Myelinated nerves have larger axon diameters and feature axons surrounded by concentric layers of Schwann cell membrane, allowing for salutatory conduction. In contrast, unmyelinated nerves have smaller axon diameters and are surrounded by Schwann cell cytoplasm, lacking salutatory conduction. Examples include preganglionic fibers in the autonomic nervous system - myelinated fibers are over 1 μm in diameter while unmyelinated are under 1 μm.

1. DIFFERENCES
D R N I L E S H N K A T E , P R O F E S S O R , P H Y S I O L O G Y , / D I F F E R E N C E S Page 6
Difference Between
Myelinated & Unmyelinated Nerves.
Myelinated Unmyelinated Nerves.
1
Axons – Larger
Diameter
Axons – Smaller
Diameter
2
Axon – Surrounded
by concentric
layers of Schwann
cell plasma
membrane
Axon – Surrounded by
cytoplasm of Schwann
cell.
3
Salutatory
conduction -
present
Salutatory conduction
- absent
4
Density of voltage
gated Na channels -
more
Density of voltage
gated Na channels –
Less.
5
Energy
consumption - less
Energy consumption
– less
6
Example – all
Preganglionic
fibres in ANS, in
PNS fibres more
than 1 μm in
diameter
Example – all
Preganglionic fibres
in ANS, in PNS fibres
less than 1 μm in
diameter