PHYSIOLOGY
GENERAL PHYSIOLOGY
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Question
[CLICK ON ANY CHOICE TO KNOW THE RIGHT ANSWER]
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they have a more negative resting membrane potential than the individual muscle cells.
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they open rapid calcium channels to speed up repolarization.
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they open fast sodium channels to make sure they depolarize rapidly.
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they prevent potassium leakage from the cell in order to deolarize faster.
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Detailed explanation-1: -SA node pacemaker cells depolarize at a rate of 60 to 100 per minute, while the AV node at 40 to 60 per minute. The pacemaker with the highest rate of depolarization takes over as the primary pacemaker. In healthy individuals, this is the SA node.
Detailed explanation-2: -What is meant by depolarization of the heart? Depolarization of the heart is the orderly passage of electrical current sequentially through the heart muscle, changing it, cell by cell, from the resting polarized state to the depolarized state until the entire heart is depolarized.
Detailed explanation-3: -If the membrane potential becomes more positive than it is at the resting potential, the membrane is said to be depolarized. If the membrane potential becomes more negative than it is at the resting potential, the membrane is said to be hyperpolarized.
Detailed explanation-4: -After a cell has established a resting potential, that cell has the capacity to undergo depolarization. During depolarization, the membrane potential rapidly shifts from negative to positive.