phys- skin

  1. dysfunction of the skin barrier leads to:
    • injury
    • dehydration
    • infection
    • inflammation
  2. atopic dermatitis
    a chronic skin condition associated with barrier dysfunction
  3. functions of the skin:
    • barrier function
    • immunologic function
    • temp regulation
    • protection from radiation
    • nerve sensation
    • injury repair
    • appearance, quality of life
  4. dysfunction of the immunologic barrier leads to:
    • infection
    • skin CA
    • inflammatory skin conditions
    • allergy
  5. molluscum contagiosum
    a skin infection caused by a virus
  6. dysfunction of temp regulation leads to:
    • hyper- or hypothermia
    • Another example of thermoregulation dysfunction is Raynaud phenomenon (chronic episodic attacks of digital ischemia provoked by exposure to cold)
  7. what protects cells against UV radiation?
    dark pigment in the epidermis
  8. dysfunction of the sensory receptors leads to:
    • pruritus (itch), dysesthesia (abnormal sensation), & insensitivity to injury
    • chronic ulcer of a pt c/ peripheral neuropathy related to diabetes
  9. 4 phases of cutaneous would repair
    • coagulation
    • inflammatory phase
    • proliferative-migratory phase (tissue formation)
    • remodeling phase
  10. Lipoatrophy
    • can be assoc c/ HIV
    • characterized by loss of fat throughout the face
    • Atrophy of buccal fat pads can be of particular concern to patients since it gives the appearance of facial wasting and can have an impact on self-esteem
  11. 3 layers of the skin:
    • epidermis
    • dermis
    • subcutis (panniculus or hypodermis)
  12. what type of cells are primarily in the epidermis?
  13. dermis mainly consists of what type of cells?
    • fibroblasts
    • collagen
    • elastic fibers
  14. 4 major layers of the epidermis
    • stratum corneum
    • stratum granulosum (granular cell layer)
    • stratum spinosum (spiny layer)
    • stratum basale (basal cell layer)
  15. which layer is the source of epidermal stem cells? and cell division occurs here, keratinocytes start in this layer and move upwards
    basal layer
  16. which layer:
    -center of epidermis
    -has a "spiny" appearance due to desmosomal junctions, which hold the keratinocytes together
    spinous layer
  17. which layer is made up of desquamating keratinocytes? thick outer layers of flattened keratinized non-nucleated cells provide a barrier against trauma & infection
    stratum corneum
  18. flattened keratinocytes are filled with what?
    keratin and flaggrin
  19. what surrounds the keratinocytes and what does it do?
    lipid mixture and it provides the water barrier
  20. what protein is found in the granula cell layer of the epidermis?
  21. what does filaggrin retain?
    water within keratinocytes
  22. what does a mutation in filaggrin cause?
    atopic dermatitis
  23. Bullous Pemphigoid
    • an autoimmune blistering disease, typically affects older patients.  Autoantibodies form to antigens directly beneath the basal layer of the epidermis. Clinically, presents as tense bullae on an erythematous base on the skin (mucous membranes may also be affected)
    • causes loss of adhesion
  24. what causes the scale appearance in psoriasis?
    The accelerated rate of movement through the epidermis doesn’t allow adequate time for differentiation
  25. in psoriasis, what leads to skin thickening?
    the rate of epidermal turnover is increased
  26. most common form of skin cancer:
    composed of cells that resemble:
    presents as:
    • Basal cell carcinoma
    • basal keratinocytes
    • Most commonly presents as pearly, erythematous papules or plaques with rolled borders and telangectasias in sun-exposed areas
  27. what are the 3 main types of cells that make up the epidermis?
    • keratinocytes
    • melanocytes
    • Langerhan cells
  28. how are keratinocytes held together?
    Keratinocytes are held together by macromolecular structures that look like stripes (or spines) between cells, called desmosomes (primarily visible in the spinous layer)
  29. which type of cell in the epidermis is found staggered along the basal layer at around one in every 10 keratinocyte?
  30. what are melanocytes?
    They are the pigment-producing cells, and transfer their pigment, called melanin, to the keratinocytes in the basal cell layer
  31. what is melanocytic nevi?
    • moles, benign collections of melanocytes
    • malignancy of melanocytes
  32. what are Langerhan cells?
    what is their main function?
