Question

The motor end plate is

A) a folded area of muscle cell membrane with ACh receptors clustered at the top of each fold.
B) the same as the neuromuscular junction.
C) the same as the synaptic cleft.
D) formed by the membrane of enlarged axon terminals, or boutons, that lie on the surface of skeletal muscle cells.
E) a special fibrous matrix whose collagen fibers hold the axon terminal in proper position.

Answer 1

B) the same as the neuromuscular junction.

The motor end plate is a critical part of the neuromuscular junction, featuring a folded area of the muscle cell membrane that contains acetylcholine receptors, which are crucial for muscle contraction.

Step-by-step explanation:

The motor end plate is an integral component of the neuromuscular junction (NMJ), specifically it is a folded area of muscle cell membrane with acetylcholine (ACh) receptors clustered at the top of each fold. When a motor neuron releases the neurotransmitter ACh, these molecules diffuse across the synaptic cleft and bind to the ACh receptors on the motor end plate. This interaction leads to the opening of ion channels, resulting in depolarization and eventually triggering a muscle contraction. The motor end plate is therefore essential for translating the nervous system's signals into muscular action.

It's important to clarify that the motor end plate itself is not the same as the neuromuscular junction, but rather a component of it. It is the specific location on the sarcolemma (muscle fiber membrane) where ACh receptors are concentrated, allowing for efficient signal transduction. The NMJ includes the motor neuron's axon terminals, the synaptic cleft, and the motor end plate.