hey everyone welcome to professor long lectures in anatomy and physiology this video is the last in a series of the nervous system for my lecture test five for my 24:01 or for 20mp students we've gone over brain structure and function in the last video which parts of the brain control which things we barely scratched the surface on it you know I try to give you a basic fundamental idea we like I said we could spend a whole in two years talking about the brain alone it's so incredibly diverse and amazing in all the functions and how it works we're still figuring it all out now what we need to do is we need to do the 12 pairs of cranial nerves as you know there's 12 pairs of nerves coming off the brain 12 on the right 12 on the left and those nerves each have specific functions now one of the things you're going to learn when we get to the spinal cord is that all spinal nerves are mixed nerves what that means is one spinal nerve has axons going out motor neurons going out to muscles and sensory neurons coming into the same nerve so every spinal nerve is a two-way street both sensory and motor in the same nerve when it comes to the cranial nerves some of the cranial nerves are in almost entirely sensory they only have sensory neurons coming in some of the cranial nerves are almost entirely motor only motor commands coming out and some of them are a mix okay now we're gonna go down page 79 we're just simply gonna go down the list I'm not even to write all this out I will only write on the board on a couple of these to show you some detailed information the olfactory nervous cranial nerve number one you should always know the Roman numeral they're written in the note set you got to learn the Roman numerals if you never learned them and you need to know the name of the nerve the olfactory nervous cranial nerve number one and it is almost entirely sensory it does the sensible Faction the sense of smell that connects your nose into your brain and then up to your temporal lobe where we can interpret smells the optic nerve cranial nerve number two is almost entirely sensory as well all the neurons coming from your eyeball from your red go in through the optic nerves cross at the optic chiasm and back to the visual cortex so it's all a vision if you cut the optic nerves your eyeball would not be able to communicate to your brain and you would be blinded okay no oculomotor tells you ocular eyeball and motor movement it moves your eyeball um and in particular the oculomotor nerve not only moves your eyeball but it can control your eyelids for blinking and opening and closing your eyes and it controls pupil diameter the nerves going to do pupil to constrict and dilate your pupil all go through the oculomotor nerve so the oculomotor nerve can move your eyeball it can help you blink and open your eyes and close your eyelids and constricts and dilates cranial nerve number four has the trochlear nerve the trochlear nerve is also going to control your eyeball and does eyeball movement and it gets its name for the fact that it has it controls a muscle that loops through a little pulley or trochlea and pulls on your eyeball so they give it gets the name for that function um the trigeminal nerve the trigeminal nerve gets its name because it has three bodies is the trigeminal nerve is cranial nerve number five Roman numeral five for trigeminal the the base of the nerve comes off of the sides of the pons and that has three branches three major branches and if you look at it it really kind of goes along with the person's face like this one of the branches of the trigeminal nerve is called the ophthalmic branch well you know ophthalmologists is an eye doctor so the ophthalmic branch kind of monitors that sensory part of your face or your yeah I'm sorry yeah well does the sensations from like the scalp area down to about your eyeball so something if something's brushing your fore those sensations are going to go in through the trigeminal nerve okay this branch is going to go to a part of your body where these bones called the maxillary bones are so that's called the maxillary branch the maxillary branch of the ophthalmic nerve I'm sorry that the trigeminal nerve is going to monitor sensations from your face from about your upper lip all the way up to about your eyeballs so most of this area here if you cut that nerve you would be extremely numb in this part of your face and then the last one is called the mandibular branch because it goes to where your mandible is so the mandibular branch is going to monitor the area of your face all around where your chin or your mandible are they can also monitor sensations from your teeth and part of your tongue okay so those are sensory information going into your brain now there is a motor function for the trigeminal nerve and one of the motor functions is it controls the muscles of mastication to masticate means to chew so the motor function of this nerve is to control chewing okay mastication that's your trigeminal nerve it's mixed it does both sensory from these parts of the face these three branches and then it does motor from mastication by the way if you go to the dentist and they're shooting up your your jaw to numb you up they're trying to numb part of the mandibular branch okay all right the next nerve is called the abducens nerve and if you look at the name the name should tell you something so we erase all of this and let's look at the name and then I'm going to go back and talk about something else abducens gets its names from the word abduct okay the abducens nerves if this is your eyeball and somebody's pupil they're looking in this direction we're gonna have a series of muscles on the eyeball if you were looking at someone's right eyeball looking in that direction there's a muscle out here on the side called the lateral rectus when this nerve fires on the lateral this muscle and make sure eyeball abduct or move away from midline so there's another nerve that pulls on your eye this way and loops through a little piece of connective tissue at this called the trochlea and so this muscle is called a superior oblique the abducens coat controls the lateral rectus muscle of your eyeball now we haven't learned the eye muscles we do that in part two but nonetheless this is called the trochlear nerve oops didn't spell that very well the trochlear nerve so the abducens nerve is cranial nerve 6 the trochlear nerve is cranial nerve 4 and it's going to control a muscle called the superior oblique muscle this muscle helps rotate the eye a little bit when we look in a certain