| S.N. | Medullated (Myelinated) nerve fiber | Non-medullated (Non-myelinated) nerve fiber |
| 1. | It comprises of neuraxis, which is covered by two sheaths;
i) inner thick myelin sheath of fatty material called myelin ii) outer thin neurilemma |
It comprises of neuraxis which is covered by a single sheath, the neurilemma. Myelin sheath is absent. |
| 2. | They appear white in fresh state. | They appear grey in fresh state.
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| 3. | Nodes of Ranvier are present in intervals. | Nodes of Ranvier are absent. |
| 4. | Extracellular fluid is in contact with the axon only at the nodes. | Extracellular fluid is in contact with the axon along its entire length. |
| 5. | Voltage-gated ion channels are concentrated at the nodes. | Voltage-gated ion channels are spread all over the axon. |
| 6. | Ion exchange can occur only at the nodes. | Ion exchange occurs all along the axon. |
| 7. | Action potential doesn’t propagate over the internodes, and jumps from node to node. | Action potential propagates all along the axon. |
| 8. | Nerve impulse conduction is salutatory. | Nerve impulse conduction is smooth. |
| 9. | These carry nerve impulses much faster than non-medullated nerve fibers. | These carry nerve impulses much slower than the medullated nerve fiber. |
| 10. | These are present in the white matter of brain and spinal cord and in the cranial and spinal nerves. | These are present in the grey matter of brain and spinal cord and in the autonomic nerves.
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| 11. | Collateral nerve fibers are present. | Collateral nerve fibers are absent. |
| 12. | They are more common in vertebrates. | They are found in few vertebrates and almost all the invertebrates. |