The circulatory system consists of one heart, five liters of blood, and approximately 96,000 kilometers of blood vessels, responsible for transporting nutrients and waste throughout the body.

This short 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. There is a detailed ...

Find out about the different stages of a human life ... in the digestive system. What is the circulatory system? Find out how the circulatory system takes oxygen around the body.