Hydrostatic and osmotic pressure

 Hydrostatic and osmotic  pressure, drive fluid out of and back into your blood vessels. 

These pressures might seem a bit unimportant at first, 

but the help us explain some interesting cases of edema or tissue swelling

Here we have a tissue like muscle or nervous tissue, which is being supplied with blood by this network of capillaries 

capillaries with their Thin wall  pores and gaps are specially designed to allow for the exchange of nutrients, gases waste and fluid between the blood and the tissues. They’re the place in the cardiovascular system where we can get stuff into the blood and get stuff out of the blood. for example, as blood into capillary on the arterioles noticed that some fluid is filtered out of the blood vessel. However we normally don’t want that fluid to stay in the interstitial space as this could lead to fluid collecting in the tissues causing swelling. Many of you have probably experienced this before if you’ve ever stayed standing for too long, you might’ve noticed that your ankles which looked normal before started to swell up or experience was called Adema. This is caused by fluid, staying outside the blood vessel within the interstitial space, causing the tissue to swell to prevent the swelling from happening much of the fluid that was filtered out is normally reabsorbed back into the capillary at the venule Outside the blood vessel within the interstitial space, causing the tissue to swell prevent the swelling much of the fluid that was filtered out, is normally reabsorbed back into the capillary at the venous end, so fluid out fluid out and fluid back in, but why was fluid forced out in the first place and how does it get reabsorbed? Well let’s zoom in first on the fluid being filtered out to see what’s going on the pressure that drives fluid movement out of the blood is called hydrostatic pressure instead of some fancy definition of hydrostatic pressure is I’m just gonna show you what it is using an example that some of you might be able to try out at home. I have a straw like what you might use to drink, but I’m gonna do is put my finger on this end of the straw preventing fluid from leaving. Then I’m gonna fill up the straw with Water if I were to take this straw and poke a hole in it over here what do you think would happen you might’ve guessed it Water is gonna begin to leak out static pressure and generates an outward pressure that will dry fluid out of the straw. You might be thinking I’m all right dude we don’t care about the straw what is with this straw what I just showed you is basically the same thing that happens in your capillary. Your cardiovascular system is basically just a long straw with holes in the capillary and in our capillaries due to the amount of fluid in our cardiovascular system and the hydrostatic pressure in the arterial capillaries fluid is forced out through microscopic, pars and channels in the capillary walls, but if hydrostatic pressure were all we had fluid would collect in the tissues and we Adema or swelling just about all the time OK, so time for second key term osmotic pressure pressure is based on one key fact, bi, osmosis water always flows towards regions in the body. They have a higher osmolarity or a higher concentration of solute particles. For example, we have some water surrounding vessel shown here in yellow. This vessel has some pores or small holes which allows certain particles to cross and prevent others from crossing inside this vessel upper high concentration of some particle shown here in orange notice that this particles concentration is much higher on the inside of the vessel compared to the outside, but if this particle is relatively large, maybe like a protein molecule and cannot leave this vessel through the small pars, that means that the concentration of these large protein molecules is going to remain high inside the vessel and remain low on the outside of the vessel, but since water always flows towards regions with the higher concentration of particles, what do you think Water is gonna do in this case in this case, Water is going to be reabsorbed back into the vessel towards the higher concentration of particles. This situation again is exactly what is happening in your capers in your blood. You’ll find a higher concentration of proteins like the serum protein albumin compared to outside the blood vessels in the interstitial space because of this higher concentration of proteins in your blood fluid tends to be reabsorbed back into the blood driven by osmosis and by osmotic pressure so hydrostatic pressure tends to dry fluid out of your blood osmotic pressure tends to drive it back in quick sidenote. This osmotic pressure caused by large molecules like proteins is called colloid osmotic pressure or oncotic pressure so as I mentioned osmotic pressure in this video I’m really talking specifically about what’s called colloid osmotic pressure. Just FYI. Also we do have other solids in our blood besides proteins like ions like sodium and chloride. however, these do not contribute to the osmotic pressure or the reabsorption of fluid. If you’re curious as to white you can check out the comments below zooming back out let’s put it all together to see how high Rostatic pressure and osmotic pressure, filter and reabsorbed fluid at the cap at the arterial end of the capillary hydrostatic pressure is higher than the osmotic pressure. This causes fluid to be forced out into the interstitial space, but is hydrostatic pressure decreases as we move through the capillary. Osmotic pressure eventually becomes equal to, and even greater than the hydrostatic pressure, causing nearly all of the filtered fluid to be reabsorbed back into the capillary at the Venyl end of the capillary, you might notice that there’s still a small fraction fluid sitting in the tissues, though not all of it is reabsorbed back by osmotic pressure. That’s why our final player comes in the lymphatic system vessels of the lymphatic system will help re absorb the remaining small fraction of filtered fluid that wasn’t reabsorbed by osmotic pressure, helping us to prevent swelling or enema, and they have it in the next review a few cases were fluid. Does Collect with the tissue caused by abnormal changes in hydrostatic pressure or osmotic pressure, for example, ox explain in detail why our ankle swell up when we sit or stand for too long. 

