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Melanosomes, which are organelles containing melanin, must be transported and increased during hyperpigmentation and tanning, while they shrink during hypopigmentation. [4] Skin pigmentation is frequently caused by sun exposure. To protect itself against UV radiation from the sun, the body makes more melanin. As a result, the skin may become ...
Melanin is the primary determinant of the degree of skin pigmentation and protects the body from harmful ultraviolet radiation. The same ultraviolet radiation is essential for the synthesis of vitamin D in skin, so lighter colored skin – less melanin – is an adaptation related to the prehistoric movement of humans away from equatorial ...
The positive advantage, however, would have had to be strong enough so as to produce a significantly higher reproductive fitness in those who produced more melanin. The cause of a selective pressure strong enough to cause this shift is an area of much debate.
Your hair color is produced by cells called melanocytes, which produce melanin. Melanin is what gives your hair and skin its color. As you age, you produce less melanin, resulting in gradual graying.
MCH is a cyclic 19-amino acid neuropeptide, as it is a polypeptide chain that is able to act as a neurotransmitter.MCH neurons are mainly concentrated in the lateral hypothalamic area, zona incerta, and the incerto-hypothalamic area, but they are also located, in much smaller amounts, in the paramedian pontine reticular formation (PPRF), medial preoptic area, laterodorsal tegmental nucleus ...
What causes lower left abdominal pain? Lower left abdominal pain can have many causes, ranging from minor to serious, says Andrew Boxer, M.D., gastroenterologist of Gastroenterology Associates of ...
The best candidates are men who have a curvature of less than 30° and no ED. Pentoxifylline. This vasodilator may also help stabilize Peyronie’s disease and reduce calcium buildup in plaques by ...
Vitiligo is a condition that causes depigmentation of sections of skin. It occurs when melanocytes die or are unable to function. The cause of vitiligo is unknown, but research suggests that it may arise from autoimmune, genetic, oxidative stress, neural, or viral causes. [116] The incidence worldwide is less than 1%. [117]