A brief explanation of the cardiac cycle and easy – The cardiac cycle involves all core activities with a full heart beat, according Cliffsnotes.com. The cycle includes the ventricles, which are the two lower chambers of the heart that receives blood from two small heart chambers called atria, according to MedicineNet.com. The cardiac cycle also includes two major phases: the systolic phase and the diastolic phase. The systolic phase refers to the period when the ventricles and atria of the heart contract, while the diastolic phase is the period between contractions when the ventricles relax and fill with blood.
A brief explanation of the cardiac cycle and easy
During the relaxation period, the ventricles and two types of valves — atrioventricular (AV) and semilunar valves — remain closed. The AV valves allow blood to flow from the atria to the ventricles, while the semi-lunar valves prevent blood from flowing back into the heart, according to WordNet. The volume of the ventricles remains unchanged during the relaxation period.
The AV valves open and deoxygenated blood fills the ventricles of the headset. The first step of the filling process is a fast filling, which occurs as a stream of voids in the ventricles and the atria relaxed blood, which allows to increase the ventricles quickly volume. The ventricles remain in the diastolic phase during this period.
An event occurs then filling slower because most of the volume of the ventricles is already occupied by blood. The atria contract and force blood from the atria into the ventricles remaining, according to the University of Utah. The volume of blood at the end of this period is called the end-diastolic volume.
The ventricles then contract. The stop valves are forced AV and also a moment of semi-lunar valves are closed, causing the volume of the ventricles remain unchanged. The permanent contraction of the ventricles increases the pressure in the ventricles and semilunar valves open force. The blood is then forced out of the ventricles.
The ventricles begin to relax and the blood in the aorta and the pulmonary trunk begin to flow backward, causing the semilunar valves to close. The pulmonary trunk divides into the arteries that carry deoxygenated blood to the lungs, while the aorta is the main artery that carries blood from the heart to the body, according to the National Institutes of Health. The closure of semilunar valves causes a small thrust of the blood pressure. The amount of blood that remains in the ventricles during this period is called the end-systolic volume.