Nerve fibers are long, slender projections of nerve cells, or neurons, that transmit electrical signals throughout the body. They are essential for communication between the brain and various body parts, allowing for functions such as movement, sensation, and reflexes. Nerve fibers can be classified into different types based on their diameter and conduction speed, including myelinated and unmyelinated fibers. Myelinated nerve fibers are covered with a fatty substance called myelin, which acts as insulation and speeds up signal transmission. In contrast, unmyelinated fibers lack this coating and conduct signals more slowly. Together, these fibers form the complex network that enables the nervous system to function effectively.