The circulatory system is responsible for continuous movement of blood through the body via capillaries. These capillaries permeate every tissue and reach every cell in the body, carrying essential nutrients as waste products are removed. The blood that circulates constantly through the body is pumped by the heart. In this module, we will look at the numerous mechanisms involved in circulation. We will discuss the structure of the heart and the diseases or defects that affect the circulatory system and how they are treated.