MUSCLE PHYSIOLOGY

Detailed explanation-1: -The unmyelinated C fibers respond to thermal, mechanical, and chemical stimuli and produce the sensation of dull, diffuse, aching, burning, and delayed pain. The myelinated A-delta fibers respond to mechanical (pressure) stimulus and produce the sensation of sharp, localized, fast pain.

Detailed explanation-2: -“Fast pain”, which goes away fairly quickly, comes from the stimulation and transmission of nerve impulses over A delta fibres, while “slow pain”, which persists longer, comes from stimulation and transmission over non-myelinated C fibres.

Detailed explanation-3: -C-type fibers are unmyelinated fibers that form one of these groups, and they are involved in the afferent transfer of temperature, burning pain, and itch from the periphery to synapse, principally in lamina I and II of the dorsal spinal horn.

Detailed explanation-4: -These two separate sensations are several seconds apart because a fast transmitting information sensation is carried via A delta fibers and is followed several seconds later with slow transmitting pain information carried via C fibers. This phenomenon is known as “double pain sensation” (Figure 6.9).