Final answer:
The post-synaptic side of the neuromuscular junction involves the binding of acetylcholine (ACh) neurotransmitter to ACh receptors on the motor end-plate of the muscle fiber membrane. This causes depolarization of the muscle fiber, which is essential for muscle contraction.
Step-by-step explanation:
The post-synaptic side of the neuromuscular junction involves the binding of acetylcholine (ACh) neurotransmitter to ACh receptors on the motor end-plate of the muscle fiber membrane. When ACh binds, a channel in the receptor opens and allows positively charged ions to pass through into the muscle fiber. This causes depolarization of the muscle fiber, which is an essential step towards muscle contraction.