Skin Flashcards
The Integumentary system includes:
Skin, hair, nails, glands
Functions of integumentary system
protection thermoregulation water regulation sensation storage & synthesis
Structure of the EPIDERMIS
-Stratified squamous epithelium (layered, flat, scale-like cells, basic cell type)
-no blood vessels
-4-5layers
(Corneum, Lucidum, Granulosum, Spinosum, Basale
Cells of the epidermis:
- keratinocytes
- melanocytes
- merkel cells
- langerhans cell
-melanin produced by melanocytes enter the keratinocytes and shield the nuclear DNA from UV damage
THick VS THin
-presence or absence of stratum lucidum
- thick = hairless
- thin = hairy
Dermis:
- Strong flexible connective tissue rich in collagen and elastin
- contains:
- fibroblasts, macrophages, a few adipocytes, nerve endings, blood vessels, glands, hair follicles
Skin colour determined by…
- blood circulation (haemoglobin)
- thickness of stratum corneum
- pigments (carotene and melanin)
Melanin
-produced by melanocytes in stratum basale
2 main variants:
UV radiation, genetics
Albinism
- People with OCULOCUTANEOUS ALBINISM typically have a very low level of melanin production
- 1 in 20000 people
Accessory structures of skin
- hair, nails, sebaceous glands, sweat glands
- derived from epidermis but extend into dermis
Sebaceous Glands
- produce sebum by holocrine secretion
- lubricates skin
- located in dermis on entire body except on palms and soles
Sweat Glands:
- Eccrine sweat glands
- Apocrine sweat glands
Ageing
-increased fragility, loss of elasticity, transparent quality
Sun exposure:
- as much as 80% of facial ageing due to sun
- changes in organisation (and functionality) of collagen and elastin in dermis
- sun burn = dna damage
Skin cancer::
-UV radiation exposure 3 types: -basal cell carcinoma (aka rodent ulcers)-most common -squamous cell carcinoma -malignant melanoma
