Study Set Content:
is below the surface and the hair bulb
root
- is the expanded base of the root.
hair bulb
A hair has a hard
cortex
which surrounds a softer center, the
medulla
The cortex is covered by the
cuticle
- a single layer of overlapping cells that holds the hair in the hair follicle.
cuticle
Hair is produced in the
hair bulb
- is an extension of the dermis that protrudes into the hair bulb and contains blood vessels.
it is also where the hair bulb rests on
hair papilla
hair is formed by mitosis of epithelial cells within the hair bulb; these cells divide and undergo keratinization.
growth stage
- Hair is produced in cycles, with a growth stage and resting stage.
- Hair is produced in cycles, with a growth stage and resting stage.
When the next growth stage begins, a new hair is formed and the old hair falls out.
When the next growth stage begins, a new hair is formed and the old hair falls out.
Eyelashes grow for about
30 days
Eyelashes rest for
105 days
whereas scalp hairs grow for
3 years
scalp hair rest for
1-2 years
Hair color is determined by varying amounts and types of
melanin
- With age, the amount of melanin in hair can decrease, causing the hair color to become faded, or the hair can contain no melanin and be white.
- With age, the amount of melanin in hair can decrease, causing the hair color to become faded, or the hair can contain no melanin and be white.
- which can contract and cause the hair to become perpendicular to the skin’s surface
arrector pili muscle
The major glands of the skin are the
- sebaceous glands and the sweat glands.
- are simple, branched acinar glands, with most being connected by a duct to the superficial part of a hair follicle.
Sebaceous glands
