Name: Fetal circulation right before birth | Circulatory system physiology | NCLEX-RN | Khan Academy
Uploaded: 2017-04-10T12:56:27.000Z
Duration: 11 min 52 s
Description: Thousands of YouTube videos with English-Chinese subtitles! Now you can learn to understand native speakers, expand your vocabulary, and improve your pronunciation...

of adaptations that we see that allow the baby

and oxygen to the different cells that need them

So what I wanted to do is kind of draw out

for you in one diagram all the kind of things

These are all the things that are happening

Well, this structure over here, this is our placenta.

This is partially mom and partially fetus.

So the placenta has mom's blood kind of pooling in this area.

And the baby actually sticks its little capillaries

And you can see that the purplish blood is

kind of going in, and the reddish blood is coming out.

to draw there is that oxygen is getting picked up.

is joining into this blood vessel down here.

So this is kind of the smiley part of our face.

going to carry oxygen and blood back towards the liver area.

So let me actually just jot that name down, umbilical vein.

And this is actually the first of the adaptations

So I'm going to make a little list of adaptations over here

on the side, just so we can keep track of what they are.

And the first one will be the umbilical vein.

So once the blood goes into the umbilical vein,

You can see that it can either go to the right or the left.

And if it goes to the left, it's going to enter the liver.

So if it goes kind of this way, it's going enter the liver.

And it's going to take a while for that blood

to come out on the other side, because it

has to go through all the little capillaries in the liver

So the shortcut-- let me just circle it here.

The shortcut is actually going to be right here.

So let me just make sure it's very clear what

going to allow blood to go from the umbilical vein, through it.

So it is just like any other blood vessel.

And on the other side, it hits and meets up

is a large vein picking up blood from the right leg

with the blood coming from the umbilical vein, which

And so this blood I'm going to draw is kind of purplish

now, because it's kind of got some oxygen,

but it's not as rich as what was coming out initially

from the umbilical vein because it mixed in with the IVC.

And that blood dumps into the right atrium.

So this is our right atrium on this side.

And simultaneously, you actually have blood

This is our head and arm region, draining down this way.

And this blood also kind of ends up in the right atrium.

And now I'm going to draw it as kind of a deeper purple,

let me just make sure I don't skip out on these.

The second one would be the ductus venosus,

from the umbilical vein over to the inferior vena cava.

First, it could simply go down into the right ventricle.

It just goes right down into the right ventricle.

And once it gets squeezed, it goes into the pulmonary artery.

And we know the pulmonary artery has a branch

So we've got some blood going to one lung and some blood

But remember, once that blood kind of approaches the lungs,

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Fetal circulation right before birth | Circulatory system physiology | NCLEX-RN | Khan Academy

essentially

basically

simultaneously

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