Skin Flashcards
What are the basic layers of the skin?
Epidermis
Dermis
Subcutaneous tissue
What is the epidermis made up of?
Stratum: Corneum (outermost) Lucidium Granulosum Spinosum Basal (innermost)
What is the outer most layer of the epidermis?
Stratum corneum
What is the stratum corneum made up of?
Corneo desmosomes
Which diseases see:
Increased no of corneo desmosomes?
Decreased no of corneo desmosomes?
Psoriasis-thickening of corneum
Atopic eczema-thinning of corneum (increased risk of inflammation)
What is the dermis made up of?
Thick fibrous + elastic tissue
Strength and flexibility
What is the hypodermis made up of?
Fatty connective tissue
What are some functions of the skin?
Protection against UV Protection against trauma Barrier to infection Vitamin D synthesis Thermoregulation Regulate H2O loss
Protection against UVB
What cells protect against UV?
What do these cells produce?
Where are the products of the cell stored?
Melanocytes
Melanin
Stored in adjacent cells (in melanosomes-vesicles)
What do melanocytes do?
Give skin pigment
What are the 2 types of melanin?
Eumelanin - black/brown
Pheumelanin - red/orange
What happens when you tan?
More melanin produce when exposed to more UVB
Number of melanocytes=
Conc of melanin they produce=
Same
Different
Vitamin D synthesis
What Happens in the skin?
UVB cleaves 7-dehydrocholesterol —-> cholecalciferol (D3) in skin
D3 from here and D2 from where is processed where?
D3 from skin and D2 from diet and supplements processed in liver
What happens in regards to vitamin D in the liver?
25-OH D3 In liver —-> 1,25 diOH (D2) in kidneys
What is the pH of skin?
5 to 5.5
What are corneocytes filled with?
NMF
Natural moisturizing factor
What does NMF do?
Helps maintain skins hydration, keep H2O inside skin
Also maintains acidic environment at the outer surface of the stratum corneum
What 2 substances produce NMF?
Profillagrin —-> fillagrin —-> NMF
What is desquamation?
Shedding dead skin cells by degrading corneo desmosomes under protease enzymes
Balance basal cell production and removal
What pH of skin is 5.5 which allows?
Proteases to remain on the skin, thereby enabling the balance of new cells from basal layer
Acidic pH inhibits….
Degratory proteases
Protects corneo desmosomes
What does the lipid lamellae do?
Keeps water inside the skin cells
What does the lipid lamella make irritants and allergens do?
Bounce off surface of skin
Acidic pH increases lipid…..
Delivery and processing, produce lipid lamella
