Neurology | Adrenergic Receptors

I ninja nerds in this video we are gonna talk about adrenergic receptors these are extremely important so let's go ahead and get started so adrenergic receptors we're gonna talk about these in in two classes right so here let me write up here we're gonna have a drone urge ik receptors ok adrenergic meaning that they're very very sensitive to what adrenaline but again we call adrenaline nowadays we actually call it epinephrine but there's also other neurotransmitters such as norepinephrine so when we talk about adrenergic receptors we're gonna talk about specifically the receptors that are sensitive to epinephrine and norepinephrine okay and there is other different types of molecules that are very similar in their activity we call those adrenergic agonists those would be things like isoprene alene and dobutamine all those different types of things we'll talk about those very very briefly but what I want you to understand is that adrenergic receptors are sensitive to chemicals such as epinephrine and norepinephrine now next thing I want to do is I want to say okay let's separate these two receptors okay well let's separate these receptors into two subclasses right so now we have two classes here we're gonna have alpha adrenergic receptors so we're gonna put this as alpha adrenergic receptors and the other one is going to be beta adrenergic receptors okay now what is important to know about these is specifically their subtypes if we really want to dig into this and really understand it we have to understand their subtypes so alpha adrenergic receptors there's actually two types alpha 1 a generic receptors and alpha-2 adrenergic receptors okay beta-adrenergic receptors there's three types okay there's three types and these are simple beta-1 adrenergic receptors beta-2 adrenergic receptors and beta 3 adrenergic receptors okay so now we know what adrenergic receptors are the receptors that are sensitive to epinephrine norepinephrine we know there's two classes alpha and beta we know that alpha is sub classified into alpha 1 alpha 2 and beta is sub classified into beta 1 beta 2 beta 3 why should we know this now here's what we're gonna talk about with respect to this cell each one of these receptors for the most part respond they to a specific chemical such as epinephrine norepinephrine but exert an intracellular signal that is unique and different so what I mean alpha 1 we're going to go over it but alpha 1 adrenergic receptors primarily work through GQ proteins so GQ coupled protein receptors okay alpha 2 is primarily through G inhibitory okay primarily through G inhibitory but beta 1 beta 2 and beta 3 primarily work through what's called G stimulatory so now what I'm gonna do is I'm gonna go over the different intracellular mechanisms of these adrenergic receptors in detail and why that's important to know okay so let's go ahead and do that then okay first things first let's start off with the alpha 1 add your nergic receptor alright so let's say here we're gonna have this part of the cell membrane here right and at this part of the cell membrane here's going to be our receptor and this receptor is going to be an alpha 1 we're gonna start with that one first so here's going to be our alpha 1 adrenergic receptor ok so alpha 1 adrenergic receptors we said act through G q protein-coupled receptors so let's pretend here that we have either one of the two chemicals we can have Noro epinephrine or we can have epinephrine both of these guys can act on the alpha one adrenergic receptors now technically if we want to be particular epinephrine has a higher affinity for the alpha 1 then norepinephrine does anyway both of these guys can come over here and act on this receptor now let's say that they bind to the receptor we know that these receptors are usually linked or connected with a g-protein we said in this case that the g-protein is actually G q GQ protein we said that GQ is normally bound to gdp but it throws away the gdp and takes on gtp gtp when it binds to the GQ protein stimulates it then this GQ protein will come and stimulate an effector enzyme that's located within side of the plasma membrane this enzyme is what we refer to as phospholipase C so we call this enzyme here phospho lipase see what phospholipase c does is is it breaks down a chemical which is called phosphorus phosphatidyl and a Seidel diphosphate and what it does is it breaks down to two chemicals one is called dye Aseel glycerol the other chemical is called an acetyl triphosphate now diacylglycerol goes and activates a special type of enzyme we call this enzyme a protein kinase and if we really want to be a particular protein kinase c so this is going to stimulate that ip3 works through a different mechanism it actually activates different types of calcium storage centers and when it activates these calcium storage like the sarcoplasmic reticulum or the endoplasmic reticulum it increases the release of calcium out of those structures now calcium will then go and bind on to a special protein as usually located within these cells which is called calmodulin now when calcium binds with calmodulin it forms what's called a calcium calmodulin complex or sometimes they even say kinase okay now why is this important okay calcium calmodulin complex and protein kinase II can phosphorylate different types of proteins so this can come over here and what it can do is it can phosphorylate different types of proteins let's say here I draw in red this is going to be some type of protein here and here's its amine end and then here is its carboxyl end right what it's gonna do is it's going to put phosphates onto this protein and when you phosphorylate proteins it can either activate or inactivate the enzyme at all obviously depends on that protein or enzyme in this case same thing with the protein kinase C just remember it can exert the same type of activity here by phosphorylating different types of proteins / enzymes and why is this important depending upon the tissue these proteins might be different types of membrane proteins and maybe this membrane protein is some type of channel and it can allow for cations to leak into the cell maybe these proteins can actually go and do other different things like certain metabolic functions metabolic functions or maybe it could actually go to the nucleus and trigger DNA transcription so there's many different functions of these different types of proteins or enzymes so it can change the membrane permeability there's so many different functions okay and again that's not the biggest thing the biggest point here is I want you to understand that the intracellular mechanism is increasing calcium and protein kinase C phosphorylating proteins that can have various different