Pacemaker potentials involve hyperpolarization followed by a slow Na+ influx that brings the membrane to threshold (-40 mV), triggering calcium channels to open for depolarization. Repolarization occurs due to K+ efflux.
1. Hyperpolarization from previous AP open closes K+ channels and open slow Na+ channels 2. Na+ influx drifts the membrane potential to threshold at appx -40 mV 3. When pacemaker potential reaches threshold VG Ca chanels open 4. Rapid Ca influx causes depolarization phase 5. Repolarization phase is due to VG K channels that generate K efflux <img src="paste-820463c91b63ca0f732fc9bf7f9b0c8e4b705920.jpg">
| Front | Explain the phases of pacemaker potentials |
|---|---|
| Back | 1. Hyperpolarization from previous AP open closes K+ channels and open slow Na+ channels 2. Na+ influx drifts the membrane potential to threshold at appx -40 mV 3. When pacemaker potential reaches threshold VG Ca chanels open 4. Rapid Ca influx causes depolarization phase 5. Repolarization phase is due to VG K channels that generate K efflux |
Learn with these flashcards. Click next, previous, or up to navigate to more flashcards for this subject.
Next card: Channels ion responsible hyperpolarization pacemaker potential? sodium/potassium previous
Previous card: Node sets pace heart? sa generates aps faster
Up to card list: Anki Anatomy, physiology, microbiology