all right Ninja nerds in this video we're going to talk about micro circulation so if you look here we have a pretty big diagram kind of pre-drawn and set out we got our brain here our central nervous system we got the lungs here we got a skeletal muscle tissue here okay we got some blood vessel serving those spe specific tissues here I just produ some generalized tissue cells just some general tissue cells nothing specific here is what we're going to look at this is going to be our artero venous and asmosis and capillaries that we're going to talk about in great depth and then over here I just wanted to draw a lymphatic vessel over here so it's just a little tiny little lymphatic vessel and then over here we have our skin epidermis and dermis and then over here I drew the GI tract with our end end of the esophagus stomach and then part of the small intestine so all of these we're going to go over every single one of these things here so let's go ahead and first start off right here the capillary beds so first off let's get some anatomy of our specifically this micro circulation here so if you look here I have the thing that actually gets ready to go into the uh capillary bed here is actually this this arterial here so this arterial that I'm going to I'm going to write down this one right here is called the terminal arterial so let me write that down so this one right here is called the terminal arterial and again this is is the one that's basically getting ready to feed into that capillary bed here or our AV shunt that we're going to talk about okay so this right here is the terminal arterial it's what's feeding it and then we have here this chunk here that I drew in red this is our meta arterial so we could say all this part here before we kind of go over into the vein here this chunk right there is our meta arterial okay so that's our meta arterial so again we got terminal arterial then we have meta arterial coming off of The Meta material are these true capillaries so these are our true capillaries so let's write that up there too so these right here are our true capillaries okay and you have about 10 to 100 True capillaries per capillary bed right so that's a true capillary coming off of The Meta arterial and then it's dumping over here into this structure right here and we're going to call this structure right here from there to there this is called the all right this is called the thorough right this is called the thorough Fair Channel okay that's called the thorough Fair Channel guys all right so we got meta arterial then we have true capillary and then we have thorough Fair Channel now if you think about it from The Meta arterial and cons can taking into consideration this Thorofare Channel and actually the Thorofare Channel actually come over here actually where that blue point starts right because it's going to be right after this this met AR then we have Thorofare channel the combination of these two this whole distance right there is referred to as the vascular shunt it's the vascular shun this is an example of an arterio Venice an asmosis all right so this is an arterio Venice and asmosis it's just the vascular shunt now next thing over here what's going to be draining out of draining this thorough Fair channel is going to be called the post capillary venel okay so again let's real quick recap this structure because it's going to be extremely important that we get it terminal arterial feeds this part feeds into the meta arterial coming off the meta arterial is the true capillary the capillaries after they undergo gas exchange can dump into the Thorofare Channel and again The Meta arterial all the way to the Thorofare channel that whole distance here is the vascular shunt and it's a type of arterio Ven an asmosis right and then after that it gets drained by the postc capillary veniel all right now that we got all that let's go ahead and look and focus in here on these true capillaries before I do that there's a ring of smooth muscle that I want to talk about right around this there's actually this ring of smooth muscle it's a sphincter and it actually kind of covers right over these true capillaries and it it controls the blood flow to these true capillaries to take it to the tissue cells these sphincter muscles here are called I'm going to write it right over here let's write it right here actually is called the pre capillary shter okay it's the precapillary sphincter the precapillary schiner is a smooth muscle tissue that basically whenever it constricts no blood can come out here into the true capillaries if it's dilated then blood can come out to the true capillaries and this is controlled by the sympathetic nervous system and it can also be controlled by other things like local chemicals that we'll talk about in detail in a little bit again precapillary shiners are those ring of smooth muscles right around the true capillary next thing let's say that we're going to go over the entire bulk flow or the the the mixing of the fluid between the plasma and the interstitial fluid so we're going to have to talk about a lot of pressures here so bear with me all right so let's go ahead and follow this so the blood flow is going through the terminal arterial Down The Meta arterial pre-capillary sphincter is open comes through this true capillary and now we have the blood coming in through here so now blood is made up of what two things cells and plasma right and that's the most basic thing it say cells and plasma we're going to mainly care about the plasma so there's a specific pressure you know our blood pressure we have systolic blood pressure so whenever systolic blood pressure is actually you know basically we say it's normally 120 millim of mercury as the blood is flowing through this area it's going to create a pressure designed to push substances out of the capillary beds that pressure is called hydrostatic pressure HP okay HP and we're going to put C so what is HPC HPC is the hydrostatic pressure within the capillaries and this is the pressure designed to push things out of the capillary beds so this is going to try to push it out of the capillary bed so what is this going to be uh normally uh you know