functions with inside of this cell that's alpha 1 alpha 2 is a lot easier okay so now let's do alpha 2 here let's do this one here nice purple color so here we're gonna have a receptor right here and alpha 2 is thankfully a lot easier here so here's our alpha 2 and alpha 2 receptors alpha-2 adrenergic receptors are actually going to be G inhibitory we said so whenever epinephrine or norepinephrine bind on to these receptors and again epinephrine has a higher affinity than norepinephrine it'll activate an intracellular G inhibitory protein now what's important about this is that the G inhibitory protein has three subunits in alpha inhibitory a beta inhibitory and a gamma inhibitory okay now why is this important whenever epinephrine binds on to the adrenergic receptor it separates these two so alpha inhibitory separate and beta inhibitory separate now the Alpha inhibitory come over here and they bind on to this special type of membrane protein here this special type of affect our enzyme and we're gonna call this adenylyl cyclase right so a denill I'll cyclase you might see in other videos I've usually been lazy and just denote it as a C alright alright but anyway this alpha inhibitory subunit is going to come over here and what it's going to do it's just going to inhibit the identify cyclase now adenylyl cyclase is normally responsible for being able to convert ATP into a molecule called cyclic a MP right but if the Alpha inhibitory unit is binding to the adenylyl cyclase it's inhibiting it is it gonna be able to make cyclic a MP no so as a result the cyclic a MP production will decrease cyclic a MP is normally supposed to activate protein kinase a right and then protein kinase a is important because it can go and do what phosphorylate different proteins and enzymes but if it's not able to do that will it be able to phosphorylate the different proteins and enzymes No so that's the whole significance here now what else what about this beta and gamma 10 hibbett or unit let's do this in orange now there are special channels usually in most of these cells that have this gene hibbett or unit and these are sensitive to the beta and gamma subunits so let's say that the beta and gamma subunit come over here to this orange channel and it binds on to this channel when it does that it opens this channel up alright so it opens this channel up and allows for potassium ions to leave the cell if potassium ions leave the cell what's that going to do to the inside of the cell it's gonna make it negative it's gonna try to hyperpolarize the cell you're gonna see why this is important because the main location of alpha-2 adrenergic receptors is on the presynaptic nerve terminals and it's gonna make sense when we go over that okay again we're just laying down the groundwork for this stuff now easiest thing is that's alpha 1 alpha 2 beta 1 beta 2 beta 3 all have the same intracellular pathway and thank goodness for that what is that one that one is G stimulatory so now we've already pretty much laid down the groundwork so watch this okay here we're gonna have our next receptor and again this can be beta 1 it can be beta 2 or hey let's do like this beta 1 beta 2 or beta 3 adrenergic receptors these guys again they're sensitive to epinephrine and they're sensitive to norepinephrine when they bind on to this receptor they're going to activate a intracellular G stimulatory protein that G stimulatory protein is going to pop off a GDP and pick up a gtp activating this enzyme if this is stimulated what is it going to do it's gonna act on a dental on cyclase it's gonna stimulate a dental on cyclase what is that going to do that's going to increase the conversion of ATP to cyclic AMP II that's going to increase the actual activation of protein kinase a which is then going to go and phosphorylate different types of proteins and enzymes with inside of the cell so now we should understand the different types of receptors we should understand their difference in intracellular pathways in the overall significance of it now what we got to do is we go to got to go ahead and talk at all the different types of target organs or locations of these different types of receptors so let's go ahead and do specifically focusing on the blood flow I think that's a good way to get started on these because it kind of glaze down a nice groundwork for us so first thing we're going to talk about is these adrenergic receptors located on the tunica media right you know within blood vessels you have your really simple diagram here let's say here's a blood vessel you have an inner lining which is called the Tunica intima after that you're gonna have smooth muscle lining which is called your tunica media and then after that you have some connective tissue outside of it which is called the Tunica externa or the tunica adventitia the tunica media has a lot of adrenergic receptors and because of that it's very very sensitive to epinephrine norepinephrine so it can control the diameter of the blood vessels so that's where we're gonna start with first talking about the adrenergic receptors on these two Nigam media these blood vessels so first one we're gonna talk about is the blood flow to the integrant airy system or the skin okay I want you to think about these things logically it's best when we think logically if you're in a sympathetic crisis we know that the sympathetic nervous system primarily functions in different types of fight or flight or crises like types of situations so we've used the example of like running away from an orangutan or fighting with Chuck Liddell whatever something that's gonna get you hyped up and really really nervous okay now think about this the skin is that gonna help you run away from orangutan or fight Chuck Liddell no it's not gonna do anything for you so we don't really care about the blood flow going to the skin we'd rather that blood go to the skeletal muscle so that we can run or fight so in that concession I want you to think about that usually on the vascular smooth muscle of the skin is going to be what's called alpha-1 adrenergic receptors that's what we're gonna find there now think about alpha one what did it do before well it increased the GQ which increased the calcium and protein kinase C I know that calcium helps to activate the muscles to start undergoing contraction they need that for the cross bridge formation oh that's why okay that makes sense now the blood flow to the skin is going to be reduced if the blood flow to the skin is reduced what normally will someone in like a sympathetic situation what color will their skin be usually they're gonna have like a pale ish skin appearance or skin hue right okay so that's one big thing and the next thing we should understand you know there's a muscle that's