The Function Of The Circulatory System

1368 Words6 Pages
Throughout the studies of biology, there are many overarching themes. These themes help define patterns seen with life on Earth. One such theme would be the structure to function equilibrium, in which the structure of a certain specimen corresponds to its main function. Examples that show this include the mammals’ circulatory system, the respiratory systems of fish and countercurrent exchange, antibodies, tRNA and the replication of DNA, vertebrate skeletons, and muscles and their contraction. The mammals’ circulatory system, as well as the blood they carry, have such a system in which structure plays a big role. Blood transports substances throughout the body. Suspended in the plasma of its extracellular matrix are red blood cells which carry oxygen, white blood cells which act as defense against infection, and platelets which aid in blood clotting. The main function of the circulatory system is to take nutrients, such as oxygen, from the heart and lungs and to the cells of an organism’s body so that they can perform their functions, and to take oxygen-poor blood back to the heart and lungs again. Gas exchange occurs in both of the lungs of mammals in double circulation, gills of fish in single circulation, and lungs and skin of amphibians in double circulation, as the blood is replenished, and the capillaries of the upper area, the abdominal region and lower areas as oxygen is taken up by the body’s cells. Capillaries are small and thin-walled, so that the exchange of
Open Document