During the depolarization phase of the nodal action potential, the cardiac myocyte membrane is most permeable to _-• Kt Na+• Ca2+
Question
During the depolarization phase of the nodal action potential, the cardiac myocyte membrane is most permeable to _-• Kt Na+• Ca2+
Solution
During the depolarization phase of the nodal action potential, the cardiac myocyte membrane is most permeable to Ca2+.
Here's the step by step process:
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The action potential in cardiac myocytes begins with the opening of voltage-gated Na+ channels, causing a rapid influx of Na+ ions. This is the initial depolarization phase.
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However, these Na+ channels quickly inactivate and close, stopping the influx of Na+ ions.
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At the same time, voltage-gated Ca2+ channels open up. These channels are slower to open and close than the Na+ channels.
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The Ca2+ ions entering the cell cause further depolarization, and this is the phase where the membrane is most permeable to Ca2+ ions.
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The Ca2+ channels eventually close and K+ channels open, allowing K+ ions to leave the cell. This causes repolarization and returns the membrane potential to its resting state.
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The K+ channels then close, ready for the next action potential.
So, during the depolarization phase of the nodal action potential, the cardiac myocyte membrane is most permeable to Ca2+.
Similar Questions
Q5. During the plateau phase of the myocardial action potential the membrane is most permeable to _____________ .a) Calcium and potassiumb) Sodium and potassiumc) Calcium and sodiumd) Calcium and magnesium
A recently depolarized area of a cell membrane cannot generate an action potential because of theMultiple ChoiceThe high concentration of potassium ions in the cytoplasmPresence of receptor sites on the membraneAbsolute refractory periodHigh concentration of sodium ions in the extracellular fluid
The upstroke li mb of the action potential in SA node cells in the cardiac muscle is inresponse to:A. Opening of voltage gated Na+ channels.B. Opening of Transient Ca 2 + channels.C. Opening of Longer lasting Ca 2+ channels.D. Opening of voltage gated K+ channels.E. Opening of voltage gated Na+ channels
During the depolarisation stage of an action potentialThe membrane potential returns to resting conditionsSodium (Na+) enters the cell down it's concentration gradientVoltage gated K+ channels are openPotassium (K+) enters the cell against its concentration gradient
What cation (positive charged ion) rushes into the cell during depolarization period of action potential?
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