Parasympathetic Nervous System PDF

Y'all doing all right? Okay, all right, so we are gonna cover the parasympathetic nervous system today, and actually the plexuses, rather than visceral sensory, I mean a little bit of sensory, but plexuses are in here too. This is much more straightforward compared to sympathetic nervous system, so...

Y'all doing all right? Okay, all right, so we are gonna cover the parasympathetic nervous system today, and actually the plexuses, rather than visceral sensory, I mean a little bit of sensory, but plexuses are in here too. This is much more straightforward compared to sympathetic nervous system, so that's good. But I do actually, you don't have this, so don't freak out. I want to just do this one time with you. I can give you this slide if you want. Don't you like my lovely drawings? Okay, so sympathetic nervous system. I just wanted, so I give you a lot of information, a lot of details, I still want you to know, like spinal levels and things like that, but I wanted to do it one more time as straightforward as I possibly can, okay? So if this is our spinal cord, and if this is recorded and I will also send this out, if you want, and then, so just watch. So this is our spinal cord, right? And we have certain levels, right? Cervical, thoracic, and then lumbar levels, we know that. On the side, either side, we have our sympathetic trunk, that entire structure, and really ganglia on a string, right? These ganglia are those paravertebral, paravertebral on either side. I simplified this side just for you guys. And then, in addition, when we're talking about our sympathetic nervous system, we also have our pre in front of the vertebrae ganglia, right? So those are the ones associated with sympathetic nervous system. And then the weird thing about our sympathetic nervous system is it's limited in where it comes off of our spinal cord, right? So that's that T1 to L2, three-ish, right? Depending on which resource you look at. And it's important because that's the only place we can get on the sympathetic trunk from the spinal cord. So I think you guys kinda know that part. But what I wanna do is just make sure you are clear on these different locations that we can send in relation to. So let's start with the skin, because the skin is a lot, it's all over our body, and we have to sometimes travel really far on our path to get where we need to go. So let's say that, and let me think, I'm gonna take that one off. So say we are sending skin to the torso. There's our belly button, okay? What we're gonna do is we're gonna come off the spinal cord on our right right rami, and we're gonna synapse, we're gonna connect with the second set of neurons here before we get off on our gray rami. And our gray rami are gonna join spinal nerve to the skin right there. So we can kinda think about that in terms of our dermatomes that we already know, right? Spinal nerves go to specific levels of the skin. This is the most straightforward one because we don't have to go anywhere else. So we're gonna get on via our white ramus onto the sympathetic trunk. We're gonna do that silly loop-the-loop, which isn't included in here. Get off on our gray ramus. We're talking about the path of the nerves. Go on our spinal nerve, join with our spinal nerve to the skin. But since we've got this funky organization between T1 and L2, sometimes we gotta go up our sympathetic trunk to join those spinal nerves at higher levels. So say I wanted to send sympathetic innervation to the neck, right, through our cervical plexus. We're gonna get on at the highest level that we can. So it would be T1. We're gonna get on and we're gonna travel up that sympathetic trunk till we get to where we need to go. Various levels, depending on which dermatome, right? Before we get off, we're gonna synapse. They're always gonna synapse right before they get off. Get off on that sympathetic trunk on the gray ramus and join those spinal nerves to the skin. We're gonna do the same thing for lower limb because, again, we don't have our white rami down in below L2, right? But we know that we have spinal nerves way down there that are gonna create at least part of the femoral and then the sciatic nerve and so forth. So we're gonna get on our sympathetic trunk, travel on down, synapse, go on our gray ramus and go to the lower limb. So our gray rami, when we talk about them, are really limited to, and I don't think I made this clear enough, the skin. So when you see gray rami, when we talk about them, it's that sympathetic innervation to the skin. Because otherwise, when we're going to internal organs, including those in our head, thorax and abdominal pelvic cavities, we're gonna get off the sympathetic trunk via these special nerves, splenchnic nerves. So I think that's where I got wishy-washy a little bit for you guys. So let's just do really quick, we're gonna get on our sympathetic trunk, just like we did on the other side, and we're gonna head on up because we're gonna send innervation to the eyeball, right? So we can, our pupillary constrictor muscles. And right before we get off, we're gonna synapse up by the eyeball, we have a special splenchnic nerve that comes off the sympathetic trunk. It's gonna be that cephalic arterial branch. It's because it does a lot of really important stuff. So that splenchnic nerve has a special name. Cephalic, whoop, cephalic arterial branch. But again, we have to travel, and specifically on our sympathetic trunk, we have three special ganglia in our cervical area rather than one for each vertebral level. We have a superior and a middle and an inferior pair of vertebral ganglia, right? If we are going to the thorax, our heart and our lungs, we can even draw our lungs in there, we're gonna do something similar. Some of our fibers have to travel upwards to get to the level of the