What is happening during the plateau phase of cardiacdepolarization? A) Sodium ions block voltage-gated calcium ion channels. B) Acetylcholine is hyperpolarizing the SA node C) Nothing - all ion gates and valves are closed. D) voltage-gated potassium ion channels open to allowpotassium ions to diffuse out. E) Calcium ions enter the cystol of cardiac myofibers fromsarcoplasmic reticulum and through voltage-gated slowchannels. What is happening during the plateau phase of cardiacdepolarization? A) Sodium ions block voltage-gated calcium ion channels. B) Acetylcholine is hyperpolarizing the SA node C) Nothing - all ion gates and valves are closed. D) voltage-gated potassium ion channels open to allowpotassium ions to diffuse out. E) Calcium ions enter the cystol of cardiac myofibers fromsarcoplasmic reticulum and through voltage-gated slowchannels.
Explanation / Answer
During the plateau phase of cardiac depolarization, two thingshappen There is a balance between inward movement of calcium ions andoutward movement of potassium ions. So the answer is both D and E.