difference between medullated and non medullated nerve fibres.
Answers
1. Medullary sheath is present.
2. They appear white in fresh state.
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3. Nodes of Ranvier are present at intervals.
4. Collateral nerve fibres are present.
Difference # Non-Medullated Nerve Fibres:
1. Medullary sheath is absent.
2. They appear grey in fresh state.
3. Nodes of Ranvier are absent.
4. Collateral nerve fibres are absent
Answer:
Medullated (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
2-They appear white in fresh state.
3. Nodes of Ranvier are present in intervals
4. Extracellular fluid is in contact with the axon only at the nodes.
5. Voltage-gated ion channels are concentrated at the nodes.
6. Ion exchange can occur only at the nodes.
Non-medullated (Non-myelinated) nerve fiber-
1-It comprises of neuraxis which is covered by a single sheath, the neurilemma. Myelin sheath is absent.
2- They appear grey in fresh state.
3- Nodes of Ranvier are absent.
4- Extracellular fluid is in contact with the axon along its entire length
5- Voltage-gated ion channels are spread all over the axon.
6- Ion exchange occurs all along the axon.