szívciklus

The szívciklus, or cardiac cycle, is the sequence of events that occurs during one complete heartbeat. It consists of two main phases: diastole and systole. Diastole is the period when the heart is relaxed and filling with blood. It begins with the closure of the atrioventricular (AV) valves, allowing the atria to fill with blood from the veins. This phase ends with the opening of the AV valves, marking the beginning of systole. Systole is the period when the heart contracts, pumping blood out to the arteries. It begins with the closure of the aortic and pulmonary valves, preventing backflow of blood into the ventricles. The cycle repeats approximately 72 times per minute in a resting adult, but this rate can vary with physical activity and other factors. The cardiac cycle is essential for maintaining blood flow and oxygenation throughout the body.