Neuron Functions and Communication Explained lecture test 4

Yeah, you can let them in. Thank you. It's easier to put the trash can than that little stopper if y'all want to do that. Okay. Somas and dendrites. What type of gates are on somas and dendrites? Good. And what type of potential for number four occurs on somas and dendrites? Which one? Yep. Okay. Axon has... What type of gates? The axon. Sodium and potassium. And what type of potentials occurs on the axon? Everyone agree? Okay. And then the synaptic end bulbs. And then if I had a number six, what type of potentials occurring on the synaptic end bulbs? Which one? Action. Action. The end bulbs are just... part of the axon. They just have a different voltage gate. Okay. Okay. Get those clickers ready. We're going to have, before we go over everything, we have another quiz. Not a day to miss class for points. Okay. You'll get five minutes for this one. So there's six questions and only five answers. What does that tell you about answers? Yeah, one has to be used twice. Y'all can work together. Every point counts. I got two minutes. When you get a chance, one of each. Okay, I'm just missing four people. It could be one answer that you're missing. Awesome, everyone's in. That excites me. Okay, which letter do we have summation of GPs? Does everyone agree with A? Okay, where is... A occurring on the neuron. Where does summation of GPs occur? Okay. So one and five are answers. Okay. Now number two says too many potassium ions rush out. If too many are leaving, we're going to be in D. What is D? What is that letter? Hyperpolarization. Is that more negative or more positive? Got it. Okay. At which letter, and y'all can be confused on this one, so you have to look really closely, at which letter do the sodium VGs fly open? Okay, B's already the fact that they're open. When, what number? Think about numbers. What number do gates open for action potentials? Negative 55. What is pointing to negative 55? Letter E. Okay, so once B occurs, B, the gates have already opened because we're already going way up to depolarization. So this is just making sure that you scan the whole picture before answering. This is not tricky, it's just making sure you look, okay? So... Number three, the answer is E. Once E occurs, then B will occur because B is the sodium ions rushing in already to go to positive 30. OK, opening of potassium VGs. Yeah, so it really occurs right at positive 30. But if I put the C up there, you wouldn't have been able to see it. So I had to move it down just a little bit. What is this event called? The C event. We're going back to resting, R-E. You got it. Okay, and we already did five. Okay, occurs at the hillock for a new AP. This is the same answer as three. It's occurring at the hillock. It's going to be E. Negative 55 is threshold. Okay, the whole point of this though, y'all, these are just low stakes, one point questions. The whole point of this is for y'all to understand on the test what to look for. Make sure that you read the questions thoroughly. Make sure I have pictures on the test, which I often give you a picture, not for anything, but for a reference, just so you can draw on it, label it and stuff like that. So it'll help you understand what to look for on tests. Okay, so we're going to go over this one more time, and then we are going to add, where's the picture I want? Then we are going to add a little bit new stuff, and I gave you a drawing for the new stuff. Okay, what type of gates are on the somas and dendrites? Okay, when a ligon gate opens, if sodium rushes in, Will that cause depolarization or hyperpolarization? Okay, and that's our goal. So let's just say sodium rushed in or calcium. Calcium can do the same thing. Okay, will one event of sodium rushing in cause an action potential? Okay, it's causing a graded potential, but is one graded potential going to lead us to an AP? What do we need to do with those GPs? Okay, so here we're going from negative 70, and we're going to go through summation. to hopefully hit what magic number and where do we need to hit that magic number where am i writing this at you got it okay as long as we hit negative 55 at the hillock we're going to begin a new action potential aps are going to be a series of events that occur over and over again those events are depolarization repolarization what's the last one Hyper so those are just going to occur over and over again until we hit the end of the axon. Yes, okay No, as long as it's 55 or past it negative 55 So can be negative 55 if you have a super strong stimulus you may have hit negative 20 already as long as it's negative 55 or past it at the hillock you're good to go. Okay, but if it's negative 56 is that threshold yet? No, so it wouldn't occur. It has to be 55 or past it. Okay, so this is the picture we just went over. So we're going to talk about this. This right here is basically at the somas and dendrites. So what event is occurring right here? Summation of graded potentials. Okay, so these are your GPs. They are summating. Okay, our goal though is to hit what magic number at the hillock? Negative 55. So that goal is going to be right here. That's going to be negative 55. We're pretending it's at the hillock. Okay, once we hit negative 55 at the hillock, what gates fly open? Sodium what? Voltage. Okay, so right there where this big old little dot is we have sodium vgs opening once they fly open where does sodium want to move since we have all this sodium moving in are we going to be more positive or more negative and what do we call that more positive Now, we know that sodium VGs fly open. What do we know about our friend potassium VGs? They go really slow. So at negative 55, they think about opening. They start. It's really, really slow. Okay, so just keep that in the back of your mind that they started opening, but they're super slow. So we are going to depolarize all the way to positive 30. At positive 30. right here, what gates close? Okay, so that's occurring right here, and what gates are opening at the same time, finally? Okay, once those potassium VGs open, where is potassium naturally found? So where is the potassium going to move? Okay. Okay, so now potassium is rushing out. So we're losing all these positives. So now we're going back down to resting. What do we call that phase? Now the problem is potassium voltage gates are slow to open. So what are they also slow to do? Okay, so the problem is they're not going to close right here. We want them to, but usually they can't. Okay. So that means we're going more negative. What do we call it when we go more negative? And this is occurring because what failed to close on time? No one gave me credit for good handwriting ever. Okay, now that these potassium VGs Haven't closed yet. Do you see where I drew that line right here? How it's basically plateauing out? Let's say it's negative 75 Well, once we plateau out, what do we know the gates finally did? Yeah So once we plateau out, we know that the gates somewhere around here finally closed But the problem is we're still negative and we need to get back to resting. What's the? easiest way even though it takes energy for us to get back to resting and what's the easy way to say sodium potassium pump and a okay okay so for us to get back to resting we are going to use the magic of the NAK pump it's the fastest way to get back to resting but it's not too energy efficient because we're using tons of ATP now as soon as we're back to resting Remember, APs are all or nothing, meaning once they start, they're going to go all the way to the end of the axon. So once we get back to resting, what's the next phase we're going to go right back into? What's the first phase here? Depolarization. And then after depolarization, what do we go into? Re. And then most likely we're going to go into? And then right when we get back to resting, what's after hyper again? D. And then we go into? And then we go into? It's just a cyclic event. It's going to occur all the way to the end of the neuron. So if, let me clear this out real quick. So what happens if this is your axon and here's the end bulbs? Okay, this is going to occur all the way till the end of the neuron, just like this. So all these events are occurring over and over again. So as long as they start, they will go all the way. Each of these peaks is D. Each of the fall is Re. And then if it goes beneath it, it's hyper. So it just keeps going over and over again. Now, what can speed this up? What can be on an axon that would speed up the APs? Myelin. If myelin's there, it's going to speed it up. Because what happens with myelin is the APs can only happen in the nodes. So that means they're basically jumping each of the areas that have myelin on it. Okay. So we're going to have a few questions here. I think we have a few questions. Let me see. We did those. We did those. We did that. Okay, maybe not. Maybe I did all the questions. Okay. So the last thing I wanted to add today to this chapter was how neurons communicate with each other. So what do we call it when a muscle and a neuron communicate? A muscle and a neuron. Neuromuscular junction. So do you all see this just beautiful little pac-man monster picture? Okay this is what we're talking about here. So if you look at the bottom, I drew an NMJ. We've already talked about NMJs. It's just a single page one. Okay we've already talked about NMJs. What we're going to talk about now is how two neurons communicate. The reason I drew them on the is the steps are almost identical, which means once you know one, you know the other. The difference is going to be terminology because one of them is talking about a neuron and a muscle. One of them is talking about two neurons. So a neuron and a muscle is a neuromuscular junction. You hear the word neuron, you hear the word muscle. When two neurons communicate, it is called a synapse, so a neuron synapse. I always think about the word synapse. You snap your fingers, they're coming together. Two neurons communicating are coming together. Now if you look really closely in this picture, if you look at the one I drew, do the two neurons touch each other? No. So we're always going to have space between two neurons. What do we call that space? It's the same as what we call the space in the NMJ. Cleft, what's another word? Gap and then space. So any of them are fine. Okay, so you're gonna see a lot of similarities. So right here in this picture, what I have here is I have the end bulb of neuron number one. Okay, this neuron is before the synaptic cleft. So do you think this neuron is going to be called pre-synaptic or post-synaptic neuron? Pre. So the first neuron is known as the presynaptic neuron. So this