Skin colour is determined by a dark pigment in the skin called melanin. Melanin is made in cells called melanocytes which is found in the skin and at the root of the hair in the follicle. They are simulated by a hormone called MSH (melanocyte- stimulating hormone). On the surface of melanocyte cells you will find receptors for MSH. The melanocytes place melanin on organelles called melanosomes. They are usually collected/found around the nucleus and their function is to protect the DNA from harmful UV light.
Darker skinned and haired people have more receptors giving them a better protection against sun burn.
The proportion of MSH and MSH receptors are determined by UV light, it increases it making it more active and causing skin to darken.
People are adapted to this, e.g. people living in hotter countries have more MSH and MSH receptors to protect them from harmful radiation.
Darker skinned and haired people have more receptors giving them a better protection against sun burn.
The proportion of MSH and MSH receptors are determined by UV light, it increases it making it more active and causing skin to darken.
People are adapted to this, e.g. people living in hotter countries have more MSH and MSH receptors to protect them from harmful radiation.
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melanin
genetic differences exist in the amount of melanin found in the skin
genetic differences exist in the amount of melanin found in the skin
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As well as blood, which would make a fair toned person pinkish.