SKIN COLOUR AND DAMAGE Flashcards
What are the three elements that determine anatomy of skin color?
- Blood supply to dermis
- Thickness of stratum corneum
- Variable quantities of three pigments
What is pale skin?
Hemoglobin in dermal blood vessels
Pink hue of skin =
Oxygenated hemoglobin
Blue hue of skin (cyanosis) =
Deoxygenated hemoglobin
Redness of skin =
Blood vessel dilation (increase blood flow)
Carotene
Yellow/orange
Pheomelanin
Red/yellow
Melanin
Brown/black
How is the function of melanin determined?
Genetically determined
What are melanosomes?
Vesicles from melanocytes
What is the pathway for the production of melanin?
Melanosomes are transferred to keratinocytes and then coloured (pigmentation)
As keratinocytes move superficially, melanosomes are destroyed by lysosomes (pigmentation loss)
What is the pathway for the production of melanin in darker skin?
Melanosomes are larger and transfer to keratinocytes and persists to more superficial layers of skin (darker and more persistent pigmentation)
What do melanocytes increase the rate of and transfer in response to?
Rate of melanin synthesis and transfer in response to UV radiation exposure (tanning) to prevent DNA damage
What are the two types of UV-induced skin damage in the epidermis?
- Chromosomal damage
- Causes skin cancer
What are the three types of UV-induced skin damage in the dermis?
- Damage to fibroblasts
- Alters composition of extracellular matrix
- Premature wrinkling
