Skin B&B

Question 1

what are the 5 layers of the epidermis?

Answer 1

1. stratum corneum
2. stratum lucidum
3. stratum granulosum
4. stratum spinosum
5. stratum basale

Question 2

what forms the “spines” of the stratum spinosum?

Answer 2

desmosomes connecting keratinocytes

Question 3

what makes up the granules in the stratum granulosum?

Answer 3

keratohyalin granules that form keratin filaments

Question 4

hyperkeratosis

Answer 4

thickening of stratum corneum due to excess keratin

occurs in calluses, psoriasis (thickened plaques), etc

Question 5

parakeratosis

Answer 5

hyperkeratosis + retained nuclei in stratum corneum

indicates hyper-proliferation, seen in skin diseases (such as psoriasis) and malignancies

Question 6

hypergranulosis

Answer 6

increased thickness of stratum granulosum

classic finding in linchen planus

Question 7

spongiosis

Answer 7

fluid accumulation (edema) of epidermis

seen in skin disorders such as eczema

Question 8

acantholysis

Answer 8

loss of connections between keratinocytes (often desmosomes)

—> “rounded” keratinocytes that are detached and freely floating in epidermis (because layers of skin separate)

key feature of pemphigus vulgaris

Question 9

acanthosis

Answer 9

diffuse epidermal hyperplasia

—> elongated rete ridges due to spinous layer thickening

ex - acanthosis nigricans (insulin resistance, malignancy)

Question 10

acantholysis vs acanthosis

Answer 10

acantholysis: loss of connections between keratinocytes, often desmosomes (pemphigus vulgaris)

acanthosis: elongated rete ridges due to spinous layer thickening

Question 11

what is the cause of acanthosis nigricans and with what is it typically associated?

Answer 11

hyperpigmented plaques on skin folds (neck, axilla) due to diffuse epidermal hyperplasia and spinous layer thickening

associated with insulin resistance (obesity, diabetes), rarely malignancy (gastric adenocarcinoma most common)

Question 12

macules vs patches

Answer 12

both flat (not raised) lesions

macules are <1cm (ex, freckles)
patches are >1cm

Question 13

papules vs plaques

Answer 13

both raised lesions

papules are <1cm (mole/nevus)
plaques are >1cm (psoriasis)

Question 14

macule vs papule

Answer 14

macule: flat lesion <1cm (ex, freckle)

papule: raised lesion <1cm (ex, mole)

maculopapular rash has some macules, some papules

Question 15

vesicle vs bulla

Answer 15

both are fluid-filled lesions

vesicles are <1cm (chickenpox)
bullae are >1cm (bullous pemphigoid)

Question 16

what is the classic cause of wheals and how do they appear?

Answer 16

smooth, elevated papules or plaques surrounded by erythema, itchy

due to dermal edema, classically caused by urticaria (allergic reaction)

Question 17

what is the cause of skin scaling?

Answer 17

secondary skin lesion caused by peeling and flaking of the stratum corneum

Question 18

what is the cause of skin crusting?

Answer 18

secondary skin lesion caused by dried exudate of skin lesion (ex, impetigo)

Question 19

fissure vs erosion vs ulcer

Answer 19

fissure: narrow tear with walls, epidermis or dermis

erosion: involves only epidermis

ulcer: involves both epidermis and dermis

Question 20

what type of collagen is found in the basal lamina?

Answer 20

Type IV collagen

Question 21

Goodpasture syndrome affects what component of skin?

Answer 21

Goodpasture syndrome also referred to as anti-glomerular basement membrane (anti-GBM) disease, is an autoimmune disease that affects both the kidneys and lungs by the formation of autoantibodies that attack type IV collagen in basement membranes.

Question 22

Alport syndrome affects which component of skin?

Answer 22

Alport syndrome is a genetic condition in which your kidneys don’t produce normal type IV collagen proteins —> kidney disease, loss of hearing, and eye abnormalities

Question 23

what 2 types of proteins make up tight junctions?

Answer 23

1. occludin
2. claudin

Question 24

in which type of epithelial cell junction is E-cadherin found?

Answer 24

adherens junctions duh !

found below tight junctions, form belts around cells (belt desmosomes)

cadherins (calcium-dependent adhesions): made of cell membrane glycoprotein, attach to actin filaments in cells

Question 25

to what intracellular filament do cadherins vs desmosomes attach?

Answer 25

cadherins (part of adherens/belt desmosomes) attach to actin filaments

desmosomes (spot/ macula adherens) attach to intermediate filaments

Question 26

desmosomes are linked by _____, while hemidesmosomes are linked by _____

Answer 26

desmosomes (between cells) - linked by cadherins

hemidesmosomes (basement membrane) - linked by integrins

both attach to keratin intermediate filaments in the cytoplasm

Question 27

what type of autoantibodies form in pemphigus vulgaris vs bullous pemphigoid?

Answer 27

pemphigus vulgaris - autoantibodies to desmosomes [“Peripheral” vulgaris]

bullous pemphigoid - autoantibodies to hemidesmosomes [“Basement” pemphigoid]