Melissa is walking around barefoot and steps on a sharp nail. She feels the pain and immediately pulls her foot off the ground away from the nail. Which neurons were involved in her response?

• A. Interneurons only
• B. Interneurons and motor neurons only
• C. Sensory and motor neurons only
• D. Sensory neurons, motor neurons, and interneurons

Answer: (D)

Verified step by step guidance

1. Identify the sequence of events that occur when Melissa steps on the nail: sensory input, processing, and motor response.
2. Understand that sensory neurons are responsible for detecting the painful stimulus from the nail and sending this information to the central nervous system.
3. Recognize that interneurons, located in the spinal cord, process the information received from sensory neurons and facilitate communication between sensory and motor neurons.
4. Acknowledge that motor neurons carry the command from the central nervous system to the muscles in Melissa's leg, causing her to pull her foot away from the nail.
5. Conclude that the involvement of sensory neurons, interneurons, and motor neurons is necessary for Melissa's reflexive response to the painful stimulus.