When a muscle fiber receives an action potential from a neuron, how many sarcomeres in the fiber contract?
A) The number that contracts is inversely proportional to the strength of the action potential.
B) The number that contracts is directly proportional to the strength of the action potential.
C) All of the sarcomeres in the fiber contract.
D) Approximately one half of the sarcomeres in the fiber contract.

Question

Quizplus · Accepted Answer

All of the sarcomeres in a muscle fiber contract when it receives an action potential due to the all-or-none principle of muscle contraction. This ensures a coordinated contraction of the entire muscle fiber.

When a Muscle Fiber Receives an Action Potential from a Neuron