Fibers terminate at Rexed lamina I.> Because of their higher conduction velocity, Ad fibers are responsible for the sensation of a sharp 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, dull, longer-lasting, second pain.> C fibers are considered polymodal because they can respond to thermal, mechanical, and chemical stimuli.> 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.">