heart, because it's kind of bridging that T1 and C area, cervical area. So some fibers are gonna go up and send a splenchnic nerve to the heart. Some fibers, we're gonna send some from T1 to T5 to the heart too. So we'll just, and this is all of those, to the heart. So from the superior cervical ganglia, each one of these ganglia, down to T5, it's gonna send a splenchnic nerve to the heart to make sure we get innervation there, right? The lungs, they don't have to travel at all because we have T1 to T5 that, that level, both in our spinal cord and our ganglia, those are gonna send splenchnic nerves to the lungs. We're already at the level that we need to be. These are simply called our cardiopulmonary splenchnic nerves. Finally, we have one more route that we need to talk about, and this is the one that's gonna skip through and not synapse in our sympathetic trunk, but it's gonna go somewhere else, right? So we're gonna get on our sympathetic trunk, but we don't need that pair of vertebral ganglia. We're gonna go to the pre-vertebral ones. That's where we synapse. And then from those pre-vertebral ganglia, which are specific, right? Pre-vertebral ganglia have specific names, celiac, aortic or renal, superior and inferior mesenteric. Then from those, that's where we send our splenchnic nerves. And from superior to inferior to our abdominal pelvic cavity, we're gonna have the greater splenchnic nerve, the lesser splenchnic nerve, the least splenchnic nerve, and then the lumbar. For our really lowest organs, our pelvic cavity organs, we will have some of these fibers get on the sympathetic trunk and travel down to our lumbar or inferior mesenteric ganglia down here before synapsing and splitting it and sending out splenchnic nerves. That's because it's way low in the cavity, in our pelvic cavity, right? So for the most part, our abdominal pelvic cavity stuff, we're gonna get on, we're gonna leave, travel to a different set of ganglia, and from that different set of ganglia innervate the different organs. So all of that craziness that we talked about, if we simplify it down to these four different kind of pathways, that's it. So when we say synapse on the post-ganglionic neuron, it's just because it's meeting up with a different series of neurons in those ganglia. Does that help a little bit? Make it a little less daunting and so forth? I hope it does. Again, we wanna know like greater splenchnic nerve is gonna be created from the levels of T5 to T9. They're all gonna contribute because we wanna know like if we get an injury in that location, our sympathetic response to, well, the best one is gonna be the lesser splenchnic nerve. Lesser splenchnic nerve is gonna go to the aorticoreno ganglia and go to the kidneys and the superenal gland, right? So if we're not getting a superenal gland response sympathetically, that means we don't have adrenaline. So that's something you're really gonna notice. So that's where I'm at. So gray ray might only applies to the Pareto division? I'm sorry? The gray ray might only applies to the Pareto division, the skin division? Just the skin. All of our skin though. Well, okay. Except this part, because this is gonna be done by cranial nerve five. So sensory to our face is a cranial nerve, but everything else even like backed by our ears is gonna be that cervical plexus. So skin and gray ray mai. So as confusing as a gray ray mai might seem and feel, we're just gonna throw it in with that fairly straightforward pathway that meet up with the spinal nerves and so forth. All right, a little bit better. Parasympathetic. All right, what does this do? We know this. All right, it's gonna be the one that's most active all the time, right? Cause we are gonna be hopefully, mostly, unless you're in grad school or medical school, you're hopefully in homeostasis, right? You don't need to rest and digest and do all those things. Anatomically, it's more restricted, right? So the only contributions are coming away from our brainstem or way down in our sacral spinal nerves or sacral, yeah, sacral spinal nerves, S2 through S4. So a lot less is put into it in terms of kind of structural resources. The axons won't travel, and I know I just explained, aren't gonna travel with the spinal nerves like we talked about for the skin. They're gonna travel with cranial nerves or splintchnic nerves down here. So the parasympathetic division, also called the craniosacral division, which reminds us where it's coming from, can be described as this. So if we think about when we have those two different neurons, we still have that pattern, right, so we have one neuron talking directly to a second one that sends to our target organ. If we think of the cranial part, our cranial nerves are going to have our pre-ganglionic cell bodies in those cranial nerve nuclei. So we talked about these before and we talked about that pathway that sends motor to the face, right? We also, and then they'll leave the brainstem via those cranial nerves to those four ganglia that we talked about last time very quickly, we're gonna do it again, synapse and then send their fibers to the target organs. A little bit more straightforward. Sacral parasympathetic outflow, we are going to send these fibers out of S2 through S4. So in that spinal cord level, that very end of it, we're gonna have in our anterior horn those neuronal cell bodies, we're gonna exit via the anterior roots because it's motor of that level and then come together to form splenchnic nerves, pelvic splenchnic nerves, despite the fact that we call it cranial sacral. So there is a sacral region versus our sacral splenchnic nerve, which is gonna be sympathetic. That's a point of confusion, right? So for our parasympathetic, we create pelvic splenchnic nerves in the sacral region. So again, confusing terminology, but that's how they decided to name them. They