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skin and its accessory organs, example- the hair, nails, and cutaneous glands
integumentrary system
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made of stratified squamous epithelium, 5 layers
epidermis
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made of connective tissue
dermis
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functions of skin
- resistance to trauma and infection
- barrier
- need for absortion
- thermoregulation
- social function
- cutaneous absorption
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cells of the epidermis
- karatinocytes
- stem cells
- melanocytes synthesize melanin
- tactile or merkel cell
- dendritic cell
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5 layers of the epidermis
- 1. stratum basal
- 2. stratum spinosum
- 3. stratum granulosum
- 4. stratum lucidum
- 5.stratum corneum
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-dermal- epidermal junction
-barrer to cell and large molecules
basebem membrane
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-made of collogen, elastic, and reticular fiber, fibroblasts
-blood vessels, sweat gland, sebaceous glands, nerve endings
smooth muscles called pilorector muscles
dermis
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2 layers of dermis
- papillary layer
- reticular layer
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single layer of cuboidal or low columnar stem cells and kaeratinocytes sitting on basement membrane
stratum basale
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several layers of karatinocytes thick erich in RNA for keratin production
stratum spinosum
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3-5 layers of flat keratinocytes
contains keranohyalin granules
-produces lipid filled vessicles that release a glycolipid and exocytosis to water proof skin
stratum grulosum
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keratinociytes are packed with eleidin, a precursor to keratin
stratum lucidum
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up to 30 layers of dead cells
stratum corneum
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two types of melanin and their pigment
- eumelanin-brownish black
- pheomelakin- reddish yellow sulfur containing pigment
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red pigment of red blood cells
hemoglobin
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yellow pigment of vegitable and egg yolk
cerotene
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blueness resulting from deficiency of oxygen
cyanosis
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redness due to dilatied cutaneous vessels
erythema
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yellowing of skin and sclera due to excess of billifubin in blood
jaundice
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known as subustaneous tissue or superficial fascia
hypodermis
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-energy reservoir
-thermal insulation
-hypodermic injections
hypodermis
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the boundary between the papillary and reticular layers is often vague
reticular layers
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