The respiratory center

so in this video what I wanted to focus on is one particular area of the brain actually two areas I'm going to sketch out not just one but I'm going to show you how I think that these two areas can be kind of United in a way so these two areas where I'm sketching out these little green circles are going to be responsible for breathing how fast you breathe how deep you breathe and there are lots of little neurons in these two areas and these neurons are going to be communicating let's say this neuron sends a little axon down here maybe this guy sends an axon up here they're going to be communicating information among themselves and between themselves to kind of make sure they're working in a coordinated way so that the breathing that you do is is the way that it should be you know how fast it should be given a particular situation so the way I think of it is kind of uniting these two areas in fact sometimes it's subdivided even further but I kind of just put it all together and say this part of the brain that I'm kind of sketching out in green this area then is our respiratory center this is going to be responsible for all the important activities of breathing so let me just write that out here respiratory center so a respiratory center is going to gather information from different places and then it's going to have to make a decision and execute based on all the information it receives so one key piece of information is going to come from cells right here kind of neighborhood cells and these cells are called the central chemoreceptors the reason I'm calling them central is because they're also part of the brain right there they're right in the same neighborhood and so these central chemoreceptors don't have to go too far to communicate their information and specifically they're going to gather information on things like carbon dioxide levels and pH levels one thing they don't do is oxygen levels so that's these guys right here now if you have central chemoreceptors you also probably can expect that there would be some peripheral chemoreceptors and these ones are also very important and they exist outside of the brain right so they're going to be actually sending their information along through neurons that are going to extend all the way into the brain so for example you might have two key groups one is called the aortic body and the other is called carotids body they ordered body in the carotid body they're coming from different locations and actually you're going to use different nerves to get into the brain so the carotid body for example is going to let's say extend out this way through a neuron and that's going to be through a nerve called the right here called the glossopharyngeal nerve this is cranial nerve number 9 also called the glossopharyngeal nerve glossopharyngeal so this is one of the key peripheral chemoreceptors you've also got some nerves or neurons kind of projecting from the aortic body going through the vagus nerves this is our vagus nerve or cranial nerve number 10 goes by two different names this is our vagus nerve these peripheral chemoreceptors are going to detect things like oxygen in fact that's probably I want one of the most important things they detect as well as carbon dioxide and pH so that's information coming to the restaurant Center from our peripheral and central chemoreceptors then is mostly about chemicals now in addition there's another whole group of receptors called mechanoreceptors Meccano receptors and these ones are actually going to be sending information about pressure now you may be thinking well wait a second I thought baroreceptors told us about pressure and it turns out baroreceptors are one type of mechanoreceptor that's found inside of the blood vessels so there are many other types in many other locations and so the bigger kind of more general term would be Meccano receptor and you can find them in places like the nose you can find them in the lungs in the GI tract so lots of different locations for these mechanoreceptors and they're all sending kind of their own projection over to the to the respiratory center in fact the lungs and the GI tract are going to kind of hitch a ride in this vagus nerve and the nose mechanoreceptors they're going to travel through another nerve that's called the trigeminal nerve or cranial nerve number five trigeminal nerve so these are the the routes that these receptors are going to take to get to that respiratory center but how do these work exactly these mechanoreceptors let's take an example let's say you're walking and you inhale some pollen well that's going to trigger one of these mechanoreceptors in your nose and it's going to want to relay that information over to your respiratory center so you're going to get you know a little nerve impulse through that cranial nerve number five similarly in your lungs let's say you actually inhale some cigarette smoke and let's say the lungs don't like that and then mechanoreceptor feels that little particle it's going to trigger cranial nerve number 10 the vagus nerve similarly you have these stretch receptors that are in the lungs these are actually kind of interesting because what they're doing is they're saying hey you know these lungs are starting to get really really full really distended and so they want to let the rest rate Center know that maybe it's time to exhale and similarly in the GI tract you can imagine let's say a baby's taking milk and the stomach is getting really distended you might also imagine that that information would go back to the restor center as well in this case through cranial nerve number 10 so we have information about pressure or stretch we also have information about chemicals coming in but what about information on things like I don't know things like anxiety for instance or fear let's say someone's having these emotions right their breathing pattern may change maybe they're in pain so these kinds of things are actually coming from the hypothalamus the hypothalamus so this is another region of the brain that's sending information down to the respiratory center and helping to affect how we breathe and finally this is probably the largest part of our picture this is our cerebrum and the cerebrum is responsible for all the voluntary stuff that we do things like singing where you got to control your breath or maybe you're playing a musical instrument or maybe you're yelling or screaming let's put yelling down here anything like that you're going to want to control your breath right and so that's all voluntary control so this is our voluntary control and it's good that actually we have this mechanism so that we can if we want to we can change our breathing pattern but it's also great that our rest or center can can work on its own can you imagine if you had to always think about taking a breath you couldn't do anything else right couldn't sleep you couldn't eat you'd always just be thinking about taking a breath so that you you wouldn't miss the next breath and you know subsequently run out of air so this is all the information coming into our rest right center let me just scoop this over and actually show you now what our brain can do with that information to actually make sure that we're breathing comfortably this is our spinal column and I'm actually just going to label out the motor nerves and some of the muscle groups so we've got motor nerves and muscle groups and there are four key muscle groups that are going to be controlled by a respiratory Center and we're going to go through them kind of one by one so the first one and the one that people usually always kind of talk about or think about is this one right here this is going to be C 3 C 4 and C 5 so C 3 through C 5 and the muscle is the diaphragm this is the giant muscle that kind of sits right below our lungs and when it contracts you taking a nice deep breath but it doesn't work alone right we've got other muscles involved as well and so I'm actually going to sketch out what these other muscle groups are the first one is t1 through Tia Levin all these levels are going to send off a little nerve and each nerve will go through a different intercostal muscle so intercostal muscles or these are the muscles that kind of go between the ribs these are going to help expand or pull out your ribs right so these are important for breathing as well a little bit lower then you also have these abdominal muscles abdominal muscles here are going to be t6 through l1 these are the levels where the little nerve fibers come out and are going to help innervate or help these muscles abdominal muscles contract so this is a third group of muscles and they're controlled by these spinal levels and the final group would be this group up here so this is actually c1 through c3 c1 through c3 and these would be the accessory muscles accessory muscles are the ones usually I think of them as the ones around your neck area and they're going to also how to help pull out the rib cage and expand the lungs so there you have it you have information coming in that's the stuff that we started talking about all the different locations around chemicals information about pressure and you know your emotional status and what you're thinking about doing involuntarily all that information is going to come in and then the respiratory center has to decide how to kind of balance all that information and then on the way out it's going to be able to execute by controlling all these different muscle groups and sending information down the motor nerves that we just listed to these four big groups of muscles