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The skin is composed of?
- Skin (Integument)
- Skin derivatives
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What are the different skin derivatives?
- Sweat glands
- Oil glands
- Hair
- Nails
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What are the different skin functions?
- 1) Protects deeper tissue from:
- 2) Aids in heat regulation
- 3) Aids in excretion of urea and uric acid
- 4) Synthesizes vitamin D
- 5) Detection of stimuli
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Skin protects deeper tissue from:
- Mechanical damage
- Chemical damage
- Bacterial damage
- Thermal damage
- Ultraviolet radiation
- Desiccation
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What are the different skin structures?
- Epidermis
- Dermis
- Hypodermis
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Epidermis (5 strata)?
- Stratified squamous epithelium
- Keratinocytes from several layers
- Layers of epidermis
- Melanin
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Whats are the layers of epidermis?
- Stratum basale
- Stratum spinosum
- Stratum granulosum
- Stratum corneum
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What are the two layers of dermis?
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What does the Papillary layer consist of?
- Supports and nourishes overlying epidermis
- Projections called dermal papille
- Pain receptors
- Capillary loops - inside the dermal papillae
- (There are less fibers in papillary layer which means less white blood flow/cells)
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What does the reticular layer consist of?
- Meshwork of collagen and elastic fibers
- Blood Vessels
- Glands
- Nerve receptors
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Hypodermis (subcutaneous) "below the dermis"
- Not part of the skin
- Anchors skin to underlying organs
- Composed mostly of adipose tissue (accounts for half of the bodys stored fat) "subcutanecus fat"
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What are the different aooendages of the skin?
- Sebaceous glands
- Sweat glands
- Hair
- Nails
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Sebaceous glands:
- Produce oil (sebum) a lubricant for the skin
- Most with ducts that empty into hair follicles
- Glands are activated at puberty (under hormonal control) ex-acne
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Sweat glands:
- Widley distributed in skin
- Two types :
- Eccine (Merocrine)
- Apocine
- Modified sweat glands
- ceruminous glands - produce ear wax
- mammary glands
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Eccine (Merocrine)
coiled portion in dermis, distributed body wide, helps dissipate excess heat through evaporative cooling)
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Apocine
ducts empty into hair follicles, axillary and pubic regions, activated by stress, pain, and sexual excitement, fatty acid and protein secretion
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Hair:
Strand of dead, hard keeatinized epthielial cells
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Hair follicle consist of:
- Tubelar invaginations of the epidermis
- Formed by mitotically active statum basale cells
- Melancocytes provide pigment for hair color
- Dermal capillaries provide blood supply
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Nail structure:
- Nail fold (lateral and proximal skin coverings)
- Eponychium
- Nail bod: sheet of hard keratin attached to nail bed, Lunula-crescent shaped vascular area at proximal end of the nail bed and visable through the nail. used for visual check of oxygen status in patients (clinical: Eponychiitis, ingrown toenail)
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Clinical Application:
- Injection sites
- Blisters
- Lines of cleavage
- Streach marks
- Decubitus ulcers or "bed sores"
- Burnes
- Skin Cancer
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Where are the different injection sites?
- Intadermal (ID) within the dermis ex-collagen
- Subcutaneous ("subcue" or SQ) ex-insulin for diabetics, lots of blood vessles
- Intramuscular (IM) Small amounts is faster than SQ
- Intravenous (IV) fastest method "fastest delivery to the heart"
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Blisters:
Fluid-filled pocket between epidermis and dermis
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Lines of cleavage:
Formed by uniform alignment of collagen and elastic fibers
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Stretch Marks
Tearing of the dermis due to rapid stress
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Decubitus ulcers or Bed sores
- Blood suppy restricted --> ischemia (no oxygen/reduced) --> necrosis (tissue death)
- Bacterial infections result, difficult to heal, secondary intention
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Burns
Tissue damage and cell death caused by heat, electricity, UV radiation, or chemicals
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Associated dangers with burned skin:
- Dehydration
- Electrolyte imbalance
- Circulatory shock
- Infection
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Rules of nine?
Ways to determin the extent of the burn
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Severity of burns
- 1st (redness and swelling) epidermis only
- 2nd (Blistering) epidermis and part of dermis
- 3rd (destruction) death of tissue, through entire dermis and sometimes lower
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Types of skin cancer?
- Basal cell carinoma (least malignant, but most common)
- Squamous cell carcinoma (usually a sun induced mutation and grows rapidly and will metastasize if not removed)
- Malignant melanoma (most deadly)
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Key to servival is early detection...what is the ABCD rule?
- A (asymmetry) not same size
- B (irregular border) not smooth
- C (color) different colors in same spot
- D (diameter-greater than 6mm)
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