Skin and Function Part 1 Flashcards
What is the epidermis?
Outer layer of skin, stratified cellular epithelium
What is the dermis?
Layer beneath the epidermis, connective tissue
What is the epidermis formed from embryonically?
Ectoderm-form a single layer periderm, gradual increase in layers of cells, periderm cells cast off
What is the dermis formed from embryonically?
Mesoderm
What are melanocytes?
Pigment producing cells from neural crests
What is gastrulation and when does it occur?
Cellular organisation into germ layers; occurs days 7-10
What does the skin look like at 4 weeks?
Periderm on top of basal layer, both sit atop dermis (corium)
What does the skin look like at 16 weeks?
Keratin layer (top layer), then granular layer then prickle cell layer, finally basal layer atop of dermis, melanocytes migrate from neural crest
What does the skin look like at 26 weeks?
Epidermis has formed, melanocytes have appeared as well as sebaceous glands, arector pili muscle and hair follicles
What are Blaschko’s lines?
Developmental growth pattern of skin caused by mutations within cells, not following vessels/nerves/lymphocytes, normal development up until 18 weeks
What is the other name for Blaschko’s lines?
Epidermal nevis
What does skin consist of?
Epidermis, appendages, dermo-epidermal junction, dermis, sub-cutis (predominantly fat)
What are the four layers of the epidermis, starting from the most superficial?
keratin layer, granular layer, prickle cell layer, basal layer
What are other cells found in the epidermis?
Melanocytes, Langerhans cells, Merkel cells
What is 95% of the epidermis made from?
Keratinocytes (contain structural keratins)
