Ventricular filling occurs during what phase of the cardiac cycle?
Mid-to-late ventricular diastole
During what phase of the cardiac cycle does the ventricle contract, raising intraventricular pressure and, thus, closing the AV valves?
Isovolumetric contraction
What pressure difference causes the aortic semilunar valves to close?
Pressure in the aorta that is greater than left ventricular pressure
What pressure difference causes the AV valves to open?
When pressure in the atrium is greater than in the ventricle
During this phase of the cardiac cycle, the pressure in the ventricle increases and forces the semilunar valves open.
Ventricular ejection
State which valves are open or closed during isovolumetric relaxation.
AV valves closed; semilunar valves closed
During the cardiac cycle, heart valves open and close because of:
differences in blood pressure on their two sides.
The tricuspid valve directs blood flow in which direction?
From the right atrium to the right ventricle
The bicuspid valve directs blood flow in which direction?
From the left atrium to the left ventricle
The filling of the ventricles is caused mainly by:
passive flow of blood through atria into ventricles.