Because cerebral cortex has too many work already. If we have to think about contolling the hair may be we can be only the porcupine instead of two legs mongky. ^^
The arrector pili muscle is responsible for causing hair to stand on end when contracted. It is a small bundle of smooth muscle fibers attached to the hair follicle. When this muscle contracts, it pulls on the hair follicle, making the hair upright.
Makes the hair follicle stand upright
Hair follicle receptors
The root of each hair follicle is connected to the small arrector pili muscles are small muscles attached to hair follicles in mammals. Each arrector pili muscle has a bundle of smooth muscle fibers which attach to the follicular units which have nerves.
The structural and cellular features of a hair follicle include the papilla, root sheath, matrix, bulge, and hair fiber. The arrector pili is another hair structure that is a very small muscle fiber attached to the follicle.
arrector pilli
A hair is housed in a hair follicle, which is a small cavity in the skin where the hair grows from. The hair follicle also contains sebaceous glands that produce oil to keep the hair and skin moisturized. Each hair follicle is connected to a tiny muscle called the arrector pili muscle, which can cause the hair to stand on end when contracted.
i assumed you are referring to the arrector pili muscle. usually when you are cold or scared, this muscle contracts, pulling the hair follicle in a upright position. the dents created are called goosebumps. it provides insulation and protects the hair
Standing hair is caused by the tiny muscle that connects the hair to the follicle. This muscle is called the arrector pili.
The pilosebaceous unit consists of a hair follicle, sebaceous gland, and associated arrector pili muscle. The hair follicle produces hair, the sebaceous gland secretes oil to lubricate the skin and hair, and the arrector pili muscle is responsible for causing hair to stand up on end.
in the dermis there is the hair shaft, oil and sweat glands, follicle, and muscle.
Follicle.