end bulb from neuron number one is also known as the presynaptic neuron. Then we have our space right here. So we have our synaptic space cleft gap, whatever you want to call it. And then we have our second neuron. So right here is the second neuron. And it's going to be the dendrites and the somas. The second neuron is after the synapse. So after the collapse. Do you think we call this one presynaptic or postsynaptic? Okay, so the second neuron is known as the postsynaptic neuron. Okay, so basically what y'all have here is the same thing that I just went over. Come on, draw. Not as pretty. Okay, so here's our presynaptic neuron, neuron number one. Here's our postsynaptic neuron, neuron number two. Okay, this area between the two is your space cleft or gap. Okay. Now, your presynaptic neuron's end bulb is just like the end bulbs you've already learned about. What gates are on your presynaptic neuron end bulb? Calcium what? Okay, so right here, we have calcium VGs. Okay. What are those circles inside the end bulb called? They're called vesicles. Now, in the vesicles, I want you to give me the generic term. What do we store in vesicles? Do not give me a specific term. Give me a generic term. You got it. Okay, now what is one neurotransmitter we've learned a lot about? Okay, so we can have ACH in there. But do y'all notice on that sheet I also drew another one called GABA? Okay, so we're going to draw both of them. if it lets me. Okay, this is GABA. It's a square. I don't know why I chose a square and a diamond. That was the stupidest decision, but it's over with, so just deal with it, y'all. And then we have our ACH. Okay. Now, over here, we go through this whole cleft. We have our second neuron. The second neuron we're seeing are the somas and the dendrites. What gates do we have on somas and dendrites? Okay. I think someone just had an aha moment. I know my picture. I'm not drawing it the exact same. I drew it for y'all, but y'all can just kind of get the idea of it. Okay. Now, let's talk about the events. They are absolutely no different than the NMJ events. Okay, what needs to come down this presynaptic neuron? An AP, what's the, today is not my day with this machine. Okay, what is, what does the AP stand for? Okay. As an AP comes down the neuron, it makes it more positive. What do we call that event when we get more positive? Okay, so we're depolarizing the neuron. We're depolarizing the end bulb. That's part of the neuron. What gates open to a change in charge? The voltage gates. So first step is depolarization. Because of that, what voltage gates open? What's on the end bulb? You got it. Calcium VGs open. So we're depolarizing the neuron. Calcium VGs are going to open. Now if calcium VGs open, what's going to move through the calcium VGs? Yeah, so we have little calciums floating around out here. So the calcium will rush in. Now that calcium rushing in causes what to happen to your vesicles. The fancy word is vesicles go through exocytosis. What does that really just mean in common terms? To release what? What are we releasing? The neurotransmitters. Okay. So the calcium rushing in causes the release of the neurotransmitters. The calcium rushing in causes the release of those neurotransmitters. Instead of writing all that out, you can say exocytosis. You just have to know what that word means. Now, when we release neurotransmitters, basically they're just chemicals. So they're going to float across this cleft. And what kind of gates do chemicals like? You got it. So where do you think they're going to bind? To the ligand gates. Okay, so the neurotransmitters will bind through ligand gates on which neuron, presynaptic or postsynaptic? I hope y'all have gotten my shorthand. We only have two weeks left. If y'all don't know my shorthand yet, we're in trouble. Okay, now when they bind to those ligand gates, what are the ligand gates going to do? Okay, now if y'all looked at my notes on that page I gave you, GABA, which is all supposed to be capitalized, likes anions. And what do we know ACH likes? Okay, so if GABA bonded to this gate and opened this gate, anions are negative. So what's the only thing that can go through this gate that we've learned? We have calcium, sodium, potassium, and chloride. Which one of those is negative? So if GABA opened this gate, the only thing that can move in is chloride. Would that cause this neuron to get excited or would it cause the neuron to be inhibited? Inhibited, okay? That happens all the time. But if we actually want the second neuron to send a signal, do we need it to be excited or inhibited? So if we want the second neuron to send a signal, do we want ACH to bind or GABA to bind? ACH is going to open these gates. It likes cations. What's its favorite cation? Sodium. If sodium enters, so these are my little sodium flies, if sodium enters, sodium carries what charge? A positive. So that's going to bring us from negative 70 to hopefully what number? What's threshold? Okay, where do we want to hit threshold? So our goal is when sodium rushes in that we summate to threshold at the hit lock. That's our goal. So our goal is that we summate two thresholds at the hillock. Oh yes, mm-hmm, no, all combined. So in this particular picture I have GABA binding, so let me just, let me add another gate here that was going to help us out some. I can have both go, it's whichever one opens more gates. Right now, just for the sake of this picture, I have two cation gates and only one anion gate. So which one are we going to have more going in, more sodium or more chloride going in? More sodium, which means we're going to excite the neuron. But it just depends on how many gates are opening. So neurons in your body, depending on the gates, can be excitatory neurons or inhibitory. So it depends on the exact situation occurring. So both can be released. It just depends on which one's being released more, which gates are opening more. But for our goal, we really want to know what happens if we excite that neuron. And that's going to start another AP. That's the goal. Okay, so if an anion gate opens, is that an inhibitory or excitatory effect? If a cation gate opens, is that inhibitory or excitatory? Excitatory. Now... Just because they open, does that guarantee we are going to summate to threshold? It does not. But our goal is that we add enough up that we reach threshold. Where do we need to reach threshold? Once we hit threshold at the hillock, what voltage gates fly open at the hillock? Sodium. What thinks about opening at that point? Just thinks. Potassium. They just think about it. They're slow. They will eventually open, but they're not quite open. Okay, so I want you all to look at the picture. I'm going to erase this picture, and we're going to, y'all have y'alls drawn. This is the exact same events that we talked about. when we talked about the NMJ. Okay, here's your neuron, here's your muscle cell. This is the NMJ, and what do we call that area between the neuron and the muscle cell? Okay, so so far it's very similar. It's just instead of having two neurons, we have a neuron and a muscle. Okay, what gates are on this end bulb? Calcium VGs. Okay, since this is an NMJ, though, we only have one neurotransmitter that's going to be inside. What is that neurotransmitter? Okay, what type of gates do we know are on the muscle cell membrane? Ligon, you got it. Okay, these ligon gates love ACH, which means it's a cation gate. What are these gates favorite cation? You got it. Okay, so an AP has to come down the neuron. When that AP comes down that neuron, it's getting more positive. What do we call that event? Depolarization. What gates open to a depolarization? Calcium VGs. When those calcium VGs open, what rushes in? Calcium rushing in causes what to happen? Release of ACH. ACH is a chemical. What do chemicals bind to? Ligon gates. So this chemical right here is going to bind right to this gate. When it binds to that gate, what happens to those gates? And when they open, who's their favorite? Sodium rushes in. Now the muscle's at negative 70, but when sodium rushes in, that's a positive charge, so what's our goal to reach? As long as we reach negative 55, are we going to have a new AP? We will. It's threshold. Threshold is the magic number. So as long as we hit negative 55, we're going to have a new AP. Okay. That new AP travels down the muscle cell membrane. What is that called? And how does it get deep into the muscle cell? And the T-tubules overlap with all of that kind of web stuff that stores calcium. Terminal cisterns are just the end of the SR. You got a sarcoplasmic reticulum. Okay. The sR gets excited, it releases its jailmates, which are really known as calcium. Calcium floods out to the liquid. Who's calcium's lover? Binds the troponin, we go through that whole process. You'll see how this picture is almost identical to the two neurons communicating. Yeah, the steps are almost to a T identical. So once you know one, you know the other. Y'all already know the NMJ. Now we're just changing a few of the structures when we talk about two neurons. Okay. Any questions? Okay. I want you all to turn to each other. You're going to spend four minutes, and you're going to explain the NMJ and the synapse. So that's two minutes each of you. One minute for each story. You all got this. We'll get your pictures if you need to. I want to hear talking. I'm going to guarantee you're going to see these types of questions. Angel, did you grab your clicker? Okay. Stephanie, scooch down here. Talk to them. They're almost exactly. I mean, they are. Even the events, because we do have other gates on the muscle cell. I just don't talk about them because it's not the main importance. You said that it really just depends what kind of gates. Yes. So there are some neurons that will only have gates for negative ions. There are some that will only have for positive, and there are neurons that have both. So it's truly dependent on where in the body. We're not getting into that detail. It's just If I give you a situation, know what event happens. So if I say a cation gates opens, it's going to be positive. If I say an anion gate opens, it's going to be negative. Do you see this picture? You see how in that picture presynaptic neuron one is causing an excitatory effect, two is inhibitory, three is excitatory, four is inhibitory, five is excitatory. Do we have more excitatory or more inhibitory? We have more excitatory. So is that neuron going to get excited or inhibited? Excited. It just depends on how many are being sent and how many signals. Oh, okay. Yeah. So that's just showing you that you can have lots of neurons communicating or one neuron that is . bipolar and sensitive two different things at once it just depends on the gates okay y'all good i just gave you a big hint about essays on the test okay so we're gonna go over just a few questions and then we're gonna jump into 13. 