<prompt> C-fibres carriesItchProprioceptionVibrationPain  <response>: D Pain Primary afferents are classified by their diameter, degree of myelination, and conduction velocity. Largest-diameter afferent fibers, A-beta Ab, respond maximally to light touch andor moving stimuli; they are present primarily in nerves that innervate the skin. In normal individuals, the activity of these fibers does not produce pain. There are two other classes of primary afferents: the small-diameter myelinated A-delta Ad and the unmyelinated C fiber axons.Schallanger Glassers ClassificationaProprioception, somatic motorbTouch, pressure, motorgMotor to muscle spindledPain, cold, TouchBPreganglionic autonomicCDorsal root: Pain; Temperature, vibration Sympathetic: Post... sympathetic These fibers are present in nerves to the skin and to deep somatic and visceral structures. Some tissues, such as the cornea, are innervated only by A6 and C fiber afferents. Most Ad and C fiber afferents respond maximally only to intense painful stimuli and produce the subjective experience of pain when they are electrically stimulated; this defines them as primary afferent nociceptors pain receptors. The ability to detect painful stimuli is completely abolished when conduction in Ad and C fiber axons is blocked. A delta fibers, or Ad fibers, are a type of sensory fiber. They are associated with cold and pressure, and as nociceptors stimulation of them is interpreted as fastfirst pain information. They are thinly myelinated, so conduct signals more rapidly than unmyelinated C fibers, but more slowly than other, more thickly myelinated A class fibers. 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. 