Although melanin is usually discussed as a single pigment, there are two types of melanin that contribute to pigmentation in the hair, skin, and eyes of humans and animals:. A third type of melanin, called neuromelanin, exists within the human brain and gives pigment to the structures in this area.
Melanin production begins in large cells called melanocytes, which can be found all over the body. Melanocytes are responsible for producing organelles called melanosomes.
These melanosomes are the site of synthesis for both eumelanin and pheomelanin, which is then distributed to a variety of cells, such as keratinocytes skin cells. However, there are some other factors that can influence the production of melanin, such as:. In addition to providing pigmentation in humans and animals, melanin also plays an important biological role by providing protection against damage from the sun. However, research on these potential benefits is scarce, so pigmentation and photoprotection remain the two primary benefits of melanin for humans.
Despite the many variations in human skin, hair, and eye color, almost all human beings have roughly the same number of melanocytes. However, people with dark skin tones have melanosomes that are higher in number, larger in size, and more pigmented than those with light skin tones. Interestingly, these melanosomes also seem to display specific distribution patterns based on skin color.
These differences all contribute to the wide variety of skin colors and tones in human beings. For more information or to order, visit our online Sun Sense Plus campaign page. Treating Sunburn If you do get sunburned, following these tips can reduce your discomfort and help you heal safely.
September, Developing and Implementing Tobacco-Free Worksite Policies Tobacco use can result in serious diseases and health problems, includin August, July, As we June, Yet this is t It's the body's natural defense mechanism against sunburn. Everyone looks better with a glow, but it comes at a cost. Spending extended amounts of time in the sun or in a tanning bed is dangerous.
Take a sunburn, for example. It takes time for melanocytes to produce melanin and protect the skin from the sun's harmful rays. When melanocytes can't work quickly enough to create a tan, the UV rays from the sun can burn the skin and leave it looking pink or bright red.
Sun damage also accumulates over time, which can lead to skin cancer. The lighter your skin, the greater your risk of developing skin cancer. So make sure that you see a dermatologist regularly for a skin exam. Direct sunlight isn't all bad, however. The skin uses sunlight to make vitamin D, which absorbs calcium and is essential for bone strength and growth. Sign up for our Health Tip of the Day newsletter, and receive daily tips that will help you live your healthiest life.
MC1R gene. Updated August 18, Crosstalk in skin: melanocytes, keratinocytes, stem cells, and melanoma. J Cell Commun Signal. Endocrine Society. Melanocyte-stimulating hormone MSH. Updated January 6, Melanin, like sunscreen , has an SPF or sun protective factor. That might not sound like very much, but an SPF 2 represents doubling the amount of protection from the sun. Following DNA damage or repair from UV light exposure, we increase the production of melanin and this creates a tanning effect.
In mammals, it is known that more than genes have a role in pigmentation. There is evidence that in addition to its photoprotective qualities, melanin can also be toxic to cells grown in culture dishes after UV exposure. Specifically, melanin can produce reactive oxygen compounds that can lead to a break in a single strand of DNA, and pheomelanin can generate hydrogen peroxide which may cause mutations.
Whether this happens in human skin and whether it impacts cancer is unknown at this time. In recent years, melanin research has expanded from studies aimed at understanding how melanin protects us from UV light to a variety of applied disciplines including materials science, drug delivery, and electronics. By providing your email address, you are agreeing to our privacy policy.
We never sell or share your email address. All rights reserved. Always consult your doctor about your medical conditions. Use of the site is conditional upon your acceptance of our terms of use.
0コメント