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, spinal cord, and other parts of the body. Nerve fibers can be classified into two main types: myelinated fibers, which are covered with a protective sheath that speeds up signal transmission, and unmyelinated fibers, which lack this sheath and transmit signals more slowly. These fibers are grouped together to form nerves, which can be found in both the central nervous system (CNS) and the peripheral nervous system (PNS). The proper functioning of nerve fibers is crucial for activities such as movement, sensation, and reflexes, making them vital for overall health and well-being.