are gonna go out of that spinal cord, out those anterior roots as splenchnic nerves too, and this was, there is a mistake on the pre-class activity. It's not intermural, it's intramural. I just, I don't know, fingers do things that my brain doesn't tell them to do sometimes. So intramural ganglion are either close to or within organs. And then it's in little tiny fibers to that organ where it needs to go, it's just to innervate the parasympathetic nervous response. So let's talk more about our cranial nerves here. So we're gonna do this next week. There are 12 cranial nerves, there's pairs, right? There are, so if we think about it, there's actually 24 cranial nerves, right? They're gonna come out either side and they're gonna be numerically ordered using Roman numerals, right? So we don't use the Arabic numbers like we were at, one, two, three. It is specifically and intentionally these Roman numerals. So if you don't know your Roman numerals, definitely practice that. So I didn't say it earlier on purpose because, do you guys remember the spinal cord pathway that provides motor to the face? Yeah, cortico ball bar. All right, so we're bringing it back in. So cortico ball bar, remember we're gonna start in that pre-central gyrus because it's motor and then we're gonna send our axons down and they're gonna go to those cranial nerve nuclei, which, I will show you better here in a second, are these, right? So we have all these nuclei in our cranial nerves in our brainstem, which are simply bundles of neuronal cell bodies, right? They're little clumps of gray matter. So instead of our anterior posterior horn gray matter, we're gonna have clumps of cranial nerve nuclei. Sensory and motor, let's see, are gonna be carried by these. When we get to the cranial nerves, cranial nerves one and two, they are actually not going to have nuclei in the brainstem. All other cranial nerves will. So they're gonna be at a different location, we'll talk about it. They're gonna travel through these openings in our meninges, our meningeal layers, and then out those fossa and foramen and canals that we already learned out of the head. So we're gonna bring those back, some of them, right? So we're gonna link which cranial nerve is exiting through a witch hole. Communication between cranial nerves occurs. So you might be like, okay, I have this cranial nerve traveling here and here and here, but you follow them on into your head and we might send some fibers up here to meet with that cranial nerve. Or maybe down here we're gonna send some fibers to meet with a different cranial nerve, kind of like a plexus. It is a plexus. So it gets more complicated and that's what the LMS ones are learning now and we do cranial nerve light, so you're gonna get to those branches next year. Just to show you how those rheumatomerals can help you, they're gonna be, the smaller rheumatomerals are gonna come out more superiorly. So we're gonna have cranial nerve three, for example, come out of the midbrain. Cranial nerve seven is gonna come out of the pons. If we go even further down, nine and 10, they're gonna come out pretty close to one another. They're gonna come out in the medulla. So we're going to see mesencephalic nuclei, and medullary nuclei for these that we're gonna say, okay, this is part of the pathway. And this is gonna be true for all cranial nerves. The smaller the number, the more superiorly they're gonna come off. We're gonna revisit here those cranial ganglions, right? Those cranial ganglions are scattered throughout our cranial vault. There are more. These are the four that we're gonna focus on today, right? These are going to be associated with that parasympathetic activity. So in terms of these, our ocular motor nerve is going to be associated with the ciliary ganglion right here in that orbit. We already talked about that. Our facial nerve is actually going to be associated with our pterygopalatine ganglion here. Our glossopharyngeal nerve, cranial nerve nine, is gonna be associated with our otic, so glossootic ganglion. And then vagus nerve is gonna be associated with a number. Submandibular will also be associated with cranial nerve seven. And we're gonna go through this again. Vagus nerve has three nuclei or three ganglia that we're gonna see is kind of part of the nerve. And then they're gonna go to target organs after they synapse there. So that post-ganglionic fiber to where it needs to go. So let's talk about cranial nerve three more specifically. We're looking inside the orbit here. And then so this is going to be our midbrain or mesencephalon. Here's our pons and here's our medulla, right? Cranial nerve three is also called the oculomotor nerve. It's gonna do most of the movements of those, of the muscles that move the eye from the outside. So muscles that move up and down and not the sphinctoral muscles, right? So we have pre- ganglionic cells that cell bodies are going to come from our mesencephalic nuclei, leave the brainstem and come on through. And we're actually gonna go through our superior orbital fissure cause that's the one we wanna look for. So our superior orbital fissure is going to carry or hold within it oculomotor nerve. And then we are going to synapse. Our pre-ganglionic fibers are gonna synapse in our ciliary ganglion. And then we're gonna send that second set of neurons right to post- ganglionic fibers through the ciliary muscle. And then also the sphincter pupillae muscle of the ion iris, right? So sphincter pupillae muscle. Now we get into more and more sphincter muscles, which are gonna do something kind of counterintuitive, right? So when they are contracted, they're smaller cause the muscle is contracting and going smaller. When they are relaxed, they're bigger, right? And this is gonna apply to the sphincters that are gonna help control our stomach, our urinary