College of Massage Therapists of Ontario (CMTO) Practice Test

Pain fibers differ in myelination and conduction speed, which shapes how the pain feels and when it’s perceived. A-delta fibers are small-diameter and myelinated, so they conduct signals quickly and carry the initial, sharp, well-localized pain that occurs right after tissue injury. C fibers, by contrast, are unmyelinated and slower, producing a dull, aching, poorly localized pain that starts a bit later and lasts longer. The statement that correctly pairs a fiber type with its pain description is the one that says A-delta fibers are myelinated and carry sharp, fast pain. The other options mix up myelination and the quality of pain associated with each fiber type.