skin Flashcards
what are the functions of skin?
barrier
sensation
thermoregulation
psychosexual communication
immunity
metabolic functions
what are the layers of epidermis?
stratum basale
stratum spinosum
stratum granulosum
stratum lucidum (thick skin only)
stratum corner
what are melanocytes?
melanin producing cells associated with basal layer
what are langerhans cells?
antigen presenting cells of immune cells
what are Merkel cells?
touch receptor cells in basal layers
disorder of keratinocytes
actinic (solar) keratosis
chronic sun exposure cause epidermal dysplasia
appears scaly and red patch
can lead to cancers
non melanoma skin cancers
basal cell carcinoma - follicular keratinocyte
squamous cell carcinoma - basal keratinocytes
what causes psoriasis?
extreme proliferation epidermal basal layer, response to inflammatory cytokines
turnover of cells reduced to 3-7 days
plaque psoriasis 90% of cases, affects elbows, knees, scalp or anywhere
treat w/ sunlight, Vit D or steroids
sun exposure
freckles - overproduction of melanin
sunburn - keratinocytes apoptosis, reddening, oedema
what causes vitiligo
Autoimmune disease, immune system attacks melanocytes
what causes malignant melanomas
Uncontrolled growth of melanocytes
more superficial the better
warning signs- ABCDEFG
asymmetry, border, colour, diameter, elevated, firm, growth
what is Merkel cell carcinoma
very rare, but aggressive and difficult-to-treat cancer.
What causes acne?
Blockage of the sebaceous gland
what is excessive sweating called?
hyperhidrosis
what causes alopecia?
hair follicle is targeted by the immune system, leading to hair loss
alopecia areata - patches on scalp
Alopecia totalis - total loss of scalp hair
Alopecia universalis - all body hair
