What is a "hair follicle"?

A hair follicle is a small anatomical structure found in the skin that produces and houses hair. It consists of a hair shaft, which is the visible part of the hair above the skin's surface, and a root embedded within the dermis or subcutaneous tissue. The hair follicle is responsible for hair growth and regeneration, with each follicle going through a cycle of growth, rest, and shedding. It also contains sebaceous glands that secrete oils to lubricate the hair and surrounding skin. Hair follicles are distributed throughout the body, except for areas like the palms of the hands and the soles of the feet, and they contribute to insulation, protection, and sensory perception.