Your circulatory system is made up of three parts: the heart, blood vessels and the blood itself. Your heart keeps all the blood in your circulatory system flowing. The blood travels through a ...

Your heart's will to beat ... film offers a look at respiration and a tour around the circulatory system and digestive system in the human body, through blood vessels and into mitochondria.

Veins between two capillary networks are portal systems. Closed circulatory system, but fluid constituents of blood leak out of capillaries and return to the heart by the second component of the ...