Question

Arrange the sequential operation of AV valves:
A. Atria contract, forcing additional blood into ventricles.
B. Chordae tendinae tighten, preventing valve flaps from entering into atria.
C. Ventricles contract, forcing blood against AV valve flaps.
D. Blood returning to the atria puts pressure against AV valves, and valves are forced open.
E. AV valve flaps hang limply into ventricles.

• A. D, E, C, A, B
• B. D, E, A, C, B
• C. D, E, B, C, A
• D. D, E, C, B, A

Hint:

Think “Open → Hang → Atria push → Ventricles push → Chordae tighten” for AV valve sequence.

Answer 1

The Correct Option is B

Step 1: Function of AV Valves.
Atrioventricular (AV) valves, specifically the tricuspid and mitral valves, control blood movement from the atria to the ventricles, ensuring it flows in one direction.
Step 2: Operational Sequence.
1. Increased pressure in the atria as blood returns causes the AV valves to open (D).
2. When open, the valve leaflets relax into the ventricles (E).
3. Atrial contraction supplements ventricular filling (A).
4. Ventricular contraction creates pressure against the AV valve leaflets (C).
5. Chordae tendinae tension prevents AV valve regurgitation by holding the leaflets shut (B).
Step 3: Option Evaluation.
The accurate sequence is D $\rightarrow$ E $\rightarrow$ A $\rightarrow$ C $\rightarrow$ B.
Step 4: Significance.
This sequence is crucial for maintaining unidirectional blood flow from atria to ventricles and subsequently to the arteries, preventing any backflow.