it's usually about 35 millimet of mercury it's about 35 millimet of mercury so the capillar hydrostatic pressure is due to changes in systolic blood pressure the greater your systolic blood pressure the greater your capillary hydrostatic pressure the lower your systolic blood pressure the lower your hydrostatic capillary pressure all right so that's important so remember this is directly dependent upon systolic blood pressure there's another pressure and this is dra generated by proteins you know there's proteins within your bloodstream like albumin right albumin is really really important because what albumin does is he helps to be able to keep water in the bloodstream so it's actually referred to as I'm going to write it in Black here osmotic pressure but we're going to write o p C let's actually capitalize that P there so we make it look good o p c this is referred to Astic osmotic pressure or sometimes they even say oncotic pressure so osmotic pressure is the pressure that albumin or plasma proteins are exerting to keep or pull water into the bloodstream all right and that's generally on average about 25 to 26 to keep the math simple we're just going to make it 25 but it can be about 26 millimet Mercury okay now there's got to be pressures out here because fluid's getting pushed out all right so this is trying to push things out this is trying to push things in but there's going to obviously going to be a net change and we'll talk about that net change but there's going to be fluid accumulating out here and as the fluid accumulates there might be some pressures out here that we got to talk about so now let's talk about two pressures out in this area there is a hydrostatic pressure so we're going to put hydrostatic pressure i f and what does hydrostatic pressure If means it means it's the hydrostatic pressure within the interstitial fluid now on average this should be zero okay so this should be on average about 0 millimet of mercury assuming a healthy individual should be about 0 millim of mercury what is it trying to do it's trying to push the interstitial fluid into the capillary bed so it's trying to push this interstitial fluid that's accumulating out here into the capillary bed but it's usually zero so there is no change here now here's where it gets really interesting there's another one over here that I want to talk about and this one is actually going to I'll write it in Brown still it's going to be same thing osmotic pressure of interstitial fluid now this one is on average usually about 1 mm of mercury because sometimes a little small amounts of solutes there should be no proteins coming out here if there is there must be tiny tiny amounts of proteins but usually when solutes are leaving water likes to follow and so sometimes this can create an osmotic gradient to want to pull things out into this area so he's trying to pull substances out here okay he's trying to pull things out here now if we look at this it's going to be pretty much if I kind of put like a vertical asmode right down the middle of this guy and I kind of separate the arterial side from the the Venus side all these things are going to be pretty much the same the only thing that's going to be different is that we already pushed a lot of that plasma out so our hydrostatic pressure is going to drop so what happens is the hydrostatic pressure over here of the capillaries it drops to about 17 millimeters of mercury the osmotic pressure it retains the same thing because you should still have plasma proteins there so it should still be osmotic pressure of the capillaries and as long as you didn't lose any of your albumin it should still be 25 mm of mercury because this is dependent upon plasma proteins like alumin hydrostatic pressure is dependent upon blood pressure same thing out here these pressure shouldn't have changed so I'm going to do the same thing over here it should not have changed for this guy okay so again this guy should still be one for this one and then over here I'll do it in brown over here hydrostatic pressure of the interstitial fluid should still be zero millimeters of mercury but again we show it's Vector going in okay but regardless here's where I wanted to mention before I do that let's mention the net filtration pressures between these two areas so let's come over here so we have some more room and we going just do this little calculation real quick so let right over here net filtration pressure but let's put a for on the arterial part of it and then let's do the net filtration uh pressure over here but let's put V for that Venice side of the capillary all right in general all we're trying to do is take the combination of the things that are pushing things out well one of them was pushing it out was the hydrostatic pressure of the capillaries it's trying to push thing out and it's going to push out at about an average of 35 mm of mercury all right that's one thing then we have to take and add in okay what else can we add in we can add in now something else that's trying to push things out or pull things out and that thing that's trying to pull things out here let me actually fix this here would be the osmotic pressure of the interstitial fluid trying to pull things out and that was on average about 1 millimeter mercury all right so this is the thing trying to push out or pull out now let's say what are the things that are trying to keep it in or push it in so we're going to subtract that and once the thing that's trying to pull it in the major one that's the osmotic pressure of the capillary which is regulated by abum and he's about 25 millimeters of mercury and then what's the other thing the other thing is the thing trying to push it back in in the interstitial fluid and that's the hydrostatic pressure of the interstitial fluid and that's on average about zero millimeters of mercury and so these are the basically the things that are trying to stay in or get put in right so if you take the difference here 35 + 1 is 36 and 36 - 25 is going to give us a total of about 11 millimet of mercury so that's our average so it's going to be around about 10 to 11 millimet of mercury so that's the average that's the average that's