Which type of nerve fibers are distributed to the arrector pili muscles attached to the hair follicles?

The correct choice is motor nerve fibers. These fibers are responsible for transmitting signals from the central nervous system to the muscles. In the context of the arrector pili muscles, which are small muscles located at the base of hair follicles, motor nerve fibers play a crucial role in controlling muscle contraction. When these fibers send signals to the arrector pili muscles, they cause the muscles to contract, resulting in the hair standing upright, commonly referred to as "goosebumps."

Understanding the function of these nerve fibers is essential in fields such as cosmetology, where knowledge of hair physiology and the body's response to stimuli can enhance service delivery and overall client experience. Sensory nerve fibers, while important for detecting sensations, do not control muscle movements. Secretory nerve fibers are involved in the secretion of substances (like sweat or oil) but are not connected to muscle movement. Interneurons primarily relay information between sensory and motor neurons in the nervous system but do not directly control muscle contractions themselves.