hair follicle
Meaning of hair follicle: A hair follicle is the tunnel shaped skin structure surrounding a hair root, distinct from the visible hair shaft that extends above the skin surface.
Definition of hair follicle
A hair follicle is a small, tunnel shaped structure within the skin that surrounds the root of a hair and from which the hair grows. It extends from the surface of the skin down into the dermis, the deeper layer of skin, and contains the cells responsible for producing new hair.
Each hair follicle is associated with a sebaceous gland, which releases oil onto the hair and surrounding skin, and with a small muscle that can cause the hair to stand upright. The visible portion of a hair above the skin surface is called the shaft, while the living, growing portion sits within the follicle itself.
Hair follicles cycle through phases of active growth, transition, and rest throughout life, and conditions affecting the follicle, including inflammation, infection, or disruption of the normal growth cycle, can affect hair growth, texture, or density in the area involved.
Used in a sentence
Biopsy of the scalp showed inflammation centered on the hair follicles.
Good to know
The hair follicle, the structure beneath the skin surface that produces the hair, is distinct from the hair shaft, the visible portion of the hair above the skin, though the two terms are sometimes used loosely as if interchangeable.
Word origin
Where “hair follicle” comes from
Formed from Latin folliculus, meaning a small sac, a diminutive of follis, meaning bag or bellows.