Name: 循環系統生理學 - 循環系統生理學 - NCLEX-RN - 可汗學院| 循環系統生理學｜NCLEX-RN｜可汗學院 (Meet the heart! | Circulatory system physiology | NCLEX-RN | Khan Academy)
Uploaded: 2021-01-14T07:54:25.000Z
Duration: 10 min 9 s

情態副詞

I really like this picture that I found. It actually

程度副詞

shows you really neatly where the heart sits in our body

基礎被動語態

so you can see the heart is surrounded, on both sides, by ribs, right?

And in fact, I didn't draw it in yet, but let me show you where the

and on this side you'd have the left lung. So this is where

your heart sits: between two lungs. And I'm saying

left and right from the perspective of the the person who owns this

heart. So this is their left and right, which is the opposite

of us if we're looking at it. The heart is actually sitting between the two

the ribs are basically there to keep all these important organs

safe. And then below them, so if you draw

a really really important muscle. So this muscle

people don't talk about this muscle, or this is not the kind of muscle

that you usually see people working on at the gym, but this muscle is called the diaphragm.

and your ribs are enclosing a space, right? The diaphragm becomes the floor, and the ribs are kind of the

And if you look at the contents of this space, you'd have your lung

and you'd have your heart. So, this entire space then

So what exactly does the heart do? Let's actually make a little bit of

Let me start by orienting you to the heart. This is our right lung

and on the other side we have our left lung. And all this would be

inside of the rib cage, but I'm not going to draw that now, because that would

make it harder to see the heart itself. So to think

about exactly what the heart does, I think one, kind of neat way to do it is

to actually imagine that you're a cell. So put yourself in the perspective

of a cell, and let's say you're a cell hanging out

think about any part of the body that you could be. Let's say a little

and your job, of course, is to live and be happy,and you've got

near by, a little blood vessel. And in fact, every cell in our body

has a little blood vessel that's near by. And this toe cell

cells need certain things, right? They need, for example, let's say oxygen.

I'll write it in white so it's very clear. They need oxygen

So cells need certain things to live and be happy.

And on the flip-side, they also make waste. They're in

a sense just like us, they make waste. And that waste could be

all sorts of things, and one that kind of jumps to mind is

carbon dioxide (CO2). So carbon dioxide is waste

waste and for the moment let's imagine that there's no blood flow.

So, even though there's a blood vessel near by,

really, no flow is happening, so I'll just write "no flow".

makes waste. That waste, let's draw a little ball right here,

it's going to start accumulating, you're going to start collecting more and more of it

since the blood is not really flowing. And it might kind of

end up getting all the way around our toe cell. So our toe cell is getting

swamped, literally getting kind of covered by its own waste.

And on the flip-side, is it getting oxygen or nutrients? No.

It's not getting either of these things. So, before very

long, I would say within minutes, our toe cell

is thinking, "Well this is not a very happy way to live!" this is

actually really very sad, this is awful. And if this continues

cell needs, and what every cell needs, and that could be a finger cell or a

skin cell, or really any cell that's living, needs

flow. Right? It needs this blood to be flowing nicely

then you get a very different picture, right? If there's flow then all the sudden all the

waste product is actually now lifted and taken away.

It's flowing away, and it's a little bit like having

someone come by and pick up the trash, then you don't have trash all over the house.

in return, oxygen and nutrients are delivered. So this stuff

gets delivered as well. So, all of the sudden the cell is going to be

very, very happy, and is going to be living just fine.

So, really if you want all of the cells in your body to be living just fine

like this cell here, you really want good flow throughout the

body. And so this is really point number one. Is that you really

need, somehow, to have blood flow moving and pushing

to do this for billions and billions of cells you would need a pretty powerful

pump, right? Something that's going to be able to pull

in all the blood from the body, and then push it back out. And that's what the heart

is. I mean at its core, that's exactly what the heart is doing.

It's an amazing pump, pushing blood, so that

going to write that on the side as kind of job number one. These are the jobs of the heart.

that systemic means is that I'm refering to the entire body. So systemic

when I say that word, I just mean the entire body. All the cells

in the body. Now, exactly how that happens actually

you can see on this picture. So, here you have a giant

vein, this is a vein, and you have an artery.

And blood is actually going through the artery, that way.

And it's actually coming into two veins, the one

字幕列表影片播放

循環系統生理學 - 循環系統生理學 - NCLEX-RN - 可汗學院| 循環系統生理學｜NCLEX-RN｜可汗學院 (Meet the heart! | Circulatory system physiology | NCLEX-RN | Khan Academy)

literally

stuff

perspective

constantly