Question

The ___ is the conduction area where the axon of the motor neuron ends on a skeletal muscle fiber.

1) Dendrite
2) Myelin Sheath
3) Neuromusclar junction
4) Nodes of Ranavier

Answer 1

The area where the motor neuron's axon ends on a skeletal muscle fiber is called the neuromuscular junction. It is where acetylcholine is released to initiate muscle contraction.

Step-by-step explanation:

The conduction area where the axon of the motor neuron ends on a skeletal muscle fiber is known as the neuromuscular junction (NMJ). This specialized synaptic structure features multiple axon terminals from the motor neuron synapsing with the muscle fiber sarcolemma. At the NMJ, the axon terminal releases a neurotransmitter called acetylcholine (ACh) which binds to ACh-receptors in the muscle fiber sarcolemma.

Upon binding, acetylcholine triggers the opening of ligand-gated ion channels, allowing for an influx of cations, which depolarizes the sarcolemma and initiates muscle contraction. Every skeletal muscle fiber is innervated at the NMJ, and it is the primary site where excitation signals from the neuron activate the fiber to contract. The strength of contraction can vary based on the frequency of the motor neuron impulses.