13, I'm only covering highlights of it, so don't stress about it. You also have my notes and lectures online for 13. Okay. Go ahead. Grab your clicker. talk to your to your partners okay i'll have 15 more seconds okay okay i'm gonna stop it okay If calcium VGs are blocked, well, the calcium VGs, where are they located? Where on the presynaptic? N-volves. So these voltage gates are on the N-volves. So if they are blocked, can calcium rush in? If calcium cannot rush in, what will never happen? Exocytosis, which is a fancy word of saying which one? A. Now, if... When exocytosis doesn't occur, will ligon gates ever open? And if ligon gates never open, can anything rush in or out? No. So that means B and C are correct, but is that the best answer? No. Okay. So you always want to go with what's the direct effect. If calcium VGs never open, nothing can rush in and cause the rest of those effects. On the test, if you tell me... the muscle won't contract or the neuron won't send a signal. That is incorrect. That is the long-term effect, but why? I want to know the details. Okay. This is what happens with tetanus. Y'all have heard of tetanus. We all get tetanus shots. Tetanus actually affects your body in two different ways. One of the ways it affects it is by blocking calcium voltage gates. Okay? So that's one way. Okay. I'll tell you what IP and EPSP mean. You have to click send after you put your answer in. Okay. IP means inhibitory. EP means excitatory. Okay, so if think about if sodiums carry a charge, what charge do they carry? Are they going to cause inhibitory or excitatory? And then you know what the rest of them mean. Remember, you have to click send after this one. Remember to click send. E is excitation. I is inhibit. I'm just missing a few of y'all. Make sure you click send. Yeah, so you have, no, you just click whatever letter you want to answer and then you click send. Okay, super proud of y'all. Everyone got it right. What's the answer? Okay, so if we're exciting something, that means we're getting more positive what's the fancy word for more positive depolarization okay so if we're inhibiting it are we going to be depolarizing or hyperpolarizing hyperpolarizing okay so if you hear the word inhibit means we're getting more negative if you hear the word excitatory it means we're getting what more positive okay So still have to click send after it. The key here is potassium ions leaving the soma. Potassium ions leaving the soma. So this means we're going to bind to a gate that likes potassium ions. So think about what charge potassium carries and realize we are in the soma. Someone has two answers by accident. So double check your clicker to make sure that you only send one in. Okay, missing one person. Okay. Okay. Potassium ion carries what charge? If it leaves the soma, it brings those positives with it, which makes it more negative or more positive. Okay. If we're going more negative, are we inhibiting or exciting? So we know it has to be an IPSP. Now, since it's going more negative, what's that term? Hyper. So IPSP and hyper is what answer? E. Hold on, I gotta get the right setup. Don't crash. I think it's gonna crash on us. It crashed. Okay, we'll just do these real quick. Okay, a GP. A car is on the soma or the axon. okay aps soma are the axon voltage gates where are those guys located ligand gates repolarization primarily axon. Okay, okay. Okay, so y'all's test is Thursday, tomorrow. Y'all's test is Thursday. You need an 882 e-scantron. This is the one you've been using. There'll be two short answers on the test. You get to choose from a variety of questions, but know that I've kind of been prepping y'all a lot for the short answer, so y'all should be fine. Okay, make sure you're here on time if you want the full time in class for this test. Any questions before we add new material? Okay, what's, yes. because the sodium potassium pump is going to be shoving two so two potassiums back in and shoving three sodiums out so we're getting rid of a little bit more positive and that's going to slowly get us back to negative 70. but it's happening very very quickly so once we shove those potassiums in and the sodiums out we're still staying negative we're not equalizing it so we're not getting to zero we're Yeah. It's more positive, but it's still negative 70. So it's always going to maintain it at that negative 70. Now, depending on the cell, it could be negative 60, negative 80. It depends on which cell in the body is the sodium potassium pump's goal. Now, the pump doesn't know the numbers of the cell. So what the pump's doing is it's constantly working. And then the leakage channels and the anions inside also help contribute to maintaining that negative. Now when the gates open, no matter what the pump does, it can't control the charge inside. Because the gates have such an influx or efflux of materials that no matter what the pump does, it can't manage that constant rapid change. Okay, so the test is just chapters 10 and 12. Okay, so what we're adding now is not on the test. Okay, no that's on there. That was still chapter 12. 11.1 is about muscles still. So it's about lever systems and how muscles interact. That's more just to give you exposure to the material. In a, you know, in a perfect world I would be able to cover everything in this chapter. But if I did not talk about it in class you don't need to know it. So I always every semester I have to rewrite my test because I don't cover the same stuff every semester So I haven't written the test. Yeah. Yeah, I just know what type of questions. All right, okay Um, so the first question I have on here is a clicker question, but I don't have the clicker Machine up so I just want you in your head to think this means did you read my announcements? 29th, I heard that. Anyone know the time? Y'all got it. So test four is online. Let's do the 29th at 11 p.m. It doesn't open until the 20th. So you basically have nine days to take it. If you read my directions, what would I suggest? I'm, yeah, I just pulled that number. You can, you know, just do a little bit a day. That way you're not sitting, I can tell when students sit in front of the computer for seven hours. There's no reason to do that. That's just going to stress yourself out and overwhelm yourself. Do a little bit a day. It's open book does not mean it's easier because you need to still be organized. You want to be familiar with the material. So that means you want to read through the notes. You may want to tab them. So when a question comes up, you're not spending 20 minutes looking for the answer. You're like, oh, I remember reading this. I know it's in this chapter. I remember it's kind of in this area. And then you can turn to it. Okay, you got it. Exactly. Or if you skip a question. So if you don't feel like, oh my gosh, this question's killing me, just close it down. Come back to it when you have fresh minds. No time limit, meaning like I might see some people on there for 40 hours. I know you didn't sit there for 40 hours, but you left it, you know, you closed it and went over a few days. So I would not leave it to the day. This is a great way to kind of cushion your grade. What do you mean all reading? So I give you all notes that are a little bit easier to follow because the notes cut out some of the content So I would use the notes, but that doesn't mean when you're reading through the notes You should always still reference that portion of the textbook I just cut out some of the textbook the textbooks thick has a lot of material in it It's not realistic that we can cover everything in every chapter Okay, but I do want to go over a little bit of chapter 13 because that's gonna really help us for when we hit chapter 15 hard, okay So, chapter 13 is on the spinal cord and spinal nerves. Y'all know what this is a picture of? A spinal cord. Okay. So, we're going to go over the parts of the spinal cord because anatomy really helps with physiology. So, I gave y'all a packet today that has not this picture. I'll show you the picture y'all have in y'all's packet. This one. Okay. So we're going to go over all these parts in the spinal cord. This is just showing you what a real spinal cord section looks like. What do y'all notice the two colors y'all see? Kind of white and what else? Brown. Okay, the brown lacks myelin. So what do we call this brown area? Gray matter. And then the white has myelin. So what do we call this? White matter. Spinal cord white matter is usually a little bit whiter than your brain's white matter. Your brain's white matter is almost a beige-y color, whereas the gray matter is just a dark brown. So don't get stuck in your head that it has to be white and gray. It's actually brown and beige. Okay, so this is the spinal cord picture I have. This right here is the front of your spinal cord, so this is anterior. This is posterior part of the spinal cord in that picture. If you don't know your front from your back, it's easy to miss answer questions. Okay, so the first part is going to be, we're going to go over the roots. So in the back of the spinal cord, you're going to have posterior roots. We also call them dorsal. We also call them sensory. I like sensory the best because it tells you the function. So in the back of the spinal cord, we have sensory roots. sensory roots are always going to bring information into the spinal cord so all sensory information goes in the back of the spinal cord oh this is sad I've never seen this I can't draw okay so all sensory information goes in the back of the spinal cord. Now I want you to look closely at this picture. We covered this in chapter 12. What type of neuron is that blue neuron? Is it multi, uni, or bipolar? What type of neurons are sensory neurons? Unipolar. So in the sensory roots they're actually made up of unipolar neurons because all sensory neurons are unipolar. Okay, now in the sensory roots, do y'all see this area that's really swollen right here? Right there? Okay, that is known as the sensory root ganglion. Sensory root ganglion. Ganglions are just bundles of somas, and they're only found in the PNS, so they're peripheral. So if you look here, we'll see that it's only showing us one unipolar neuron, but if we had lots of unipolar neurons, it would have lots of somas right in that spot. and lots of somas are round so it causes swelling. So ganglias are just bundles of those somas. Okay, now in the middle of the gray matter, we may or may not have an interneuron. It doesn't have to be there, it can be