The Heart, High Cholesterol, and Blood Circulation Issues / Question
Published: June 11, 2002
Dear TeenHealthFX,
What makes a heart pump?
Signed: Wants Info On Heart Pumping
Dear Wants Info On Heart Pumping,
The heart is a muscular four-chambered organ, the primary purpose of which is to pump blood throughout the body. The two upper chambers are called atria and the two bottom chambers are called ventricles. A wall called the septum separates them. The walls of each chamber differ because of their different pumping actions.
The heartbeat is generated by the conduction system of the heart. The sinoatrial node initiates the heart's conduction system. It also possesses a built-in rhythm that maintains a constant heart rate. For this reason it is called the body's pacemaker. The sinoatrial impulse spreads throughout the atria to cause contraction. As the atria contract, impulses spread to stimulate the ventricles to also contract. A cardiac cycle is composed of complete contraction and relaxation of both the atria and ventricles. The phases of contraction-relaxation occur in sequence - creating a pumping heart.
Signed: TeenHealthFX
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