The heart is an amazing muscular organ that works tirelessly to pump blood throughout our entire body.
The structure and function of heart chambers and valves is intricate and purposeful. The heart has four main chambers - two upper atria and two lower ventricles. The right atrium receives deoxygenated blood from the body through large veins called the superior and inferior vena cava. This blood moves through the tricuspid valve into the right ventricle, which then pumps it to the lungs through the pulmonary valve and pulmonary arteries. In the lungs, the blood picks up oxygen and releases carbon dioxide. The oxygen-rich blood returns to the left atrium through the pulmonary veins, passes through the mitral valve into the left ventricle, and is finally pumped out to the rest of the body through the aortic valve and aorta.
The blood flow through the heart and cardiovascular system follows a specific path that ensures oxygen-rich blood reaches all our tissues and organs. The heart's powerful muscle walls contract and relax in a coordinated manner thanks to special pacemaker cells and cardiac conduction pathway. These specialized cells generate electrical signals that spread through the heart muscle in a precise pattern. The signals start in the sinoatrial (SA) node in the right atrium, often called the heart's natural pacemaker. The electrical signal then travels through both atria, causing them to contract. Next, the signal moves through the atrioventricular (AV) node, which briefly delays the signal before sending it through the bundle of His and Purkinje fibers to the ventricles. This careful timing ensures the atria contract first, followed by the ventricles, creating an efficient pumping action that moves blood throughout our body. This complex system works continuously throughout our lives, beating about 100,000 times per day to keep us alive and healthy.
