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Epidermis characteristics
- -avascular (nutrition from dermal capillaries)
- -from keratinocytes
- -cells progress from stratum basale to stratum corneum in 4 weeks
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Dermis characteristics
- connective tissue divided into 2 regions
- a) papillary: many capillaries, supply nutrition to dermis and epidermis
- b) reticular: strong structure for skin, collagen bundles woven together along elastic fibers, fibroblasts, macrophages
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Subcutaneous tissue characteristics
lipids in fat cells mostly
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Skin appendages
epidermal in origin, can extend into dermis
eg. hair, nails, cutaneous glands
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Sebaceous gland
- part of pilosebaceous unit, produce sebum secreted ito hair follicle via sebaceous duct covers ksin surface(protective fn)
- sebum = antifungal
Found on all skin surface, except palms and soles
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Apocrine sweat gland
Apocrine duct empties into hair fllicle above sebaceous gland
-location:axillae, perineum
-fn: produce scent
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Eccrine sweat gland
NOT part of pilosebaceous unit
Found over entire skin surface except lips, nail beds, glans penis
Fn: temperature regulation via secretion of sweat to cool skin surface.
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Fn of Skin (4)
- Protection
- -barrier to insults (UVL, Mech, chem)
- Thermal
- -keeps body temp regulation
- Sensation
- -touch, pain, temp sensation
- Metabolic function
- -Vit D synthesis
- -energy storage (form of TG)
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Purpura
extravasation of blood into dermis...hemorrhagic lesion
-non-blanchable
- Petechiae: small pinpt purpura
- Ecchymoses: large flat purpura, 'brusie'
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