National League for Nursing (NLN PAX) Practice Exam

The function of the myelin sheath that surrounds many neurons is to do what?

1. Prevent meningitis

2. Slow the rate of impulse transport

3. Increase the flow of ions into the axon

4. Increase the rate of impulse transport

The correct answer is: Increase the rate of impulse transport

The myelin sheath is a crucial component of the nervous system that surrounds the axons of many neurons. Its primary function is to enhance the speed of electrical impulse conduction along the nerve fibers. This is achieved through a process known as saltatory conduction, where the electrical impulses jump from one node of Ranvier (gaps in the myelin sheath) to another, rather than traveling continuously along the entire length of the axon. This jumping significantly accelerates the transmission of signals, allowing for more efficient communication between neurons. This increased rate of impulse transport is vital for the proper functioning of the nervous system. In practical terms, faster impulse conduction means quicker reflexes and more rapid processing of information. The myelin sheath essentially acts as an insulator, allowing for the rapid propagation of action potentials. Hence, the correct answer highlights the essential role of the myelin sheath in facilitating faster neural communication.