bladder and our ******, right? So sphincter muscles, a lot of the time are going to be contracted or actively contracting to be closed. So we want to make our pupil smaller. If we're not in flight or flight, we wouldn't be able to kind of use that to manage the light coming in. The ciliary muscles, and I misspoke less, the ciliary muscles are gonna be attached to our lens and they're gonna allow for lens accommodation. So whether they stretch or relax, we'll go through this when we do the eyeball a little bit more so we can see far away or closer. Creone nerve three for this image, we're looking at the anterior brainstem. These are those mammillary bodies that we looked at before. This is gonna be the pons. We have our cerebellar peduncle here and this is cranial nerve three. They're gonna come right out above the pons. All right, the next one, cranial nerve seven, the facial nerve, oh my goodness, the facial nerve is just this crazy nerve and it does all kinds of things and takes all kinds of different routes. So we'll get into it a little bit more but it is gonna be a really important one because it's going to also carry, it not only carries motor to our face but it's going to allow us to create saliva for digestion and to cry and also make our nose run inside. So in terms of our facial nerve, it's gonna leave at the base of the pons so it's gonna be from a pontic nuclei. It's gonna travel out of our cranial vault here or out of our crania and that facial nerve is going to split and travel with a number of different nerves in different directions because again, it's gonna do tear production which is up by our eyes and salivary production which is obviously by our mouth. So we're gonna travel there. So the two different routes it can take to allow that to happen is through this specialized nerve called the greater patrosyl nerve. We're gonna synapse in our pterygopalatine ganglion and then we're gonna send those post-ganglionic fibers to our lacrimal which is lateral above our eyes. I don't know why I always think it's, like when I grew up it was like, oh tears come from the middle, the medial part of our eyes. I didn't say medial because I had no idea what that was but lacrimal glands over here, that's where your tears come from. They flow medially and then into your nose which is why you get a runny nose and you cry. And then it'll also send some branches to the lining of our nasal cavity and a little bit of our posterior oral cavity to make secretions because it's moist in there, right? The other route the fibers will take are through something called our cortetimpony. The cortetimpony is crazy. It's gonna do this thing where it goes this way and it goes through our middle or our inner ear. So our inner ear when we have like the snail-shaped thing, it's gonna go through there. It's not gonna really do much in there but it's gonna go through. So the great patricisone goes through our ear. Then it's gonna come out and travel on down in synapse in our submandibular ganglion, sending innervation to our salivary glands, at least well, technically two of our through salivary glands. So submandibular and sublingual glands. We do have a parotid gland which we'll talk about later. This is a little bit better, right? A little bit, it's like, oh, it's just the other there. They're all gonna have a same general pattern. Okay, cranial nerve nine, glossopharyngeal. You will come to know that I always mix up glossopharyngeal with hypoglossal, nine and 12 is gonna happen but I got it today. So glossopharyngeal is gonna go through the otic ganglion, right? So it's gonna come out of our medulla or medulla oblongata. Those nerves are gonna come on down and is going to send fibers to our otic ganglion. So it takes kind of a funky route here. There we go. And then that is going to provide our saliva too, is going to produce, tell our parotid gland, there we go, to produce saliva. So we're gonna go to that otic ganglion and then we're going to say, hey, big parotid gland, right here, if you feel kind of right there, it feels kind of chunky. That's your parotid gland. Sometimes it can go even kind of down here by your mandible as well, underneath your mandible. So glands always look like a piece of chewed up gum. That's kind of what you're feeling right there. Anyways, it's gonna produce a lot of saliva. The tricky thing is, and we'll get here, this is the other part of cranial nerve seven, the facial nerve, which does these two down here. The facial nerve does salivary secretion by telling down here glands to do their thing. Travels through the parotid gland, doesn't tell to do anything. Just travels through it even though, I don't know, it seems like a very inefficient way. Either way, don't mix those two up, we'll talk more about them. Okay, so there we go. Cranial nerve seven is just, yeah. All right, the majority of our parasympathetic innervation is going to come from the vagus nerve, the wandering nerve. The vagus nerve is going to provide or give off all of our parasympathetic innervation, basically from the head down. So all of this, well, wait, oh, don't do that, bottom part, all of this. So heart, lungs, accessory glands for the digestive system, most of the digestive system, kidneys, all of that is going to be innervated by the vagus nerve, which flows through our neck, along with our carotid arteries and jugular veins, sandwich in between there, down into all the important stuff. So basically we covered this. The reason that it is going to also provide innervation to our gonads and our testes, because we are going to talk about that pelvic splintered nerve. So our gonads, so testes and ovaries, are going to actually develop in our abdomen and descend. Some descend further than others, but that is why we have this specific pelvic organ or set of organs being innervated by the vagus