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Exocrine glands in accessory structures
- sebaceous (oil) glands
- aprocrine sweat glands
- merocrine sweat glands
- mammary glands
- ceruminous glands
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Sebaceous (oil) glands
- secretes sebum into hair follicle
- sebaceous follicles are sebaceous glands that empty directly onto surface of skin - not into a hair follicle
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Apocrine sweat glands
- abundant only in armpits, around nipples, and in groin
- secretes a sticky, cloudy and odorous secretion into hair follicles
- active at puberty and beyond
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Merocrine sweat glands
- widely distributed
- secretes water and electrolytes
- water evaporation on skin surface allows for cooling of skin and body
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Mammary glands
- located in breast tissue
- development and secretions controlled by pituitary and sex hormones
- basically - modified sweat glands that produce milk
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Ceruminous glands
- located in external ear
- secretes cerumen (i.e. earwax)
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Structural elements comprising the hair follicle
- hair root
- hair shaft
- cuticle
- cortex
- medulla
- hair papilla
- hair matrix
- arrector pili muscles
- melanocytes
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Hair root
in the follicle
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Hair shaft
beyond the root, above sebaceous gland and skin
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Cuticle
helps coat the hair
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Cortex
- cell for keritinization process
- contains hard keratin
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Medulla
- cell for keritinization process
- contains soft keratin
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Hair papilla
connective tissue that contains blood vessels and nerves
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Hair matrix
- surrounds papilla
- location where basal cells divide, migrate upward and cause hair growth
- cells in the center form the medulla whereas more peripherally located cells form the cortex
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Arrector pili muscles
- responds to emotional states or temperature
- causes goosebumps!
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Melanocytes
- pigment producing cells located in the papilla providing hair color
- decreased melanocyte activity causes the gray hair associated with aging
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