What is a Schwann cell's primary function?

A Schwann cell's primary function is to form myelin sheaths around axons in the peripheral nervous system. Myelin is a fatty substance that wraps around the axons of neurons, providing insulation. This insulation is crucial because it increases the speed of electrical signal transmission along the axon through a process known as salutatory conduction, where the nerve impulse jumps between the nodes of Ranvier (gaps in the myelin sheath).

In contrast, the options regarding hormone production, electrical signal transmission, and nutrient absorption do not accurately describe the specific role of Schwann cells. Hormones are produced by endocrine glands, electrical signals are conducted by neurons themselves, not by the supporting cells like Schwann cells, and nutrient absorption is a function typically associated with intestinal cells rather than neurons or their support structures. By focusing on the formation of myelin sheaths, we recognize the essential part Schwann cells play in the nervous system's functionality and efficiency.