The cardiovascular, or circulatory, system in humans is composed of the heart and the blood vessels—arteries, veins, and capillaries. Its purpose is to provide nutrients and oxygen to the tissues and to remove wastes from them. It is also where the body fights infections.
"Circulatory system." Britannica School. Encyclopædia Britannica, Inc., 2015. Web. 2 Sep. 2015. <http://school.eb.com/levels/middle/article/273674>.
The circulatory system of humans consists of two parts: the cardiovascular system and the lymphatic system. The main fluid in humans and most other animals is blood. It is transported through the cardiovascular system. This system consists of the heart and a network of blood vessels. The fluid that helps fight infections is called lymph. It is carried in the lymphatic system.
"Circulatory system." Britannica School. Encyclopædia Britannica, Inc., 2015. Web. 2 Sep. 2015. <http://school.eb.com/levels/middle/article/352964>
To read the rest of these articles, click on the links above.
circulatory system . Art. Encyclopædia Britannica. Web. 2 Sep. 2015. <http://school.eb.com/levels/middle/article/352964/media?assemblyId=171939>.
circulatory system, human. Art. Encyclopædia Britannica. Web. 2 Sep. 2015. <http://school.eb.com/levels/middle/article/273674/media?assemblyId=53101>.