nerve, because they do originally start out right by your kidneys, actually. Okay. So if we look at this, there are three, there are four nuclei involved with this, or ganglia, excuse me, four ganglia that are involved with this. I want you to know these three, because they're kind of the most essential. So the cranial nerve will synapse. It has its, along the way, it has its own ganglia really kind of embedded within it. We're going to have a solitary nucleus, which is going to be associated with visceral sensory. Right, sensory. We have the dorsal nucleus, which is going to provide that visceral motor, which is how most of this works, right? And the nucleus ambigus is going to provide visceral motor to the heart. So these are specific to the vagus nerve, and they're going to have different important roles. Visceral sensory, when we get there, sympathetic actually does the pain portion of this, but visceral sensory, you can think of monitoring our internal environment, that sensory. All right, they're going to come down, they're going to synapse in one of these locations. The post-ganglionic fibers are going to then travel from those nuclei to their associated organs, right? Let's see, so what does that mean? In our thoracic cavity, we're going to increase those things that are necessary for rest and digest. And as we pass into the abdominal cavity from the diaphragm, which is going to be located right here, it's going to do really smooth muscle motility. So it's really very closely associated with the GI tract. Okay, all right, we got more than half of it done. Sacral outflow, all right, so sacral outflow, we're going to come out those, yeah, go ahead. Okay, the dorsal nucleus is probably because it's dorsal to something else, yeah, so all within context. So we're not talking about like a dorsal root or a dorsal something, probably of those nuclei, it's the most posterior, it's a good question, I don't know. Would have been helpful if it was like the vagal nucleus or something, right? We've got patterns and there's always the weird thing, right, okay, so pre-ganglionic cell bodies from S2 to S4, or in the spinal cord there, shooting out. We're going to leave you the anterior root because it's mostly motor, if it's sensory, it'll come in through that posterior root, but continue on the same path here in these splantianic nerves. We're going to come on out and form the pelvic splantianic nerves, as we can see here, and that's going to do the last portion of our intestines, which is our descending colon and our sigmoid colon and our ******, you don't have to know this specifically really, and then also other glands that are associated with our reproductive organs. Okay, they are going to go to intramural ganglia or target ganglia, they're also called. This is just to kind of help you visualize what in the world we're talking about, right? So when we talk about our digestive system, specifically in this image here, we can see the colon, the large intestines. When we think about, and I said this on Tuesday, but proximal versus distal, it's going to be a little bit different when we're talking about tubes. This is going to be something that we're going to apply to the kidney, something that we apply to the GI tract and so forth. The closer it is to the origin, so my esophagus is more proximal compared to my large intestines. So you want to think of the path of what it's carrying. So is it at the beginning of that path or is it the end of that path? So a more extremum would be, my mouth is more proximal in my digestive tract to the ******, right? And so no matter how the tubes are fashioned, if they're wiggly or convoluted like we see in the kidney, it's still the distance that's been traveled, okay? Here's the ascending colon, just to give us a little bit more reference when you see these terms, transverse colon, large intestines, descending colon, sigmoid colon, and then our ****** is here. Trying to think why I included that one, I don't think so. When we talk about, I specifically included this because when we talk about these plexuses coming up, this is the messy of this that we're talking about. These bundles of nerves that we find throughout the body in our abdominal and pelvic cavity that carry both sets of autonomic divisions, they're messy like this. Sometimes boundaries are less pretty than we want them to be. All right, so autonomic plexuses, let's go. So what we are doing now is taking this network of nerves and thinking about what is contributing to that specific plexus from the sympathetic and parasympathetic. So we're gonna bring in what we talked about on Tuesday to really almost always the vagus nerve unless you're down in the pelvic cavity, and then we're gonna have the pelvic split-chick nerve. So that's pretty straightforward. If you recall, we talked about the length of these fibers between the sympathetic and parasympathetic fibers. That is because if you think of this box as the plexuses that we talk about, they are going to be comprised of pre-ganglionic parasympathetic fibers because that's the long one, and post-ganglionic sympathetic fibers. So they're gonna be at different states in their path, their adventure when we're viewing these plexuses. Axons do not interact or talk to one another between these two divisions, but they will run next to one another, right? So there's no communication, kind of like we learned about how the placenta, the maternal and fetal placenta, they get really close but they don't talk, right? Kind of similar idea. They're gonna be named for where they're at, what they surround, so cardiac pulmonary esophageal plexuses. The abdominal plexus we're gonna further define by the large vessels that they're around. We defined our pre-vertebral ganglia in the same way, but they're not the same thing. So our pre-vertebral ganglia, our