vickyy :
The heart functions as a double, continuous muscular pump that beats approximately 100,000 times a day to keep blood constantly moving 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 entire body returns to the heart through the vena cavae and enters the right atrium. This chamber contracts and pushes blood through the tricuspid valve into the right ventricle, which, upon contracting, sends 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 into the left ventricle, which is the thickest and most powerful chamber of the heart, responsible for pumping blood with great force 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 at 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 the Purkinje fibers, triggering ventricular contraction. This cyclical process consists of two main phases: diastole, which is the relaxation phase when the chambers fill with blood, and systole, which is the contraction and emptying phase, thus ensuring an uninterrupted vital flow. IT DOESN'T COST THEM ANYTHING TO COPY AND PASTE.
2026-09-08 01:31:10