Question

What are medullated and non medullated nerve fibres?

Answer 1

Medullated Nerve aka Myelinated Fibre: -axon is surrounded by a layer of fatty proteinaceous materials called myelin sheath which provides white colour to the nerve fibre; -presence of nodes of Ranveir; -faster conduction of nerve impulse; -found in brain and spinal chord. Non-Medullated Nerve aka Non-Myelinated Fibre: -Myelin sheaths are absent hence appears grey in colour due to absent of myelin sheath; -absence of Nodes of Ranveir; -slower conduction of nerve impuls; -found in sympatric and para-sympathetic nerves.