ciliac ganglia, our superior mesenteric, inferior mesenteric, and aorticoreno are in kind of the similar area, but again, they're not gonna be the same thing. So our ciliac plexus is in the region, our superior mesenteric plexus is there, and so our inferior mesenteric plexuses, make sure you're distinguishing or reading closely which one we're talking about. And our hypoglygastric plexus is gonna be way at the bottom here, all quite messy. So our cardiac plexus, so heart plexus, our autonomic innervation to our heart. So we talked about at the beginning here, what contributes to the sympathetic heart innervation is going to be those sympathetic ganglia, the whole way from our superior cervical ganglia, the whole way down to T5 ganglia. Those are all gonna send those fibers and contribute to the cardiac plexus. There is a difference though, of course, between our sympathetic ganglia, our para-vertebral ganglia, and the spinal levels that contribute, right? It's gonna be T1 to T5 that send fibers across that white remus bridge to the sympathetic trunk, right? So there's a bit of a difference in terms of spinal cord contribution and para-vertebral ganglia contribution. You guys okay on that? So if I draw that spinal cord, T1 to T5, those are gonna give off those fibers. So this is what contributes to sympathetic innervation of the heart in terms of our spinal cord, sending fibers on, superior cervical, the whole way down to T5, ganglia. Those are where our splintered nerves will come off. Keep looking at it, I promise you'll get there. And then the greatest thing is for our para- sympathetic innervation, vagus nerve. And our nucleus, ambiguous because we want to, we wanna know that, right? Our heart is super important in terms of surviving. So that is what's gonna play a role in this. I don't feel like I need to describe the para-sympathetic innervation, what happens as a result. So it's there for you down here, if you want to go through those each, but it's what we expect in flight or flight versus breast and digest. Increased heart rate or decreased heart rate. So that's there for you to review. If you are not sure, review it. All right, pulmonary plexus, right? Breathing. These are going to impact the surrounding size of our bronchi, the tubes in our lungs, and then also our blood vessels supplying oxygen to our lungs. So post-ganglionic fibers, sympathetic trunk levels, T1 through T5, are gonna contribute to that, right? And then vagus nerve. And because we're talking about motor, it is going to be that confusing, but still there, dorsal nucleus of vagus nerve. We can see that that plexus is going to be really located around our bronchi. So here's our trachea. That first foot that we have is going to be the primary bronchi or a single bronchus. There is no sympathetic innervation to our esophagus, which is nice. It's just vagus nerve. And if we're thinking a bit, again, about what's nucleus contributes to it, it's gonna be that dorsal nucleus of the vagus nerve. Our esophagus just kind of hangs out there. It's a closed tube unless we're forcing food through it, right, so vagus nerve. Abdominal plexus, again, we have to be careful about what we're talking about. They're named for the vessels that they surround and are kind of associated with those ganglia, those sympathetic ganglia as well, right? We have our superior, we have our celiac superior and inferior mesenteric plexus. This might be helpful to actually talk about. I know why I put that picture in. I'm gonna go back up for a minute to that picture that we have of this. This material right here and this material right here is mesentery, this fatty wall of tissue that organizes our intestines, our digestive system here is called mesentery. That is where mesenteric comes from. So if we have mesenteric in the name, it's associated with the GI tract. Doo, doo, doo, okay. The other thing to recognize is in the ones before, we are talking about pervertebral ganglia, right? Now we are talking about the prevertebral ganglia. So recall they are the ones in front when we're talking about the sympathetic nervous system. And then, yay, vagus nerve for almost everything here in the abdomen. Similar to that other slide that I told you all to pay attention to, this is another one, right? So this is one that kind of summarizes the big picture for you. So that celiac plexus will receive contributions from the sympathetic nervous system, the greater, lesser, and least splintic nerves, right? So that means T5, the whole way down to T12 is going to contribute to this plexus. And that's going to include the celiac aortic, renal, and superior mesenteric ganglia, which means almost all of the organs in our abdominal cavity. There is going to be overlap here that you'll see. The superior mesenteric plexus receives innervation from, and I'm not talking about parasympathetic because it's all from the vagus nerve. Least splintic nerve is going to contribute to superior mesenteric plexus. And great superior mesenteric ganglia, and then inferior mesenteric plexus is going to be our lumbar splintic nerves. L2, L1 through L2, maybe three. Hypogastric plexus, there's a superior and inferior hypogastric plexus. We are going to just talk about them as one. It's going to innervate the viscera of the pelvic region, right? So this is where it gives a little bit more complex because we're going to not talk about the vagus nerve. Instead, that pelvic splintic nerve because it's parasympathetic for pelvic splintic nerve. Our lumbar and sacral splintic nerves are going to be that sympathetic response. So when we talk about, for example, that point and shoot situation so we can reproduce and we can have seven billion people in the world, right? Our hypogastric plexuses are going to play a role in that. We're going to have that pelvic splintic nerve playing