Ch.12 Neuromuscular Junction (Bio)

Skeletal muscle can contract without nerve stimulation.

False

What happens to the neurotransmitter once an action potential is propagated on the muscle sarcolemma?

It is immediately broken down by an enzyme.

By what process does the motor neuron stimulate the muscle cell?

Neurotransmitter is released into the synaptic cleft to cause an action potential in the muscle cell.

A single action potential will create a single momentary contraction, not a continuous contraction.

True

The function of the neurotransmitter is to cause the opening of sodium channels in the muscle cell membrane.

True

The opening of sodium channels is essential for the initiation of an action potential in the muscle cell membrane.

True

The neurotransmitter released by the motor neuron to cause muscle contraction is

acetylcholine

When the electrical impulse of the motor neuron reaches the synapse, the release of neurotransmitter is caused by

an increase in intra-cellular calcium when voltage-gated calcium channels open.

The impulses that initiate muscle contraction originates in the

brain or spinal cord

A group of muscle cells stimulated by a single motor neuron is known as a

motor unit.