Question

Cutaneous pain

A. Can be caused by overstimulation of touch receptors.

B. Can be caused by excitation of receptors by chemicals released in injured tissue.

C. Can be elicited more readily if the tissue has been injured recently.

D. Receptors adapt to stimulation more quickly than touch receptors.

E. Transmission at spinal cord level is facilitated by opening of potassium channels in the post-synaptic membrane.

Answer 1

A. False Pain is due to excitation of specific pain receptors.

B. True Such substances include histamine, bradykinin, 5-hydroxytryptamine, prostaglandins, nitric oxide and substance P.

C. True Chemicals released in the injured tissue reduce the stimulation threshold to cause hyperalgesia.

D. False Pain receptors adapt much more slowly than touch receptors.

E. False This would inhibit synaptic transmission and may explain how enkephalin and endorphin modulate transmission of pain impulses in the substantia gelatinosa.