ANATOMY

Detailed explanation-1: -Goosebumps occur when tiny muscles in our skin’s hair follicles, called arrector pili muscles, pull hair upright. For animals with thick fur, this response helps keep them warm.

Detailed explanation-2: -Arrector pili muscles are enwrapped by sympathetic pilomotor nerves, which release the neurotransmitter norepinephrine (NE) to trigger muscle contraction and cause hairs to become erect in response to cold.

Detailed explanation-3: -What are goosebumps? Goosebumps are the result of tiny muscles flexing in the skin, making hair follicles rise up a bit. This causes hairs to stand up. Goosebumps are an involuntary reaction: nerves from the sympathetic nervous system-the nerves that control the fight or flight response-control these skin muscles.

Detailed explanation-4: -The arrector pili muscle is a smooth muscle that attaches to the hair follicle, on one side, and the dermis, on the other. Contraction of the arrector pili muscle causes the hair follicle to stand on end, creating goose bumps.

Detailed explanation-5: -Each arrector pili is composed of a bundle of smooth muscle fibres, which attach to several follicles (a follicular unit) and is innervated by the sympathetic branch of the autonomic nervous system. The contraction of the muscle is, therefore, involuntary .