okay class welcome to the language of medicine we're going to do chapter 10 the nervous system so a lot of good information again um don't get overwhelmed uh it is just medical terminology i won't ask you on the real specifics of the nervous system but it is i love the nervous system just like the muscular system uh the respiratory system cardiovascular system a lot of good information let's uh look at the chapter goals dame locate and describe major organs of the nervous system and their functions learn nervous system combining forms and use them with suffixes and prefixes define pathological conditions affecting the nervous system uh describe nervous system-related lab tests clinical procedures abbreviations apply your new knowledge to understanding medical terms so again the nervous system complex 10 billion nerve cells allows for voluntary and involuntary functions it carries electrical messages and it has external and internal receptors the nerve cells are called neurons they're very microscopic they're collected into macroscopic nerves they carry electrical messages all over the body so internal external stimuli activate the cell membranes to release stored electrical energy called the nervous impulse external internal receptors receive and transmit these impulses to the brain and spinal cord which is and collectively called the central nervous system the central nervous system then recognizes interprets and relays impulses to other nerve cells that extend through parts of the body such as the muscles the glands and the organs so here's a good breakdown of the two major divisions you have the central nervous system which is your brain and your spinal cord then you have the peripheral nervous system which is your cranial nerves your spinal nerves your plexes such as the brachial plexus and then peripheral nerves throughout the body like l1 l2 l3 l4 so the cranial nerves carry electrical impulses between the brain and the head and the neck spinal nerves carry impulses between the spinal cord and the chest abdomen and your arms and legs cranial and spinal nerves sensory nerves carry messages toward the brain then motor nerves carry messages from the brain and some of them have a mixed nerves carrying both sensory and motor nerves now i'm sure you've heard of fight or flight or rest or digest and you've also heard of the autonomic nervous system so the autonomic nervous system carries impulses from the central nervous system to your organs sympathetic which is your fight or flight nerves stimulate the body under stress so if you see a bear you're going to either fight that bear or you're going to run away from that bear parasympathetic nerves balance the sympathetic system so what do they do they slow down the heart rate they lower your blood sugar so that's called the rest and digest system right because after you eat you want to rest you want to digest your food when you're if you're being chased by a bear you're not really thinking of being digestion or resting okay so that's different so when you see a bear think okay what are you going to get you're going to get dilated pupils you can get rapid heart rate right but you don't have time to pee and poop so parasympathetic is when you pee and poop so the autonomic nervous system contains a large number of nerves that function automatically it controls the heart the blood vessels the glands involuntary muscles like the intestines and hollow organs such as the stomach and urinary bladder so sometimes whether it's athletes or some people they're always in a sympathetic state they just can't rest and digest they can't slow their heart rate down that's the they can't lower their blood pressure they're always uh what we call it type one and they're just uptight and it's very difficult a lot of anxiety uh very difficult probably when you guys take the exams you your sympathetic system's on fire right your people's dilate your heart rate you're like oh man um so that that's involuntary right your body response so our goal is to tell the sympathetic system to say hey buddy chill it's okay it's only a test don't worry until the parasympathetic system say slow down right so here's a good review central nervous system brain spinal cord the peripheral nervous system 12 pairs of cranial nerves 31 pairs of spinal nerves then you have autonomic nerves that break down into the parasympathetic and sympathetic so this is a good review for you right there a neuron is an individual nerve cell it has dendrites it has a cell nucleus has an axon which is a myelin sheet as a neurolemma terminal n fibers secrete neurotransmitters and neurotransmitters transfer impulses across a synapse so that's how nerves communicate and there's lots of neurotransmitters in the body uh the most famous one that you probably know is dopamine right so there's acetylcholine epinephrine norepinephrine um there's tons of them you don't again it's not an anatomy or physiology class so you won't have to memorize the neurotransmitters but perfect example so that you understand the concept is let's say you're on your cell phone you get a text and somebody says hey how's it going or you're on facebook instagram and you get a like well your body gets a sudden hit of dopamine and dopamine is a neurotransmitter