what is melanogenesis ?

Question

related to pigmentation.

Answer 1

i learned about this in class last semester, but instead of typing it all out i'm just gonna copy and paste from wikipedia....hopefully you don't take credit away from me for doin it that way. lol.

Melanogenesis
Through a process called melanogenesis, these cells produce melanin, a pigment in the skin, eyes, and hair.

There are both basal and activated levels of melanogenesis; lighter-skinned people generally have low basal levels of melanogenesis, and exposure to UV radiation generally causes increased melanogenesis.


Human differences
There are typically between 1000 and 2000 melanocytes per square millimeter of skin. They comprise from 5% to 10% of the cells in the basal layer of epidermis. Although their size can vary, melanocytes are typically 7 micrometers in length.

The difference in skin color between fair people and dark people is due not to the number of melanocytes in their skin, but to the melanocytes' level of activity.

Albinos lack an enzyme, tyrosinase, that is required for melanocytes to produce melanin from the amino acid tyrosine.


Embryology
Embryologically, melanocytes come from the neural crest, a completely different source than that of the surrounding skin cells (keratinocytes).

All melanocytes have the capacity to migrate widely in the embryo, and therefore a cancer of a melanocyte, a melanoma, will spread (metastasize) very easily. For this reason, melanomas are often fatal, and when surgically removed, a lot of surrounding tissue must be taken as well.


Stimulation
Numerous stimuli are able to alter melanogenesis, or the production of melanin by cultured melanocytes, although the method by which it works is not fully understood. Vitamin D metabolites, retinoids, melanocyte-stimulating hormone, forskolin, cholera toxin, isobutylmethylxanthine, diacylglycerol analogues, and UV irradiation all trigger melanogenesis and in turn, pigmentation.[1] The production of melanin is also initiated by ACTH (another hormone).

Once made, melanin is moved along arm-like structures called dendrites in a special container called a melanosome which is shipped to the keratinocytes. Melanosomes are vesicles or packages of the chemical inside a plasma membrane.

When ultraviolet rays penetrate the skin and damage DNA; thymidine dinucleotide (pTpT) fragments from damaged DNA will trigger melanogenesis[2] and cause the melanocyte to produce melanosomes, which are then transferred by dendrite to the top layer of keratinocytes.

The melanin is in organelles called "melanosomes" that are organized as a cap protecting the nucleus of the keratinocyte.

Answer 2

Yes, I agree that whilst there are many facial cream in the market which whitens or brightens your face but not much for the body. I suggest you have a look at St Ives and or Nivea, I vaguely recall that they have brightening/whitening body lotion, "it won't happen over night, but it will happen". I used to pour 1 cup of 3% hydrogen peroxide in my bath to remove dried-up unwanted tanning lotion/tan marks (yep stripy tan lines/streaks does not look good nor does that betacarotene look). I just soak for about 10 minutes, rinse in the shower and exfoliate, works like magic everytime! Then I just moisturise my whole body for baby smooth skin...hehehe...perhaps this will help you with exfoliating your tanned skin to reveal a lighter/more desirable shade? But becareful if you have hyper sensitive skin as the hydrogen peroxide might cause redness as with any cream that contains salicylic acid or benzoyl peroxide. Also do as the other person has mentioned earlier, use spf30 or higher (certain parts of Europe sells spf60 lotions/creams) when you're in the Sun as well as minimise Sun exposure. Just about an hour or 2 a day with a hat on is sufficient. You need Sunlight to stay happy otherwise you will have to take vitamin D supplement should you avoid Sun exposure altogether. Good luck!

Answer 3

Melanogenesis Process

Answer 4

production (-genesis) of melanin (melano-), which is the pigment which gives skin its colour. melanocytes are the skin cells that do this.

Answer 5

Its what Michael Jackson thinks he has. It is some kind of disease that turns your skin a different color.