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Flashcards in Introduction to Dermatology Deck (96):
1

skin is the __ of the body

largest organ

2

main physiological functions of skin are... (10)

1) protection - acts as barrier against water entry/loss, chemicals, various microorganisms, and minor trauma
2) sensation - contains nerve receptors, and small nerve endings for touch, position, pressure, temperature and pain
3) thermoregulation - eccrine sweat glands
4) immunological defense - langerhans cells
5) vitamin d synthesis - through sun exposure
6) pigmentation - UV protection
7) wound healing
8) reproductive function - sexual attractiveness may depend on smell and appearance of skin
9) metabolism
10) absorption and excretion

3

two main regions of skin are...

epidermis, dermis

4

role of dermis and epidermis

each provide a distinctive role in the overall function of skin

5

what is the dermis attached to?

hypodermis

6

hypodermis is also called...?

subcutaneous connective tissue

7

what is hypodermis also recognized as in gross anatomy?

superficial fascia

8

what's the function of the hypodermis

store adipose tissue

9

which structures does the skin consist of?

epidermis, dermis, subcutaneous fat, appendages

10

what kind of tissue is epidermis?

statified squamous epithelium

11

what does epidermis consist of?

keratinocytes, dendritic cells, langerhans cells, merkel cells

12

into how many layers can the epidermis be subdivided into?

5

13

which layers can the epidermis be subdivided into?

stratum basale (basal layer), stratum spinosum (spinous or prickle cell layer), stratum granulosum (granular layer), stratum lucidum, stratum corneum (surface layer)

14

the basal layer consists of...

1 cell layer of cuboidal cells attached by hemidesmosomes to a thin basement membrane which separates it from the underlying dermis

15

what causes the characteristic "prickles" of the stratum spinosum (prickle-cell-layer)?

spinous cells are separated from each other by lots of intercellular connections (desmosomes) which causes this appearance under the microscope

16

keratinization

the process of the stratum granulosum (SGR) cells to accumulate dense basophilic keratohyalin granules. inside these granules are lipids. together with desmosomal connections, this helps to form a water-proof barrier to prevent fluid loss

17

what does the thickness of epidermis depend on and does it vary?

- varies throughout body
- depends on frictional forces so thickest on palm and soles

18

where is stratum lucidum only seen and its a transition of what?

- in thick epidermis
- transition from s. corneum to s. granulosum

19

what is the s. corneum (SC) made up of?

dead and dying cells containing mature keratin

20

do stratum corneum cells have desmosomal junctions?

the deeper ones do but lose them when they're pushed further to the surface by new cells formed in the stratum germinativum (basal layer)

21

desquamation means...

dead cells in the s. corneum that break apart and are shed from the surface

22

how long is the cycle of a keratinocyte? (normal cornification)

from basal layer to s. granulosum - 14 days
from stratum granulosum to surface - 14 days
28 days in total

23

how do basal and cornified keratinocytes differ?

basal - mitotically active, contain least keratin
cornified - mitotically inactive, contain most keratin

24

when is the keratin in keratinocytes synthesized?
what is the function of keratin?

- gradually, as it moves upward to the surface
- serve as a protective barrier between body and environment

25

epidermal transit time

the time it takes for keratinocytes to move from basal to surface layer, 28 days

26

what are melanocytes?

pigment cells.
they produce melanin for skin pigmentation

27

what is a melanosome?

organelle within melanocyte which contains melanin (pigments)

28

what do melanosomes do?

they are transported by melanocyte dendrites to keratinocytes where they form a cap over their nucleus to protect them against UV radiation

29

how is melanin synthesis controlled?

by melanocyte stimulating hormone (MSH) in the pituitary gland

30

what are langerhans cells?

- dendritic antigen-presenting cells
- involved in immune response of the skin

31

the dermis is subdivided into...

papillary and reticular layers

32

the dermis is mainly made up of...

fibroblasts

33

what are the functions of fibroblasts in the dermis?

secrete collagen, elastin, and ground substance that make the skin elastic, and provide support

34

besides fibroblasts, what else is present in the dermis?

immune cells, involved in the defense against foreign substances invading the epidermis

35

what does the papillary dermis contain and what are its functions?

- vascular network
- functions:
1) provide vital nutrients to avascular epidermis
2) thermoregulation - heat can be conserved or dissipated through decreased or increased blood flow through this vascular network respectively

36

what are the areas called in which the vasculature of the papillary dermis interdigitates?

dermal papillae (DP)

37

besides a vascular network, what else does the papillary dermis contain?

- free sensory nerve endings
- Meissner corpuscles (in the highly sensitive areas)

38

what is the reticular dermis made up of and how does it differ from the papillary dermis?

- dense irregular connective tissue
- papillary dermis: loose connective tissue

39

functions of the reticular dermis?

- provide strength and elasticity to skin
- contains important epithelial-derived structures, eg hair and follicles

40

what are the adnexal structures (epidermal appendages)?