actually connected to the hair follicle and whenever we're in a sympathetic situation like we're scared usually the hairs stand up okay well there's a muscle there called the erector pili muscle and that erector pili muscle guess type what we guess what type of receptors they're in alpha one adrenergic receptor and again what is that going to do that's going to cause the contraction of this actual muscle which is gonna cause the hairs to stand up so as a result when this is stimulated the Iraq door pili muscle when that's stimulated it's gonna cause the hair to stand up okay so far we got that okay so that's the skin so the first thing we want to make sure that we do is we divert the blood away from the skin vaso constricting the blood vessel if we do that the skin will be more pale ish and also it's sensitive to the erector pili erector pili has alpha one adrenergic receptors if it contracts it causes the hairs to stand up next place next place is going to be going to your kidneys so now let's think about the kidneys or the renal system so this is going to be specifically for the kidneys the blood flow going directly to the kidney so here's our kidneys here right so kidneys and the kidney right we specifically want to know what's gonna happen to the blood flow in the kidneys well if you're running away from an orangutan or fighting Chuck Liddell you don't want to pee yourself so you want to be able to restrict the urine from being formed so if that's the case do I want a lot of blood going into the kidney so that they can filter that blood and then make urine no so if that's the case I'm gonna want to reduce the blood flow to the kidneys if I want to reduce the blood flow to the kidneys what type of receptors would you expect to be on these blood vessels going to it it would be alpha one adrenergic receptors and again that's going to reduce the blood flow bf4 blood flow right and then as a result you're going to make less urine as a result of that okay all right that covers that next one the GI T if you're running away from an orangutan or fighting chocolate Dell are you gonna be worried about digesting like a hotdog or something no you don't give a rip you don't care about that right now you'd rather spend that blood going to your muscles or useful vital organs so if that's the case let's constrict these puppies here so now what we're going to do here is for this one the blood flow going to thee g.i T our splanchnic circulation we don't really care about that so let's constrict those bad boys so we're gonna have the alpha-1 adrenergic receptors located right here and if they're located right there it's going to reduce the blood flow to the GI T decreasing different digestion absorption decreasing secretions right so that's the purpose there okay next one this one's a little interesting okay so far we've been pretty much hitting all the unnecessary or not vital organs like the skin the kidneys the GI T what about this the blood flow to the skeletal muscles okay well I know that if I have a lot of blood flow going into the skeletal muscles that's going to be helpful for me because I got to run away from this orangutan or fight Chuck Liddell so I need a lot of blood flow going to the muscles but if I constrict them if I can strict these blood vessels that's not going to help me at all instead I need to dilate them so here's what I want you to remember if that's the case then if we want to dilate these bad boys the main receptor the main receptor that's located on these guys is going to be what's called beta-2 adrenergic receptors because the beta-2 adrenergic receptors they work through a G stimulatory pathway right so they're going to increase cyclic a and P if they increase the cyclic A&P it's going to increase the protein kinase a right well what protein kinase a does is it actually inhibits a special enzyme that's controlling the blood flow to these actual muscles so and then that case the muscles are going to relax so it's gonna be increased perfusion to the muscles so what should happen to the blood flow to the muscles the blood flow to the muscles should be increased and these blood vessels should dilate okay so the skin constricted the kidneys constricted the GI T constricted but the blood flow to the skeletal muscles vaso dilated increasing the blood flow alright what about the blood to the actual heart itself you know the blood has a system called the coronary circulation that serves itself here's what's interesting this one has kind of about an equal amount of alpha 1 and beta 2 here's what I want you to remember these receptors alpha 1 and beta 2 these are usually the only ones specifically that you're going to be found on our spatula smooth muscle so with the receptors that are present on the tunica media there is mainly of two types alpha 1 beta 2 alpha 1 is going to cause constriction beta 2 is going to cause relaxation this one has about an equal amount of beta-2 adrenergic receptors and alpha 1 adrenergic receptors now why is that significant our heart cannot rely upon the sympathetic nervous system or the autonomic nervous system because it's fluctuating all the time so if the blood flow going to our actual myocardium is actually dependent on the autonomic nervous system it could be very very dangerous so because of that the blood flow going to the heart itself is under what's called metabolic control in other words if there's a decrease in oxygen right if there's some type of situation like a decrease in oxygen or an increase in what's called adenosine these type of things can actually dilate the blood vessels so because of that they have what's called an auto regulation in other words they can regulate their blood flow on their own based upon different types of metabolic substances so if there's like a decrease in oxygen an increase in adenosine that could actually cause the blood vessels to dilate increasing the blood flow so depending upon the chemical factors that are in the blood that can alter the actual blood vessel vasoconstriction and dilation so I want you to remember that so the autonomic nervous system doesn't have a very significant effect on the coronary circulation in the same sense central nervous system we can't leave the blood flow to the central nervous system or to the heart at the mercy of the sympathetic nervous system because it fluctuates so much so if that's the case then we do not want to just have primarily alpha-1 adrenergic receptors we want to have a mixture of alpha 1 and beta-2 adrenergic receptors and again if that's the case then then the actual central nervous system has to have its own regulating system and again we call that auto regulation and this auto regulation is usually through what's called a Myo genic mechanism and we've