The human heart is made up of two pumps: one pumps blood to the lungs; the other pumps blood to the rest of the body.
The presence of valves between the atria and ventricles, and at the entrance of the pulmonary artery and aorta ensures that the flow of blood in the heart is in one direction.
Both atria contract at the same time, pushing blood into the ventricles.
Both ventricles contract at the same time, pushing blood out of the heart.
The coordinated rhythmic pumping of the heart is possible because of the pacemaker and the electrical signals it transmits to the heart tissue.
The beating of the heart forcing the blood out into the arteries gives rise to the pulse.
The heart tissue gets its blood from coronary arteries. These branch from the aorta just as it leaves the heart. Blockage of any part of these arteries could cause the heart tissue they supply, to die.
The risk of getting a heart attack can be reduced by leading a healthy lifestyle that involves proper diet and exercise.