BSF Vascular chapter Part 2 – Transcript

00:01okay this is part two of the vascular system let me share my screen again okay so the second part is your hepatic portal circulation is what we're starting with this is a subdivision of the systemic circulation um in which where blood from the abdominal digestive organs and the spleen circulates through the liver before returning to the heart Okay so

00:32basically this is to protect the person in case they have ingested or eaten or drank something that is toxic so all the blood from the digestive organs which are the stomach the small intestine the large intestine which is the colon the pancreas and the spleen they all flow into two large veins the superior

00:59mesentary vein and the splenic vein now I want you to go on page 300 and I want you to find these I want you to see what I'm talking about okay so we have those two veins they come together to form the portal vein and remember portal means liver so the portal vein takes blood into the liver and it empties blood into

01:26the sinusoids remember sinusoids are just large capillaries and remember we said at the beginning of the chapter that they are found in the liver so from the sinusoids blood flows into the hepatic veins and then back to the inferior vnea and then it takes it back to the right atrium so what is the point of this it is to enable the liver to

01:50modify the blood from the digestive organs and spleen so it's going to detoxify anything that is bad that's the point of it so it's going to like look at bullet to it can def detoxify alcohol if our glucose or our sugar is too high it changes it to glycogen and puts it in stored form some nutrients can be stored

02:17or changed it takes Billy ruin from the spleen and it excretes it in the bow any potential poisons are detoxified before it gets to the rest of the to the heart and the rest of the body so the whole whole point of hepatic portal circulation is to protect the person from um any toxins that may have been

02:40ingested during digestion so it's only the uh digestive organs okay so like right here remember when I said we want to find the superior mesenteric vein and the splenic vein okay so here is a superior mesenteric vein

03:04right and here see it says splenic so right here okay so it's two of those see that okay and then if you look at the very end you see this is called the portal vein see how it goes actually up into the liver and then inside the liver

03:28it will um do the capillaries the sinusoids it's going to go through there and it's going to you know detoxify anything it finds like I said work on the um you know nutrients got too much glucose it's going to store it just a whole bunch of stuff okay all

03:53right so that is what we're talking about the superior mesenteric and the splenic they join together and then they go to the poral vein into the liver right okay fetal circulation the fetus is dependent on the mother for oxygen and nutrients and for removal of carbon dioxide and waste products so the

04:18baby relies on the mama to do the exchanges so the Mama's giving the baby the oxygen and the nutrients and taking away the waste products in the carbon dioxide now where this exchange takes place is in the placenta it contains fetal and maternal blood vessels they're very close to one another but they don't actually mix blood they just have the

04:45diffusion and active transport so the blood's not supposed to touch mama and baby's blood are supposed to remain separate there are sometimes when it does touch and we'll get into that um in our specialty class okay the umbilical cord of course is what Hooks the uh placenta to the baby right now with that there are two

05:11arteries and you need to know that there are two arteries they carry blood from the fetus to the placenta so they carrying that carbon dioxide and those waste products away from the baby and away from the fetal blood and they put it inside the maternal circulation so

05:33that the mama can get rid of it okay all right so the umbilical vein there is one vein so two arteries one vein it carries oxygenated blood from the placenta to the fetus so this is giving the oxygen to the baby so within

05:56the fetus the umbilical vein branches and it takes some blood to the fetal liver but most of it passes through the ductus venosus now venosus s Vin that sounds like vein right because this is a vein ductus vosis it's a vein so it takes it straight to the inferior vena

06:21which takes it to the heart okay the ductus phosis closes after birth so in other words the whole point of this little bypass here this ductus phosis is that the mama has already oxygenated the blood and it's sending nutrients in so it doesn't have to go you

06:45know any specific place it h it's already oxygenated so it's ready to go okay all right now fetuses their lungs are deflated because they're in water right so they're not breathing water so the fetal lungs are deflated they do not provide for gas

07:12exchange so therefore the the fetal circulation causes blood to be shunted away from the lungs and directly to the the body because the mama has sent all the oxygen and stuff that they need so we have something called the foran O Val that is is an opening in between the two atria where the two atria are hooked together and there's a wall between them so there's a little

07:38hole in that wall and so it lets some blood flow from the right atrium to the left atrium okay so I'm gonna skip over this I want to show you that first okay all right so here's the right atrium here is the left atrium and if you see

08:03there's a hole right here that comes out right here so the blood this already oxygenated blood it doesn't have to go to the lungs so it can go some of it will go straight across to the left atrium then to the left ventricle and then out to the body through the aorta okay so You' got to know your heart circulation to understand

08:29this all right so one more time some of the fetal blood this already oxygenated it's going to come into the right atrium it's going to go through the formin O Valley and it is going to go straight to the left atrium which then dumps into the left ventricle and then it goes out to the body via the aort

08:55right now I said some blood did that okay so it's just a small opening it's not anything huge so some of the blood that enters the right atrium goes through the normal right ventricle pulmonary arteries come back through the pulmonary veins into the left atrium left ventricle and then out to the

09:19body okay so it's happening at the same time these two things are going on okay so we don't have to really send any blood to the lungs because they're not breathing the the blood's already oxygenated so here we go comes in right atrium it's

09:44going to go through the forment ovali into the left atrium left ventricle aorta to the body some of the blood that doesn't fit in the hole is going to go to the from the right atrium to the right ventricle pulmonary arteries back to the left atrium I mean pulmonary veins left atrium left ventricle and then out to the body okay just like

10:11normal right so the forino valley is from is a uh um hole I guess that allows blood to go from the right atrium to the left atrial okay all right okay we've already done that so

10:38the blood that does enter the right ventricle is pumped into the pulmonary artery just like normal okay now we have another pathway it's called the ductus arteriosis arterio sounds like what artery so this is an artery and so it got it connects artery to artery where

11:03the ductus phosis connected vein to vein so the ductus arteriosis is a short vessel that diverts most of the blood in the pulmonary artery straight to the aorta to the body okay so most of the blood right so it's kind of like what we were talking about with the other one okay because both of these allow

11:29the blood to bypass the lungs so let me go back let find it okay here we go again okay so we've got here is a ductus arteriosis the ductus arteriosis so it connects this little part right here

11:55this little tiny part right here so it connects the pulmonary artery straight to the aorta so we don't even have to send any blood to the lungs okay remember it said most some will go through there doesn't matter it's already oxygenated okay so in this one we

12:21have blood entering the right atrium we're going to go with the one that enters the right ventricle and you know up here when it's supposed to go pulmonary artery to the lungs now we have the ductus arteriosis which goes which is going to connect the pulmonary artery it's going to take it straight to the aorta out to the body so it's just bypassing the