Solved UPSC CDS/OTA Question
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Q · Circulatory Systemmedium · 45s
Which node initiates the electrical impulse in the heart?
TopicCirculatory System
Question Typemultiple choice
Difficultymedium
Marking+1 / −0.33
Test Duration30 min
Step-by-Step Solution
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The sinoatrial (SA) node, located in the right atrial wall near the superior vena cava, is the heart’s natural pacemaker. It spontaneously depolarizes ~60-100 times per minute, setting heart rate under autonomic modulation.
Final Answer: Option B - SA node