going to be filtrated right the average pressure for the filtration for the vein the only thing that changes is your capillary hydrostatic pressure it just change him to 17 that's all you got to do so it's 17 mm of mercury plus 1 millim of mercury minus 25 millim of mercury plus 0 millime of mercury and if you take the difference between that it's going to be 17 + 1 which is 18 and you're going to do 18 minus 25 and so if you do that it's going to come out to about roughly 7 -7 millimeters of mercury so that's going to have a net flow in so if you think about it this is going to produce a net flow out that's important we got to write that down this is the net flow out and this is going to be the net flow in okay that's I just wanted to mention that I know it's a some raw boring math but just putting that in perspective to understand what's really happening at the capillary bed this is really important let's come back all right so if we look over here I want to mention one more thing before we finish up but with these pressure differences and gradients and stuff like that all right so if we look here we got the osmotic pressure of the capillaries and we already said that that's regulated by the abum proteins so let's say that there's a disease in which or there's a condition maybe someone has what's called um glarin aritis or maybe nephrotic or nephritic syndrome where they're losing a lot of the proteins in the urine and so if they're losing a lot of proteins they're losing alumin and then what happens their osmotic pressure goes down and then what happen to the actual filtrate pushing out then there's going to be more getting pushed out and then over here it's going to drop so there's actually going to be not as much getting pulled back in this is going to lead to edema all right it's going to lead to edema so that's common it's usually just say it as Alum hypo albuminemia or hypoproteinemia which can lead to severe edema all right so I just wanted to mention that one other thing I wanted to mention is this uh hydrostatic pressure of the interstitial fluid let let's say that someone developed unfortunately maybe some type of cancer and that cancer caused a uh occlusion within this lymphatic vessel here and if there's an occlusion within the lymphatic vessel can the lymphatic vessel drain appropriately no so then what's going to happen it's not going to go this way it's going to actually start backf flowing and then what's going to happen to this area it's going to start swelling and swelling and swelling and causing a lot of Edema here so this is really important so if there's some type type of uh again maybe some type of cancer occurring here where there's some type of lymph node blockage or lymphatic vessel blockage Hodgkins are non hodkin syoma it can cause this fluid to back up which will do what to the hydrostatic pressure of the interstitial fluid it's going to want to try to rise it and push things into it right so that's that's one thing that can happen and obviously this can lead to a lot of stagnation here so that's what I wanted to get to with this with respective of the micro circulation one last thing I wanted to talk about here with respect this before we get into the blood flow is I want to talk about I mentioned briefly what's called arterio venous an asmosis I want to come over here and I want to write two other ones that are extremely important we have to know them so let's write down all the three anastamosis before I do that what is an anastomosis an anastomosis is basically defined as alternative or collateral channels for blood to flow through and that's an extremely important thing so let's write down the three different types of an asmosis one is actually called arterial you can call you can do two things you can say arterio arterial an asmosis we're just going to say arterial arterial anastomosis and then we're going to do another one which is called Venice anastomosis and then the last one which is going to be called arterio Venus anasta mosis so again if we think about it we got these three anastomoses and we know what they mean they're alternative or collateral channels for the blood to flow which is important because where we're going to find a lot of these we don't if there is some type of blood clot or an occlusion within that vessel we want to provide an alternative route for the blood to get around that area let's say we have a vein here and then we have a vein over here and then there's a connection between these veins this is really common within the legs and within the arms okay this actually be a very good example of let's say that this is the basilic vein and this is the calic vein and then that this is actually going to be called the median cubital vein so this is a good example of a Venice an asmosis I'll actually write that down real quick let's write that down so let's say here's thumb side here's pinky side so if it's thumb side it's going to be the calic vein and over here on the pinky side is going to be the basilic and then between them is going to be the median cubital let's say someone develops a clot right up here so blood's coming through right it's coming through this vein and as it's coming through this vein it gets blocked by that area well that's not good because if we have a you know a blockage of blood flow that's going to lead to a lot of issues right but look we have this collateral Channel where the blood can flow to get up to where it needs to go that's the advantage of these venous an asmosis and they are of all of these three that I mentioned the most abundant and the most common all right so you rarely ever hear about aeia occurring within you know veness and asmosis you obviously hear of dvts so thrombi can form but they're still going to be some adquate blood flow and you know there's not going to be as much aeia arterial vanest an asmosis we already talked about that one that's our capillary beds all right so it's that again meta arterial I'll write it down anyway that's obviously going to be from The Meta arterial to the thorough far channel right so from our thorough Fair ch channel so this is the actually this right here is an arterio venous and asmosis