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2011-05-08 13:55:31

structure skin
Show Answers:

  1. what are the 6 main functions of the skin?
    • 1. physical barrier prevents: entrance of micro-organisms/chemicals and loss of body fluids/protein
    • 2. reduces penetration of UV irradiation
    • 3. thermoregulation
    • 4. sensory organ
    • 5. immune surveillance
    • 6. vitamin D production
  2. what are the 3 main layers of the skin? and what is each made of?
    • epidermis: keratinised stratified squamous epithelium
    • dermis: collagenous connective tissue
    • subcutis: fat, nerve endings, blood vessels
  3. from the dermis upwards, describe the layers
    • dermis
    • BM
    • (epidermis)
    • basal cells
    • squamous cells
    • keratin layer
  4. which is the main mechanical layer of the skin?
  5. what are the main 5 epidermal appendages?
    • hair
    • sebaceous glands
    • eccrine sweat glands
    • apocrine sweat glands
    • nails
  6. what are sebaceous glands?
    the appendages of hair follicles
  7. where are sebaceous glands found?
    in dermis throughout body except palms and soles
  8. what do sebaceous glands secrete?
    • sebum
    • protective agent to maintain skin texture and hair flexibility
  9. where are eccrine glands found?
    throughout body
  10. what is primary function of eccrine gland?
    • evaporative cooling
    • ie sweat glands
  11. what are apocrine glands? and where found?
    they empty into hair follicles in axillary and anogenital regions
  12. what type of secretion do apocrine glands release?
    • odourless secretion
    • which is then acted on by commensal bacteria
  13. when do apocrine glands begin to function?
    at puberty
  14. where in skin does acute eczema affect and why?
    epidermis as it is rough and scaly
  15. where in skin does dermatofibroma affect and why?
    its a firm papule and is smooth so its in dermis - pushing up
  16. where in skin does erythema nodosum occur?
    • they are tender, red nodules on shins which occur DEEP
    • in fat
    • panniculitis
    • so superficial biopsy is unhelpful
  17. what does psoriasis look the same as under microscope?
    clear cell acanthoma
  18. where does lichen planus affect?
    • wrists, ankle, genitalia
    • mouth: striae
  19. if there is a melanocytic lesion, what needs to be done?
    complete excision
  20. how can you tell between a melanoma and a mole?
    • melanoma: asymmetrical, inflammation, irregular border, variable pigmentation
    • mole: symmetrical, sharp lateral cut off
  21. what is actinic keratosis?
    areas of sun damage
  22. how should actinic keratosis be biopsied?
    punch biopsy - as need to get to basal layer where changes occur
  23. what is a cutaneous horn?
    when there is no substance to the base of the lesion
  24. what is the differential for cutaneous horns?
    • actinic keratosis
    • viral warts
    • SCC
    • trichilemmoma
  25. what are the 3 main types of BCC?
    • superficial
    • infiltrative
    • nodular
  26. what is Rx for each type of BCC?
    • superficial: can do just topical creams
    • infiltrative and nodular must excise
  27. what are the 2 main autoimmune bullous disease? and difference between 2?
    • pemphigus vulgaris: more superficial. intraepidermal split
    • bullous pemphigoid: deeper. subepidermal split. get tense blisters
  28. what investigation needs to be done for blistering conditions?