an important role for our parasympathetic nervous system, sacral splintic nerve for our sympathetic nervous system, and then also our lumbar splintic nerve. So why do we care? So something that someone's going to come to a physician to complain about, if we have an injury, if we have surgery in our pelvic region, these nerves are at risk, right? Because they are scattered, they're all over the place. You have to be careful in the pelvic region because you don't want to mess up someone's reproductive things, right? So why do we talk about these plexuses? It's because they are in the region, if you go into surgery or if you have an injury, they're going to be impacted. I mean, hopefully you're not, none of you are going to be that physician that removed the splint, the liver instead of the spleen, but you still got to be careful while you're in there. And this is why we learned this stuff. Because if you impact these, you're going to impact someone's quality of life. I don't know how that person removed a friggin liver instead of a spleen. There are vastly different connections and vastly different sides of the abdominal cavity. It's, I don't even, okay. Internic nervous system, this is so cool. And I'll let you have a break. Guys, the enteric nervous system plays such an important role in so many things. And we are just learning about it. So with anatomy, it's kind of like, here are the things that we've known since likely in our da Vinci kind of thing. Cause he looked at muscles and whatnot for drawings. Anyways, the enteric nervous system is an integral part of our gut brain axis, right? So what happens in our gut plays a really important role in our brain and we're still learning about it. And we're still learning about how it can impact different treatments and disorders and predicting things. So cool. If you want to do a capstone on the enteric nervous system, I would happily read your paper. So we are going to primarily, we're going to really think about the parasympathetic iteration here, right? Cause that's really going to be involved in that gut motility. So it's more than just telling our gut to do its thing. It's this communication between these nerves. Our biggest nerve is like the telephone between our gut and our brain. It's so cool. Things actually travel up it. So amazing. So it's called the second brain. One, because it can function on its own through reflexes. So in addition to that connection, it can like do its own thing without talking to the upper parts of the central nervous system. So a reflex mean, if you remember when we talked about them, we're going to have sensory information coming in and then at a spinal cord level, it's going to talk immediately to those motor neurons and have an immediate response. We don't involve the brain or it can go the other way, but usually sensory coming in and coming out, right? So sensory like our patella, we hit it and then our knee, our muscles respond by jerky. So this is really cool. Also, that's a great title for a paper. Dr. Deacon really likes to share cool paper titles with you, but I like it. I also just watched the Hangover last night like, sorry, it's been a rough month. I had, don't worry about it. I'm not going to dump that on you. I'm not going to go through this with you. This is a resource for you to work through to kind of figure these out. The great thing is the parasympathetic innervation is almost always the vagus nerve, cranial nerve 10. So there you go. We're going to end with these autonomic reflexes, I think. No, we have a little bit of histologies like one slide. So visceral autonomic reflexes. This is going to help us maintain homeostasis quickly. We don't need to bug the brain by bringing in extra information if we don't have to, right? So smooth muscle contractions in our digestive tract, but also our heart and our glands can respond really by themselves to a specific stimuli, right? It can also bring in information about what's going on in our internal environment, whether that's distension. So, distension in terms of swelling or bloating, right? The levels of gas in our blood, blood pressure, right? That information is going to be brought into our central nervous system by, what we haven't really talked about yet, that sensory autonomic response. Again, it's going to take the same path in terms of our splantistic nerve. It's going to go through our sympathetic trunk. It's just going the opposite way in terms of the information, but they are also then going to go into the spinal cord via our posterior roots, right, to the posterior horn. So we're still keeping that sensory pattern the same. So when we, this will allow, for example, if we look at this diagram here, it's connected to the heart, right? So we're going to be up in the superior stuff, those cardiopulmonary splantistic nerves that we talked about, carrying information and so forth. We are going to have information from our heart coming in, let me find the sensory, there we go, coming in. We're going to travel through those cardiopulmonary splantistic nerves into our sympathetic trunk. We're going to go out the white rheumus. Don't spend time on that. Don't worry about it. There's our neuronal cell body into the posterior, our dorsal root, or dorsal horn, excuse me. That can immediately communicate with our motor sympathetic nervous system and say we need to speed up or increase the volume of our heart in terms of how much blood is pumping because we need more for some reason. I don't know. Maybe there's low oxygen in the blood going to our heart. So then it's going to come out, take that root that we know that we're talking about and tell our heart to do its job in a different way. So these reflexes are nice because they can maintain us and don't involve the cerebrum. Here we go, visceral sensation. So these fibers are going to