right so this is going to be our vascular shunt this last one I want to mention is arterial an asmosis and these are very very important I want to give you the one of the most important one here it's called The Circle of Willis when we get into pathophysiology we'll discuss a lot about aneurysms or certain types of clots and stuff like that so arterial anoses one of the most common ones the most important ones is the circle ofis there is other ones like around the coronary circuit and the joints but I want to show you guys I want to actually show you guys the anatomy of the circle Wills let's come over here to this brain and let's kind of take a piece out all right guys so what I did is I took uh the circle of Willows kind of pre-rework eyes are situated here and I'm looking up okay so just real quick there's a couple arteries I want to talk about there's these ones down here which are called your vertebral arteries they actually run through the transverse veram then there's this straight artery right here which is called the billar artery and then you got your posterior cerebrals this is your posterior communicating arteries right here these guys right there posteri communicating these are your middle cerebrals these are your anterior cerebrals and then this is your anterior communicating arteries and in these little things right here imagine me drawing smiley faces right here these are my internal cored arteries okay so these are my internal cored arteries so this right here is the Circle of Willis now why did I want to mention this because we'll talk about this in a lot more detail in pathophysiology we'll actually look at clots in different areas and talk about that and Barry aneurysms and hemorrhages but for right now I just wanted you to understand the purpose of this anastomosis so let's imagine again like we did with the Venice an asmosis blood flow let's imagine that there just so happens to be a clot developing right there within the poster communicating arteries if that happens now obviously blood is going to be kind of affected here but look what we can do we can have this Blood obviously can flow this way it can flow this way it can flow this way up here down here out here oh look at that we can get around that so there is a way to kind of get around that is it going to be as effective is there still going to be aeia yes but it's just showing that there is alternative routes to be able to get blood to the tissues this is more likely to cause esea and maybe a transient es schic attack or a stroke but I just wanted to give you an idea that there is alternative routes for these anastomosis specifically the anterior communicating and the posterior communicating if something gets stuck out here in the middle cerebral artery all right they're in trouble they're fricked they're probably going to get a stroke probably G to end up with some type of brokas or worex aasia but as long as we understand this part right here it's it's it's good to understand so again circle is one of the big arterial anastamosis I wanted to talk about but again you can see them in the heart and you can also see them around your joints and stuff all right now that we talked about all the anastomosis I want to go over blood flow to specialized areas because now we're going to talk a little bit more about that uh localized blood flow first one let's look at let's just look at the muscles so right here this is our skeletal muscle let's say how do you know see the point point is we want to know how is blood how is blood changing the blood flow to this organ changing in certain circumstances most commonly whatever our muscles used for so let's say that someone's exercising all right so they're they're exercising right and whenever someone's ex exercising you'll notice that uh they can get a little sore it can burn and stuff like that right and the reason why is they might be producing lactic acid lactic acid is a metabolic acid that can actually decrease the pH right they might be producing CO2 right they might be producing just generalized H+ because you know CO2 can actually combine with water we'll get into all that later but for right now just I guess trust me that it can actually lead to protons okay so you can get high CO2 in the bloodstream you can get high amounts of H pluses in the bloodstream you can get high amounts of lactic acid in the bloodstream and conversely this can lead to what we'll talk about later in the respiratory system as the bore effect but we don't care about that now what we care about is what can this do to the blood vessels it can mediate a a localized regulation in other words these guys here they can act on these smooth muscle cells here this Tunica Media here so they can work on these actual muscle cells and cause these muscle cells what are they going to do they're going to inhibit them and they're going to cause the muscle cells to relax and if the muscle cells relax what's going to happen to the blood flow through this area it's going to increase so we can get more blood flow more oxygens more oxygen molecules to the muscles and clean out that waste product okay so this is DET this is called localized or active hyper emia so it's called active localized hyperemia that's one example I wanted to give you all right what about this cool brain so you can see here we got the blood vessels coming in we're showing it just kind of going into the brain here what is could this be affected by big thing and we're going to talk about it later it's called mean arterial pressure I'm just going to put map okay so this is could be affected by mean arterial pressure so mean arterial pressure there obviously two circumstances I'm going to I'm going to write those down over let's put a map over here let's put m a p here because I want to have show the two circumstances so let's say that someone has on this condition let's say that they have extremely high mean arterial pressure and over here this person has extremely low mean arterial pressure now mean arterial pressure espe specifically the cerebral blood vessels we already talked about them a little bit they're there's fragile you got to be careful because if there's high