talked about this and many other videos like the microcirculation video ok but the myogenic mechanism is just basically if there's an increase in pressure it constricts the vessel if there's a decrease in pressure it dilates the vessel so this has its own way of being able to control the blood flow that's not dependent upon the autonomic nervous system ok sweet deal ok now that we covered that let's kind of start working our way down may have multiple different types of structures okay so we get to the eyeball we've talked about this again and a lot of this is going to be kind of like a continuation of what we talked about in our sympathetic nervous system video what kind of just going through the target organs that we had there and talking about the receptors that are present there okay so if we think about this the sympathetic nervous system wants us to see far if you guys remember we said we wanted far vision so there was two different muscles that we wanted to target here one was called the silly eros muscle if you remember we have the silly eros muscle and the silly eros muscle we said Smith should be specifically relaxed if this muscle relaxes then what happens is is these little zone yells the ciliary the suspensory ligaments are the ciliary zonules those who become nice and tight if those become really really tight the lens gets really flat so if that's the case then we don't want this muscle to contract because if it contracts it pulls the muscle up this way and cause those o'neill's to get really really relaxed so instead we want this muscle to relax if we want it to relax what type of receptors would you expect to be there beta 2 so beta-2 adrenergic receptors should be located there ok and again because of that the ciliary muscle it will relax if the ciliary muscle relaxes this is going to cause the lens to flatten and if the lens flattens that's gonna allow for the vision to be set for faraway objects ok next thing what about this muscle you know the muscle around the IRS you have specifically they call it the dilator pupil a right this muscle if it contract-- it opens up the pupil hole so that's if that happens it causes pupillary dilation so now as a of that it's going to cause pupil dilation and again if we dilate the pupils it's going to increase the amount of light rays hitting the retina and again both of these are going to function for overall far vision and it should make sense if you're running away from an orangutan you want to know all the different types of options you know you can go to all right to be able to escape that all right sweet now here's the thing though we said that there's beta-2 adrenergic receptors in the ciliary muscle but we said that the dilator pupil a its function is to open the pupil that means that the muscle contracted if the muscle contracted then it has to be it has to be an alpha one adrenergic receptor okay alpha one adrenergic receptor okay now let's go to this one the salivary glands not super super crucial to this but again it's understanding why you know what would happen here so if we go to the salivary glands are you gonna be worried about making a lot of saliva being able to digest different carbohydrates or maybe lipids within the mouth No so you're not really like obsessed with that so because of that the salivary glands have specific receptors on them and generally these are going to be beta-2 adrenergic receptors and what this is going to do is it switches the salivary secretions into making less water and electrolyte rich saliva so it's going to it's going to decrease the amount of water and electrolytes that are in the saliva and it's going to increase the mucin proteins and increase different types of salivary enzymes if that's the case then it makes the overall salivary secretion it makes it a thicker saliva okay so it makes this saliva really thick and really viscous another thing is there's blood vessels that are going to the actual salivary glands and if the blood vessels are going to the salivary glands the actual receptors can be present on these actual blood vessels going there and if that's the case we can constrict these blood vessels and decrease the blood flow to the actual salivary glands which would decrease the water and the electrolytes that we can filter out so if that's the case we're going to want the blood vessel to constrict so this should be alpha one adrenergic receptors and again that's t gonna decrease the blood flow which is going to decrease the amount of water and electrolytes that are going to be put into the saliva okay all right now let's go over here we already talked about the blood flow to the central nervous system but we have to talk about one more thing okay we said that we have these things called presynaptic nerve terminals right so okay let me actually fix this for a second and let's do this like this so here you're going to have your pre ganglionic motor neuron right coming out of the thoracic region of the spinal cord you know the thoracic regional spinal cord is from t1 all the way up to about l2 right so we have t1 all the way to l2 these are your pre ganglionic motor neurons right but let's say that just in general we come over here and we have like let's just say that this is a ganglion and then here I'm gonna balloon up this axon terminal okay if you guys remember we've talked about this in certain videos that you know that we have vesicles synaptic vesicles that are located within the axon nerve terminal and they consist of neurotransmitters in this situation we're gonna say that it's norepinephrine so in this one is nor epinephrine norepinephrine norepinephrine and we know that whenever there's an action potential being carried down the axon it opens up special voltage-gated calcium channels that are located within the axon terminal so let's say that here in green is going to be these voltage-gated calcium channels and we said that whenever the action potential travels down it opens up these calcium channels calcium rushes in and then stimulates the migration of these vesicles to the actual membrane where it will fuse and if it fuses it will release these chemicals there's norepinephrine by exocytosis well guess what there's another receptor that's kind of sitting right here okay let's put him right here let's make it nice and red here here's this receptor here's a nice little receptor here and this receptor is going to be very sensitive to the norepinephrine that's being released when norepinephrine is released what it can do is is it can go and act on its target organ let's say just say here's its target organ right but another thing that can happen is that norepinephrine can come over here and act on these receptors that are present on the actual presynaptic nerve terminal