Term
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Definition
1. skin
2. appendages (hair, nails, glands) |
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Term
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Definition
1. Homeostasis
-regulate body temp
-regulate fluid volume
-protection against UV radiation
-protection from minor trauma
-protection against disease organisms
-excretion
2. sensory function
3. Vitamin D synthesis |
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Term
|
Definition
-keratinized, stratified squamous epithelium
-locally specialized to form hair, nails, glands |
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Term
|
Definition
1. keratinocytes
2. melanocytes
3. Langerhan cells
4. Merkel cells |
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Term
| Characteristics of keratinocytes |
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Definition
1. predominant epithelial cell type, derived from ectoderm
2. as cells get further from nutrients, cells die and keratin is left
3. fibrous, insoluble due to disulfide bonds
4. soft keratin in skin
5. hard keratin in nails, hair |
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Term
|
Definition
1. stratum basale
2. stratum spinosum
3. stratum granulosum
4. stratum lucidum
5. stratum corneum |
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Term
| Characteristics of stratum basale |
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Definition
1. single layer of columnar cells attached to basal lamina by hemidesmosomes and to neighbors by desmosomes.
2. stem cells, mitotically active
3. synthesize tonofilaments for keratin formation |
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Term
| Characteristics of stratum spinosum |
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Definition
1. polyhedreal cells attached by many desmosomes
2. tonofibrils form from tonofilaments and attach to desmosomes
3. spiny appearance during histo processing |
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Term
| Characteristics of stratum granulosum |
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Definition
1. 1-3 cells thick
2. contain 2 types of granules
-keratohyalin granules:stain purple; contain filaggrin
-membrane-coated (lamellar) granules:secretes lipid envelope-->epidermal water barrier |
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Term
| Characteristics of stratum lucidum |
|
Definition
1. most visible in thick skin
2. pink-staining, layer of dying cells
3. filaggrin combine with tonofibrils to form dense matrix |
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Term
|
Definition
1. varies in thickness
2. consists of dead, flat cells, mostly keratin |
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Term
|
Definition
-has all 5 layers
-hairless
-palms of hand, soles of feet |
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Term
|
Definition
-no stratum lucidum visibile
-has hair |
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Term
| Characteristics of melanocytes |
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Definition
1. second most numerous cells
2. derived from neural crest cells
3. involved in pigmentation
4. lie between cells of s. basale |
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Term
| How to visualize melanocytes |
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Definition
1. tyrosinase oxidzes tyrosine to form
2. DOPA
3. converted to melanin pigment |
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Term
|
Definition
| -due to rate of melanin degradation |
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Term
|
Definition
| -results when no tyrosinase activity |
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Term
|
Definition
| invasive tumor of melanocytes |
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Term
|
Definition
-star shaped, reside in stratum spinosum
-antigen presenting cells
-delayed-type hypersensitivity rxns
-derived from bone marrow |
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Term
|
Definition
| -sensory receptors that respond to pressure |
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Term
|
Definition
1. papillary layer-loose, vascular CT
-contains Type I and III collagen and elastic fibers
2. reticular layer-avascular, dense irregular CT
-Langer's lines-lines of tension or cleavage in skin |
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Term
|
Definition
1. supports epidermis
2. nourish epidermis, regulate body temp
3. inflammatory and immune response
4. sensory receptors
5. thermoreceptors
6. nocireceptors |
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Term
| Types of mechanoreceptors |
|
Definition
1.Uncapsulated
-free nerve endings: light touch
-Merkel endings: light touch
2. Encapsulated
-Pacinian corpuscles: vibration, touch
-Krause endbulbs: light touch
-Meissner's corpuscles: touch
-Ruffini corpuscles: mechanical stress |
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Term
|
Definition
-loose connective tissue
-lots of fat cells
-superficial fascia of gross lab
-contains largest vessels to supply skin |
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Term
|
Definition
1. eccrine--light cells (water), dark cells (granules)
-merocrine secretion of hypotonic sweat
-not related to hair follicle
2. apocrine glands--viscous, protein-rich fluid
-axillary, labia, breasts
-merocrine secretion |
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Term
|
Definition
| consists of hair follicle, sebaceous gland, arrector pili muscle |
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Term
|
Definition
-holocrine secretion of sebum
-sebum acts as moisturizer |
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Term
|
Definition
-band of smooth muscle
-arises from papillary layer and attaches to hair follicle at angle |
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Term
|
Definition
1. external root sheath
2. germinal matrix
-medulla:soft keratin
-cortex: hard keratin, pigment
-cuticle: hard keratin, shingles
-internal root sheath |
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Term
|
Definition
1. anagen-growth
2. catagen-growth stops
3. telogen-follicle atrophies, hair falls out |
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Term
|
Definition
1. nail plate--analogous to s. corneum
2. nail matrix--hard keratin
3. cuticle--s. corneum of adjacent skin
4. lunula--white area, thick layer of partially keratinized cells |
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Term
| Epidermis and wound healing |
|
Definition
-24-48 hrs for epidermal continuity
-epidermis thickens
-cells cluster and migrate to become contiuous
-capillary sprouts appear, collagen produced
4. collagen scar
3. skin appendages will not reappear |
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Term
|
Definition
-skin red from dilation of capillaries and veins
-mild sunburn |
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Term
|
Definition
-blistering
-hair follicles and glands intact
-renewal occurs |
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Term
|
Definition
-skin and subcutaneous tissue damaged
-follicles and glands destroyed
-may never heal, only at edges |
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Term
|
Definition
1. free split grafts
-thin layer of epidermis and upper part of dermis
2. free full thickness grafts
-epidermis and entire dermis
-donor site must be covered with split graft
3. artificial skin |
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