The simplest version of a withdrawal from pain reflex is a
A) pain receptor that synapses onto an interneuron, which in turn activates a motor neuron in the spinal cord.
B) pain receptor that projects to the thalamus, which then projects to motor cortex and then back down to the spinal cord.
C) motor neuron within the spinal cord that is spontaneously active.
D) sensory neuron in the visual cortex that synapses onto a motor neuron in the spinal cord.
E) motor neuron that activates sensory fibers.

Question

Quizplus · Accepted Answer

The simplest version of a withdrawal from pain reflex involves a pain receptor that synapses onto an interneuron in the spinal cord, which in turn activates a motor neuron. This causes the muscles to contract and move the affected body part away from the painful stimulus. This reflex pathway is known as the spinal reflex arc and does not require input from the brain. Therefore, choice A is the best answer.

The Simplest Version of a Withdrawal from Pain Reflex Is