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The heart functions as a continuous, double muscular pump that beats approximately 100,000 times a day to keep blood circulating throughout the body. Physiologically, this organ is divided into four chambers: two upper chambers called atria, which receive blood, and two lower chambers called ventricles, which pump it out. The cycle begins when deoxygenated blood from the body returns to the heart through the venae cavae and enters the right atrium. This chamber contracts and pushes the blood through the tricuspid valve into the right ventricle, which, upon contracting, pumps the blood to the lungs via the pulmonary artery. There, the blood releases carbon dioxide and is replenished with fresh oxygen. Once oxygenated, the blood returns to the heart through the pulmonary veins and enters the left atrium. From there, it passes through the mitral valve to the left ventricle, the heart's thickest and most powerful chamber, responsible for pumping blood forcefully into the aorta to distribute it throughout the body. All this mechanical movement is perfectly coordinated by an intrinsic electrical system that generates its own impulses. The electrical journey begins in the sinoatrial node, the natural pacemaker located in the right atrium, which sends a signal for both atria to contract simultaneously. This current then travels to the atrioventricular node and spreads rapidly through the ventricles via the bundle of His and Purkinje fibers, causing ventricular contraction. This cyclical process consists of two main phases: diastole, the relaxation phase where the chambers fill with blood, and systole, the contraction and emptying phase, thus ensuring an uninterrupted flow of vital blood. It costs you nothing to copy and paste. ❤️🩹
2026-08-23 17:27:16