since we're a closed cardio system remember blood has to be somewhere in your body so we have what's called a blood reservoir basically extra blood that were maybe not using right at this moment your veins are providing this so if I killed you right now and drain your blood most of your blood would be deoxygenated as most of your blood would be in your veins and in your venules this is a good thing because that gives you quote-unquote extra blood that you could pull out of reserve and bring to the arterial side if you had more oxygen demands so how would we do this well we would use the sympathetic nervous system which remember kinks your hoses speeds up the blood so V no constriction would force the blood out of this reservoir so my little circle picture there is trying to demonstrate that to maintain your blood pressure and get that blood back to the heart it seems we end every chapter with things that can go wrong so there are plenty of things that can happen of course to the heart and to the vessels themselves so a flow sclerosis is when you start to get plaque buildup due to cholesterol mostly but it can be other things as well arterial sclerosis is the damage as a result of that so we need our vessels to really respond to blood pressure right we need them to constrict and relax depending on need well if you have a buildup on the walls of your blood vessels you're gonna lose the ability for those walls to then expand and snap back so they're going to lose their elasticity so atherosclerosis leads to arterial sclerosis aneurisms they scared the bejesus out of me mostly because you may not even know you have one so this is when you get a ballooning of an artery or a widening of an artery or just a general weakness and so you can look there's different types of aneurysms which we don't have to know but some of these are easily clipped off like this little picture shows and then there's some that are fairly horrific like on your aorta itself so this is something that you could just be walking down the street and it could literally explode freaks me out like if I die I want a reason I don't want to just be walking and I fall down and it's all over so these are fairly terrifying so sometimes people will know they have an aneurysm but it can be in a place that they can't get to surgically so it's one of those things you could live a hundred years normal or it could blow tomorrow phlebitis that's a fun word so phlebitis is when the veins get inflamed any tissue can get inflamed but the problem with this is you can sometimes get a clot as a result so a thrombophlebitis is when you get the clot from the inflammation basically the inflammation narrows the passageway for the blood to flow and so because that blood is moving so slowly in the vainest side it can clot if you're going into teaching or nursing varicose veins are sort of something you're going to get so I recently got a varicose vein and I'm not happy about it it's not attractive at all it's horrifying it looks like there's like a worm on my leg I do not like this so remember veins have a huge problem veins are Fighting Gravity and you know you're you're have that issue veins do not have that musculature that arteries have and so remember the veins have valves Bane starts with the valves starts with P so this picture is kind of showing those little valves in a normal normal vein but just like anything else sometimes things can go backwards and so sometimes the valves will actually invert and so usually due to gravity the vein or the valves cannot prevent the backflow any more so this is really depressing so the blood starts to pool in these veins so you can get varicose veins dealt with I have a friend who had hers removed but then the other veins go varicose because they have to step up and pick up the other pressure so there's really just not much you can do other than wear those sexy socks you know those pressure socks that they suggest that you wear if you're going to nursing trust me where the pressure socks because I wish I had started wearing them 20 years ago gravity is the devil so this is just showing how contracting those skeletal muscles moving around helps prevent helps prevent edema because that's helping to squeeze the blood back to the heart and then you have those little valves that they're there to make sure that all your effort isn't wasted and the blood doesn't back pool so a lot of things affect blood pressure so blood pressure is the mean pressure in your large arteries so the more resistance there is in your arteries the higher the pressure so resistance can be something like excuse me like cholesterol building up the more flow the higher the pressure like you get pissed off your blood pressure is gonna go up so this key point here is in red the more blood your heart pumps and the narrower your arteries the higher your blood pressure which is why high blood pressure can sometimes be symptomatic of heart disease liquids always go from high pressure to low pressure so this is just like diffusion right molecules always go from high concentration to low concentration so blood is no exception to this so arteries have the highest pressure because they're coming off the squeeze of the heart it's never going to be any higher than that and then pressure drops as you move into the arterioles the capillaries the venules and the veins the standard as we will do in lab is to take blood pressure in your brachial artery which is the main one in your arm systolic pressure over diastolic pressure is basically a measurement of how hard the top number is how hard your ventricles contracting and then the bottom number is how much it's relaxing so the standard is 120 over 80 but we're starting to realize that that's kind of crap so it's basically whatever is normal for you for example my top number is never a triple number so that would be extremely high if I was a hundred and ten I would think I was dying so really you want to compare your blood pressure to what yours normally is rather than this standard of 120 over 80 so how does your body regulate blood pressure because that's part of homeostasis your kidneys pick play a huge role with this which is one of our hardest chapters it's also our last full chapter we will see how the kidneys do this the heart obviously can step up and pump harder and the arterioles and arteries can change their diameter so the different factors that influence blood