these receptors are called alpha-2 adrenergic receptors if alpha-2 adrenergic receptors are activated by this norepinephrine guess what they're going to do they are going to decrease the actual cyclic ANP production which is going to decrease the protein kinase a if protein kinase a is actually in decreased amount guess what can happen it can actually inhibit these calcium channels from opening another thing is if it binds on to the alpha-2 adrenergic receptors remember what else it did it opened up special channels on the membrane that were sensitive to the beta and gamma subunit and allowed for potassium to leak out of the cell if potassium starts leaking out of the cell it makes the cell increasingly more negative if this cell becomes increasingly more negative is it going to be able to be stimulated is it gonna be able to depolarize open up the calcium channels that they can cow can come in and cause the release no so because this norepinephrine bonds onto the alpha-2 adrenergic receptors it can cost potassium ions to leave hyperpolarizing cell making it unable to release norepinephrine so that's a cool little mechanism right there okay so that's what I want you to remember the biggest biggest target organ of alpha-2 adrenergic receptors is these actual nerve terminals the presynaptic nerve terminals and what norepinephrine do can do is actually buying on to them increase the potassium ion efj lux hyperpolarized this nerve terminal and make it unable to allow for calcium to come in if calcium cannot come in it's not gonna trigger the release of norepinephrine that's so cool all right that covers that part now let's go and let's talk about the heart the heart we already know the blood flow we know that has its own auto regulation and we know that the central nervous system has its own auto regulation mechanisms this one more by metabolic the central nervous system or by myogenic but the heart has its own nodal system if you will let's do this in orange here it has its own nodal system okay like the SA node if you remember it has the AV node it has the bundle of hiss and it has the bundle branches and the Purkinje system well on the SA node and the AV node and the bundle of hiss they have special receptors and these special receptors that are located on the SA node the AV node the bundle of hiss the bundle branches but primarily SA node AV node in the bundle of hiss these are specifically going to be beta-1 adrenergic receptors easiest way to remember is beta-1 adrenergic receptors are usually only located in about two important play this one is the SI no specifically the heart the myocardium of the heart SA node AV node bundle of hiss and another part which is the actual contractile myocardium and the second place is the juxtaglomerular cells in the kidney that caused the release of renin and there's one more which is it's not significant but it can actually cause the release of Grillin from the stomach a hunger hormone but the big ones is beta one are located on the heart and the kidney so remember that two big ones and you covered beta one now we said that it's located on the SA node AV node bundle of hiss and the actual contractile myocardium so if that's the case then if it's located on all these different locations I want you to remember what's the overall effect if it acts on the AV node SA node and paren the bundle of his it's gonna increase the action potentials that is going to increase the heart rate heart rate increases cardiac output increasing cardiac output increases blood pressure so that should make sense okay at the other end of this it's gonna increase the contractility increase in the calcium loading into these cells if that happens it's gonna increase stroke volume if you increase stroke volume increase cardiac output and if you increase cardiac output you increase blood pressure okay so we know that there's beta-1 adrenergic receptors located on the SA node AV node bundle of hiss and the contractile myocardium alright let's go to the next one which is the muscle so we talked about the blood flow but there's something else really special about the muscles there is actually these things called muscle spindles and these muscle spindles are actually responsible for being able to determine the stretch the appropriate receptors basically help us to determine the position of our actual muscles in space and specifically determining the stretch of the muscles right either the beginning of the stretch or the progression of the stretch well they have special receptors on them and these were set there's that a present on them can increase the muscle spindle firing if you increase the muscle spindle firing it increases the contraction of those muscles which causes a slight tremor effect as that's why sometimes if any of you I have asthma so I have sometimes I have to take an hailer all right I'll beautiful and how butyl is just basically a beta-2 agonist meaning it acts on beta 2 receptors just like epinephrine and norepinephrine would when it binds on to it its main that does goal is to cause dilation of the actual bronchi that's the whole purpose about butor all but as a side it also can act on these muscle spindles and if any of you do have asthma you've taken our beuter or sometimes you're a little shaky and it's a little bit of a tremor and that's because of these actual muscle spindles so there's going to be beta-2 adrenergic receptors on the muscle spindles which is going to produce kind of like a little tremor okay it also has another function to that with the beta-2 adrenergic receptors our muscles are constantly depolarizing and repolarizing and so what they're doing is they're pushing out potassium and they're constantly bringing in sodium and because of that we want to be able to maintain that gradient so there's an in there's a protein called a sodium potassium ATPase and what it does is it pumps three sodium out of the cell and two potassium into the cell well the beta-2 adrenergic receptors guess what they can do they can stimulate the this dang marker it can stimulate these sodium potassium ATPase --is and increase the influx of potassium and increase the e-flat of sodium maintaining those gradient so that whenever there's another stimulus to the muscle it'll be ready to contract it'll have this it's the necessary ions in the extracellular fluid and the intracellular fluid so it'll be able to depolarize and repolarize okay so we covered that so that's going to be important for the sodium potassium ATPase and the muscle spindles let's go up and we go to the GI tract the GI tract we already know the blood flow we don't really care about the blood flow so we want to constrict the vessels going to the GI T but another thing and what you remember is are you gonna be