Question

when brian touches a hot object, which body structures help him react appropriately to protect himself?
○ the sensory neurons, the brain, and the motor neurons
○ the sensory neurons, the vertebral column, and the brain
○ the sensory neurons, the interneurons, and the motor neurons
○ the vertebral column, the interneurons, and the motor neurons

Explanation:

To solve this, we analyze the reflex arc components. When touching a hot object, the reflex action (like pulling the hand back) involves:

1. Sensory neurons: Detect the heat (stimulus) and send signals.
2. Interneurons: In the spinal cord (or CNS) that process the signal.
3. Motor neurons: Send signals from the CNS to muscles to produce the response (e.g., moving the hand).

• Option 1 includes the brain, but reflexes (like this) are spinal - mediated, so the brain is not the main structure here.
• Option 2 includes the vertebral column (a structure, not a functional neuron type) and the brain, which is incorrect.
• Option 4 includes the vertebral column (not a neuron type) and misses sensory neurons.
• Option 3 has the correct neuron types involved in the reflex pathway: sensory (detect), interneurons (process), motor (respond).

Answer:

C. the sensory neurons, the interneurons, and the motor neurons