MICROANATOMY

Detailed explanation-1: -Alpha motor neurons (also called lower motor neurons) innervate skeletal muscle and cause the muscle contractions that generate movement. Motor neurons release the neurotransmitter acetylcholine at a synapse called the neuromuscular junction.

Detailed explanation-2: -The neurotransmitter, acetylcholine, is released from synaptic vesicles into the synaptic cleft when a nerve impulse reaches the motor end plate. Once the acetylcholine is released, it will stimulate receptor sites on the postsynaptic muscular membrane, causing the contraction of skeletal muscle fibers.

Detailed explanation-3: -Motor neurones are cells in the brain and spinal cord that allow us to move, speak, swallow and breathe by sending commands from the brain to the muscles that carry out these functions. Their nerve fibers are the longest in the body, a single axon can stretch from the base of the spinal cord all the way to the toes.

Detailed explanation-4: -The given statement is “false”. A motor neuron and all the myocytes (muscle cells) that it stimulates are called a motor unit, not a motor end plate. A motor end plate also called a neuromuscular junction, is a chemical synapse formed between the terminal branches of the motor neuron’s axon and a target muscle cell.

Detailed explanation-5: -motor unit is a motor neuron plus all the skeletal muscle fibers it stimulates. Motor units are therefore the most basic unit of a skeletal muscle and are what causes a contraction.