worried about contracting you know there's receptors here right you have you have smooth muscle all around this actual GI T right within the muscularis externa you don't want that to contract you don't want to waste energy because remember the sympathetic is for fight-or-flight parasympathetic is for resting digesting urinating defecating we're not gonna want to enhance the GI motility so if that's the case we want to have inhibitory receptors which is our beta-2 adrenergic receptors and if we have these on all of the GI smooth muscles throughout the entire GI smooth muscle what is it gonna do it's gonna decrease GI motility and decrease GI secretions and as a result it'll decrease the absorption across the GI tract so remember that there's beta-2 adrenergic receptors on the actual smooth muscle of the GI tract but here's where it gets a little tricky okay it gets a little tricky because there's sinkers of the GI tract one is called the pyloric sphincter so right here we have what's called the pyloric sphincter and then there's another one right here which protects your due to hole and that's called the internal anal sphincter your sympathetic nervous system is very very kind to you he prevents you from crapping your pants right so nicely he has to have receptors here that are stimulatory and will constrict so in this one at the pyloric sphincter it constricts because it wants to prevent the movement of chyme out of the stomach and into the small intestine that's the purpose here for the pyloric sphincter we want this to contract so that we can prevent the movement of the food we don't want the food to go from the stomach into the small intestine next thing is we're not really worried about dropping a Lincoln Log okay so because of that we don't need this internal anal sphincter to control we don't need it to relax because we don't want to allow for the putu move down so if that's the case we want this structured sucker to be constricted hard right so you want there to be alpha one adrenergic receptors there because it'll constrict it and prevent that log from going down okay let's move on next to the actual kidney alright so we did the kidney we did the blood flow but remember I told you inside of the kidney is a special apparatus we talked about this in the renal system so there's no use in going into super detail here but if you remember we had these structures which are called your J G cells J G cells and these guys were really specific they were baroreceptors and they could respond to their own blood flow by releasing Wrentham well at the same time they also have receptors on them that are sensitive to epinephrine and norepinephrine and what did I tell you beta one is only located on real to important places the heart and the JG cells of the kidney so right here we're gonna have beta-1 adrenergic receptors on the JG cells and again what is the significance of it when epinephrine and norepinephrine bind here the whole significance is it's going to stimulate the release of renin and if you remember the purpose of Renan Renan cleaved angiotensinogen that was made by the liver angiotensinogen converted into angiotensin one angiotensin one went to the lungs got converted into angiotensin 2 by ACE angiotensin 2 then bind onto the actual smooth muscle of our vascular smooth muscle and constrict those puppies and then on top of that it released ADH from the posterior pituitary and aldosterone from our adrenal cortex to increase the sodium in the water reabsorption from the kidneys to increase our blood volume and our blood pressure so it should all make sense ok now let's think about this again here's our ureters right are you gonna be worried about spending and wasting energy and contracting the orders to push urine down no just like you didn't want to drop a Lincoln Log you don't want to pee your pants so because of that you wanted minute you want to minimize the urine output alright that's the whole goal here you want to try to minimize that urine output that's for the parasympathetic nervous system so if that's the case then are you gonna want to have these your udders contract no you're gonna want them to relax so smacking inhibitory smack on one that's gonna do that that would be the beta to the beta-2 adrenergic receptors are gonna cause the smooth muscle in this area to relax and if the ureters relaxed is it gonna push yarn down no now obviously urine can move down by gravity so there's not a significant effect here but the ureters do have a little bit of peristaltic activity that they can push urine down next thing your bladder are you gonna be worried about evacuating the bladder causing the bladder to contract no you don't want to urinate so because of that you're gonna want to smack your beta-2 adrenergic receptors on this puppy and recent research has also showed that there's actually beta 3 adrenergic receptors present on this smooth muscle here which is they call it the detrusor muscle okay but big one is the - but again just want to show you that there is another one out there of that being beta 3 and again this is going to relax the bladder and if it relaxes it's not going to cause the evacuation of the urine into the urethra next thing we have another protective mechanism so now only we decrease the urine flow through the ureters we've also decreased the blood flow to the kidneys we've also decreased the contractions of the actual bladder let's squeeze this sucker as hard as we possibly can right so let's go ahead and have this internal your wreath ro tur also really really tight so in the same way that our internal anal sphincter was constricted we're gonna want this internal urethral sphincter constricted so let's throw on an alpha one add your nergic receptor okay now let's come up here to the actual adipose tissue so the adipose tissue why would this be important when you know you're out of post tissue your sympathetic nervous system is trying to get as much nutrients as much blood flow to your vital organs as possible because we need those muscles to have as much ATP as they can to contract and to perform the fight-or-flight activity these are stored with energy systems called triglycerides lipids if our sympathetic nervous system can tap into that and get some of those lipids broken down we now have a very very powerful energy source so now our sympathetic nervous system should have receptors on our adipose tissue so this is our adipose tissue or our Depot sites right and what happens is there should be receptors here which are going to respond to the epinephrine and norepinephrine or epinephrine and break down look here's our glycerol here's our fatty acids we've drawn this in many many diagrams before this is the glycerol in the fatty acid glycerol and the fatty acid