there. Interneurons, what are their jobs? What does the name interneuron kind of sound like? Integrate. So interneuron's job is to do analyzation, integration. Interneurons are always in the gray matter, so what do they always lack? The interneurons will always lack myelin. Do you remember what type structurally an interneuron always is? Multi or uni? Always multi. Now, we don't have to have an interneuron, but a lot of times there are interneurons there. Okay. In the front, do you all see this little yellow area in the front? These are known as... anterior or ventral roots. I like to call them motor roots because that tells you the function. So in the front of the neuron, we're going to have motor roots. Motor roots are going to contain motor neurons leaving the spinal cord. Motor roots contain motor neurons leaving the spinal cord. There's two we're about to go over. There's a red and a green. Can you see the colors, the red and the green one? It may not look quite green. So the red one you can see, and then we have this green one right there. So the motor roots contain motor neurons that are leaving the spinal cord. all sensory information enters the spinal cord in the front or the back? In the back. And then all motor information leaves the spinal cord where? In the where? In the front. So it's really just like a path. You enter the back, you exit the front. What's entering? Is sensory information entering or motor? Yeah, sensory. Once it enters, then we're going to integrate it. And then when it exits it's leaving where where does the motor neurons exit the front okay if you don't get this anatomy down the physiology won't make sense I could just say I severed the dorsal roots if I severed dorsal roots am I losing sensory information or motor information okay now it doesn't mean that my whole body is losing sensory it may just be that segment of the spinal cord But if I sever motor roots, will I be able to use my muscles? Because no signals will go to those muscles. So it's really important where the information is flowing. Now, in this picture, we have two motor neurons in this picture. One motor neuron is red. Can you all see the red one? It's in the front, closer to the front. Okay, this motor neuron is a somatic motor neuron. What does somatic tell us? Is it cardiac, smooth, or skeletal muscle? Skeletal. Good job. So this red one only goes to skeletal muscles. Now let's look at this green one. The green one's a little bit higher off to the side. The green one is autonomic. Autonomic sounds a lot like what word? Automatic. And what muscles in our body don't we really think about controlling it automatically does its job? Cardiac, smooth muscle, so GI tract. And then I heard someone say the other one, salivation, glands. Okay. So this autonomic motor neuron is going to travel to cardiac, smooth, and glands. But what's important is that they're both leaving the front or the back of the spinal cord. They're both leaving the front. they just go to different paths because they have different jobs. Now we went over these nerve structures of the spinal cord. All of this stuff that comes off of the spinal cord, so your sensory roots, your motor roots, all of this stuff comes off the spinal cord. Since it's off of the spinal cord, is it peripheral or central nervous system, peripheral. The spinal cord itself is part of which system though? Central. So your spinal cord and brain, central, but anything coming off of them, even if the word is spinal nerve, is still peripheral. If it's not the spinal cord, if it's not the brain, it is the peripheral nervous system. Those are the only two things in the central. Okay. Now I can't write on this, which is driving me crazy. So I'm gonna have to go back to a different picture. Yes. Let's see. I can't, I can probably go out and draw without this. Oh, thanks. That's probably why. I didn't see that. Well, no, no, that's probably going to be the key to me getting this to work. Doesn't look right out. You're a hero. Yay. Okay, so we have all this stuff here. Okay, now the next step I'm going to go over is internal anatomy. I'm going to go over anatomy inside the spinal cord. So all of these terms that I'm going over in the spinal cord, are they part of the peripheral or central nervous system? Central. So everything we just went over is more peripheral. Now we're going to go over central. Okay, so we have our gray matter and we have our white matter. The white matter is going to be known as columns. So what I like to remind you all about is when you drive down St. Charles, we have lots of beautiful mansions. All those beautiful mansions have columns. What color are those columns usually? White. So we call white matter columns and we name them for their location. So these columns are in the back. of the spinal cord. So what do you think we call these columns? Posterior columns. Okay, these columns are in the front of the spinal cord. What do we think we call those columns? These columns are on the side of the spinal cord. What do we call those? You got it, lateral columns. Okay, in general, the columns are going to be made up of myelinated axons that travel to and from the brain. So the ones that go up to the brain, we call those ascending. They're going up to the brain. That means they're bringing sensory information to the brain. The ones that are leaving the brain and going down the spinal cord, those are descending. What are those going to be carrying? Motor. So these myelinated axes are going to and from the brain. So we're going to have ascending. descending and we call these myelinated axons track so we're gonna have ascending and descending tracks this is not something that will be on your tests all the tracks are not going to be on the test because there's tons of them but in general the tracks are going to be named for what parts of the body they're connecting so are they connecting your spinal cord to your thalamus spinothalamic track lots of weird names But the ones in the back of the spinal cord, do you think those are going to be more sensory or motor? Because they're in the back. You got it. The ones in the front of the spinal cord, what do you think those are mostly going to be? Motor. And then the ones in the side are a mix because they're going to contain both areas. Okay. Now, your tracks and the columns, those are all white matter. Now your gray matter though is going to be called something different. Your gray matter is going to be known as horns, and the horns are named for their location. So these horns are in the back. What do we call those horns? What about these horns in the front? What do you think we call those? Now, if you don't like the word anterior and posterior, what else can you use? dorsal and ventral if you're more comfortable with that okay but do y'all notice how i'm kind of missing this section right here okay if this section is present if it is present this is known as lateral horns so if this section is present it's known as lateral horns and lateral horns are only located in your thoracic and lumbar region. If lateral horns are present, they are only located in thoracic and lumbar. So if lateral horns are present, they are only located in the thoracic and lumbar region. Do y'all see this little bitty dot in the center? This is known as the central canal. And the central canal has fluid traveling up and down. And do y'all happen to know the name of the fluid that travels in your brain and in your spinal cord? I heard someone say it loud, Renee. And what's the easier way to write cerebrospinal fluid? CSF. So in the central canal you have CSF circulating. Okay now do you ever think both halves of your spinal cord might want to communicate with each other? Do you ever use both sides of your body at the same time? So if you're walking are you using both sides of your body? Okay so we need our our halves of our spinal cord to communicate so i need my right half and my left half to communicate okay do y'all see how around the central canal i have all this gray matter that gray matter is known as the gray commissure the gray commissure allows the right and left gray halves to communicate with each other. The gray commissure allows the right and left gray halves to communicate with each other. So it's just the area around the central canal. Now the gray halves communicate. Do you think the white halves need to communicate? Okay, do y'all see in the front I have this little section right here? This is known as the white commissure. It's only in the front and it allows my right and left white columns to communicate. It's only in the front and it allows the right and left white columns to communicate. The Y commissure is only in the front. It's a really small area and it allows the right and left white columns to communicate. Only in the front and it allows the right and left white columns to communicate. Okay, so now what I want y'all to do is dig deep. Go back to chapter one. Go back to the feedback cycle. We have five components. What detects stimuli? Sensory one. Okay. Those receptors are going to send a signal. What do we call that signal? Input goes to where? The control center evaluates and what does the control center send? And that output goes to where? Okay, this is absolutely what we just went over here. Okay, do y'all see this little blue arrow coming in? It says nerve impulses for sensations right there. Okay, basically there was a stimulus. So here is our stimulus, a receptor detects it. The receptor is going to send a signal in the back of the spinal cord. What do we call that signal? Input. Now, what type of neuron does input go down? Input's going in the back of the spinal cord. So what type of neuron, sensory or motor? So in this case, our input is a sensory neuron. So our receptor detects a stimulus, and then... We send input down a sensory neuron. That sensory neuron is going to the gray matter of the spinal cord, which is considered what? Control center. And what do we need to do in this control center before we can do anything else? Analyze. Okay, so we're going to analyze this information in the control center. Once we analyze this information, we're going to want to send output. What type of neurons takes the output away from the spinal cord? Those motor neurons are going to take information to where? What's the last component? The effectors. If it's taking it to skeletal muscle, is it somatic or autonomic? If it's taken into your heart, smooth muscle, or glands, what is it? So you can determine what type of system is involved based on the effectors. Okay, so test Thursday. Next, a week from today, we'll finish Chapter 13 and start 15. Don't lose those handouts. I only print out enough for the class. Uh-huh.