that gives you pleasure gives you satisfaction okay so what happens is the more dopamine you get the happier you feel so and the more likes you get the more text you get you get that artificial feeling of oh i feel good then what happens is you crave more likes you crave more texts and so your body relies on that self-assurance from text and likes for you to feel good now recreational drugs work the same way molly's you know e they work very well and then they secrete serotonin and dopamine and people really rely on them and when they go to raves they start popping a molly and they get the artificial dopamine and serotonin but then they rely on it just to get that same natural high so you have to be careful and then ganglia are small clusters of nerve cell bodies anatomical parts of a neuron contain dendrites cell body cell nucleus the axon myelin sheath terminal n fibers and the synapse if you look right here the image shows the parts of the neuron here's the dendrites you get the stimulus at the dendrites here's the cell body cell nucleus here's where the nerve impulse will come neurotransmitters translate from one to another so here's the neurotransmitter here's the receptor so you release dopamine you release acetylcholine you release a norepinephrine here um and then the receptors will say okay what do i need to do do i need to speed up slow down what do i need to do and then so if you look at the terminal n fibers then they connect to another nerve and same thing on and on and it just goes throughout the body glial cells contain the health of the nervous system they do not transport impulses but they are they go through mitosis whereas neurons nerve cells so neurons don't go through mitosis so you don't get cancer of neurons or nerve cells but you can get cancer of glial cells so glioblastoma would be cancer of the glial cells there's four types of glial cells okay there's astrocytes which are astroglio cells there's microglial there's microglial cells oligodendroglia which is oligodendroglial cells and epidermal cells these are supportive protective and connective cells of the central nervous system all right let's take a brief tour of the brain the anatomical structures of the brain include the frontal lobe the sulci which are the depressions the gyri which are the bumps parietal lobe cyber lobe warnicky area temporal lobe and broca's area so if you look at here what does the frontal lobe do well first of all the brain is divided into right and left hemispheres okay so here's the frontal lobe here's the temporal lobe here's the occipital lobe and here's the parietal lobe so the frontal lobe does thought processes behavior personality emotion some motor control broca's area this is where you express your language it's on the left side here's the temporal lobe which does hearing understanding speech and language both sides here's the parietal lobe that does body sensations visual and spatial perception here's the body movement which is part of the frontal lobe occipital lobe does vision and then you have the wernicke's area which is part of the temporal lobe that does language comprehension so if you speak a second language your wernicke's area will be well developed the cerebrum is the largest section of the brain surface nerve cells called cerebral cortex manages speech vision smell movement hearing and thought the cerebellum looks like a little cauliflower coordinates voluntary movements maintains uh balance so if you have damage to the cerebellum you can call that cerebellar ataxia they'll have a shuffling gait uh they'll feel like they're you when they walk you're like oh my gosh they're gonna fall right over the thalamus i like to call that uh um really air traffic control because at the airport you have a whole bunch of flights coming in and a whole bunch of flights uh leaving so the thalamus gets a whole bunch of uh information integrates and monitors impulses from the skin and pain so it's gonna give all the sensory information and then the brain is gonna decide what to do with it so think of the thalamus as air traffic control basically air traffic control monitors all the flights that come in and all the flights that go out while thalamus gets all this information from your body and then it'll decide what to do with it the hypothalamus controls the body temperature sleep appetite sexual desire and emotions regulates release of hormones from the pituitary gland and monitors sympathetic and parasympathetic nervous systems it's a good quiz question right so know what this hypothalamus does the pons it bridges the cerebrum and cerebellum with the rest of the brain it houses nerves for the face and eyes the midbrain uppermost portion of the brainstem contains pathways connecting the cerebrum with lower portions of the brain the medulla oblongata is like saying medulla oblongata it connects the spinal cord to the brain nerve tracts from side to side it regulates blood vessels heart and respiration here's the spinal cord it's the column of nervous tissue from the medulla oblongata all the way down to the second lumbar vertebrae so spinal cord ends at l2 it serves as a pathway for impulses to and from the brain the intersection of the cross-section of spinal cord is called gray matter the