What is the first event in muscle fiber contraction?
A)The muscle fiber membrane is stimulated and a muscle impulse travels deep into the fiber through transverse tubules.
B)Acetylcholine diffuses across a gap at a neuromuscular junction.
C)Acetylcholine is released from the end of the motor neuron.
D)Calcium ions diffuse from sarcoplasmic reticulum into the sarcoplasm and bind to troponin molecules.

Question

Quizplus · Accepted Answer

The first event in muscle fiber contraction is the release of acetylcholine from the end of the motor neuron, which then diffuses across a gap at the neuromuscular junction and binds to receptors on the muscle fiber membrane. This binding triggers an action potential that travels deep into the fiber through transverse tubules.

What Is the First Event in Muscle Fiber Contraction