Group C Nerve Fiber - Function

Function

Because of their higher conduction velocity, Aδ fibers are responsible for the sensation of a quick shallow pain that is specific on one area, termed as first pain. They respond to a weaker intensity of stimulus. C fibers respond to stimuli which have stronger intensities and are the ones to account for the slow, but deeper and spread out over an unspecific area, second pain.

C fibers are considered polymodal because they can react to various stimuli. They react to stimuli that are thermal, or mechanical, or chemical in nature.. C fibers respond to all kinds of physiological changes in the body. For example, they can respond to hypoxia, hypoglycemia, hypo-osmolarity, the presence of muscle metabolic products, and even light or sensitive touch. C fiber receptors include:

• C fiber nociceptors
  • responsible for the second, burning pain
• C fiber warming specific receptors
  • responsible for warmth
• ultra-slow histamine-selective C fibers
  • responsible for itch
• tactile C fibers
  • sensual touch
• C mechano- and metabo- receptors in muscles or joints
  • responsible for muscle exercise, burn and cramp

This variation of input signals calls for a variety of cells of the cortex in lamina 1 to have different modality-selectiveness and morphologies. These varying neurons are responsible for the different feelings we perceive in our body and can be classified by their responses to ranges of stimuli. The brain uses the integration of these signals to maintain homeostasis in the body whether it is temperature related or pain related.