Did you know?

William Harvey experimented using cold-blooded animals so that he could better observe the beating of the heart (their hearts beat at a much slower rate).
Oxygen takes 45 seconds to circulate around the body.
Laid end to end your veins would encircle the world twice.
The heart, arteries, veins and capillaries all make up the circulatory system.
The left side pumps blood around the body and the right side pumps blood into the lungs.
Your body may contain up to 25 billion red blood cells.
If you prick your finger and draw a drop of blood, that contains about 3000 million red blood cells. Each of those red blood cells contains 250 million molecules of haemoglobin.
We need iron in our diet to make new red blood cells.
During its lifetime a red blood cell could travel round your body 172,000 times
White blood cells help the body fight disease by making antibodies.
Scientists now can make artificial oxygen carriers – artificial haemoglobin – artificial blood.
There is a very real shortage of blood, made worse by threat of contamination with HIV and hepatitis.

This page last updated on January 23, 2007