Intro to Derm Flashcards
(16 cards)
What two major embryological element?
epidermis + dermis
What is the epidermis?
originates form the ectoderm
What is the dermis?
arises from the mesoderm that comes into contact w inner surface of the epidermis
What is the mesoderm important for?
essential for inducing differentiation of epidermal structures
What forms by Week 4?
epidermis - single basal layer of cuboidal cells
What forms by Week 5?
periderm - secondary layer of squamous, non-keratinising cuboidal
What is the purpose of the periderm?
generates vernix cases - white waxy protective substance
What forms by Week 11?
stratum germinativum - basal layer of cuboidal cells
What is the purpose of the stratum germinativum?
proliferates to form multi-layered intermediate zone –> 4 more superficial strata
What are the 5 superficial strata (in order)?
→ corneum (horny) → lucidum (clear; found on palms + soles) → granulosum (granular) → spinosum (spinous) → germinativum (granular)
What happens as the dermis develops?
epidermal ridges protrude as troughs in the dermis beneath neurovascular supply develop into dermal papillae
What happens at Weeks 9-13?
development of hair follicles in stratum germinativum + appearance of lanugo hair
What is lanugo hair?
downy hair on the body of foetus or newborn baby - first hair to be produced bye the metal hair follicles, appears after 5 months of gestation, usually fine + soft + unpigmented
Where are melanocytes derived?
in the neural crest
What is the difference between melanocytes and melanoblasts?
melanoblasts are the precursors to melanocytes
What happens once melanoblasts form?
migrate dorsally between week 6-8 to developing epidermis + dermis + hair follicles
