In the middle of your chest, between your lungs and behind the sternum, is the heart, an essential organ. The average adult heart weighs between 7 and 15 ounces and measures about the size of a giant fist
The heart muscle may be tiny, but it works the hardest of any muscle in your body. It provides every cell, nerve, strength, and critical organ with blood that carries oxygen and nutrition.
The hub of your circulatory system, a network of blood vessels, including arteries, veins, and capillaries, transports blood to and from all body parts. It is made up of several layers of tissue.
Walls of the Heart
Three layers of muscular tissue make up the walls of your heart. Namely, the epicardium, myocardium, and endocardium. These muscles contract so that your body's blood can flow.