More than the muscles there will dilate is regulated by the autonomic nervous system autonomic nervous system nervous system extends muscle either, or which of these flow options. We are going to see that, so when I talk about that on the way artery. 

That together is why we have a time of resistance and so what's happening.

 This is exploring from the elastic musk to the arterials and we get this velocity. 

Velocity Right huge drop really happens at the arterioles 

arterioles -Slow everything down

Or we reach the capillaries, we need to exchange, nutrients and gases

So again, remembering materials, they were called resistance specials as a result

Arterioles- with the muscular arteries. They also have. 

Lay's new muscle. That's very important so arterials are really critical for regulating blood flow through remembering materials. They were called resistance vessels as a result them to arterials are also going to just like what we saw with the muscular arteries. They also have layer of new muscle. That's very important so arterials are really critical for regulating blood flow through capillaries 

So arteries can help distribute bigger organ level which organs areas of the body will get more or less live. Arterials are really about regulating blood blood flow, so if we zoom in it looks like this all throughout your body blood typically coming through and travel in this direction so if you want You'll see that muscle muscle capillaries can close. This is actually the clothes of these year here here are all closed so what you see is that the blood only flows through that middle, capillary fair and you don't actually see you don't actually see any of the blood flow, the rest of the bed , but those relaxed capillary bed with blood capillary bag in the surface of your skin capillaries is when it's very cold right, so when it's cold out you don't wanna have a bunch of seats to the outside and deck environment so the more blood flow you have to the skin. The more heat is lost that's one of the reasons why it's actually beneficial  That you get all that blood flow even to the skin. If you look at people who just been out on a ride right like their face is very slush this is what's happening so there their condition is the opposite of this. They would actually have lots of bloodflow through Cavalary, but when it's very cold out, we have certain areas of the body bigger areas of the body have less blood to flow, so you're gonna have filters just like a high level of those muscles and that way and less 

Muscles or organs the more that muscle or the more blood from watch right so these pre-capillaries would be opened up if you don't want to use that as much we have the way that we option points to exchange materials every time you see this sort of weird or weird that is actually another button That lots and lots and lots of that all over the place Apple areas are even more even more tiny than ar and not bad red oxygenated blood blue, oxygen blood exchange, Lab covered it but I'm just gonna give these diagrams for you and Election slides so that you have access to them. This is this is the capillary just doing that  Only just to allow like one time to go through so they're very very very small to order. You would actually continuously slightly smaller holes and there is virtually no holes at all my vessels so very very tight very very much here those different tablet types if you want a little bit more  Specifically these this is a nine minute video that's quite nice. Is that there are you remember these sort of discontinuous tab in areas where you want so this word for Mary is actually so same with the God we need to be able to have some weakness to get those  Nutrients easily like this want to be able to be very very late because we are actually trying to get really things. MAR is actually out produced so it's really important that we have a higher amount of like the marrow so that way blood cells are to get out of the marrow and into  so now I am going to ask this video 

And you wanna have a lot of fluid these the blind that processes called filtration fluid which is fluid also has some gases Black vessels vocabulary and interstitial space -e want to leave the 

