The heart is the primary essential organ of the circulatory system.
It is present on the left side of the body, in the thoracic cavity.
The heart's main function is to pump oxygenated blood to the whole body and recieve deoxygenated blood from the body that it sent to the lungs for oxygenation.
The hormone secreted by the heart is the atrial natriuretic factor.
Cardiac muscles are responsible for the secretion of atrial natriuretic factors.
The synthesized hormones are released into the atrium to counter the high blood pressure through the heart muscle cells.