Nerve Fibre Classification & Conduction — Practice
A researcher records the compound action potential from a peripheral mixed nerve and notes that the last (slowest) wave is abolished by a local anaesthetic before the fastest wave. This selective early block of small unmyelinated fibres is best explained by which property?
ASmall unmyelinated C fibres are more readily blocked by local anaesthetics
BConduction velocity is independent of fibre diameter
CLarger fibres have a higher safety factor for conduction
DMyelinated fibres have a lower threshold to local anaesthetic