skin structure and fxn

Question 1

Layers of epidermis from deep to superficial adn what happens to keratinocytes during each

Answer 1

basale (proliferation), spinosum (adhesion), granulosum (differentiation), corneum (death)

Question 2

cell types present in epidermis

Answer 2

Keratinocytes (90%), Langerhans (dendritic APC), Melanocytes, Merkel (mechanoreceptors)

Question 3

how often does the epidermis turn over

Answer 3

every 30 days

Question 4

how does stratification happen in the epidermis

Answer 4

asymmetrical division of keratinocytes in basal layer

Question 5

Keratin subtypes and a dz associated w/ each

Answer 5

5/14 (basal layer) [epdermolysis bullosa simplex], 1/10 (other layers) [epidermolytic hyperkeratosis]

Question 6

Hemidesmosomes: where? protein base? kind of blistering?

Answer 6

keratinocytes to BM, integrin, general blistering

Question 7

bullous pephigoid, pemphigus vulgaris

Answer 7

auto-abs target hemidesmosome proteins, subepidermal blisters. Auto-abs target desmosomes, suprabasal blisters

Question 8

desmosomes: where? protein base?

Answer 8

b/w keratinocytes, cadherins plakin and armadillo

Question 9

desmogleins: what? two types?

Answer 9

cadherin, Dsg1 (corneum) and Dsg3 (basal)

Question 10

Pemphigus vulgaris and pemphigus foliaceus

Answer 10

anti-Dsg3, anti-Dsg1

Question 11

what is responsible for waterproofing the skin? Where is it most seen?

Answer 11

lipid excreted from lamellar bodies. Stratum corneum. Also tight jxns

Question 12

The atopic march

Answer 12

ichthyosis vulgaris (filaggrin mutation disrupts cornified envelope)->atopic dermatitis (eczema) (disrupts both H20 barriers)->asthma/allergies.

Question 13

what gives the dermis tensile strength and in what dz is this affected?

Answer 13

Collagen. Scleroderma (tightly packed bundles, destruction of vessels).

Question 14

What anchors dermis to BM?

Answer 14

Collagen types 4 (in BM) and 7.

Question 15

What types of cells are found in the dermis?

Answer 15

Fibroblasts, papilla cells (spec fibroblasts), mast, monocytes, lymphocytes (also seen in epiderm in dzs like psoriasis)

Question 16

Hair is of ___ origin and associated with ____ muscles and ___ and ___ glands

Answer 16

epithelial (keratinocytes), arrector pili, sebaceous, apocrine sweat

Question 17

Three stages of hair follicle cycle

Answer 17

Anagen (HF bulge communicating with dermal papilla), Catagen (involution), Telogen (rest)

Question 18

Eccrine sweat glands

Answer 18

cool body, ducts directly to skin surface, stratified cuboidal

Question 19

apocrine sweat glands

Answer 19

odor producing, axila, perineum, secrete onto HF, simple cuboidal