class you can pause now you are done with concept one but for my honor students I want to talk a little bit more about some of these nerves so a reminder nerve is just a bundle of axons in your peripheral nervous system and they mean they can be classified as cranial if they're arising in your brain or spinal if they're arising in your spinal cord so you have 12 pairs of cranial nerves in your peripheral nervous system that are associated with the brain and then 31 pairs of spinal nerves in your peripheral nervous system that are associated with your spinal cord so all the cranial nerves are serving your head and neck structures except for the vagus nerves which they go all the way your abdomen which is kind of crazy and then your spinal nerves are serving all the other parts of your body other than your head in some parts of your neck so honors I want you to know the 12 cranial nerves so here's what I want you to know I want you to know their classification are they sensory or afferent nerves meaning they're carrying impulses only to the CNS are they motor or efferent nerves meaning they're carrying impulses only away from the CNS or can are they both can they can do they have commode sensory and motor nerve fibers that can transmit impulses both directions alright so we're gonna talk about each one now really quickly and you're gonna label them in your chart in your notes so the olfactory nerve is a sensory nerve it's then sent info from your nose to your brains only going towards your CNS your optic nerve is a sensory nerve as well it's just gonna do this with your eyes so it's gonna send visual info from your eyes to your brain your oculomotor nerve is a motor neuron so it's gonna send info away from your brain it controls the movement of four out of six by muscles as well as your pupils response to light if they're gonna dilate or not your trochlear nerve it's a motor neuron as well it's controlling the movement of one of those six eye muscles both of the else you'll see a picture of this and our concept e-notes the trigeminal nerve is a both it's sensory and motor it is the largest nerve it has three main branches that innervate your face and jaw muscles so they it takes in sensor info and is also motor the abducens nerve is a motor one it controls movement for that other eye muscle you might be wondering why they're going in this order because they are numbered so this is the sixth one so you're like why don't you just put the eye ones together because I'm putting them in the numerical order that they are numbered as all right elastic the facial nerve does both it operates muscles for most of our facial expressions your taste buds salivating blinking and then it sends and so also from our outer ear into the brain your vestibulocochlear nerve is a sensory nerve it's an auditory info from your cochlea to your brain and is really important for hearing and balance your glossop pharyngeal nerve does both it is related to sensations to taste swallowing and sending sensory info from the sinuses in your face to your brain your vagus nerve is your longest earner this one's crazy this one goes all the way to your abdomen and it controls mainly your heart and your digestive tract your accessory nerve is a motor one it controls the muscles and your neck and then the hypoglossal nerve is a motor one that controls most of the muscles in your tongues that you can swallow and talk and that is the longest notes I think we will ever have you did it that's concept one