monitor the internal body environment, specifically things that are normal, right? So parasympathetic is going to monitor our normal stuff. Almost all of our autonomic sensory is going to travel with the parasympathetic fibers, meaning cranial, sacral, cranial nerves and our sacral nerves, cranial nerves. Don't forget the vagus nerve goes into our abdomen, right? Pain, almost all pain, right? So pelvic, so parasympathetic is going to be responsible for knowing what's going on in our body, right? It is going to go through, the information is going to travel with those pelvic splintered nerves up our spinal cord or come in through our vagus nerve or other cranial nerves into our head, right? So fairly limited. Pain, when our body is in trouble, when something's going on, we have to trigger our cerebral nervous response, sorry. If you're online, I should probably use that, but I didn't. So anyone's heart grow, can I wake anybody up? So when there's an emergency situation in our body, it makes sense that our pain is going to travel with sympathetic fibers. So that's going to include those greater, lesser, at least the lumbar splintered nerves. Those are going to include cardiopulmonary splintered nerves into the sympathetic trunk and so forth, right? Which is important. Now, what do we mean by pain? So you can have a lot going on in your internal organs. That's not going to elicit pain. You can like clamp something and that's not going to elicit pain in your head. If you handle with care, internal organs, they're not really going to feel it. If you have something drastic happen, like sudden distention, spasms, muscle spasms, chemical irritants, hopefully that's not a thing for you guys ever, mechanical stimulation, so when an organ's active and you mess with it, and then pathological conditions, especially when we have ischemia, our blood supply is cut off to say our ascending colon through our, what is that going to be, inferior mesenteric artery. Why is this integral to our survival? Why do we need to know when our tissue dies? We can't see it. We don't know it's happening, right? So if we don't know something's going wrong inside of us, but we do kind of squish our body around a lot, so we don't want to have like really sensitive pain, but if we have tissue death, it's going to send a pain response. That's all of our sensory stuff. Parasympathetic histology, all right. So the question on the pre- class activity, the goal was to help you define our ganglia, whether they are sympathetic or parasympathetic, right? So we are going to have ganglia in our sympathetic trunk and our, so para and prevertiburganglia for sympathetic. If we see a ganglia that's in an organ, like a chunk of our digestive tract, between our muscular layers here, between here and here, if we see a ganglia, that's going to be a parasympathetic ganglia by definition, an intra-mural ganglia. And we have some lovely big neurons here, primarily distinguished by their large nuclei, and that's the difference that I'd like you to take in, right? This is basically it, let me show you, ready? So intra-mural parasympathetic ganglia, it's within an organ. We're going to look specifically if you go on to the histology between the outermost muscular layers, what you will learn, I have errors pointing to that. Here's a really nice ganglia for us. This is going to be part of our enteric nervous system. Specifically, it's going to be these ganglia right here, which is going to be the my enteric plexus of on an algal ganglia. Here's a very nice large neurons. They will also have satellite cells. Those that orbit go around neurons to help them survive, help them do their jobs. Everything else in this is for you to do. I'll do this one with you. You don't have to copy it down, just pay attention. So we talk about all these things, we don't talk about the context in the body, right? So we talked about our vagus nerves, really important. Did you know they do, some of you obviously know, but they do vagus nerve stimulation. Sometimes they'll put you upside down in an ED, the ED department and it'll stimulate your vagus nerve to help your heart, crazy. So vagus nerve, very important. It is going to travel next to, this is gonna be, don't worry about identifying it right now, common carotid artery, which will split into an external internal branch. With the jugular vein, internal jugular vein here, we'll have these within a sheath of tissue, protecting our vagus nerve here, coming on down, as well as those really important vessels for maintaining our brain. As it comes down into the thoracic cavity, we can see it here and here on either side. It's gonna do a really neat thing where it actually sends up the recurrent laryngeal branch, which is gonna wrap around the aorta, we'll talk about that later. But you can see it coming down. It's going to be sandwiched between our trachea and our bronchi and our heart, our vagus nerve. As it continues on down, it is going to split into an anterior and posterior vagal branch. We can see the anterior one. Note that it's going through our diaphragm here with the esophagus to send an innervation to our abdominal pelvic organs, abdominal mostly. These are all labeled for you, for when you get to the ID manual, just to provide additional context, right? And this is just to end with what it looks like in a real person, but it's not yellow. It's just white-ish. It's like all these stringy fibers that you gotta get through to see things. All right, so that's all we have. You guys doing all right? We're front-loading this material. If you are like, I don't even know where to start, I'm very confused, come talk to me sooner rather than later, because if you don't talk through this and you're frustrated and you can't figure it out, it's gonna be much harder to get through. See you tomorrow at Research Day.