direction there are 5 or 4 other muscles that control your eyeball there's a medial rectus a superior and inferior rectus superior rectus makes you look up inferior rectus makes you look down the medial reptile would make you look across the midline all the other nerves are controlled by training ulnar 3 the oculomotor nerve okay so the oculomotor nerve controls to all my muscles except these tube the superior oblique and the lateral rectus the superior oblique is controlled by the trochlear nerve because that muscle goes through a Trillium and the abducens nerve controls the lateral rectus which would abduct your eyeball so eyeball movement must be extremely important for finding predators finding food and finding mates for survival and reproduction because we have 25% or 3 of the 12 cranial nerves dedicated for eyeball movement okay now the facial nerve is the next nerve so I'm gonna erase all this I'm gonna talk about the facial nerve the facial nerve helps you make faces okay it's also sensor it's a mixed nerve so when we look at the human tongue if this is anterior and this is posterior this is your tongue sticking out this is the back of the tongue if we divided the talc into three regions then cranial nerve number seven the sensations from the anterior two-thirds of the tongue and if you taste things like if I asked you to close your eyes and I put some lemon juice on your tongue you go you would make a face so cranial nerve number seven not only monitors the anterior two-thirds of your tongue it controls all the muscles for facial expression got it so anterior two-thirds of the tongue for sensory and motor is the facial expression cranial nerve number eight is called the vestibulocochlear nerve to the studio cochlear nerve goes by three names the most accurate name is vestibular cochlear this nerve goes to a part of your inner ear called the vestibule which monitors our equilibrium and the cochlea which all monitors hearing but it is also called the auditory nerve audition is hearing it's also called the acoustic nerve so it goes by all three names vestibular cochlea auditory or acoustic nerve it is primarily sensory for hearing and equilibrium okay you damaged that nerve you feel dizzy you can't hear or both cranial nerve number nine is called the glossopharyngeal nerve the pharynx is the upper part of your throat and glossa means tone and this nerve controls a part of your swallowing muscles and your salivary glands so it's going to control movement of your some of the muscles in the pharynx for swallowing and saliva production it also does the posterior one-third of your tongue taste and sensation okay so seven is the front of the tongue nine is the back of the top okay the vagus nerve cranial nerve number 10 gets its name because it wanders Vegas means to wander and that is one of the few cranial nerves that wanders down into the thoracic cavity and it controls some of your viscera and it can alter heart rate and breathing rate it can control a lot of the structures involved in breathing and heart rate and some of our digestive function so the vagus nerve actually has a lot of control autonomic control of the ventral body cavity viscera part of its sensory by the way as it does sensations of trunk position like if you're swinging a baseball bat that proprioception that sensation the idea of where is your chest and your body position if you're swinging back and then as you're swinging through if you need to make adjustments it's doing sensations from the from the positioning of your chest muscles called the proprioception of the trunk spinal accessory nerve also simply called the accessory nerve is cranial nerve number 11 that one controls a lot of throat muscles for swallowing as well and then the hypoglossal nerve number 12 hypo means below and glossa means tongue the hypoglossal nerve will move your tongue for a speech so when you're speaking you have to move your tongue to help you make to alter the sounds that you're making and help you form some of the words it also does some sensory from some of those muscles involved in speaking so number one olfaction smell - optic vision 3 oculomotor moves your eyeballs all the iBall muscles except for our two of them number four trochlea controls one of your eyeball muscles for movement five is trigeminal the trigeminal is the motor part is chewing mastication and the sensory part is the three branches going to your face thalmic maxillary and mandibular branch four sensations from the surface of the face the abducens nervous cranial nerve number six it controls one of the eyeball muscles for movement abduct your eye facial nerve cranial nerve number seven is going to do taste from the anterior two-thirds of your tongue and the muscle a facial expression cranial nerve number eight the vestibulocochlear nerve does hearing an equilibrium also called the auditory nerve in the acoustic nerve because the hearing part that leads out the equilibrium cranial nerve number nine glossopharyngeal is going to do part of your pharynx and part of your tongue for swallowing and saliva and the sensations from the posterior 130-year tongue cranial nerve number 10 is the vagus nerve the vagus nerve controls a lot of the viscera and the ventral body cavity cranial nerve 11 would be spinal accessory and that nerve is going to move a lot of throat muscles involved in swallowing and actually a little bit of some of your neck muscles as well but don't worry about that and the hypoglossal nerve number 12 is going to move your tongue for speech okay so those are the 12 pairs of cranial nerves there will be some questions on a quiz about those our last nervous system quiz is going to involve these last two videos all the brain structures and functions and the 12 pairs of cranial nerves so I hope this was helpful I hope you learned something I hope you had as much fun as I did all right listen guys hang in tight and keep pushing we're almost done I know we don't have a lot of time but the college did extend the semester up to two weeks and we're going to bleed into some of that those of you that have made master courses I'm sorry I don't know what else to do but we've gotta finish this stuff and finish off this semester it's an unfortunate set of circumstances but we're gonna do the best we can you and I together so you know if you're having issues contact me we'll try to work through them but keep plugging keep pushing work as hard as you can and do the best you can alright thanks for watching again I hope you have as much fun as I did see you guys on the flip side