The diameter of Type C fibers is: (A) 13-20mm, (B) 4-13mm, (C) 3-6mm, (D) 0.5-2mm
Answer is D. Unmyelinated fibers carrying pain, itch, temperature, and crude touch sensations (0.5 to 2 micrometers in diameter; they are type C fibers in the generalclassification).Ref: Guyton; 13th edition; Chapter 47 Sensory Receptors, Neuronal Circuits for Processing Information