Unmyelinated C fibers are thought to carry which of the following pain sensations?
(A) aching
(B) burning
© dull
(D) gnawing
(E) pricking
Explanation:
(B) It is now believed that specific pain receptors (free nerve endings) are stimulated mainly by chemicals such as bradykinin, and that two types of pain sensations (“pricking” and “burning”) are transmitted by different types of nerves. The burning pain sensation is transmitted by small C-fibers, and the pricking pain sensation is transmitted by larger, myelinated A-delta fibers. The pain fibers eventually terminate in the thalamus in a somatotopical fashion. Choices A, C, D, and E are incorrect.