pressure a big one is blood flow or cardiac output so we've had this defined already on a previous slide we've got to have a standard so cardiac output is the measurement of how much blood is leaving your heart in a given time so we say how many milliliters of blood leaving that left ventricle because remember that's gonna shoot out the aorta and feed your whole body per minute so we can calculate this we can take heart rate times stroke volume so heart rate is the number of beats per minute so usually between 60 and 80 and stroke volume is the amount of blood leaving the left side in milliliters so a comparison here what would your cardiac output be if you were exercising versus at rest so if you look down at the bottom of the slide the average person at rest 70 beats per minute is a good average as six to 80 is the range 70 milliliters per beat because again the average person has 70 milliliters in their left ventricle gives us 4900 milliliters or let's say five thousand milliliters which is five liters well the average person's blood volume is also five liters so the key take-home message from this is every minute you send all of your blood around your body one time so if you were exercising which is the top example of course you would expect your blood to speed up right because now your heart rates going up your stroke volume is not changing so if you go up to 100 beats per minute when you're exercising times 70 that would give us seven thousand milliliters or seven liters so again the basic take-home messages when you're exercising your heart's going around about one and a half times which is good because your blood is what's delivering all the oxygen and picking up all the waste so it makes sense that you would want that delivery mechanism to be sped up when you were exercising resistance was again mentioned on a previous slide so this is opposition to flow I believe the example I gave was like sliding down a hot metal slide in a park in the summertime versus a water slide a hot metal slide is going to have a lot more resistance so that's opposition to flow you're not getting down the slide as fast so one thing that causes resistance is the fact that your blood is running through your blood vessels blood is not running in outer space it's not running in a vacuum so it's going to be making contact with those vessel walls so if you look at the difference between a and B a you're gonna have less contact with the vessel walls than B because you're gonna have an a a lot of blood that's in the center not making contact with the walls but when you constrict your vessels there's going to be more blood making contact with the vessels so that's going to affect blood flow so we would call this peripheral resistance this can be caused by plaque built up on the vessel walls so again if you look at this picture normal blood flow versus trying to get by the plaque you're now going to be making contact with the plaque which is going to slow the blood down increase in viscosity viscosity is just thickness so blood is thicker than water right which means blood is going to have more resistance than water and then vasoconstriction if you decrease that diameter the blood is going to make more contact with the vessel walls which is increasing resistance so viscosity again is the thickness of liquid you've probably heard the phrase blood is thicker than water so blood is thick because it has the blood cells themselves and it has all those large proteins if you're anemic your Bloods not as thick because if you're anemic you don't have as many red blood cells which we'll be talking about in the next unit so increased blood thickness means increased resistance which means increased blood pressure have you ever ever noticed that when you're really dehydrated you can hear the blood literally pounding in your ears that's because the blood has gotten thicker because it's lost water the heart has to pump a lot harder so which one of these examples is more viscous water or milk well of course it would be the milk because milk has stuff in it a milkshake or milk this little shamrock shake which is one of my reasons for living it's a lot harder to suck on a straw to get a milkshake than it is regular milk right same thing with peanut butter versus juice it's obviously the peanut butter is a lot thicker than the liquid juice so this class is all about control it's all about homeostasis so there's multiple ways you control control blood pressure because it's such an important thing the first thing is that cardiac output this is the frank-starling law of the heart which sounds so fancy basically the amount of blood entering the heart equals the amount leaving I'm not sure where it would go so I'm not sure why this is such a big deal but I guessed hey somebody had to notice it first so if more blood enters your stretch receptors get triggered and the ventricles gonna pump harder so if you start exercising your heart it's gonna your blood pressure is going to go up there's also neural control as we saw with the little tubes your blood vessels can get kinked by the sympathetic nervous system and stretched out by the parasympathetic increasing and decreasing your blood pressure certain hormones some of these we've talked about and the endocrinologist for losing water epinephrine which is basically adrenaline is gonna speed up the heart an array throw poitain we haven't talked about we will be talking about that in the next chapter so you don't need to worry about it that much right now but it's basically a wreath Row is red blood side blood cells and poised to make so this is the hormone that causes you to make more blood cells so if you make more blood cells your blood gets thicker heart rate has to increase blood pressure has to increase and certain drugs of course can lower or raise your blood pressure but other factors come into play right to emotions when you're upset when you're sad when you're crying when you're throwing a fit which I tend to do at least once a week when you have a lot of stress that all affects blood pressure body temperature when you're really really hot as I've said already you can hear the blood pumping in your ears right when you're really really hot your blood pressure goes up when you're hot because you're trying to pump blood to all of those capillaries to release that heat and of course exercise the answer is always exercise it's never tequila and tacos