Which statement about alpha motor neurons is correct?

• A. They innervate skeletal muscles
• B. They innervate smooth muscles
• C. They sense tendon stretch
• D. They transmit pain signals

Answer: (A)

Alpha motor neurons are the nerve cells that directly drive skeletal muscle contraction. They originate in the ventral horn of the spinal cord and send their axons to skeletal muscles, forming neuromuscular junctions with extrafusal muscle fibers. When they fire, they release acetylcholine to trigger muscle fiber action potentials and contraction. This is why the statement that they innervate skeletal muscles is correct. They do not innervate smooth muscle (that’s handled by autonomic motor neurons), they do not sense tendon stretch (that’s the role of proprioceptive receptors in the muscle spindle and Golgi tendon organ), and they do not transmit pain signals (pain fibers are sensory, not motor, neurons).