we want to be able to stimulate the breakdown of these actual triglycerides so what is that called when you want to break down lipids into glycerol and fatty acids if I want to do that I want to break this down into glycerol and fatty I'm gonna put FA for fatty acids that process is called lipolysis what hyper receptor will you went there generally we would say okay we would say Oh beta one right well there's a modified beta one receptor that modified beta one receptor is called a beta three adrenergic receptor thankfully there isn't many beta three adrenergic receptors in the body except from the adipose tissue and the recent research has shown also on the detrusor muscle that makes it a lot easier so if you can remember the beta one is on the heart and the JG cells of the kidney the beta three is mainly only on the adipose tissue and on the detrusor muscle alpha one is on the vascular smooth muscle that needs to be stimulated or constricted and the beta two is on the vascular smooth muscle that needs to be inhibited or relaxed makes it a lot easier okay let's come over to the pancreas what about the pancreas okay well there's two parts of the pancreas right you have the Ascend eye which is important for the digestive juices and then you also have the islets of langerhans okay now the islets of langerhans if you remember we had this in an individual video in our endocrinology system we have two different types of cells right alpha cells and beta cells the beta cells were the ones that released insulin and the alpha cells were the ones that were loosed released glucagon and if you remember insulin was basically trying to increase protein synthesis increased glycogenesis it's trying to increase glucose uptake so it's all generating pathways anabolic pathways glucagon is trying to do catabolic pathways break down glycogen into glucose make glucose from non carbohydrate sources and break down lipids that sounds like a good idea in this situation cuz I want them to get as much glucose into the blood and I want to get as much fat into the blood as I possibly can so that's the case I'd want to stimulate this soccer and inhibit that sucker so guess what it's a little weird okay the Alpha cells we said that the sympathetic nervous system we would prefer to stimulate this one and then the beta cells we would prefer to inhibit that one remember I told you if you want to inhibit things usually that's beta 2 so guess what it's not beta 2 though in this one it's actually alpha-2 adrenergic receptors so alpha-2 adrenergic receptors are located on the beta cells and if these are stimulated by the actual norepinephrine or the epinephrine it's going to increase potassium ion a flux which is going to affect the beta cells from being stimulated so if that's the case then it's going to inhibit the release of insulin the alpha cells though we want to stimulate them and so weird as it is they also have alpha-2 adrenergic receptors but whenever they're activated it actually acts on the alpha cells it stimulates the release of glucagon and again glucagon is gonna increase your blood glucose levels by gluconeogenesis and glycogenolysis and it's gonna act on your adipose tissue and cause the breakdown of lipids via lipolysis so that should make sense liver again the liver is a super metabolic organ you should think you know your liver for what it does for us but one of the big things that the liver does is two significant pathways one is it breaks down glycogen into glucose and another thing that it can do is it can take amino acids it can take glycerol and it can take lactic acid and convert that into glucose right and thankfully we have receptors that are located on our liver that can actually stimulate their glycogen to glucose stimulation and lactic acid glycerol and amino acids to glucose what do you call this bottom one lactic acid glycerol an amino acids making glucose they call that gluco neo Genesis we want to increase that activity we want glucose in the blood so that we can have our muscles having an energy source we want to break down glycogen into glucose that is called glencoe jeno lysis we want to increase that activity so we need to have receptors that are located on the liver and these receptors are called beta-2 adrenergic receptors okay now let's go to the next one the next thing that we want to do is we want to focus on the respiratory system the respiratory system the biggest thing is we know that we want to get as much nutrients into the blood fats glucose right we also want to increase the blood flow to the actual skeletal muscles we want to decrease the blood flow to the non vital organs we don't want our GI tract akin to be functioning and we don't want our urinary system to be functioning but we want as much air to come into our lungs as we possibly can because we want to get those lungs properly ventilated so that we can have good perfusion so if that's the case then we want to make sure we open up those bronchi as best as we possibly can so now in the actual bronchi so here's our bronchi and I'm just kind of zooming in on that bronchi which is going into the lungs right there's smooth muscle here within the bronchi they call it the bronchial smooth muscle the bronchial smooth muscle is really really rich in special types of a generic receptors and those are beta-2 adrenergic receptors remember if we want the smooth muscle to relax we throw on some beta - if we want the smooth muscles to contract we throw on some alpha but we want the smooth muscle to relax if the smooth muscle relaxants what happens to the diameter of this airway it's gonna increase which is gonna cause more ventilation more ventilation increases perfusion so we're gonna have more oxygen in the blood another thing is you know which is really cool when I was doing some research here there was these suckers here called your mast cells they sit in the lamina propria right the connective tissue the areolar connective tissue and these mast cells it's really really cool they also have receptors and these receptors are also beta-2 adrenergic receptors and whenever epinephrine and norepinephrine acts on these beta-2 adrenergic receptors on the mast cells it inhibits the mast cells from releasing histamines if the mast cells don't release a lot of histamines what's it gonna do to the blood flow going through this area so imagine here I have a little blood vessel the bronchial remember these are our bronchial arteries this is not the pulmonary arteries I'm gonna repeat that one more time this artery is not a pulmonary artery it is a bronchial artery now histamines can act on your bronchial arteries right and generally what they do is they cause vasodilation and increase the capillary permeability well if there's decreased