Final answer:
A withdrawal reflex employs interneurons along with sensory and motor neurons to quickly respond to a painful stimulus. Interneurons allow for more complex coordination, such as inhibition of opposing muscles and involvement in the cross extensor reflex for balance.
Step-by-step explanation:
A withdrawal reflex employs interneurons in conjunction with sensory and motor neurons. Somatic reflexes involve a simple, direct pathway from sensory neurons to motor neurons, which allows for a quick response. However, more complex reflexes such as the withdrawal reflex incorporate the action of interneurons for central processing within the spinal cord. This processing can include the inhibition of antagonist muscles and coordination of postural muscles, making the reflex arc more sophisticated.
In the example of touching a hot stove, sensory neurons carry the painful stimulus to the spinal cord, where interneurons facilitate the activation of motor neurons. These motor neurons then cause contraction of muscles like the biceps brachii to withdraw the hand. Interneurons may also contribute to a cross extensor reflex on the other side of the body to maintain balance.