PATHOLOGY

Detailed explanation-1: -Even though humans have evolved to have relatively little body hair, we still produce goosebumps when cold. 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: -The arrector pili muscle (APM) consists of a small band of smooth muscle that connects the hair follicle to the connective tissue of the basement membrane. The APM mediates thermoregulation by contracting to increase air-trapping, but was thought to be vestigial in humans.

Detailed explanation-3: -The arrector pili muscle is a tiny muscle connected to each hair follicle and the skin. When it contracts it causes the hair to stand erect, and a “goosebump” forms on the skin.