pressure it can rupture those blood vessels we don't want to rupture those blood vessels because they're very fragile so if the mean arterial pressure is high that's probably going to rupture those vessels what we want to do is we want to constrict those arterials so that we slow down the amount of blood going through that capillary bed so this is called a myogenic mechanism so when the mean arterial pressure is high what's the result let's write it up above Vaso constriction okay Vaso constriction so whenever the mean arterial pressure is high you're going to Vaso constrict them to protect those smaller cerebral vessels from rupturing so we constrict the arterials which decreases the amount of blood going out into those capillaries the converse effect whenever there's decreased Min arterial pressure you're going to vasod dilate them all right you're going to open those puppies up so this is called Vaso dilation and you want this because if the mean arterial pressure is low you're not going to have as much diffusion at those capillary beds so you're not going to get as much oxygen and guess what people are going to do what they're going to they're going to faint they're going to have Syncopy right so this is kind cause that dizziness and Syncopy if those the blood pressure isn't high enough right so we got to we got to be able to dilate them to get more profusion through that area so that talks about that let's come up to the lungs now what happens in the lungs now the lungs is a funky one all right but it's going to make sense let's say here in this area of the lung right right in this area so let's say in this lung the person has really low partial pressure of oxygen but then we come down to the bottom part of the lung all right and in the bottom part of the lung let's say that there's a high partial pressure of oxygen so now let's draw a little capillary coming up this way to this part okay so let's say that someone might have an obstruction here maybe they have some mucus build up whatever it might be there's not enough ventilation occurring there are we going to want to be able to oxygenate blood at that area no because it doesn't have as much oxygen so we're going to want to constrict that vessel going to that area the lung but then what are we're going to want to do to this area over here we're going to want to be able to get blood over there so what we do is if the blood is coming this way and it's getting ready to come up to this area where there's low partial pressure of oxygen we do not want blood going into that area because it's not going to get fully oxygenated and it's going to be a waste of time right so what this vessel is going to do is it's going to Vaso constrict and what is that going to do if we Vaso constrict this blood vessel it's going to divert the blood over here to this area where there's more oxygen so that we can get this tissue we can get these red blood cells fully oxygenated so remember that why are we constricting these blood vessels over here because there's low oxygen concentration we don't want it to go there we want it to go where there's high so constrict those blood vessels all right so that's important there now let's come over here to the git and then the skin but we're going to talk about them together as a group now git and the skin and I could have include the kidneys in this too but we're obviously running out of room here so important is this so these guys are usually going to be more along the lines of we can say not vital organs they're not specifically important in a sympathetic situation so what's important to know about about these is that whenever let's say that you uh do to thermal regulation or du to sympathetic effect let's let's just say you're getting chased by a dog if you're getting chased by a dog you don't care about digesting a piece of chicken and you don't care about how nice and you know uh plush your skin looks all right so what you're going to want to do is is you're going to want to constrict these vessels that are going to the digestive viscera and the vessels going to the skin and shunt them into your systemic veins so that you can get that blood to more vital organs so remember that what's happening between these two vessels and you can even say the kidneys too there's going to be Vaso constriction and why is this important this is important because it's going to divert the blood away from the the git and from the skin and send it deeper down to your inferior vena take it up to the heart so that you can pump that blood to the vital organs like the heart muscle like the muscle the skeletal muscles like your lungs like your brain so on and so forth those are the things that you're going to want not these all right last thing I want to talk about we're going to finish this lecture we're going to get into a lot more detail but I didn't talk too much about changes with an arterial venous anastomosis there is a very uh terrible Condition it's called an AV arterial Venice Mal formation super super weird condition and what it is is people don't have true capillaries and that's funky so if you don't have true capillaries it's just straight artery vein connections and because arterial vein connections you know the purpose of capillar is also to dampen the pressure to drop that pressure down because you got so many you got a large cross-sectional area here so you're dampening that pressure so it's not going super high into the veins well if you have an AV Mal formation it's going high pressure from the artery straight to the vein and what can happen is they can get coiled up and produce what's called aitis and that can lead to a lot of problems one specifically is a rupturing of it and these are very very common within the brain um these areas this is a rare condition but it's common in the brain um usually what they have to do for this is they even have to do what's called an imization therapy where they actually have to create an embolis going to this area to block off the blood flow pre preventing it from rupturing so I just wanted to mention that real quick all right guys that pretty much gives us everything we need to know on microcirculation and blood flow