What is a Hair Follicle
Basic Structure of a Hair Follicle
A hair follicle is essentially a skin organ, although very tiny, that produces hair. A sebaceous gland is attached to the follicle, this is a very small sebum producing gland that is found everywhere, except on the palms of hands, lips, and soles of the feet. The thicker the density of hair that people have, the higher the number of sebaceous glands that are found.
In order to enable the hair to be more perpendicular to the surface, there is a small bundle of muscles that is attached to the follicle. called the arrector pili. This muscle also causes the follicle to protrude slightly above the surrounding skin and a pore encased with skin oil.
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At the base of the hair, there is a large structure referred to as the papilla. This is made mostly of connective tissue, and a capillary loop. Around the papilla is the hair matrix, which is a collection of epithelial cells.Epithelial cells form one of the four basic types of tissues, along with connective tissue, muscle tissue and nerve tissue.
Epithelial tissues line the cavities and surfaces of structures throughout the body, and also form many glands, such as sweat glands. |
Functions of epithelial cells include secretion, selective absorption, protection, transport and detection of sensation. When you gently run your fingers along the hair, epithelial cells are what provide the sensation to the brain.
Some other structures of the hair follicle include the root sheath, composed of an external and internal part. The hair fiber, which is composed of keratin, and the bulge, which is located at the outer root sheath at the connection point of the arrector pili muscle. The bulge contains several types of stem cells, which supply the entire hair follicle with new cells. The stem cells also take a part in healing the epidermis skin layer, after a wound.
Some other structures associated with the hair follicle include the sebaceous glands, and the sweat glands. Sebaceous glands are microscopic in size, they are located in the skin and secrete an oily or waxy substance called sebum, whose purpose is to lubricate the skin and hair. Sweat glands are small tubular structures in the skin that produce sweat. Receptors are also present in the hair follicle that sense the position of the hair.
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