MEDICAL
HEART AND PERICARDIUM
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Question
[CLICK ON ANY CHOICE TO KNOW THE RIGHT ANSWER]
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When we hit the threshold of the SA Node Potential. Channels open to allow the fast influx of a molecule, causing rapid depolarization. Which molecule does this?
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Na
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Ca
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K
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Protein
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Explanation:
Detailed explanation-1: -Phase zero is the phase of depolarization. This phase starts when the membrane potential reaches-40 mV, the threshold potential for pacemaker cells. There is the opening of voltage-gated Ca2+ channels on reaching the threshold, causing the influx of Ca2+ ions.
Detailed explanation-2: -The heart’s intrinsic pacemaker, the sinoatrial node (SAN), generates spontaneous action potentials (AP) through a system of coupled oscillators whose common output initiates each normal heartbeat.
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