Question

Saltatory conduction of nerve impulses occurs in-
a. Amyelinated fibres
b. Myelinated Fibres
c. Both A and B
d. None of the above

Answer 1

Hint: Myelin is a lipid-rich (fatty) matter produced in the central nervous system (CNS) by glial cells known as oligodendrocytes, and in the peripheral nervous system (PNS) by Schwann cells. Myelin insulates nerve cell axons to amplify the speed at which information (determined as an electrical signal) shifts from one nerve cell body to another (as in the CNS).

Complete answer:
The non-myelinated nerve is the nerve cell in the autonomic nervous system which is devoid of myelin sheath enclosing its axon.

The myelinated nerve fibers are the nerve fibers that are wrapped by the myelin sheath. It is an insulating layer that does not permit nerve conduction right the way through the length of the nerve cell. So the transmission of impulse takes place at the node where the myelin sheath is absent. It involves the quick conduction of generated nerve potential.

The action potential jumps from node to node, due to which the transmission of impulse is further rapid in myelinated fibers. This kind of nerve conduction is termed as saltatory conduction.

Hence, the correct answer is option (B).

Note: As sodium hustles into the node it makes an electrical force that pushes on the ions already in the axon. This speedy conduction of the electrical signal reaches the next node and forms another action potential, thus uplifting the signal. Similarly, saltatory conduction permits electrical nerve signals to be propagated long distances at elevated rates without any deprivation of the signal. Although the action potential looks to jump along the axon, this phenomenon is essentially just the rapid, nearly instantaneous, conduction of the signal within the myelinated segment of the axon.