hair follicle

anatomy

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Last updated

June 29, 2026

Quick Summary

A hair follicle is a tubular sheath within the skin that surrounds the lower part of a hair shaft. It encloses a dermal papilla, which nourishes the growing hair. Hair is produced by these follicles, which are essentially pockets in the epidermis extending into the skin.12

Hair growth occurs in cycles: anagen (active growth), catagen (transition), and telogen (resting and shedding). The duration of the anagen phase determines hair length; scalp hair has a long anagen phase, allowing it to grow for years, while body hair has shorter anagen phases, resulting in shorter growth. This cycle is influenced by genetics, hormones, and environmental factors. Hair serves various functions, including insulation, sensory perception, and communication, though its protective value is limited in humans.3245

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sebaceous gland
…glands are usually attached to hair follicles and release a fatty substance, sebum, into the follicular duct and thence to the surface of the skin. The glands are distributed over the entire body with the exception of the palms of the hands and the soles of the feet; they are…
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…glands are usually attached to hair follicles and release a fatty substance, sebum, into the follicular duct and thence to the surface of the skin. The glands are distributed over the entire body with the exception of the palms of the hands and the soles of the feet; they are…
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integument
Skin layers
…scales, feathers, claws, glands, and hair follicles are derived from either layer or from both. There are considerable differences between the skins of different vertebrate classes, and they are closely related to the environments of the various groups.
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…scales, feathers, claws, glands, and hair follicles are derived from either layer or from both. There are considerable differences between the skins of different vertebrate classes, and they are closely related to the environments of the various groups.
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hair
…sunk in a pit (follicle) beneath the skin surface. Except for a few growing cells at the base of the root, the hair is dead tissue, composed of keratin and related proteins. The hair follicle is a tubelike pocket of the epidermis that encloses a small section of the…
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…sunk in a pit (follicle) beneath the skin surface. Except for a few growing cells at the base of the root, the hair is dead tissue, composed of keratin and related proteins. The hair follicle is a tubelike pocket of the epidermis that encloses a small section of the…
Read More