A common feature of action potentials is that they
A) cause the membrane to hyperpolarise and then depolarise.
B) can undergo temporal and spatial summation.
C) are triggered by a depolarisation that reaches threshold.
D) move at the same speed along all axons.

Question

Quizplus · Accepted Answer

Action potentials are triggered by a depolarisation that reaches threshold, which opens voltage-gated ion channels and leads to the rapid depolarisation and repolarisation of the membrane potential.

Answer: B
 Action potentials can undergo temporal and spatial summation, meaning that inputs from multiple synapses or over time can add together to reach threshold and trigger an action potential.

Therefore, the correct answer is C and B.

Option A is incorrect because action potentials cause depolarization and then repolarization, not hyperpolarization and then depolarization. Option D is incorrect because action potentials can move at different speeds depending on the axon diameter and myelination.

A Common Feature of Action Potentials Is That They