Which one of the following statements is correct ?
Answer: (C) Blood moves freely from atrium to the ventricle during joint diastole. Answer: (c) Blood moves freely from atrium to the ventricle during joint diastole Solution: During joint diastole all four chambers are relaxed, the tricuspid and bicuspid valves are open, so blood flows freely from atria into ventricles — option (c) is correct.
- A.The atrioventricular node (AVN) generates an action potential to stimulate atrial contraction
- B.The tricuspid and the bicuspid valves open due to the pressure exerted by the simultaneous contraction of the atria
- C.Blood moves freely from atrium to the ventricle during joint diastole✓
- D.Increased ventricular pressure causes closing of the semilunar valves
Correct Answer
(C) Blood moves freely from atrium to the ventricle during joint diastole
Solution & Explanation
Answer: (c) Blood moves freely from atrium to the ventricle during joint diastole Solution: During joint diastole all four chambers are relaxed, the tricuspid and bicuspid valves are open, so blood flows freely from atria into ventricles — option (c) is correct. The SAN (not AVN) generates the action potential; the AV valves are already open in diastole (not opened by atrial contraction); and increased ventricular pressure closes the AV valves while forcing the semilunar valves open, so the other options are wrong. NCERT: Ch 15, p.199, line 31 — "As the tricuspid and bicuspid valves are open, blood... flows into the... ventricle"