Which neuron has its cell body in the anterior horn of the spinal cord and sends axons to peripheral muscles?

• A. Upper motor neurons
• B. Lower motor neurons
• C. Interneurons
• D. Motor units

Answer: (B)

Lower motor neurons are the neurons responsible for directly activating skeletal muscles. Their cell bodies sit in the anterior (ventral) horn of the spinal cord, and their axons exit through the ventral root to form part of peripheral nerves. These axons then reach the muscle fibers at the neuromuscular junction to produce contraction.

In contrast, upper motor neurons originate in the motor cortex or brainstem and project down to influence lower motor neurons; interneurons are local connectors within the spinal cord that modulate circuits between these motor pathways; and a motor unit refers to a single alpha motor neuron and all the muscle fibers it innervates, not a distinct neuron type itself.