The Greeks observed the ebb and flow of tides in the Aegean Sea (which Homer called the “wine-dark sea”) and inferred that a similar to-and-fro motion of blood operated within the human body. That ...

Human circulation. video Human circulation This ... the circulatory system and digestive system in the human body, through blood vessels and into mitochondria. Human fertilisation.

Day and night, the muscles of your heart contract and relax to pump blood throughout your body. When blood returns to the heart, it follows a complicated pathway. If you were in the bloodstream ...

And why does it do that? Why can't it just have a rest? Well, the blood has to be kept moving around all the time because it's the body's delivery system. Every possible part of the body has to be ...

The human body uses three types of molecules to yield ... The cortex cells of the kidneys need a constant supply of energy for continual blood filtration, and so does the liver to accomplish ...