Fastest acting nerve fibers are?
Ans. is 'a' i.e., AaoType A fibers have maximum velocity because they are thick and myelinated. Among A fibers. Aa have maximum conduction because they are thickest and myelinated.oAmong A fibers conduction velocity is Aa>Ab>Ag>AdoType B fibers have some myelination so they are faster than C fibers and slower than A fibers.oType C fibers have slowest conduction because they are thin and non-myelinated.Classification of Mammalian Nerve fibres Group Erlanger And GasserLloyed & Hunt*MyelinationDiameter (microns)Conduction velocity (m/s)FunctionAgent to which conduction is most susceptible Agent to which conduction is most susceptibleAaIHeavily myelinated13-2070-120 MaximumProprioception Motor supply to Skeletal muscle (extrafusal to muscle spindle)PressureAbIIMyelinated4-1325-70Touch, kinesthetic sense, pressurePressureAg-Slighdy myelinated3-615-30Motor supply to intrafusal muscle fibres (muscle spindle)PressureAdIIISome myelinated1-55-30Pain, temperature, pressure, touchPressureB-Some myelinated1-33-14Preganglionic autonomic fibresHypoxiaCIVUnmyelinated0.2-1.00.2-2 MinimumPain, temperature, postganglionic autonomic fibresLocal anaesthetics Local anaesthetics
Aa
Ab
B
C
Nervous System