, we want a lot of fluid to come back into the vein 

 So one of the beauties are recording this lecture is there is a lot of kind of detail to write down so one thing that you can do report structure function look at what you’ll notice is that they have the outer wall and much thinner and big thick layer of muscle as well as elastic fibers veins and contrast to arteries what you notice is that they’re very thin, so those two layers we were talking about the outer wall and the wall that’s kind of in the middle that has muscle and the last Fibber Those are much much thinner when you compare veins right what’s is that they have a very large back diameter, arteries and veins. Arteries are slightly bigger and diameter, but there doesn’t seem to be like a huge difference right from wall to wall wall to wall. In terms of what I have to look at is, you have to actually look at the diameter of the woman is the Lan  Hollow where blood veins have a larger woman, they can actually hold a lot more rare of muscle and elastic fibre for the arteries. This is actually gonna be really important because it helps the arteries with stands very high pressure. Capillaries are going to be very very tiny diameter we talked about is really small  Arteries all these different layers, it’s just made Backup single so extreme nutrients and waste and you don’t want all these layers in between the blood and the blood between the blood and the organs because it’s gonna be a lot harder to exchange, nutrients and waste really many layers and thick layers right. The arteries veins can be these many layers because the point of arteries and bases to deliver blood to the organs or to the heart function and the capillaries, they are the actual exchange exchange so we wanna make sure we don’t have all those layers that would make it very difficult to do that function so again structure function always 

The artery has thick muscle and elastic fibers ability withstand and can change pressure.

blood flow Velocity is higher in artery and lower in capillary . 

The vein vessels wall is thinner than arteries.It has larger diameter compared to arteries. Can hold more blood volumes.

 

systemic circulation

 We have to really focus on the systemic circulation right, so the whole point was to pick up oxygen in order to deliver it to our tissues so we’re gonna zoom in into the systemic circulation which is all of this bottom part. I have two different the same thing on the bottom part is stomach circulation right, so that’s those that are going to the cell tissues and organs of our body up into four different questions so the first is why and how does blood go to the tissues we actually just kind of answer that so that’s gonna be that systemic circulation The blood to the tissues, this will be done via arteries and ar, Cheerios blood exchange materials via the capillaries and finally how does blood travel for the tissues back and we’ll see that is gonna be the veins and then tissues already answered that but this is just another way of looking at it right, so we need to deliver oxygen from the heart  The rest of the body branches, the descending aorta to the thoracic cavity organs as well as lower legs et cetera and then we have this before of the order that comes up and that’s going to form the carotid artery so we’re thinking about and also the subclavian Htoo Htoo that go more towards the right, so that’s gonna be our head in our arms  if you actually look at some of the vessels down in the lower portions of the thoracic/lower limbs, you’ll actually start to see other types of vessels so for example, here, this is gonna be a stomach/intestines and then you can see that liver, so there is actually a thing called hepatic portal that connects the intestines to the liver, and it’s actually what it’s doing. Is it taking nutrients right from the intestines the nutrients get digested so we’re talking about glucose sugar, right strips of carbohydrates, as well as acids that are broken down from proteins  so at least different types of nutrients via the hepatic portal transferred to the liver one for processing and also for storage liver is a big storage site or glucose. Glucose is actually stored. If you see this will feel very really the renal artery into the kidneys and the renal veins, the blood away from the kidneys, so the kidneys are really really important site and they are going to filter out  Waste products they’re also going to fill out extra water for electrolytes. If you have too much water or too many electrolytes in your system, the kidneys will actually filter that out and you’ll extreme it from the body via urine so that urine is kind of fill out filter that isn’t here, but I do want  Learn and 40 is that there is also going to be a Shun vessel to the spleen is gonna be a site actually filter also filter but instead of filtering out waste products are these small things like water and electrolytes what your filtering out are pathogens like bacteria, as well as damage red blood cells are white blood cells  White or red blood cells filtered out in the bleed cells. We’re thinking about much larger things right that gets filtered up this week so those are the many reasons why blood needs to go to the tissues, and then the one thing that I haven’t really written here of course blood has to return to the heart in order to exchange that carbon dioxide it’s not picked up or oxygen in the pulmonary circuits  so one major thing that you noticed as blood travels away from the hearts in this stomach circuit is that pressure decreases, so that’s what is showing so we have pressure on. We are getting farther from heart and returning back to the heart rate as the blood leaves. The heart and the vena cava is the blood returns to the heart and furthest aware , the pressure and the diastolic pressure systolic pressure is corresponding to ventricular cyst and ventricular diastole for the relaxation of the heart that is going to be lower. Individual should be around 120 where the diastolic might be around and you ventricular pressure with the diastolic pressure, what you’ll get is something called the arterial pressure, so that’s gonna be the average between the systolic and the diastolic, but from the elastic arteries outwards to the capillaries see that the pressure drops a lot and then by the time we’re at the vena cava by the time, we’re returning to the heart , the pressure is basically zero so very very little get back to the heart a lot of factors that go into regulating blood flow and blood pressure so this is some of them for example diameter, total cross-sectional area, average, blood pressure and then velocity of blood flow she can think of sort of speed which is flowing, so in your handouts, you can go ahead and answer question one looking at some of these  It’s right, so what we noticed for the diameter is the diameter goes large right in the arteries, small and the capillaries and then will come back and get larger. Once we return to the via cross. Total cross-sectional area of the arteries is low or small, then in the capillaries, it gets large or high  And then back to back total. We’re just trying to write down the rules for now so Covered it’s almost time as it starts and then velocity flow of muscle diameter. High flow. High velocity slows down and then speed back up. A little bit velocity area is to slow in order to exchange . 

