Pulmonary and aortic valves are semilunar valves having three semilunar cusps each. these valves open with the free ends facing the vessels when the heart contracts and closes when heart relaxes thus preventing regurgitation
Systole and diastole causes the opening and closing of the valves. When systole occurs the valves close after filling the ventricles then during the diastole the valves open to allow the blood from the ventricles to flow into the pulmenary artery and the aorta and also allowing the auricles to empty owt into the ventricles.
During (rapid and reduced) ejection phase of cardiac cycle
Yes, there are two times during the cardiac cycle when all four valves are closed.
During isovolumetric contraction and relaxation and atrial systole
When ventricle is in systole
yes
closed and closed
Yes, both sets of valves are closed twice during any one cardiac cycle.
Diastole is the phase in the cardiac cycle that allows filling of blood into the ventricle. It corresponds to the lower number in the blood pressure measurement. A normal upper limit of the blood pressure falls in the range less than 120/80 mm Hg. Above this value, it is considered pre-hypertension based on The Seventh Report of the Joint National Committee on Prevention, Detection, Evaluation, and Treatment of High Blood Pressure.During the diastolic period the ventricle is in the fifth phase of the cardiac cycle. This phase is termed isovolumetric relaxation which occurs immediately after the second heart sound. In this phase, all valves of the heart are closed. The volume of blood in the ventricle during this phase of the cardiac cycle remains constant. Following the fifth phase of the cardiac cycle is the rapid filling of blood into the ventricle. This cycle corresponds to the opening of the mitral and tricuspid valves located between the left and right atria and ventricle, respectively. The next phase of the cardiac cycle, called diastasis, is the longest phase of the cardiac cycle. In this cycle, the ventricle continues to fill with blood but at a much slower rate. The final phase of diastole corresponds to the first phase of the cardiac cycle. In this phase of the cardiac cycle, the atria contracts to provide additional filling of blood into the ventricle. After the final phase of diastole, the systolic phase of the cardiac cycle begins.
When the ventricular pressure exceeds the pressure in the aorta and pulmonary trunk, the semilunar valves are forced open and blood is ejected out. This signals the ejection phase of the cardiac cycle of ventricular systole.
phonocardiogram
closed and closed
Yes, both sets of valves are closed twice during any one cardiac cycle.
AV valves close during the systole phase of the cardiac cycle.
Yes, both valves can be closed at the same time. (Look at a cardiac cycle diagram and look at time period of around 0.45 seconds)
Closed
Closed
the opening and clsoing of valves that creates two beats
They are closed during the power stage.
That phase is called as isovolumetric contraction phase.
Diastole is the phase in the cardiac cycle that allows filling of blood into the ventricle. It corresponds to the lower number in the blood pressure measurement. A normal upper limit of the blood pressure falls in the range less than 120/80 mm Hg. Above this value, it is considered pre-hypertension based on The Seventh Report of the Joint National Committee on Prevention, Detection, Evaluation, and Treatment of High Blood Pressure.During the diastolic period the ventricle is in the fifth phase of the cardiac cycle. This phase is termed isovolumetric relaxation which occurs immediately after the second heart sound. In this phase, all valves of the heart are closed. The volume of blood in the ventricle during this phase of the cardiac cycle remains constant. Following the fifth phase of the cardiac cycle is the rapid filling of blood into the ventricle. This cycle corresponds to the opening of the mitral and tricuspid valves located between the left and right atria and ventricle, respectively. The next phase of the cardiac cycle, called diastasis, is the longest phase of the cardiac cycle. In this cycle, the ventricle continues to fill with blood but at a much slower rate. The final phase of diastole corresponds to the first phase of the cardiac cycle. In this phase of the cardiac cycle, the atria contracts to provide additional filling of blood into the ventricle. After the final phase of diastole, the systolic phase of the cardiac cycle begins.
When the ventricular pressure exceeds the pressure in the aorta and pulmonary trunk, the semilunar valves are forced open and blood is ejected out. This signals the ejection phase of the cardiac cycle of ventricular systole.
Closed