Question

How can an interneuron contribute to stopping a withdrawal reflex?

A) Inhibiting the activity of motor neurons involved in the withdrawal reflex

B) Enhancing the sensitivity of sensory neurons to the noxious stimulus

C) Increasing the speed of signal transmission along the sensory neurons

D) Stimulating the release of more neurotransmitters at the neuromuscular junction

Answer 1

An interneuron can stop a withdrawal reflex by inhibiting motor neurons that control antagonistic muscles, enabling a faster and unopposed withdrawal from danger.

Step-by-step explanation:

An interneuron can contribute to stopping a withdrawal reflex by inhibiting the activity of motor neurons involved in the reflex. When a part of the body encounters a painful stimulus, such as touching a hot stove, withdrawal reflexes are triggered to quickly move the affected part away from the source of pain. The biceps brachii contracts to pull the hand away, while simultaneously, an interneuron in the spinal cord inhibits the motor neuron that would otherwise cause the antagonistic triceps brachii to contract. This inhibition is crucial because it prevents opposition to the reflex action, allowing for a more rapid withdrawal. The interneuron achieves this inhibition by releasing a neurotransmitter that hyperpolarizes the motor neuron, reducing its likelihood to fire an action potential and thus preventing contraction of the triceps brachii.