Describe the cardiac cycle in the human heart

The human heart beats around 60-100 beats per minute. Blood enters the right atrium via the superior vena cava and the inferior vena cava, the blood moves through the tricuspid valve into the right ventricle. Blood from the right ventricle enters the pulmonary artery (remember 'A'rteries go 'A'way from the heart), it circulates through the lung where it becomes oxygenated in the alveolar. Blood returns to the heart via the pulmonary vein which enters the left atrium, the left atrium then drains into the left ventricle via the mitral valve. Blood is pumped out from the ventricle into the aorta which supplies the body with blood.In systole, blood is leaving the heart: the muscles in the right ventricle pump blood towards the lungs and the muscles in the left ventricle pump blood to the body. In diastole, the muscles in both ventricles are relaxed, this enables them to fill with blood.