Pain receptors are activated by tissue damage, but pain perception requires intact, functional neurons. How does this work?

Question

A.  Nociceptor neurons have special membrane repair mechanisms.
B.  The nociceptor neuron only sends action potentials as it is dying.
C.  The axon continues to fire action potentials despite damage to the cell body.
D.  The neuron itself does not need to be damaged; it responds to signals released by nearby damaged cells.

Clarify Question
What is the key concept addressed by the question?
What type of thinking is required?

Gather Content
What do you already know about pain receptors? What other information is related to the question?

Choose Answer
Given what you now know, what information is most likely to produce the correct answer?

Reflect on Process
Did your problem-solving process lead you to the correct answer? If not, where did the process break down or lead you astray? How can you revise your approach to produce a more desirable result?

Answer 1

D.  The neuron itself does not need to be damaged; it responds to signals released by nearby damaged cells.

Clarify Question
What is the key concept addressed by the question?
        · How do pain receptors work if they sense damage?
What type of thinking is required?
            o This is an analyze question because you have to break down the process of pain detection by nociceptors.

Gather Content
What do you already know about pain receptors? What other information is related to the question?
        · You already know that pain reception uses nociceptors that detect tissue damage, but how do they work. When tissue is damaged, such as a cut in the skin, an inflammatory response occurs in the tissue that releases signaling molecules such as bradykinin, prostaglandins, and a molecule called Substance P. These substances can diffuse to surrounding tissue that is not damaged and has fully functioning neurons. The molecules can affect ion movement in and out of the free nerve endings used to detect pain.

Choose Answer
Given what you now know, what information is most likely to produce the correct answer?
        · Nociceptor neurons do not have special membrane repair mechanisms, so that answer is not correct. Nociceptors need to be alive and healthy in order to send action potentials, so the answer that says the neurons only send action potentials as it is dying does not make sense. If the cell membrane of the neuron’s cell body is ruptured, then action potentials would not be possible as the ion gradient across the membrane would be lost, thus that answer is not likely. That leaves only one answer, which is that the neuron itself does not need to be damaged, but it responds to molecular signals released by nearby damaged cells.

Reflect on Process
Did your problem-solving process lead you to the correct answer? If not, where did the process break down or lead you astray? How can you revise your approach to produce a more desirable result?
o Answering this question correctly depended not only on understanding the steps of pain perception, but on your ability to discriminate among different potential means of how nociceptors work without being damaged themselves. If you got an incorrect answer, did you think that the pain signal associated with tissue damage only came from damaged neurons? Did you realize the molecular signals from damaged tissue could diffuse to adjacent areas to affect healthy nociceptive neurons?