Each Skeletal Muscle Fiber is Controlled by a Motor Neuron

Question

Each skeletal muscle fiber is controlled by a motor neuron at a single
A) synaptic knob.
B) sarcomere.
C) neuromuscular junction.
D) synaptic cleft.
E) transverse tubule.

Accepted Answer

Each skeletal muscle fiber is controlled by a motor neuron at a single neuromuscular junction. This is where the motor neuron releases acetylcholine to stimulate the muscle fiber to contract. The synaptic knob is the swollen end of the motor neuron that contains vesicles filled with neurotransmitters such as acetylcholine. The sarcomere is the basic contractile unit of muscle fiber. The synaptic cleft is the gap between the synaptic knob and the motor end plate of the muscle fiber. The transverse tubule is a deep invagination of the sarcolemma that helps transmit action potentials to the interior of the muscle fiber.