Which type of nerves carry impulses from the brain to the arrector pili muscles?

Motor nerves carry impulses from the brain to the arrector pili muscles, which are responsible for causing the hair to stand up on the skin's surface in response to cold or emotional stimuli. Motor nerves are a type of efferent nerve that transmit signals from the central nervous system to the effectors, such as muscles and glands, facilitating actions like movement and contraction.

In the context of the arrector pili, motor nerves specifically signal these tiny muscles located at the base of hair follicles. When activated, the arrector pili muscles contract, resulting in piloerection (the scientific term for hair standing on end). This mechanism is a part of the body's response to various stimuli, particularly in reaction to temperature changes or emotional states.

While sensory nerves are responsible for transmitting sensory information to the brain, they do not directly control muscle movement. The other choices, including arrector nerves and pili nerves, are not recognized categories within human anatomy or physiology, further affirming that the correct pathway for stimulating muscle movement in this context relies explicitly on motor nerves.