Yeah, you can let them in. Thank you. It's easier to put the trash can than that little stopper if y'all want to do that. Okay.

Somas and dendrites. What type of gates are on somas and dendrites? Good. And what type of potential for number four occurs on somas and dendrites?

Which one? Yep. Okay. Axon has... What type of gates?

The axon. Sodium and potassium. And what type of potentials occurs on the axon?

Everyone agree? Okay. And then the synaptic end bulbs. And then if I had a number six, what type of potentials occurring on the synaptic end bulbs? Which one?

Action. Action. The end bulbs are just...

part of the axon. They just have a different voltage gate. Okay.

Okay. Get those clickers ready. We're going to have, before we go over everything, we have another quiz. Not a day to miss class for points.

Okay. You'll get five minutes for this one. So there's six questions and only five answers. What does that tell you about answers? Yeah, one has to be used twice.

Y'all can work together. Every point counts. I got two minutes.

When you get a chance, one of each. Okay, I'm just missing four people. It could be one answer that you're missing. Awesome, everyone's in.

That excites me. Okay, which letter do we have summation of GPs? Does everyone agree with A? Okay, where is...

A occurring on the neuron. Where does summation of GPs occur? Okay. So one and five are answers. Okay.

Now number two says too many potassium ions rush out. If too many are leaving, we're going to be in D. What is D?

What is that letter? Hyperpolarization. Is that more negative or more positive? Got it.

Okay. At which letter, and y'all can be confused on this one, so you have to look really closely, at which letter do the sodium VGs fly open? Okay, B's already the fact that they're open. When, what number? Think about numbers.

What number do gates open for action potentials? Negative 55. What is pointing to negative 55? Letter E. Okay, so once B occurs, B, the gates have already opened because we're already going way up to depolarization.

So this is just making sure that you scan the whole picture before answering. This is not tricky, it's just making sure you look, okay? So...

Number three, the answer is E. Once E occurs, then B will occur because B is the sodium ions rushing in already to go to positive 30. OK, opening of potassium VGs. Yeah, so it really occurs right at positive 30. But if I put the C up there, you wouldn't have been able to see it. So I had to move it down just a little bit. What is this event called?

The C event. We're going back to resting, R-E. You got it. Okay, and we already did five.

Okay, occurs at the hillock for a new AP. This is the same answer as three. It's occurring at the hillock.

It's going to be E. Negative 55 is threshold. Okay, the whole point of this though, y'all, these are just low stakes, one point questions. The whole point of this is for y'all to understand on the test what to look for.

Make sure that you read the questions thoroughly. Make sure I have pictures on the test, which I often give you a picture, not for anything, but for a reference, just so you can draw on it, label it and stuff like that. So it'll help you understand what to look for on tests. Okay, so we're going to go over this one more time, and then we are going to add, where's the picture I want? Then we are going to add a little bit new stuff, and I gave you a drawing for the new stuff.

Okay, what type of gates are on the somas and dendrites? Okay, when a ligon gate opens, if sodium rushes in, Will that cause depolarization or hyperpolarization? Okay, and that's our goal.

So let's just say sodium rushed in or calcium. Calcium can do the same thing. Okay, will one event of sodium rushing in cause an action potential?

Okay, it's causing a graded potential, but is one graded potential going to lead us to an AP? What do we need to do with those GPs? Okay, so here we're going from negative 70, and we're going to go through summation. to hopefully hit what magic number and where do we need to hit that magic number where am i writing this at you got it okay as long as we hit negative 55 at the hillock we're going to begin a new action potential aps are going to be a series of events that occur over and over again those events are depolarization repolarization what's the last one Hyper so those are just going to occur over and over again until we hit the end of the axon. Yes, okay No, as long as it's 55 or past it negative 55 So can be negative 55 if you have a super strong stimulus you may have hit negative 20 already as long as it's negative 55 or past it at the hillock you're good to go.

Okay, but if it's negative 56 is that threshold yet? No, so it wouldn't occur. It has to be 55 or past it. Okay, so this is the picture we just went over.

So we're going to talk about this. This right here is basically at the somas and dendrites. So what event is occurring right here?

Summation of graded potentials. Okay, so these are your GPs. They are summating.

Okay, our goal though is to hit what magic number at the hillock? Negative 55. So that goal is going to be right here. That's going to be negative 55. We're pretending it's at the hillock. Okay, once we hit negative 55 at the hillock, what gates fly open? Sodium what?

Voltage. Okay, so right there where this big old little dot is we have sodium vgs opening once they fly open where does sodium want to move since we have all this sodium moving in are we going to be more positive or more negative and what do we call that more positive Now, we know that sodium VGs fly open. What do we know about our friend potassium VGs?

They go really slow. So at negative 55, they think about opening. They start. It's really, really slow. Okay, so just keep that in the back of your mind that they started opening, but they're super slow.

So we are going to depolarize all the way to positive 30. At positive 30. right here, what gates close? Okay, so that's occurring right here, and what gates are opening at the same time, finally? Okay, once those potassium VGs open, where is potassium naturally found? So where is the potassium going to move?

Okay. Okay, so now potassium is rushing out. So we're losing all these positives. So now we're going back down to resting. What do we call that phase?

Now the problem is potassium voltage gates are slow to open. So what are they also slow to do? Okay, so the problem is they're not going to close right here.

We want them to, but usually they can't. Okay. So that means we're going more negative.

What do we call it when we go more negative? And this is occurring because what failed to close on time? No one gave me credit for good handwriting ever. Okay, now that these potassium VGs Haven't closed yet. Do you see where I drew that line right here?

How it's basically plateauing out? Let's say it's negative 75 Well, once we plateau out, what do we know the gates finally did? Yeah So once we plateau out, we know that the gates somewhere around here finally closed But the problem is we're still negative and we need to get back to resting.

What's the? easiest way even though it takes energy for us to get back to resting and what's the easy way to say sodium potassium pump and a okay okay so for us to get back to resting we are going to use the magic of the NAK pump it's the fastest way to get back to resting but it's not too energy efficient because we're using tons of ATP now as soon as we're back to resting Remember, APs are all or nothing, meaning once they start, they're going to go all the way to the end of the axon. So once we get back to resting, what's the next phase we're going to go right back into?

What's the first phase here? Depolarization. And then after depolarization, what do we go into? Re.

And then most likely we're going to go into? And then right when we get back to resting, what's after hyper again? D. And then we go into? And then we go into?

It's just a cyclic event. It's going to occur all the way to the end of the neuron. So if, let me clear this out real quick. So what happens if this is your axon and here's the end bulbs? Okay, this is going to occur all the way till the end of the neuron, just like this.

So all these events are occurring over and over again. So as long as they start, they will go all the way. Each of these peaks is D.

Each of the fall is Re. And then if it goes beneath it, it's hyper. So it just keeps going over and over again.

Now, what can speed this up? What can be on an axon that would speed up the APs? Myelin. If myelin's there, it's going to speed it up. Because what happens with myelin is the APs can only happen in the nodes.

So that means they're basically jumping each of the areas that have myelin on it. Okay. So we're going to have a few questions here. I think we have a few questions. Let me see.

We did those. We did those. We did that.

Okay, maybe not. Maybe I did all the questions. Okay.

So the last thing I wanted to add today to this chapter was how neurons communicate with each other. So what do we call it when a muscle and a neuron communicate? A muscle and a neuron. Neuromuscular junction.

So do you all see this just beautiful little pac-man monster picture? Okay this is what we're talking about here. So if you look at the bottom, I drew an NMJ. We've already talked about NMJs.

It's just a single page one. Okay we've already talked about NMJs. What we're going to talk about now is how two neurons communicate.

The reason I drew them on the is the steps are almost identical, which means once you know one, you know the other. The difference is going to be terminology because one of them is talking about a neuron and a muscle. One of them is talking about two neurons. So a neuron and a muscle is a neuromuscular junction. You hear the word neuron, you hear the word muscle.

When two neurons communicate, it is called a synapse, so a neuron synapse. I always think about the word synapse. You snap your fingers, they're coming together. Two neurons communicating are coming together.

Now if you look really closely in this picture, if you look at the one I drew, do the two neurons touch each other? No. So we're always going to have space between two neurons. What do we call that space? It's the same as what we call the space in the NMJ.

Cleft, what's another word? Gap and then space. So any of them are fine. Okay, so you're gonna see a lot of similarities.

So right here in this picture, what I have here is I have the end bulb of neuron number one. Okay, this neuron is before the synaptic cleft. So do you think this neuron is going to be called pre-synaptic or post-synaptic neuron? Pre.

So the first neuron is known as the presynaptic neuron. So this end bulb from neuron number one is also known as the presynaptic neuron. Then we have our space right here.

So we have our synaptic space cleft gap, whatever you want to call it. And then we have our second neuron. So right here is the second neuron.

And it's going to be the dendrites and the somas. The second neuron is after the synapse. So after the collapse.

