The heart is a hollow, muscular organ that contracts at regular intervals, forcing bold through the circulatory system. The heart is cone-shaped, located in the thoracic cavity between the lungs directly being the sternum (breastbone). The heart is tilted so that the apex (the pointed end) is oriented to the left. The walls of the heart are made up of there layer of tissue. Outer and inner layers are epithelial tissue. The middle layer (the walls of the four chambers of the heart) is cardiac muscle tissue called the myocardium. Cardiac muscle tissue is not under conscious control of the nervous system. The heart can be thought of as two separate hearts inside one. The right side of the heart pumps blood from the body into the lungs, where oxygen poor blood (deoxygenated, usually shown in blue) gives up carbon dioxide and picks up oxygen.
Post a Comment