Question

Differentiate between myelinated and non- myelinated axons.

Answer 1

Neurons are specialized cells belonging to the nervous system that help in the transmission of information to other nerve cells, muscle or gland cells. Neurons comprises different parts- a cell body, axon and dendrites. The cell body or soma contains nucleus and is involved in protein synthesis. The dendrites consist of branches. The axon is a long cable-like projection that carries signals away from the soma and back to it.

Complete answer:
Myelin sheath is an insulating layer which is rich in lipids. They surround axons and help to increase the rate at which impulses are transmitted along the axon. Myelin sheaths are typically produced from a specialized cell called Schwann cell. Difference between myelinated and non- myelinated axon are as follows-

Myelinated axon	Non-myelinated axon
The Diameters of axons in this case are larger.	Diameter of axons in this case is smaller.
Nodes of Ranvier are present.	Nodes of Ranvier are absent.
Presence of voltage gated channels channels at the nodes where depolarization occurs.	Voltage gated channels are spread throughout the axons ; hence depolarization occurs throughout the axon.
Axon potential jumps from one node to another.	Action potential propagates along the entire axon.
Nerve impulses are transmitted faster.	Nerve impulses are transmitted slower than myelinated nerve cells.
Ion exchange occurs only at nodes.	Ion exchange occurs throughout.
Present in the white matter of the brain and spinal cord along with cranial and spinal nerves.	Present in autonomic nerves.

Note: Thus there are a variety of differences between the myelinated and non- myelinated axons that impacts the transfer of nerve impulses. Myelin sheath is thus an important component of neurons and damage to them can lead to several critical health conditions.