The term hair follicle refers to which of the following structures?

• A. Mass of epidermal cells forming a small tube or canal
• B. Dermal tissue surrounding the hair shaft
• C. Sebaceous gland opening
• D. Sweat duct

Answer: (A)

Hair follicles are tubular structures formed by an inward growth of epidermal cells that create a small tube or canal in which the hair grows. This description—an epidermal mass that forms a canal around the hair—best captures what a hair follicle is.

The surrounding dermal tissue around the hair shaft is the dermal sheath, which is different from the follicle itself. The sebaceous gland opens into the follicle but is not the follicle. The sweat duct belongs to sweat glands, not to the hair follicle.