Revision module Flashcards
What is the outermost layer of the skin?
epidermis
Which gland drains into the hair follicle?
what do the two form?
sebaceous gland
pilosebaceous unit
Which layer is between the epidermis and the subcutis?
dermis
Embryonically, where does the epidermis originate?
ectoderm
Embryonically, where does the dermis originate?
mesoderm
Embryonically, where do melanocytes originate?
neural crest
What is a blue naevus?
a mole that occurs when melanocytes stop their migration too early and dont reach the epidermis so they appear blue/black
What is the main cell type in the epidermis?
keratinocytes
What type of epithelium is the epidermis?
stratified squamous
What are the layers of epidermis from outermost to innermost?
keratin layer
granular layer
prickle cell layer
basal layer
How long does it take keratinocytes to migrate to the outermost layer of the epidermis?
28 days
Where are keratinocytes produced?
stem cells in basal layer
What happens to cell proliferation in psoriasis?
increases with greater cell turnover and production
What holds keratinocytes together?
anchoring proteins called desmosomes
What is bullous pemphigus?
an autoimmune blistering condition of the epidermis caused by IgG antibodies against desmosomes
What does histology of bullous pemphigus show?
intra-epidermal split
What is bullous pemphigoid?
autoimmune condition causing sub-epidermal blisters
What does the dermis do?
provides support and nutrition to the epidermis
What is the dermis composed of?
collagen and elastin held together by ground substance
What are dermatofibromas?
benign proliferations of fibroblasts in response to minor injury eg. insect bite
What is acne?
chronic inflammatory disease of the pilosebaceous unit
What is the pathogenesis of acne/?
poral occlusion
bacterial collonisation
dermal inflammation
increased sebum production
What nail changes are seen in psoriasis?
pitting and onycholysis
Which protein is deficient in atopic eczema? what does this cause?
filaggrin
defective skin barrier