Hair follicles

Hair Follicles

Hair follicles (/hɛər ˈfɒlɪkəl/), are part of the skin, the largest organ of the human body. They are tiny sacs lined with skin cells that produce hair. Each human has about 5 million hair follicles.

Etymology

The term "follicle" comes from the Latin word "follis", which means "bag" or "sack". The term "hair" is derived from the Old English "hær", which has Germanic origins.

Structure

Hair follicles are made up of several parts. The bulb is the base of the hair follicle, which contains the dermal papilla, a structure vital for hair growth. The sebaceous gland is attached to the hair follicle and produces sebum, an oily substance that helps to keep the skin and hair moisturized. The arrector pili muscle is a tiny muscle connected to the hair follicle that causes hair to stand up when it contracts, a phenomenon commonly known as "goosebumps".

Function

Hair follicles play a crucial role in hair growth. They go through a cycle of growth (anagen), rest (telogen), and shedding (exogen). This cycle varies depending on the location of the hair on the body. For example, scalp hair follicles have a long anagen phase of several years, while body hair follicles have a short anagen phase of a few months.

Related Terms

• Anagen: The active growth phase of hair follicles.
• Telogen: The resting phase of the hair growth cycle.
• Exogen: The shedding phase of the hair growth cycle.
• Sebum: An oily substance produced by sebaceous glands.
• Dermal Papilla: A structure at the base of the hair follicle vital for hair growth.

This WikiMD.org article is a stub. You can help make it a full article.