How Your Heart Works: Animated Explanation

The heart is a complex muscular organ with four distinct chambers.The upper chambers, called atria, receive blood. The right atrium handles deoxygenated blood, shown in red, while the left atrium receives oxygenated blood, shown in blue.Below the atria are the ventricles, which pump blood out of the heart. The right ventricle pumps to the lungs, while the left ventricle pumps to the entire body.The septum is a strong muscular wall that completely separates the right and left sides of the heart, preventing mixing of oxygenated and deoxygenated blood.Four valves ensure blood flows in the correct direction. The mitral and tricuspid valves control flow between the atria and ventricles.The aortic and pulmonary valves control blood flow out of the ventricles.Notice the left ventricle has a much thicker wall than the right ventricle, as it needs to generate more force to pump blood throughout the entire body.The left ventricle wall is three to four times thicker than the right ventricle wall, reflecting its greater workload.Blood circulation is a continuous process that begins with deoxygenated blood entering the right atrium.Deoxygenated blood returns from the body through two major veins: the superior and inferior vena cava.As blood enters the right atrium, it's low in oxygen, shown here in blue.The right atrium contracts, pushing blood into the right ventricle. From there, it's pumped through the pulmonary artery to the lungs.In the lungs, blood picks up oxygen, changing from blue to red as it becomes oxygen-rich.The oxygenated blood returns through the pulmonary veins to the left atrium.The left atrium contracts, moving blood into the left ventricle, which then powerfully contracts to pump blood through the aorta to the entire body.This incredible process repeats approximately one hundred thousand times every day.The heart's electrical system is a sophisticated network that coordinates its rhythmic contractions.The sinoatrial node, or SA node, is the heart's natural pacemaker. It initiates each heartbeat by generating electrical impulses.These electrical signals spread through the atria, causing them to contract.The impulse then reaches the atrioventricular node, or AV node, which briefly delays the signal.From the AV node, the signal travels down the Bundle of His, the main electrical highway of the heart.Finally, the electrical impulse spreads through the Purkinje fibers, a network of specialized cells that ensure coordinated ventricular contraction.This coordinated electrical activity creates the characteristic rhythm of the heartbeat, which we can see on an ECG monitor.A normal heart rate ranges from sixty to one hundred beats per minute, all coordinated by this remarkable electrical system.