General Science • BiologyHard
In human cardiac physiology, what is the precise physiological significance of the atrioventricular node delay during electrical impulse conduction through the heart?
A. It allows sufficient time for the atria to contract and empty blood completely into the ventricles before ventricular systole.✓ Correct Answer
B. It prevents retrograde propagation of action potentials back into the sinoatrial pacemaker region.
C. It amplifies the electrical signal strength to overcome high resistance in thick ventricular myocardial walls.
D. It initiates immediate closure of the semilunar valves to prevent backflow into the aorta.
💡 Solution & Explanation
The atrioventricular node introduces a brief conduction delay of approximately one-tenth of a second in the cardiac action potential pathway, ensuring that atrial contraction finishes ejecting blood into the ventricles before the ventricles begin their powerful contraction phase. Distractors incorrectly attribute this delay to signal amplification or valve closure mechanics. Proper ventricular filling is crucial for maintaining optimal stroke volume and cardiac output.
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