Do you think we call this one presynaptic or postsynaptic? Okay, so the second neuron is known as the postsynaptic neuron. Okay, so basically what y'all have here is the same thing that I just went over. Come on, draw.

Not as pretty. Okay, so here's our presynaptic neuron, neuron number one. Here's our postsynaptic neuron, neuron number two.

Okay, this area between the two is your space cleft or gap. Okay. Now, your presynaptic neuron's end bulb is just like the end bulbs you've already learned about. What gates are on your presynaptic neuron end bulb?

Calcium what? Okay, so right here, we have calcium VGs. Okay.

What are those circles inside the end bulb called? They're called vesicles. Now, in the vesicles, I want you to give me the generic term.

What do we store in vesicles? Do not give me a specific term. Give me a generic term. You got it. Okay, now what is one neurotransmitter we've learned a lot about?

Okay, so we can have ACH in there. But do y'all notice on that sheet I also drew another one called GABA? Okay, so we're going to draw both of them.

if it lets me. Okay, this is GABA. It's a square. I don't know why I chose a square and a diamond.

That was the stupidest decision, but it's over with, so just deal with it, y'all. And then we have our ACH. Okay. Now, over here, we go through this whole cleft. We have our second neuron.

The second neuron we're seeing are the somas and the dendrites. What gates do we have on somas and dendrites? Okay.

I think someone just had an aha moment. I know my picture. I'm not drawing it the exact same. I drew it for y'all, but y'all can just kind of get the idea of it. Okay.

Now, let's talk about the events. They are absolutely no different than the NMJ events. Okay, what needs to come down this presynaptic neuron? An AP, what's the, today is not my day with this machine.

Okay, what is, what does the AP stand for? Okay. As an AP comes down the neuron, it makes it more positive. What do we call that event when we get more positive? Okay, so we're depolarizing the neuron.

We're depolarizing the end bulb. That's part of the neuron. What gates open to a change in charge?

The voltage gates. So first step is depolarization. Because of that, what voltage gates open? What's on the end bulb? You got it.

Calcium VGs open. So we're depolarizing the neuron. Calcium VGs are going to open.

Now if calcium VGs open, what's going to move through the calcium VGs? Yeah, so we have little calciums floating around out here. So the calcium will rush in. Now that calcium rushing in causes what to happen to your vesicles. The fancy word is vesicles go through exocytosis.

What does that really just mean in common terms? To release what? What are we releasing?

The neurotransmitters. Okay. So the calcium rushing in causes the release of the neurotransmitters.

The calcium rushing in causes the release of those neurotransmitters. Instead of writing all that out, you can say exocytosis. You just have to know what that word means.

Now, when we release neurotransmitters, basically they're just chemicals. So they're going to float across this cleft. And what kind of gates do chemicals like?

You got it. So where do you think they're going to bind? To the ligand gates. Okay, so the neurotransmitters will bind through ligand gates on which neuron, presynaptic or postsynaptic?

I hope y'all have gotten my shorthand. We only have two weeks left. If y'all don't know my shorthand yet, we're in trouble.

Okay, now when they bind to those ligand gates, what are the ligand gates going to do? Okay, now if y'all looked at my notes on that page I gave you, GABA, which is all supposed to be capitalized, likes anions. And what do we know ACH likes?

Okay, so if GABA bonded to this gate and opened this gate, anions are negative. So what's the only thing that can go through this gate that we've learned? We have calcium, sodium, potassium, and chloride.

Which one of those is negative? So if GABA opened this gate, the only thing that can move in is chloride. Would that cause this neuron to get excited or would it cause the neuron to be inhibited?

Inhibited, okay? That happens all the time. But if we actually want the second neuron to send a signal, do we need it to be excited or inhibited?

So if we want the second neuron to send a signal, do we want ACH to bind or GABA to bind? ACH is going to open these gates. It likes cations. What's its favorite cation?

Sodium. If sodium enters, so these are my little sodium flies, if sodium enters, sodium carries what charge? A positive.

So that's going to bring us from negative 70 to hopefully what number? What's threshold? Okay, where do we want to hit threshold? So our goal is when sodium rushes in that we summate to threshold at the hit lock.

That's our goal. So our goal is that we summate two thresholds at the hillock. Oh yes, mm-hmm, no, all combined.

So in this particular picture I have GABA binding, so let me just, let me add another gate here that was going to help us out some. I can have both go, it's whichever one opens more gates. Right now, just for the sake of this picture, I have two cation gates and only one anion gate.

So which one are we going to have more going in, more sodium or more chloride going in? More sodium, which means we're going to excite the neuron. But it just depends on how many gates are opening.

So neurons in your body, depending on the gates, can be excitatory neurons or inhibitory. So it depends on the exact situation occurring. So both can be released. It just depends on which one's being released more, which gates are opening more. But for our goal, we really want to know what happens if we excite that neuron.

And that's going to start another AP. That's the goal. Okay, so if an anion gate opens, is that an inhibitory or excitatory effect?

If a cation gate opens, is that inhibitory or excitatory? Excitatory. Now...

Just because they open, does that guarantee we are going to summate to threshold? It does not. But our goal is that we add enough up that we reach threshold. Where do we need to reach threshold? Once we hit threshold at the hillock, what voltage gates fly open at the hillock?

Sodium. What thinks about opening at that point? Just thinks.

Potassium. They just think about it. They're slow. They will eventually open, but they're not quite open.

Okay, so I want you all to look at the picture. I'm going to erase this picture, and we're going to, y'all have y'alls drawn. This is the exact same events that we talked about. when we talked about the NMJ. Okay, here's your neuron, here's your muscle cell.

This is the NMJ, and what do we call that area between the neuron and the muscle cell? Okay, so so far it's very similar. It's just instead of having two neurons, we have a neuron and a muscle.

Okay, what gates are on this end bulb? Calcium VGs. Okay, since this is an NMJ, though, we only have one neurotransmitter that's going to be inside. What is that neurotransmitter?

Okay, what type of gates do we know are on the muscle cell membrane? Ligon, you got it. Okay, these ligon gates love ACH, which means it's a cation gate. What are these gates favorite cation? You got it.

Okay, so an AP has to come down the neuron. When that AP comes down that neuron, it's getting more positive. What do we call that event? Depolarization. What gates open to a depolarization?

Calcium VGs. When those calcium VGs open, what rushes in? Calcium rushing in causes what to happen?

Release of ACH. ACH is a chemical. What do chemicals bind to? Ligon gates.

So this chemical right here is going to bind right to this gate. When it binds to that gate, what happens to those gates? And when they open, who's their favorite?

Sodium rushes in. Now the muscle's at negative 70, but when sodium rushes in, that's a positive charge, so what's our goal to reach? As long as we reach negative 55, are we going to have a new AP?

We will. It's threshold. Threshold is the magic number. So as long as we hit negative 55, we're going to have a new AP.

Okay. That new AP travels down the muscle cell membrane. What is that called? And how does it get deep into the muscle cell?

And the T-tubules overlap with all of that kind of web stuff that stores calcium. Terminal cisterns are just the end of the SR. You got a sarcoplasmic reticulum.

Okay. The sR gets excited, it releases its jailmates, which are really known as calcium. Calcium floods out to the liquid. Who's calcium's lover?

Binds the troponin, we go through that whole process. You'll see how this picture is almost identical to the two neurons communicating. Yeah, the steps are almost to a T identical.

So once you know one, you know the other. Y'all already know the NMJ. Now we're just changing a few of the structures when we talk about two neurons. Okay.

Any questions? Okay. I want you all to turn to each other.

You're going to spend four minutes, and you're going to explain the NMJ and the synapse. So that's two minutes each of you. One minute for each story.

You all got this. We'll get your pictures if you need to. I want to hear talking.

I'm going to guarantee you're going to see these types of questions. Angel, did you grab your clicker? Okay. Stephanie, scooch down here. Talk to them.

They're almost exactly. I mean, they are. Even the events, because we do have other gates on the muscle cell.

I just don't talk about them because it's not the main importance. You said that it really just depends what kind of gates. Yes. So there are some neurons that will only have gates for negative ions. There are some that will only have for positive, and there are neurons that have both.

So it's truly dependent on where in the body. We're not getting into that detail. It's just If I give you a situation, know what event happens. So if I say a cation gates opens, it's going to be positive.

If I say an anion gate opens, it's going to be negative. Do you see this picture? You see how in that picture presynaptic neuron one is causing an excitatory effect, two is inhibitory, three is excitatory, four is inhibitory, five is excitatory. Do we have more excitatory or more inhibitory? We have more excitatory.

So is that neuron going to get excited or inhibited? Excited. It just depends on how many are being sent and how many signals. Oh, okay.

