Phase 3 repolarization in pacemaker cells is due to

Unlock all questions

This demo includes only 20 questions. Upgrade to access hundreds of questions, flashcards, exam simulations, and disable ads.

Full question bankExam simulationsFlashcards
From $24.99Unlock all

Prepare for the Cardiac Electrophysiology Test. Study with interactive quizzes and multiple choice questions. Each question includes helpful hints and detailed explanations. Start your journey to success on your cardiac exam now!

Multiple Choice

Phase 3 repolarization in pacemaker cells is due to

Explanation:
Phase 3 repolarization in pacemaker cells is driven by outward potassium currents while inward calcium currents diminish. As repolarization begins, voltage-gated K+ channels open and K+ leaves the cell, pulling the membrane potential back toward the resting level. At the same time, L-type calcium channels close/inactivate, reducing Ca2+ entry that would oppose repolarization. In pacemaker cells, the upstroke is actually produced by calcium influx, not sodium, so the key to phase 3 is the shift to strong K+ efflux with reduced Ca2+ influx. Chloride influx is not a major factor here.

Phase 3 repolarization in pacemaker cells is driven by outward potassium currents while inward calcium currents diminish. As repolarization begins, voltage-gated K+ channels open and K+ leaves the cell, pulling the membrane potential back toward the resting level. At the same time, L-type calcium channels close/inactivate, reducing Ca2+ entry that would oppose repolarization. In pacemaker cells, the upstroke is actually produced by calcium influx, not sodium, so the key to phase 3 is the shift to strong K+ efflux with reduced Ca2+ influx. Chloride influx is not a major factor here.

More Multiple Choice Questions
Subscribe

Get the latest from Examzify

You can unsubscribe at any time. Read our privacy policy