Question

Select all the statements that are true during the filling phase of the cardiac cycle.

Isovolumetric contraction

Ventricular Systole

Atria pressure is greater than ventricular pressure

Ventricular pressure is greater than aortic pressure

Ventricles are contracting

The AV valves are open

All valves are closed

Ventricular Diastole

Aortic Valve is open

Answer 1

Ans- Atrial pressure is greater than ventricular pressure

AV valves are open

Ventricular diastole

1. Isovolumetric contraction- false because ventricular filling occurs in four phases- (i). isovolumic relaxation (ii). rapid filling phase (iii). slow filling phase (iv). final filling during atrial systole. During isovolumetric relaxation there is rapid fall in pressure of ventricles and when this pressure becomes less than pressure in atria, it causes opening of AV valves resulting in filling of ventricles.

2. Ventricular systole- false because all the events of filling of ventricles are when ventricles relax i.e. during diastole when pressure in aorta and pulmonary artery increases and drops in ventricles.

3. Atrial pressure is greater than ventricular pressure- true because when ventricles relax, atrial pressure is more than ventricular pressure causing opening of AV valves and causing flow of blood into ventricles. However when ventricles contract, ventricular pressure is more than atrial pressure causing AV valves to close and there cannot be filling of ventricles.

4. Ventricular pressure is greater than aortic pressure- false because filling of ventricles takes place during ventricular diastole which starts with protodiastole when pressure in ventricles becomes less than aorta and pulmonary artery therefore Semilunar closes as there will be no flow of blood from ventricles to aorta or pulmonary artery.

5. Ventricles contracting- false because contraction of ventricles will lead to flow of blood put of ventricles but filling will be done when ventricles are in relaxed phase.

6. The AV valves are open- true because when ventricular pressure becomes less than pressure in atria , AV valves open for the flow of blood into ventricles.

7. All valves closed- false because Semilunar valves are closed but AV valves are opened.

8. Ventricular diastole- true as mentioned above filling takes place when ventricles are in relaxed phase.

9. Aortic valve is open- false because as ventricles relax, pressure in ventricles drops below than in aorta and aortic valve closes.