Yeah. So that's just showing you that you can have lots of neurons communicating or one neuron that is . bipolar and sensitive two different things at once it just depends on the gates okay y'all good i just gave you a big hint about essays on the test okay so we're gonna go over just a few questions and then we're gonna jump into 13. 13, I'm only covering highlights of it, so don't stress about it.

You also have my notes and lectures online for 13. Okay. Go ahead. Grab your clicker.

talk to your to your partners okay i'll have 15 more seconds okay okay i'm gonna stop it okay If calcium VGs are blocked, well, the calcium VGs, where are they located? Where on the presynaptic? N-volves. So these voltage gates are on the N-volves.

So if they are blocked, can calcium rush in? If calcium cannot rush in, what will never happen? Exocytosis, which is a fancy word of saying which one?

A. Now, if... When exocytosis doesn't occur, will ligon gates ever open? And if ligon gates never open, can anything rush in or out?

No. So that means B and C are correct, but is that the best answer? No. Okay. So you always want to go with what's the direct effect.

If calcium VGs never open, nothing can rush in and cause the rest of those effects. On the test, if you tell me... the muscle won't contract or the neuron won't send a signal.

That is incorrect. That is the long-term effect, but why? I want to know the details. Okay. This is what happens with tetanus.

Y'all have heard of tetanus. We all get tetanus shots. Tetanus actually affects your body in two different ways. One of the ways it affects it is by blocking calcium voltage gates. Okay?

So that's one way. Okay. I'll tell you what IP and EPSP mean.

You have to click send after you put your answer in. Okay. IP means inhibitory.

EP means excitatory. Okay, so if think about if sodiums carry a charge, what charge do they carry? Are they going to cause inhibitory or excitatory? And then you know what the rest of them mean. Remember, you have to click send after this one.

Remember to click send. E is excitation. I is inhibit. I'm just missing a few of y'all.

Make sure you click send. Yeah, so you have, no, you just click whatever letter you want to answer and then you click send. Okay, super proud of y'all. Everyone got it right. What's the answer?

Okay, so if we're exciting something, that means we're getting more positive what's the fancy word for more positive depolarization okay so if we're inhibiting it are we going to be depolarizing or hyperpolarizing hyperpolarizing okay so if you hear the word inhibit means we're getting more negative if you hear the word excitatory it means we're getting what more positive okay So still have to click send after it. The key here is potassium ions leaving the soma. Potassium ions leaving the soma. So this means we're going to bind to a gate that likes potassium ions. So think about what charge potassium carries and realize we are in the soma.

Someone has two answers by accident. So double check your clicker to make sure that you only send one in. Okay, missing one person. Okay.

Okay. Potassium ion carries what charge? If it leaves the soma, it brings those positives with it, which makes it more negative or more positive.

Okay. If we're going more negative, are we inhibiting or exciting? So we know it has to be an IPSP.

Now, since it's going more negative, what's that term? Hyper. So IPSP and hyper is what answer?

E. Hold on, I gotta get the right setup. Don't crash. I think it's gonna crash on us. It crashed.

Okay, we'll just do these real quick. Okay, a GP. A car is on the soma or the axon.

okay aps soma are the axon voltage gates where are those guys located ligand gates repolarization primarily axon. Okay, okay. Okay, so y'all's test is Thursday, tomorrow.

Y'all's test is Thursday. You need an 882 e-scantron. This is the one you've been using.

There'll be two short answers on the test. You get to choose from a variety of questions, but know that I've kind of been prepping y'all a lot for the short answer, so y'all should be fine. Okay, make sure you're here on time if you want the full time in class for this test.

Any questions before we add new material? Okay, what's, yes. because the sodium potassium pump is going to be shoving two so two potassiums back in and shoving three sodiums out so we're getting rid of a little bit more positive and that's going to slowly get us back to negative 70. but it's happening very very quickly so once we shove those potassiums in and the sodiums out we're still staying negative we're not equalizing it so we're not getting to zero we're Yeah.

It's more positive, but it's still negative 70. So it's always going to maintain it at that negative 70. Now, depending on the cell, it could be negative 60, negative 80. It depends on which cell in the body is the sodium potassium pump's goal. Now, the pump doesn't know the numbers of the cell. So what the pump's doing is it's constantly working.

And then the leakage channels and the anions inside also help contribute to maintaining that negative. Now when the gates open, no matter what the pump does, it can't control the charge inside. Because the gates have such an influx or efflux of materials that no matter what the pump does, it can't manage that constant rapid change. Okay, so the test is just chapters 10 and 12. Okay, so what we're adding now is not on the test.

Okay, no that's on there. That was still chapter 12. 11.1 is about muscles still. So it's about lever systems and how muscles interact. That's more just to give you exposure to the material. In a, you know, in a perfect world I would be able to cover everything in this chapter.

But if I did not talk about it in class you don't need to know it. So I always every semester I have to rewrite my test because I don't cover the same stuff every semester So I haven't written the test. Yeah.

Yeah, I just know what type of questions. All right, okay Um, so the first question I have on here is a clicker question, but I don't have the clicker Machine up so I just want you in your head to think this means did you read my announcements? 29th, I heard that.

Anyone know the time? Y'all got it. So test four is online.

Let's do the 29th at 11 p.m. It doesn't open until the 20th. So you basically have nine days to take it.

If you read my directions, what would I suggest? I'm, yeah, I just pulled that number. You can, you know, just do a little bit a day.

That way you're not sitting, I can tell when students sit in front of the computer for seven hours. There's no reason to do that. That's just going to stress yourself out and overwhelm yourself.

Do a little bit a day. It's open book does not mean it's easier because you need to still be organized. You want to be familiar with the material. So that means you want to read through the notes.

You may want to tab them. So when a question comes up, you're not spending 20 minutes looking for the answer. You're like, oh, I remember reading this. I know it's in this chapter. I remember it's kind of in this area.

And then you can turn to it. Okay, you got it. Exactly. Or if you skip a question. So if you don't feel like, oh my gosh, this question's killing me, just close it down.

Come back to it when you have fresh minds. No time limit, meaning like I might see some people on there for 40 hours. I know you didn't sit there for 40 hours, but you left it, you know, you closed it and went over a few days.

So I would not leave it to the day. This is a great way to kind of cushion your grade. What do you mean all reading? So I give you all notes that are a little bit easier to follow because the notes cut out some of the content So I would use the notes, but that doesn't mean when you're reading through the notes You should always still reference that portion of the textbook I just cut out some of the textbook the textbooks thick has a lot of material in it It's not realistic that we can cover everything in every chapter Okay, but I do want to go over a little bit of chapter 13 because that's gonna really help us for when we hit chapter 15 hard, okay So, chapter 13 is on the spinal cord and spinal nerves.

Y'all know what this is a picture of? A spinal cord. Okay. So, we're going to go over the parts of the spinal cord because anatomy really helps with physiology. So, I gave y'all a packet today that has not this picture.

I'll show you the picture y'all have in y'all's packet. This one. Okay. So we're going to go over all these parts in the spinal cord. This is just showing you what a real spinal cord section looks like.

What do y'all notice the two colors y'all see? Kind of white and what else? Brown.

Okay, the brown lacks myelin. So what do we call this brown area? Gray matter.

And then the white has myelin. So what do we call this? White matter.

Spinal cord white matter is usually a little bit whiter than your brain's white matter. Your brain's white matter is almost a beige-y color, whereas the gray matter is just a dark brown. So don't get stuck in your head that it has to be white and gray.

It's actually brown and beige. Okay, so this is the spinal cord picture I have. This right here is the front of your spinal cord, so this is anterior.

This is posterior part of the spinal cord in that picture. If you don't know your front from your back, it's easy to miss answer questions. Okay, so the first part is going to be, we're going to go over the roots. So in the back of the spinal cord, you're going to have posterior roots. We also call them dorsal.

We also call them sensory. I like sensory the best because it tells you the function. So in the back of the spinal cord, we have sensory roots.

sensory roots are always going to bring information into the spinal cord so all sensory information goes in the back of the spinal cord oh this is sad I've never seen this I can't draw okay so all sensory information goes in the back of the spinal cord. Now I want you to look closely at this picture. We covered this in chapter 12. What type of neuron is that blue neuron?

Is it multi, uni, or bipolar? What type of neurons are sensory neurons? Unipolar. So in the sensory roots they're actually made up of unipolar neurons because all sensory neurons are unipolar. Okay, now in the sensory roots, do y'all see this area that's really swollen right here?

Right there? Okay, that is known as the sensory root ganglion. Sensory root ganglion.

Ganglions are just bundles of somas, and they're only found in the PNS, so they're peripheral. So if you look here, we'll see that it's only showing us one unipolar neuron, but if we had lots of unipolar neurons, it would have lots of somas right in that spot. and lots of somas are round so it causes swelling.

