Structure/Function of skin Flashcards
Where embroyologically does the epidermis originate from?
The ectoderm
Where embroyologically does the dermis originate from?
Mesoderm
Where embroyologically do the melanocytes originate from?
Neural crest
What is the order of skin layers from outermost to innermost?
Keratin
Granular
Prickle cell
Basal
What is a normal epidermal turnover time?
28 days
Where are melanocytes found and what do they do?
Found along the basal cell layer of the epidermis. They produce melanin and protect from UV radiation
What are merkel cells?
Fine touch mechanoreceptors found along the basal layer
What are langerhans cells?
Dendritis epidermal cells that have an important role in antigen presentation (pick up skin antigens and deliver them to T lymphocytes)
What are keratoincytes held together by?
Anchoring proteins called desmosomes
What do fibroblasts do?
Produce collagen and elastin
What do mast cells do?
Release inflammatory mediators including histamine
What is a dermatofibromas?
Benign proliferation of fibroblasts in response to a minor trauma or an insect bite.
What forms the pilo sebacous unit?
Sebacous gland and hair follicle
What is filaggrin?
A protein found in the granular layer that has a major role in aligning keratin filaments in the stratum corneum . Deficiency of filaggri n has a major role in atopic excema
What are the stages of wound healing?
Haemostasis - vasoconstriction and platelet aggregation and clot aggregation
Inflammation
- Vasodilation
- Migration of neutrophils and macrophages
- Phagocytosis of cellular debris and invading bacteria
Proliferation
- Granulation tissue formation and re epitheialisation
Remodelling
- Collagen fibre re organisation
- Scar maturation
