Lecture 16 Flashcards
Melanin and its function
*melanin is a compound found wides across plants and animals (in mammals: hair, skin, pupils/irises, parts of your brain and inner ear
*function: protection from UVR (absorbs rays from UVA, UVB, UVC, and blue light
Melanocyte
A melanocyte is a type of cell in your skin that produces a pigment called melanin, which gives your skin, hair, and eyes their color.
Pheomelanin
2nd type of Melanin
*responsible for reddish pigmentation lips and nipples
(E.g. red hair: equal parts Eumelanin and pheomelanin
*does not protect against UV
Eumelanin
A type of melanin
*Eumelanin (black and brown variants)- responsible for dark pigmentation of skin, eyes, and hair
E.g. blonde hair: no black Eumelanin but some brown
E.g. black or brown hair- varying amounts of black and brown Eumelanin
Protects against UVR
Risks of Ultraviolet Radiation (UVR)
Risks:
*short term: sun burn
*long term: premature aging, skin cancer, eye diseases
*Degrades folate
*Risks higher in those of lighter hair, skin, and eyes
MC1R gene
The MC1R gene controls skin and hair color. It helps decide if you have red hair or a fair skin tone by producing a protein that affects pigment in your skin and hair. The MC1R gene produces a protein called melanocortin 1 receptor. This protein helps control the type of pigment (either red or brown/black) that gives color to your skin and hair.
*When activated, stimulates production of Eumelanin- without this signal, melanocyte produces pheomelanin
*variation of MC1R associated with varying amounts of Eumelanin
Folate
Folate is a type of B vitamin that helps your body make red blood cells and is important for cell growth and development.
When long term exposure to UVR, it degrades folate
Folate is critical building blocks (especially during embryonic development)
Vitamin D
One of the benefits of UVR: Vitamin D production (helps your body absorb calcium and phosphorous to assist in bone/growth maintenance
Tanning Response
When skin produces eumelanin pigment as a
result of seasonal high UVR exposure
• The outcome of UV-induced stress
• Regulated by melanocortins
• Tans produced under natural UVB exposure
provide minimal photoprotection
• Tans produced under UVA-rich sunlamps have
no protective bene
Neuromelanin
pigments your neurons (we never see these colors)
Melanocortins
Group of hormones which reduces the production of harmful reactive oxygen species.
*enhances DNA repair caused by UVR
