Pain is carried by -

Ans. is 'd' i.e., Ad fibers o Fastest conduction velocity - Aa fiber,o Slowest conduction velocity - C fiber.Classification of Mammalian Nerve fibresGroup Erlanger and GasserLloyd & Hunt*MyelinationDiameter (microns)Conduction velocity (m/s)FunctionAgent to which conduction is most susceptibleA alphaIHeavily myelinated13-2070-120 MaximumProprioceptionMotor supply to Skeletal muscle (extrafusal to muscle spindle)PressureA betaIIMyelinated4-1325-70Touch, kinesthetic sense, pressurePressureA gamma-Slightly myelinated3-615-30Motor supply to intrafusal muscle fibres (muscle spindle)PressureA deltaIIISome myelination1-55-30Pain temperature, pressure, touchPressureB-Some myelination1-33-14Preganglionic autonomic fibresHypoxiaCIVUnmyelinated0-2-100-2-2 MinimumPain, temperature, pressure, postganglionic autonomic fibresLocal anaesthetics