- components of epidermal origin
- extend into dermis
- include:
1) pilosebaceous unit - hair follicle, sebaceous glands, arrector pili muscle
2) eccrine (in some areas apocrine) sweat glands
3) nails

41

semiology

description of lesions according to color, shape, distribution, and location

42

macule

- circumscribed change in skin color
- no elevation or depression

43

patch

- large macule
- 1 cm or greater in diameter

44

hypopigmentation
pigmentation

lack of pigments
excessive pigments

45

erythema

reddening of skin

46

papule

- solid, elevated lesion
- 0.5 cm or less in diameter

47

plaque

- raised lesion
- greater breadth than height

48

nodule

- palpable solid lesion
- size varies, 0.5-2 cm in diameter
- may be present in dermis, epidermis or subcutaneous tissue

49

wheal (hive)

- rounded, flat-topped, elevated
- resulting from local edema

50

vesicle

- circumscribed, elevated lesion
- contains fluid
- 0.5 cm or less in diameter

51

bulla

like vesicle but greater than 0.5 cm in diameter

52

pustule

- circumscribed elevated lesion containing pus
- abscess: dermis or subcutis

53

pustule = abscess?

abscess: pus in dermis or subcutis

54

cyst

- sac that contains liquid or semisolid material
- usually in dermis

55

scale

heaping up of s. corneum or keratin

56

maceration

- occurs as a result of wetness
- skin becomes soft, white, and is susceptible to bacterial and fungal infections

57

erosion

- loss of epidermis above basal layer
- surface becomes denuded

58

ulcer

- loss of epidermis and part or all of dermis
- depressed moist lesion

59

fissure

- linear cleft in epidermis or dermis

60

excoriation

- focal loss of epidermis
- usually linear

61

define "crust" and give an example

- accumulation of blood, serum or purulent exudate
- infantile eczema

62

lichenification

- accentuation of skin markings, associated with thickening of epidermis
- caused by scratching or rubbing
- fine papules are present

63

scar

fibrous tissue which replaces normal skin after healing

64

atrophy (when pertaining to skin)

thinning of epidermis and/or dermis

65

what kind of appearance does atrophy cause and what is it called?

striae atrophieae

66

which lesions are primary ones? (9)

macule, patch, papule, plaque, vesicle (bulla), pustule, cyst, wheal, nodule

67

which lesions are secondary ones? (10)

scale, maceration, erosion, ulcer, fissure, excoriation, crust, scar, lichenification, atrophy

68

hyperkeratosis

increased thickness of stratum corneum due to an increase of keratin caused by normal or abnormal keratinocytes

69

parakeratosis

- keritinization in which keratinocytes retain their nuclei
- abnormal in skin, normal in mucus membranes

70

dyskeratosis

cell death due to premature keratinization below the stratum granulosum

71

acanthosis

- increase in keratinocytes in stratum spinosum (spinous layer) with thickening of epidermis
- papillomatous or psoriasiform

72

papillomatosis

- increase in keratinocytes and formation of projections from skin surface, ie papillae

73

give a typical example for papillomatosis

warts

74

spongiosis

- widening of interspaces between keratinocytes due to edema fluid
- no detachment of cells

75

give an example for ballooning degeneration

herpes zoster

76

give an example for reticular degeneration

herpes simplex

77

give an example for liquefaction degeneration of basal cells

SLE

78

give an example for acantholysis

pemphigus

79

give an example for munro's microabscess

psoriasis vulgaris

80

give an example for kogoj's spongioform pustule

psoriasis pustule

81

components involved in dermatologic diagnostics

history, PE, lab exams, special examinations, eg dermatographism, patch test...

82

dermatographism

sharply demarcated edema or wheal with surrounding erythematous flare seconds to minutes after stroking the skin

83

what is a patch test used for?

- used to detect hypersensitivity to a substance (ie allergen) coming into contact with skin
- allows determination of that allergen so the hypersensitivity can be treated

84

how is the patch test done?

- suspected allergen is applied to uninflamed, intact skin on a surgical pad or aluminium chamber, removed after 48 h (or earlier if necessary)
- evaluation: if hypersensitivity exists there may be certain skin lesions (ie erythema, papules, vesicles etc.). skin is evaluated after 48 h, day 4, 5 and 7

85

name the kinds theraphies used in dermatology (4)

extrapharmacotherapy
intrapharmacotherapy
physiotherapy
surgery

86

what are topical drugs?

solutions, tinctures, powers, lotions, oils, emulsions, ointments, pastes, plasters, gels etc.

87

solution

- dissolution of 2 or more substances into homogenous clarity
- the vehicle (base) may be aqueous, hydroalcoholic, or nonaqueous (alcohol, oils, propylene glycol)

88

give an example of a solution

3 % boric acid

89

tincture

hydroalcoholic solution with a concentration of about 50 % alcohol

90

give an example of a tincture

iodine

91

powders

- absorb moisture and decrease friction
- adhere poorly to skin so use is restricted to cosmetic and hygienic purposes

92

lotions

2-phase system consisting of a finely divided, insoluble drug, dispersed into a liquid in a concentration of up to 20 %

93

lotions are also referred to as...?

suspensions

94

emulsions

- 2-phase systems involving 1 or more immiscible liquids dispersed in another with assistance of emulsifying agents
- water-in-oil emulsions (cream): contain less than 25 % water, oil is dispersion medium
- oil-in-water emulsions: contain more than 31 % water, aqeous phase may comprise up to 80 %

95

example of an emulsion

zinc oxide

96

ointment

- semisolid preparations that spread easily
- protective, hydrating, and lubricating
- its bases are hydrocarbon and absorption bases