Midterm Review

Question 1

What is the pH of stratum corneum?

Answer 1

4.5

Question 2

What are 3 main differentiation specific proteins whose expression is controlled from the AP1 transcription site in the nucleus of the basal keratinocyte?

Answer 2

Involucrin
loricrin
transglutamase

Question 3

2 main parts of the dermis?

Answer 3

Reticular and papillary

Question 4

What promotes keratinocyte growth and proliferation?

Answer 4

Low calcium

Question 5

What is the precursor to intercellular lipids?

Answer 5

Lamellar granules

Question 6

Inositol triphosphate (IP3)

Answer 6

a second messenger

Question 7

What activates CaR and PLC?

Answer 7

Vitamin D

Question 8

What is the major protein in the dermis?

Answer 8

collagen

Question 9

What is hydrolyzed during differentiation?

Answer 9

Phospholipids

Question 10

What is in sebum?

Answer 10

Wax esters

Question 11

What is fillagrin?

Answer 11

Part of the natural moisturizing factor.

Question 12

What forms the cornified envelope?

Answer 12

Loricrin

Question 13

What promotes epidermal differentiation?

Answer 13

High calcium

Question 14

What is disodium oleamido MEA Sulfosuccinate?

Answer 14

A mild surfactant.

Question 15

What is the mitotically active layer of epidermis?

Answer 15

stratum basale

Question 16

What is cocoyl isethionate in?

Answer 16

Syndet bars

Question 17

Where can multese crosses be found?

Answer 17

The Friberg model

Question 18

What is TNF-alpha

Answer 18

An inflammatory cytokine

Question 19

What is the Wertz/Downing theory?

Answer 19

Stacked monolayer model.

Question 20

What are IL-4 and IL-5

Answer 20

The Th-2 class of T cells.

Question 21

What is the horny layer?

Answer 21

Stratum Corneum

Question 22

What is required for the 6nm lipid phase?

Answer 22

Saturated fatty acid

Question 23

What is required for the 13nm phase?

Answer 23

Ceramide 1

Question 24

What is sodium stearate?

Answer 24

Soap

Question 25

What is the sweat gland that indirectly produces body odor?

Answer 25

Apocrine gland

Question 26

What is onycholysis?

Answer 26

nail loss

Question 27

What are the differentiation specific keratins?

Answer 27

Keratins 1 and 10

Question 28

What are the proliferation specific keratins?

Answer 28

Keratins 5 and 14

Question 29

What is an infected eponychium?

Answer 29

hang nail

Question 30

What is in the lysine cross links?

Answer 30

Transglutaminase

Question 31

What is the sweat gland that produces sweat?

Answer 31

Ecrine gland

Question 32

What is in the basic to keratin coiled coil?

Answer 32

Heptad repeating unit.

Question 33

What are the 3 main classes of intercellular lipids in the stratum corneum and what are their relative amounts?

Answer 33

Ceramide fatty acid cholesterol 1:1:1

Question 34

What is the role of omega hydroxy ceramide in the development of the stratum corneum?

Answer 34

Forms the template by covalently attaching to the corneocyte envelope and allowing epidermal lipids to attach and form the lamellar phases.

Question 35

What is Michael's Brick and Mortar?

Answer 35

Two compartment system - heterogenous protein and a homogenous lipid commonly called the brick and mortar model.

Question 36

What is the Friberg model?

Answer 36

Layered structure, lamellar liquid crystalline or hexagonal gel at normal relative humidity and skin temperature

Question 37

What is the Norlen model?

Answer 37

Single gel phase - single coherent lamellar gel phase with mixtures of hairpin and splayed arrangements of the ceramide 1 depending on water %

Question 38

What is the Forslind domain mosaic model?

Answer 38

Coexistant of a gel domain surrounded by liquid crystalline grain borders.

Question 39

What is the Bouwstras sandwich model?

Answer 39

A liquid sublattice is located in the center of the lipid layers surrounded by a crystalline layer on each side.

Question 40

What is the Kiselev Model?

Answer 40

Proposed multilamellar structure with mixtures of hairpin and splayed arrangements of the ceramide 1 depending on water %.

Question 41

Why does the CMC decrease as hydrophobic chain length increase?

Answer 41

The larger the hydrophobe, the more bulky it becomes and fewer molecules can then accumulate at the air water interface. Therefore, micelles are formed at a lower surfactant concentration because the interface becomes crowded with the bulky molecules at a lower concentration and the molecules in solution then micellize.

Question 42

What components are part of the natural moisturizing factor in the stratum corneum?

Answer 42

PCA urea lactic acid filaggrin

Question 43

What is the prominent mode of action for urea?

Answer 43

Keratolytic

Question 44

What is the prominent mode of action for glycerine?

Answer 44

Humectancy

Question 45

What is the prominent mode of action for lactic acid?

Answer 45

Exfoliation

Question 46

What is the prominent mode of action for petrolatum?

Answer 46

Occlusive

Question 47

What instruments/techniques are used for cell turnover?

Answer 47

Dansyl chloride

Question 48

What instruments/techniques are used for reduction in dry scales?

Answer 48

Squamometry

Question 49

What instruments/techniques are used for hydration?

Answer 49

Corneometer

Question 50

What instruments/techniques are used for reduction in fine lines/surface contour?

Answer 50

Skin replicas and prolifometry to quantitate.

Question 51

Which cell type in the epidermis is involved in conferring color to the epidermis?

Answer 51

melanocyte

Question 52

What is the main protein in the top layer of skin?

Answer 52

keratin

Question 53

What is the dead cell in stratum corneum called?

Answer 53

corneocyte

Question 54

What cell type in the epidermis is responsible for the formation of the corneocyte?

Answer 54

keratinocyte

Question 55

What is the transit time of a differentiating cell through the stratum corneum to the surface?

Answer 55

14 days

Question 56

What is the transit time of a differentiating cell from the basal layer to the skin surface?

Answer 56

28 days

Question 57

What is the transit time of a differentiating cell through the epidermis in psoriatic skin?

Answer 57

5 days

Question 58

Describe the phase behavior of the SC lipids. (5 points)

Answer 58

- X-ray diffraction pattern is consistent with existence of a 6 nm (SLP – short lamellar phase) and a 13 nm (LLP-long lamellar phase) periodicities - Ceramide-1 with the linoleic acid extension is required for formation of the LLP - Fatty acid is required for formation of the SLP - Addition of fatty acid to cholesterol / ceramide mixtures results in a transition from the hexagonal to the orthorhombic crystalline phase - Cholesterol stabilizes the phases from phase separation

Question 59

What is the possible disadvantage of a fully orthrhombic lipid structure and what is the disadvantage of a fully liquid crystalline or hexagonal structure that supports existence of a ‘balance of the two phases’ in stratum corneum?

Answer 59

A fully orthrombic structure can crack and become leaky therefore could result in no barrier to water loss at all. A fully liquid or hexagonal structure can lead to excess penetration of undesirables. A balance is required.