w4-L5 intro to dermatology Flashcards
how is melanocyte regulated?
melanocortin 1 receptor `(MC1R) G protein coupled regulates the quantity and quality of melanin produced
how MC1R is activated?
agonist alpha melanocyte stimulating hormone-alphaMSH
agouti signalling protein ASP
ACTH
exposure to UV
mechanism of action of alpha MSH
activation of Mc1R by agonist, melanogenic cascade leading to eumelanin
mechanism of action of ASP
reverse effects and elicit producition of pheomelanin
mechanism of action of ACTH
unregulated the expression of MC1R
mechanism of action of exposure to UV
increased expression of transcription factor MITF and downstream melanogenic proteins, increasing melanin content
OR increased PAR2 in keratinocytes increasing uptake and distribution of melanosomes by keratinocytes
structure of skin overview
epidermis basement membrane aka dermal epidermal junction dermis connective tissue subcutaneous fat
epidermis structure
composed of keratinocytes
differentiation of layers stratum-spinosum, granulosum, lucidum (palms and soles only) and corneum
take around 30 days
what’s keratinocyte structure and function?
actin tubular and intermediate filament-aka keratin
structural properties, cell signalling, wound healing, stress response and apoptosis
function of desmosomes
major adhesion complex from keratinocyte to membrane to keratinocyte to keratinocyte
allow ells to withstand trauma
what junction are there between epidermal cells?
gap junctions, adheren junction and tight junction
gap junction function
Directly form connections between cytoplasm of adjacent keratinocytes
Essential for cell synchronization, cell differentiation, cell growth and metabolic coordination
adhere junction function
engage with actin skeleton
tight junction function
barrier polarity and integrity
what other type of cells in epidermis and function?
melanocyte- distribute melanin pigment to keratinocyte
langerhans cells-antigen presenting
Merkel cells- mechanosensory receptors
mast cells
