How the circulatory system works
Video - How blood is moved around the body
In this video, learn how blood moves around the body through the heart, arteries and more.
Find out about how blood delivers oxygen and nutrients to every cell in the human body
Come along children, we’ve come to the hospital to learn how blood is moved around the body in the circulatory system.
These humans are donating blood.
The average adult has about 5 litres of the stuff, and can make new blood so can afford to give a little away.
But what does circulation actually look like?
Time for some virtual biology!
Welcome to the heart.
The heart is a muscle which pumps blood non-stop through a huge network of blood vessels, delivering oxygen and nutrients to every part of the body.
It has two sides: one side pumps blood that’s got lots of oxygen in it.
Here we go!
The oxygen-rich blood moves quickly inside blood vessels called arteries, which have thick walls.
On its way around the body, it picks up nutrients from food that’s been processed in the intestines.
The blood then carries the nutrients and oxygen to every cell in the body through capillaries, tiny little blood vessels that are only one cell thick.
Once the blood has delivered oxygen and nutrients, it makes its way more slowly back to the heart inside thin-walled veins.
The other side of the heart then pumps this oxygen-poor blood back to the lungs, so it can load up with oxygen again.
The heart is so powerful, it only takes about a minute for the blood to be pumped out, travel all the way around the body and come back again.
Whooosh!
Oh dear, all that flowing blood made me feel a bit dizzy…
RETCHING
What is the heart?
The heart is a muscle. It pumps blood all around the body.
What is blood?
Blood is the transport system for our bodies.
It picks up and carries oxygen and nutrients to where they are needed. It also picks up waste products and helps transport them out of the body.
Blood is also part of the immune system. White blood cells fight off infections.
How does the circulatory system work?
The left side of the heart pumps blood that contains oxygen around the body through arteries.
When blood passes the intestines, it picks up nutrients that have been absorbed from food.
Blood travel from arteries into capillaries. These deliver oxygen and nutrition to every cell in the body and pick up waste products including carbon dioxide.
Veins take the blood back to the right side of the heart. It is then pumped to the lungs.
The lungs absorb carbon dioxide and the blood absorbs oxygen. It then travels back to the left side of the heart, ready to be pumped around the body again.
The heart is so strong that this whole process only takes about one minute!
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