 

 https://mediaplayer.pearsoncmg.com/assets/secs-arterial-baroreceptor-reflex

 Arterial walls are stretched stimulating, baroreceptors in the carotid sinus aortic arch and other large arteries of the neck and thorax.

 As a result these receptors send off a faster stream of impulses to the brain.

 Let’s observe these nerve impulses travel to the brain in response to increased stimulation from the barrel receptors. 

1. the brain increases parasympathetic activity 
2. decreases sympathetic activity.

 

 This leads to a reduction in heart rate and increase in the diameter of the arterials and therefore lower blood pressure.

 Blood pressure back down to normal levels. 

 

Let’s look at the effect of increased parasympathetic and decreased sympathetic activity on the heart and blood pressure with increased activity of the vagus nerve which is part of the parasympathetic nervous system and decreased activity of the sympathetic cardiac nerve heart rate is reduced. This leads to lower cardiac output and therefore lower lower blood pressure , let’s observe the nerve impulses and the effect on heart rate and blood pressure. Let’s look at the effective decreased sympathetic activity on arterials and blood pressure, vasomotor, fibbers or sympathetic nerves that innovate the smooth muscle of blood vessels with decreased activity of vasal motor fires, the vascular smooth muscle relaxes arterial diameter increases in blood pressure is reduced  The short term regulation of rising blood pressure in response to rising blood pressure, receptor stretch, increasing impulses to the brain. This leads to increased parasympathetic activity and decreased sympathetic activity resulting in slowing of the heart rate and increased in the diameter of the arterials, and consequently, a reduction in blood pressure  Now let’s look at the short term regulation of falling blood pressure when blood pressure drop. Suddenly the barrel receptors are inhibited and they send fewer impulses to the brain as a result, parasympathetic activity decreases and

 sympathetic activity increases leading to an increase in blood pressure via three mechanisms 

(1)increased sympathetic impulses to the heart, increased heart rate and contract 

(2) increased impulses to the blood vessels increase vasoconstriction. 

(3)increased sympathetic impulses to the adrenal gland, stimulate the release of epinephrine and epinephrine into the bloodstream. These hormones enhance heart rate, contractility and basal constriction together. 

These three mechanisms bring blood pressure back up to normal levels as illustrated on the following screens.

First, let's look at the effective increased sympathetic activity on the heart and blood pressure increased sympathetic impulses to the heart and decreased vagus nerve activity lead to increased heart rate and enhanced contractility increasing stroke volume. These changes result in higher cardiac output which increases blood pressure. Let's observe the response to declining blood pressure and the effect on heart rate and blood pressure. 

How does greater sympathetic activity affect arteries and blood pressure?

Motor fibre activity leads to constriction of vascular smooth-muscle. The smaller arterial or diameter gives rise to increase blood pressure. Now, let's explore the effective increased sympathetic activity on the adrenal gland and blood pressure increased sympathetic impulses to the adrenal gland, stimulate the release of epinephrine, and nor epinephrine into the bloodstream, these hormones increase heart rate contractility of the heart and vasoconstriction of blood vessels thus increasing blood pressure, because they are carried in the blood, these hormones act more slowly than nervous system controls and the effects are more prolonged. Let's watch the response to falling blood pressure. Here's a recap of short term regulation of falling blood pressure as blood pressure, Falls barrel receptors are inhibited, resulting in decreased impulses to the brain  Parasympathetic activity is decreased and sympathetic activity is increased leading to increased heart rate and contractility increased construction and the release of epinephrine and epinephrine from the adrenal gland. All of these mechanisms contribute to raising blood pressure Backup to normal levels. 

 the blood through the heart and lungs. We end up with nice oxygenated blood right so after the harder, we have to really focus on this systemic circulation right, so the whole point was to pick up oxygen and order to deliver it to our tissues.

