Question

At a neuromuscular junction

A. actin and myosin filaments slide past one another.
B. troponin and tropomyosin exchange places.
C. neurotransmitters are released.
D. intercalated discs are synthesized.

Answer 1

When a nerve impulse reaches the neuromuscular junction, it triggers the release of acetylcholine (ACh) which binds to ACh receptors on the muscle fiber, signaling the muscle contraction. The actin and myosin filaments slide past each other, causing the sarcomeres to shorten and the muscle to contract.

Step-by-step explanation:

According to the sliding filament model of muscle contraction, when a nerve impulse reaches the neuromuscular junction, it triggers the release of acetylcholine (ACh) from the motor neuron's axon terminal. ACh then binds to ACh receptors on the muscle fiber, signaling the contraction of the muscle fiber. This contraction occurs when the actin and myosin filaments slide past each other, causing the sarcomeres to shorten and the muscle to contract.