Development & Structure of Epidermis Flashcards
describe the formation of the epidermis
ectoderm layers form single layer periderm, gradual increase in number of cells, periderm cells cast off
what is the epidermis
the outer layer of skin, statified cellular epithelium
what is the dermis
layer beneath epidermis, contains connective tissue
describe what the dermis is formed from
formed from mesoderm below ectoderm
describe what is found at 4 weeks of foetal skin development
periderm, basal layer and dermis
describe what is found at 16 weeks of foetal skin development
keratin layer, granular layer, prickle cell layer, basal layer, dermis
what happens to melanocytes at 16 weeks of foetal skin development
they migrate from the neural crest
describe what Blaschko’s lines are
the development growth patterns of skin, not following nerves, blood vessels or lymphatics
what does skin consist of
epidermis, appendages, dermo-epidermal junction, dermis, sub-cutis
what type of epithelium is the epidermis and how thick it is
stratified squamous epithelium, 1.5mm thick
what are the 4 defined layers of the epidermis, from outer most to inner most layer
keratin layer, granular layer, prickle cell layer, basal layer
what different types of cells are found in the epidermis
keratinocytes(95%), melanocytes, Langerhans cells, Merkel cells
what is the epidermal turnover regulated by
growth factors, cell death and hormones
where do keratinocytes migrate from
the basement membrane
describe the features of the basal layer of the epidermis (4)
usually one cell thick, small cuboidal, lots of intermediate filaments, highly metabolically active