Intro to Derm Flashcards
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
