NERVOUS SYSTEM SPECIAL SENSE
CEREBELLUM
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Question
[CLICK ON ANY CHOICE TO KNOW THE RIGHT ANSWER]
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if nodes of Ranvier are lacking
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if the myelin sheath is continuous
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on myelinated fibers
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on unmyelinated fibers
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Detailed explanation-1: -Saltatory conduction occurs widely in the myelinated nerve fibers of vertebrates, but was later discovered in a pair of medial myelinated giant fibers of Fenneropenaeus chinensis and Marsupenaeus japonicus shrimp, as well as in a median giant fiber of an earthworm.
Detailed explanation-2: -Myelin provides insulation for axons and is necessary for saltatory conduction.
Detailed explanation-3: -Saltatory conduction in unmyelinated axons: clustering of Na+ channels on lipid rafts enables micro-saltatory conduction in C-fibers. The action potential (AP), the fundamental signal of the nervous system, is carried by two types of axons: unmyelinated and myelinated fibers.
Detailed explanation-4: -Saltatory conduction occurs in myelinated axons from one node of Ranvier to the next node. Therefore, the action potential is only generated at the neurofibrils in myelinated axons. Hence, it is faster than continuous conduction. Continuous conduction occurs along the entire length of unmyelinated axons.
Detailed explanation-5: -It is also known as node-to-node conduction since myelin sheath is absent in this region(nodes are the gaps along the axonal sheath). It is the neural conduction from node to node. Such a type of conduction occurs in myelinated nerve fibers of vertebrates.