Acetylcholine A) opens voltage-gated Na⁺ channels in skeletal muscle fibers, which causes depolarization of the muscle fibers B) may decrease the permeability of the motor end plate to Na⁺ and K⁺ when combined with the receptor sites on the motor end plate C) always depolarizes skeletal muscle fibers and postganglionic neurons D) opens voltage-gated Na⁺ channels in skeletal muscle fibers, which causes depolarization of the muscle fibers, and always depolarizes skeletal muscle fibers and postganglionic neurons E) all of these

Question

Quizplus · Accepted Answer

Acetylcholine binds to receptors on the motor end plate, causing an influx of Na+ and depolarization of skeletal muscle fibers. It also depolarizes postganglionic neurons in the autonomic nervous system.