histamines are your blood vessels going to dilate no instead there's actually going to be more constriction of those bad boys so what that does is it decreases it decreases the blood flow and if you decrease the blood flow through the bronchial arteries it's going to decrease the secretions - because your glands the different types of serum mucus glands they depend upon the blood flow if the blood flows low you don't have enough blood going to that serum mucus glands you're not going to make a lot of that mucus so it's going to decrease see cretians think about that if you decrease the sea creatures within the airway is it gonna be as plugged no so you now you're gonna have an open Peyton airway for the air to flow through all of these hoarding the sympathetic nervous system holy frak ok let's go to the the male reproductive system if we go to the male reproductive system I want you to remember this parasympathetic point that's for the erection sympathetic is for the shoot for the ejaculation so sympathetic should be on all the structures that are going to support the ejaculatory response what are some of these structures remember we had what's called the epididymis so here we're gonna call this the EPI didymus then we're gonna have this tube which is going up and this tube is called the vas deferens then we're gonna have a vesicle here which is making specifically different types of seminal fluid and this is called your seminal vesicles and then the other one is going to be your prostate gland all right all of these structures are extremely important in the ejaculatory response now they're smooth muscle which is located within the epididymis and the vas deferens so there's some smooth muscle here all the way up and then all the way over here so we want this smooth muscle to contract if we want it to contract what type of receptor should we throw on those suckers alpha one so I want alpha one adrenergic receptors here I'd want the alpha one adrenergic receptors on the vas deferens also there's a little bit of smooth muscle around these actual glands some different types of mial epithelial cells and whenever they contract it helps to squeeze some of the actual seminal fluid into this vas deferens so now we want to stimulate those puppies so if that's the case let's have alpha one a generic receptor same thing alpha one adrenergic receptor and again what's the whole purpose of this if this epididymis is contracting it's pushing the sperm up into the vas deferens if the vas deferens is contracting its pushing the sperm forward throughout the male reproductive tract if the seminal vesicles are contracting they're squeezing out the seminal fluid if the prostate gland is squeezing it's actually squeezing out the prostatic fluid and then it's going to help to make the little swimmer so then out of here is gonna become the little swimmer and he's looking to target a ovary right there our target specifically a NOAA site okay got that part now let's go to the uterus okay for the uterus it's extremely interesting the uterus has smooth muscle right within the actual they call it the myometrium right so you know you have the endometrium myometrium perineum this red layer here is called the Myo metrium now the actual smooth muscle on the myometrium can have two different types of adrenergic receptors one is alpha one and the other one is beta 2 beta 2 though is the one that's more closer within the actual labor periods like getting towards the end of labor I'm sorry getting towards the end of gestation here's why in a situation where a person has let's say premature labor right they go into premature labor if they start going into premature labor their uterus is trying to contract and expel the baby out before it needs to be expelled out and we don't want that to happen right we don't want this baby to be coming out anytime soon we want to wait a little bit so if that's the case we need to give some type of drug that can bind on to a beta-2 adrenergic receptor while they're pregnant we need to give them some type of beta-2 adrenergic receptor some type of drug that combine onto it while they're pregnant that it prevents the premature labor contractions we want to slow these premature labor contractions down they call this type of drug that you can give a toke Oh lytic agent okay usually they can give like terbutaline not really important within this but I'm just giving the whole purpose here if norepinephrine epinephrine buying on to the beta to a genetic receptor what do we say it does to the smooth muscle it relaxes it if it relaxes is not gonna start splashing out the baby prematurely okay okay now we have one last thing thank goodness and that is going to be in the blood in the blood we have these tiny little cytoplasmic fragments which are called platelets so let's say here I have some platelets whenever the sympathetic nervous system releases norepinephrine or epinephrine these two chemicals can bind on to these receptors that are present on these platelets and this is why sometimes stress can be a very bad thing there's receptors located on these platelets which are called alpha-2 adrenergic receptor so again here's one here and this is going to be alpha-2 adrenergic receptor let's say here's another one and this is an alpha-2 adrenergic receptor if it acts on these alpha-2 adrenergic receptors on the platelets guess what this does it triggers these platelets to start making chemicals and the chemicals that these platelets start making are very very dangerous some of these chemicals are like thromboxane a2 another one is called Cerro tonin and then the worst one is a DP if you guys remember from hemostasis these chemicals ADP serotonin thromboxane a2 these particularly caused a problem and this situation was called platelet aggregation and if you increase platelet aggregation what are you going to increase the formation of a deadly situation right that it will kid be deadly and that is going to be the increased formation of possibly a thrombus okay iron engineers I hope this video made sense I hope that you guys did like it I hope that you learned something if you guys did please hit that like button comment down the comments section please subscribe also guys if you're getting a chance go check out our Facebook Instagram and even our patreon account if you have the opportunity to donate we would truly appreciate it alright engineers as always until next time [Music] you

Channel: Ninja Nerd Lectures

Views: 156,082

Rating: 4.9704361 out of 5

Keywords: adrenergic receptors, neurology, norepinephrine, epinephrine, sympathetic nervous system, autonomic nervous system, alpha adrenergic receptors, beta adrenergic receptors

Id: ZLW8V7bwW4U

Length: 65min 50sec (3950 seconds)

Published: Wed Feb 28 2018