So ganglias are just bundles of those somas. Okay, now in the middle of the gray matter, we may or may not have an interneuron. It doesn't have to be there, it can be there.

Interneurons, what are their jobs? What does the name interneuron kind of sound like? Integrate.

So interneuron's job is to do analyzation, integration. Interneurons are always in the gray matter, so what do they always lack? The interneurons will always lack myelin. Do you remember what type structurally an interneuron always is? Multi or uni?

Always multi. Now, we don't have to have an interneuron, but a lot of times there are interneurons there. Okay. In the front, do you all see this little yellow area in the front?

These are known as... anterior or ventral roots. I like to call them motor roots because that tells you the function.

So in the front of the neuron, we're going to have motor roots. Motor roots are going to contain motor neurons leaving the spinal cord. Motor roots contain motor neurons leaving the spinal cord.

There's two we're about to go over. There's a red and a green. Can you see the colors, the red and the green one?

It may not look quite green. So the red one you can see, and then we have this green one right there. So the motor roots contain motor neurons that are leaving the spinal cord.

all sensory information enters the spinal cord in the front or the back? In the back. And then all motor information leaves the spinal cord where? In the where?

In the front. So it's really just like a path. You enter the back, you exit the front. What's entering?

Is sensory information entering or motor? Yeah, sensory. Once it enters, then we're going to integrate it.

And then when it exits it's leaving where where does the motor neurons exit the front okay if you don't get this anatomy down the physiology won't make sense I could just say I severed the dorsal roots if I severed dorsal roots am I losing sensory information or motor information okay now it doesn't mean that my whole body is losing sensory it may just be that segment of the spinal cord But if I sever motor roots, will I be able to use my muscles? Because no signals will go to those muscles. So it's really important where the information is flowing.

Now, in this picture, we have two motor neurons in this picture. One motor neuron is red. Can you all see the red one?

It's in the front, closer to the front. Okay, this motor neuron is a somatic motor neuron. What does somatic tell us? Is it cardiac, smooth, or skeletal muscle?

Skeletal. Good job. So this red one only goes to skeletal muscles. Now let's look at this green one.

The green one's a little bit higher off to the side. The green one is autonomic. Autonomic sounds a lot like what word?

Automatic. And what muscles in our body don't we really think about controlling it automatically does its job? Cardiac, smooth muscle, so GI tract. And then I heard someone say the other one, salivation, glands.

Okay. So this autonomic motor neuron is going to travel to cardiac, smooth, and glands. But what's important is that they're both leaving the front or the back of the spinal cord.

They're both leaving the front. they just go to different paths because they have different jobs. Now we went over these nerve structures of the spinal cord.

All of this stuff that comes off of the spinal cord, so your sensory roots, your motor roots, all of this stuff comes off the spinal cord. Since it's off of the spinal cord, is it peripheral or central nervous system, peripheral. The spinal cord itself is part of which system though? Central. So your spinal cord and brain, central, but anything coming off of them, even if the word is spinal nerve, is still peripheral.

If it's not the spinal cord, if it's not the brain, it is the peripheral nervous system. Those are the only two things in the central. Okay.

Now I can't write on this, which is driving me crazy. So I'm gonna have to go back to a different picture. Yes. Let's see. I can't, I can probably go out and draw without this.

Oh, thanks. That's probably why. I didn't see that. Well, no, no, that's probably going to be the key to me getting this to work.

Doesn't look right out. You're a hero. Yay. Okay, so we have all this stuff here.

Okay, now the next step I'm going to go over is internal anatomy. I'm going to go over anatomy inside the spinal cord. So all of these terms that I'm going over in the spinal cord, are they part of the peripheral or central nervous system? Central.

So everything we just went over is more peripheral. Now we're going to go over central. Okay, so we have our gray matter and we have our white matter.

The white matter is going to be known as columns. So what I like to remind you all about is when you drive down St. Charles, we have lots of beautiful mansions. All those beautiful mansions have columns. What color are those columns usually?

White. So we call white matter columns and we name them for their location. So these columns are in the back.

of the spinal cord. So what do you think we call these columns? Posterior columns. Okay, these columns are in the front of the spinal cord. What do we think we call those columns?

These columns are on the side of the spinal cord. What do we call those? You got it, lateral columns. Okay, in general, the columns are going to be made up of myelinated axons that travel to and from the brain.

So the ones that go up to the brain, we call those ascending. They're going up to the brain. That means they're bringing sensory information to the brain.

The ones that are leaving the brain and going down the spinal cord, those are descending. What are those going to be carrying? Motor. So these myelinated axes are going to and from the brain. So we're going to have ascending.

descending and we call these myelinated axons track so we're gonna have ascending and descending tracks this is not something that will be on your tests all the tracks are not going to be on the test because there's tons of them but in general the tracks are going to be named for what parts of the body they're connecting so are they connecting your spinal cord to your thalamus spinothalamic track lots of weird names But the ones in the back of the spinal cord, do you think those are going to be more sensory or motor? Because they're in the back. You got it. The ones in the front of the spinal cord, what do you think those are mostly going to be? Motor.

And then the ones in the side are a mix because they're going to contain both areas. Okay. Now, your tracks and the columns, those are all white matter.

Now your gray matter though is going to be called something different. Your gray matter is going to be known as horns, and the horns are named for their location. So these horns are in the back. What do we call those horns? What about these horns in the front?

What do you think we call those? Now, if you don't like the word anterior and posterior, what else can you use? dorsal and ventral if you're more comfortable with that okay but do y'all notice how i'm kind of missing this section right here okay if this section is present if it is present this is known as lateral horns so if this section is present it's known as lateral horns and lateral horns are only located in your thoracic and lumbar region.

If lateral horns are present, they are only located in thoracic and lumbar. So if lateral horns are present, they are only located in the thoracic and lumbar region. Do y'all see this little bitty dot in the center?

This is known as the central canal. And the central canal has fluid traveling up and down. And do y'all happen to know the name of the fluid that travels in your brain and in your spinal cord?

I heard someone say it loud, Renee. And what's the easier way to write cerebrospinal fluid? CSF. So in the central canal you have CSF circulating.

Okay now do you ever think both halves of your spinal cord might want to communicate with each other? Do you ever use both sides of your body at the same time? So if you're walking are you using both sides of your body?

Okay so we need our our halves of our spinal cord to communicate so i need my right half and my left half to communicate okay do y'all see how around the central canal i have all this gray matter that gray matter is known as the gray commissure the gray commissure allows the right and left gray halves to communicate with each other. The gray commissure allows the right and left gray halves to communicate with each other. So it's just the area around the central canal.

Now the gray halves communicate. Do you think the white halves need to communicate? Okay, do y'all see in the front I have this little section right here?

This is known as the white commissure. It's only in the front and it allows my right and left white columns to communicate. It's only in the front and it allows the right and left white columns to communicate. The Y commissure is only in the front.

It's a really small area and it allows the right and left white columns to communicate. Only in the front and it allows the right and left white columns to communicate. Okay, so now what I want y'all to do is dig deep.

Go back to chapter one. Go back to the feedback cycle. We have five components.

What detects stimuli? Sensory one. Okay.

Those receptors are going to send a signal. What do we call that signal? Input goes to where? The control center evaluates and what does the control center send?

And that output goes to where? Okay, this is absolutely what we just went over here. Okay, do y'all see this little blue arrow coming in?

It says nerve impulses for sensations right there. Okay, basically there was a stimulus. So here is our stimulus, a receptor detects it.

The receptor is going to send a signal in the back of the spinal cord. What do we call that signal? Input. Now, what type of neuron does input go down? Input's going in the back of the spinal cord.

So what type of neuron, sensory or motor? So in this case, our input is a sensory neuron. So our receptor detects a stimulus, and then...

We send input down a sensory neuron. That sensory neuron is going to the gray matter of the spinal cord, which is considered what? Control center. And what do we need to do in this control center before we can do anything else? Analyze.

Okay, so we're going to analyze this information in the control center. Once we analyze this information, we're going to want to send output. What type of neurons takes the output away from the spinal cord? Those motor neurons are going to take information to where?

What's the last component? The effectors. If it's taking it to skeletal muscle, is it somatic or autonomic?

If it's taken into your heart, smooth muscle, or glands, what is it? So you can determine what type of system is involved based on the effectors. Okay, so test Thursday.

Next, a week from today, we'll finish Chapter 13 and start 15. Don't lose those handouts. I only print out enough for the class. Uh-huh.

Transcript for:Neuron Functions and Communication Explained lecture test 4

Transcript for:
Neuron Functions and Communication Explained lecture test 4