Midterm Review Flashcards
What is the pH of stratum corneum?
4.5
What are 3 main differentiation specific proteins whose expression is controlled from the AP1 transcription site in the nucleus of the basal keratinocyte?
Involucrin
loricrin
transglutamase
2 main parts of the dermis?
Reticular and papillary
What promotes keratinocyte growth and proliferation?
Low calcium
What is the precursor to intercellular lipids?
Lamellar granules
Inositol triphosphate (IP3)
a second messenger
What activates CaR and PLC?
Vitamin D
What is the major protein in the dermis?
collagen
What is hydrolyzed during differentiation?
Phospholipids
What is in sebum?
Wax esters
What is fillagrin?
Part of the natural moisturizing factor.
What forms the cornified envelope?
Loricrin
What promotes epidermal differentiation?
High calcium
What is disodium oleamido MEA Sulfosuccinate?
A mild surfactant.
What is the mitotically active layer of epidermis?
stratum basale
What is cocoyl isethionate in?
Syndet bars
Where can multese crosses be found?
The Friberg model
What is TNF-alpha
An inflammatory cytokine
What is the Wertz/Downing theory?
Stacked monolayer model.
What are IL-4 and IL-5
The Th-2 class of T cells.
What is the horny layer?
Stratum Corneum
What is required for the 6nm lipid phase?
Saturated fatty acid
What is required for the 13nm phase?
Ceramide 1
What is sodium stearate?
Soap
What is the sweat gland that indirectly produces body odor?
Apocrine gland
What is onycholysis?
nail loss
What are the differentiation specific keratins?
Keratins 1 and 10
What are the proliferation specific keratins?
Keratins 5 and 14
What is an infected eponychium?
hang nail
What is in the lysine cross links?
Transglutaminase
What is the sweat gland that produces sweat?
Ecrine gland
What is in the basic to keratin coiled coil?
Heptad repeating unit.
What are the 3 main classes of intercellular lipids in the stratum corneum and what are their relative amounts?
Ceramide
fatty acid
cholesterol
1:1:1
What is the role of omega hydroxy ceramide in the development of the stratum corneum?
Forms the template by covalently attaching to the corneocyte envelope and allowing epidermal lipids to attach and form the lamellar phases.
What is Michael’s Brick and Mortar?
Two compartment system - heterogenous protein and a homogenous lipid commonly called the brick and mortar model.
What is the Friberg model?
Layered structure, lamellar liquid crystalline or hexagonal gel at normal relative humidity and skin temperature
What is the Norlen model?
Single gel phase - single coherent lamellar gel phase with mixtures of hairpin and splayed arrangements of the ceramide 1 depending on water %
What is the Forslind domain mosaic model?
Coexistant of a gel domain surrounded by liquid crystalline grain borders.
What is the Bouwstras sandwich model?
A liquid sublattice is located in the center of the lipid layers surrounded by a crystalline layer on each side.
What is the Kiselev Model?
Proposed multilamellar structure with mixtures of hairpin and splayed arrangements of the ceramide 1 depending on water %.
Why does the CMC decrease as hydrophobic chain length increase?
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.
What components are part of the natural moisturizing factor in the stratum corneum?
PCA
urea
lactic acid
filaggrin
What is the prominent mode of action for urea?
Keratolytic
What is the prominent mode of action for glycerine?
Humectancy
What is the prominent mode of action for lactic acid?
Exfoliation
What is the prominent mode of action for petrolatum?
Occlusive
What instruments/techniques are used for cell turnover?
Dansyl chloride
What instruments/techniques are used for reduction in dry scales?
Squamometry
What instruments/techniques are used for hydration?
Corneometer
What instruments/techniques are used for reduction in fine lines/surface contour?
Skin replicas and prolifometry to quantitate.
Which cell type in the epidermis is involved in conferring color to the epidermis?
melanocyte
What is the main protein in the top layer of skin?
keratin
What is the dead cell in stratum corneum called?
corneocyte
What cell type in the epidermis is responsible for the formation of the corneocyte?
keratinocyte
What is the transit time of a differentiating cell through the stratum corneum to the surface?
14 days
What is the transit time of a differentiating cell from the basal layer to the skin surface?
28 days
What is the transit time of a differentiating cell through the epidermis in psoriatic skin?
5 days
Describe the phase behavior of the SC lipids. (5 points)
- 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
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?
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.
