What is the function of the myelin sheath?

• A. To support cell structure
• B. To insulate axons and speed up nerve impulse transmission
• C. To produce neurotransmitters
• D. To generate hormones

Answer: (B)

The myelin sheath serves a critical function in the nervous system by insulating axons, which are the long, slender projections of neurons. This insulation is crucial for increasing the speed of nerve impulse transmission. Myelin is composed of lipid-rich layers that wrap around the axon, creating a barrier that reduces the loss of electrical signal as it travels along the nerve. This process is known as saltatory conduction, where the nerve impulse jumps from one node of Ranvier (gaps in the myelin sheath) to the next, allowing for faster communication between neurons.

By enhancing the speed and efficiency of nerve signal transmission, the myelin sheath plays a vital role in ensuring proper functioning of the nervous system, allowing for quick reflexes and coordinated movements. Without adequate myelination, electrical signals would slow down, leading to diminished neural communication and resulting in various neurological disorders.