outer section is called white matter because the white matter is mino myelinated and myelin helps uh it's like insulation for the nerves meninges contain dura mater a subdural space arachnoid membrane subarachnoid space and pia matter so those are the layers of the brain and dura is the outermost and p as the innermost so if you heard of a subdural hematoma you're going to get swelling right underneath the dura right here which is right here subdural space okay so again here's a good visual meninges are the three layers of connective tissue memories that surround the brain and the spinal cord so if you look at this dura mater dura mater means uh in latin tough mother right duda in spanish duda duda that's another song called that and you've got so here's your scalp here's the cranium which is the skull okay here's the subdural space arachnoid membrane subarachnoid space which contains cerebral spinal fluid so cerebral spinal fluid is basically what your brain sits in imagine you in a pool and you're just floating in the pool well that's what your brain is is basically just floating in the cerebral spinal fluid provides nutrition picks up all the waste products and just helps circulate okay and here's the pia mater all right so let's get to actual vocabulary here's acetylcholine afferent nerve arachnoid membrane so acetylcholine is a neurotransmitter chemical released at the end of nerve cells and carries messages toward the brain and spinal cord arachnoid membrane is the middle layer of three membranes that surround the brain and the spinal cord astrocyte autonomic nervous system axon astrocyte is a glial cell that transports water and salts from the capillaries the autonomic nervous system nerves that control involuntary body functions of muscular muscles glands and internal remember the autonomic nervous system is your fight or flight or your rest and digest axon is a microscopic fiber that carries the nerves impulses along the nerve cell you have a blood brain barrier brain stem and quad equina the blood brain barriers protective separation between the blood and brain cells that keep substances such as anti-cancer drugs from penetrating capillary walls and entering the brain that anti-cancer drugs are unfortunately too large so that's why you can't treat brain cancer with chemotherapy so you have to do surgery to take out parts of the brain so only small molecules can enter the blood-brain barrier so narcotics recreational drugs alcohol are small molecules that's why you get drunk or you get a high from those drugs advil is too large that's why when you take advil you don't get that high or you don't get those side effects so it depends on how big the molecules are and can they pass the blood brain barrier the brain stem is the posterior portion of the brain that connects the cerebrum with the spinal cord includes the midbrain pons and medulla oblongata the quad equina collection of spinal nerves below the end of the spinal cord remember the spinal cord ends at l2 quad it kinda kinda looks like a horse's tail let's see cell body central nervous system cerebellum the cell body is part of the nerve cell that contains the nucleus the central nervous system is the brain and the spinal cord and the cerebellum looks like a little cauliflower posterior part of the brain that coordinates muscle movements and maintains balance cerebral cortex cerebral spinal fluid and the cerebrum cerebral cortex outer region of cerebrum contains sheets of nerve cells gray matter cerebral spinal fluid circulates throughout the brain and spinal cord picks up waste products provides nutrition the cerebrum is the largest part of the brain responsible for voluntary activity vision speech taste hearing thought memory okay so you have two cerebral hemispheres so a lot of these mean the same thing you're like cerebral cerebellar is different okay so don't get cerebellum and cerebellar confused with cerebrum or cerebral cranial nerves dendrite and dura mater so cranial nerves there's 12 pairs they're not part of the central nervous system they're part of the peripheral nervous system they carry message to and from the brain with regard to the neck and head except for the vagus nerve dendrites are microscopic branching fiber of a nerve the first part to receive the nerve impulse dura mater means again tough mother the thick outermost layer of the meninges surrounding and protecting the brain and spinal cord efferent means efferent nerve epididyl and ganglion efferent carries messages away from the brain and spinal cord that's motor nerve and afferent are carrying messages to the brain and they're sensory so a is sensory e is motor epididymal cell glial cells that lines up membranes within the brain and spinal cord helps form cerebral spinal fluid a ganglion is plural collection of nerve cell bodies in the peripheral nervous system so example would be let's say you touch a hot stove well afferent nerves would say that are sensory will send that information to your brain and your brain will say oh well you better remove that hand so then efferent nerves will go carry the message away from your brain to your hand and say well you better take that hand off and that's a motor nerve there so hopefully that makes sense a fair versus efferent