Question: |
What is the anatomy of hair? |
Category: |
Health & Beauty > Hair |
Keywords: |
Keratinization, anatomy, hair |
Type: |
what |
Rating: (0 ratings) Views: 392 Discussions: 0 In Watch Lists: 1 |
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Answer:
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Hair is encompassed in the follicle located below the skin surface in the dermis, the fiber-rich layer that makes up the bulk of the skin. The follicle has a connective tissue component (muscles) and glandular component (sebaceous glands). The muscles elevate the hair and the glands lubricate the hair.
The primary components of the hair follicle are the dermal papilla and the follicle cells. The dermal papilla is the "generative zone" of hair (it contains blood vessels, nerves, and pigment-forming cells). The follicle cells generate the hair shaft; the hair shaft is composed of essentially dead cells, which are the outermost layers of the epithelium and form a solid cylinder in the dermis. Mitotic activity at the base of the hair follicle generates different layers that will "keratinize".
Hair Keratinization
Hair is composed of hard keratin (a family of proteins ranging in size from 20,000 to 70,000 Daltons) and is chemically denser than other forms of keratin (e.g., calluses, dander flakes). Keratinized cells contain more than 85% protein. Where the hair shaft separates from the follicle it undergoes "disjunctive" keratizination, which involves the splitting of layers and exposing surfaces not previously exposed.
Keratinized cells have a very distinctive appearance, and have tiny pores littering their surfaces. The cells are flattened and tightly bound to their neighbors in a very complex array. When they begin to split apart (by an unknown process), large "nooks and crannies" are formed. These types of anatomical features allow external environmental agents to be easily trapped in the outer surface of the hair.
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What is the anatomy of hair?
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