    • They are dendritic cells found in the mid-epidermis
    • Their main function is in the afferent limb of the immune response by providing for the recognition, uptake, processing, and presentation of antigens to sensitized T-lymphocytes, and are important in the induction of delayed-type hypersensitivity
  33. what is a common skin dz in which Langerhans cells play a prominent role?
    allergic contact dermatitis, such as poison oak
  34. what are the 2 layers of the dermis?
    • papillary dermis
    • reticular dermis
  35. what type of structure does the dermis provide?
    how thick is it?
    what does it contain?
    • provides a flexible but tough support structure
    • btwn 1-4 mm thick (depending on age and body location)
    • it is MUCH thicker than the epidermis
    • contains blood and lymphatic vessels and nerves which supply the skin, as well as sweat glands and hair follicles
  36. what else is in the dermis?
    • hair follicles
    • sebaceous or oil glands
  37. what cells are in the dermis? and what is their function?
    • Fibroblast cells: resp for synthesis & degradation of connective tissue proteins. They are instrumental in wound healing & scaring
    • Mast cells: specialized cells that are resp for immediate-type hypersensitivity rxns in the skin
  38. what are keloids?
    (abnormal scars) result from uncontrolled synthesis and excessive deposition of collagen at sites of prior dermal injury and wound repair
  39. what is the major effector cell in urticarial?
    • mast cells
    •  (urticarial- which is a vascular reaction of the skin characterized by wheals surrounded by a red halo or flare)
  40. What layer which separates the dermis from deeper underlying structures such as fascia and muscles?
    • its a fat layer
    • the subcutis
  41. function of the subcutis?
    insulates the body, serves as an energy supply, cushions and protects the skin, and allows for its mobility over underlying structures
  42. what is Inflammation of the subcutis called?
    • Erythema nodosum
    • (it is an example of panniculitis)
    • Clinically appears as deep-seated erythematous nodules, typically on the shins
    • Erythema nodosum may be idiopathic or a reaction to infections, medication, or an underlying autoimmune disease (e.g. Crohn’s disease)
  43. adnexal structures include:
    pilosebaceous unit and eccrine gland
  44. pilosebaceous unit consists of:
    • a hair follicle
    • sebaceous (oil) glands
    • apocrine* sweat glands
    • an arrector pili muscle (when these contract you get goosebumps)
  45. where are apocrine glands found?
    • found in the axillary and anogenital areas, which is why we do not see them on this biopsy of the scalp.
    • These glands open directly in to the hair follicle
  46. what is a disorder of the pilosebaceous unit?
    acne vulgaris
  47. what are the main 4 factors that cause acne vulgaris?
    • 1.Plugging of the hair follicle as a result of abnormal keratinization of the upper portion (gives rise to comedones)
    • 2. P. acnes (bacteria) in the hair follicle (lives on the oil and breaks it down to free fatty acids which cause inflammation)
    • 3. Presence of hormones (androgens)
    • 4. Sebaceous gland activity (increased in presence of androgens)
  48. Eccrine glands:
    • do NOT involve the hair follicle (in contract to apocrine glands)
    • they open directly onto the skin surface & are present throughout the body
    • Eccrine glands help regulate body temperature by excreting sweat onto the skin surface, where cooling evaporation takes place
    • Eccrine glands are sometimes genetically absent, which will predispose a patient to hyperthermia
  49. which tissue layer(s) function as a permeability barrier?
    and what is an associated dz?
    • epidermis
    • atopic dermatitis
  50. which tissue layer(s) function as protection from pathogens?
    and what is an associated dz?
    • epidermis & dermis
    • Molluscum contagiosum
  51. which tissue layer(s) function as thermoregulation?
    and what is an associated dz?
    • Epidermis, dermis, & subcutis
    • Hyperthermia
  52. which tissue layer(s) function as UV protection?
    and what is an associated dz?
    • Epidermis
    • albinism
  53. which tissue layer(s) function as sensation?
    and what is an associated dz?
    • epidermis, dermis, & subcutis
    • Diabetic neuropathy
  54. which tissue layer(s) function in wound repair/generation?
    and what is an associated dz?
    • epidermis & dermis
    • Venous stasis ulcer, keloid
  55. which tissue layer(s) function for physical appearance?
    and what is an associated dz?
    • epidermis, dermis, & subcutis
    • Lipodystrophy
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phys- skin