What is the end of the neuron where it meets the muscle called?

• A. Dendrites
• B. Motor end plate
• C. Sarcoplasmic reticulum
• D. Axon terminal

Answer: (B)

The signal from a motor neuron arrives at the muscle at a specialized contact point called the motor end plate. This region is on the muscle cell’s membrane (the sarcolemma) at the neuromuscular junction and is rich in receptors for acetylcholine, the neurotransmitter released by the neuron. When the neuron fires, acetylcholine is released into the small gap (the synaptic cleft) and binds to these receptors, opening channels and depolarizing the muscle fiber. This electrical change triggers calcium release inside the muscle and ultimately contraction. The motor end plate is the muscle-side counterpart of the neuronal end, forming the functional junction where communication happens.

Dendrites are parts of a neuron that receive signals from other neurons, not the site where a motor neuron communicates with muscle. The sarcoplasmic reticulum resides inside the muscle cell as a calcium store, not at the contact point with the neuron. The axon terminal is the end of the neuron that releases neurotransmitter, but the specific region on the muscle where this signal is received is the motor end plate.