When a depolarizing graded potential makes the membrane depolarize to threshold A) ligand gated Ca⁺ channels close rapidly. B) voltage gated CA⁺ channels open rapidly. C) ligand gated Na⁺ channels close rapidly. D) voltage gated Na⁺ channels open rapidly. E) none of these choices.

Question

Quizplus · Accepted Answer

When the membrane depolarizes to threshold, voltage-gated Na⁺ channels open rapidly, allowing Na⁺ ions to flow into the cell, further depolarizing the membrane and initiating an action potential.

When a Depolarizing Graded Potential Makes the Membrane Depolarize to Threshold