In into the systemic circulation

blood travel into to the cells, tissues and organs of our body.

Gonna be that systemic circulation

In terms of the how how does the blood travel from my heart to the tissues 

arteries and arterials

Then we're gonna move into blood exchange materials via capillaries, and finally

How does the blood travel from tissues back to the heart.

That is gonna be the veins and venules

Is blood goat and tissues. We have already answered that, but this is just another way of looking at it right, so we need to one 

How does the blood goes to tussue 

deliver oxygen from the heart 

the rest the body 

The aorta branches 

 travel to the thoracic cavity organs as well as two lower limbs.

E0, my God carotid arteries two subclavian arteries supply blood to our head in our arms, 

and if you actually look at some of the vessel

Down in the lower portion of the thoracic/lower lens. You'll actually start to see other types of important vessels. For example, this is gonna be a stomach/intestines and then here you can see that liver so there is actually a thing called the hepatic portal vein that connects the intestines to the liver, and it's actually what it's doing. Is it taking nutrients right from the intestines the nutrients get digested so we're talking about Glucose sugar right strips of carbohydrates as well as acids that are broken down from proteins so at least different types of nutrients via the hepatic portal transferred to the liver for processing and also for storage li is a big storage site or glucose. That glucose is actually stored if you've taken this while  in on the kidneys, the renal artery into the kidneys and the renal veins, the blood away from the kidneys, so the kidneys are really really important site, and they are going to filter out waste products to Water or electrolytes, too much water or too many electrolytes in your system. The kidneys will actually filter that out and you'll it from the body via urine so that's a whole point of forming urine is to fill out filter out some of that stuff  That isn't here, but I do wanna mention that you learned is that there is also going to be a Shun vessel to the spleen site where you actually filter. You also filter, but instead of filtering out waste products are these small things like water and electrolytes, what your filtering out are pathogens like bacteria, as well as damage red blood cells are white blood cells , so white or red blood cells filtered out in the sleeve so we're thinking about much larger than Right that gets filtered up this week so those are the many reasons why blood needs to go to the tissues and then the one thing that I haven't really written here. Of course blood has to return to the heart in order to exchange that carbon dioxide it's not picked up or oxygen in the pulmonary circuits  so that blood from the circuit is that pressure decreases so that's what is showing so the wax is here, we have pressure on. We are getting farther farther and then returning back to the heart rate, so as the blood leaves the heart and the blood returns to the heart and the furthest aware, probably hilarious  Pressure in the diastolic pressure pressure is corresponding to ventricular cyst so the heart is pumping and then the diastolic pressure is during diastole for the relaxation of the heart that pressure is going to be lower. A normal individual should be around 120 where the diastolic might be around  if you actually have ventricular pressure with the diastolic pressure, what you'll get is something called the arterial pressure, the average the diastolic from the elastic arteries outwards to the capillaries see that the pressure drops a lot and then by the time we're at the cave by the time we're returning to. The heart. Pressure is basically zero very very little pressure by the time we get back to the heart , there are a lot of factors that go into regulating blood flow and blood pressure so this is some of them for example, diameter, total cross-sectional area, average, blood pressure and velocity of blood flow which she can think of of the speed which is flowing so in your handouts right, so what we is the diameter goes from large right in the arteries, small and the capillaries and then will come back and get larger. Once we return to the heart vessel diameter so total cross-sectional area of the arteries or in the capillaries it gets large or high. For now, so average blood pressure we just covered that it's getting lower almost to 0 by the time we whereas it starts and then velocity of blood flow is it looks kind of like muscle diameter so we have high flow high velocity slows capillaries and then speed back up a little bit Velocity of capillary area, the point of that is to slow flow in order to exchange e

SYSTEMIC CIRCULATION