integumentary system
consists of skin, cutaneous glands, hair and nails
function:
-protection
-insulation and cushion
-water loss prevention
-temperature regulation
-excretory system
2 regions
epidermis- keratinized stratified squamous
dermis- dense irregular connective tissue
hypodermis not part of skin
-primarily adipose
hair shaft
outside of skin
epidermis
4 cell types:
-keratinocytes (produce keratin=durability)
-melanocytes (produce melanin=color)
-dendritic cells (perform phagocytosis)
-tactile [merkel] cells (sensitive touch receptors)
4-5 layers
-stratum lucid only found in thick skin (palms of hands a
papillary layer
areolar connective tissue
dermal papillae= fingerprints, 3 types:
-arches
-loops
-whorls
reticular layer
dense irregular connective tissue
hypodermis
...
dermis
2 regions:
-papillary
-reticular
dermal papillae
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subpapillary plexus
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sweat pore
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eccrine sweat gland
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arrestor pili muscle
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sebaceous (oil) gland
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hair follicle
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hair root
deep inside skin embedded in the follicle
hair bulb
well nourished cells at the base of the follicle
consists of:
-hair papilla: protrusions at base of bulb where nourishment occurs
-hair matrix: dividing epithelia cells located on top of papilla
arrector pili muscle
smooth muscle that causes hair to stand upright, reason for goose bumps
cutaneous glands
2 categories:
-sebacceous glands
-sweat glands
sebaceous glands
empty into hair follicle
produce sebum
sweat glands
eccrine glands- secretes perspiration (water, salts, urea)
apocrine glands- secretes perspiration and protein and fatty substances
cutaneous plexus
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adipose tissue
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hair follicle receptor
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lamellar corpuscle
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tactile corpuscle
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sensory nerve fiber with free nerve endings
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