The Colors Of Skin - What Is Skin Color Determined By - Ways The Skin Changes Colors
In this video we discuss the color of skin, and some of things that contribute to the color of skin, or alter the color of skin.
Transcript/Notes
The color of skin
The color of skin ranges widely from person to person. Skin color is determined by the amount and type of melanin released by melanocyte cells in the epidermis of the skin. Melanin is a pigment that is produced by the melanocyte cells, which gets released into vesicles called melanosomes and then gets transferred to keratinocyte cells and surrounds its nucleus to protect DNA from mutating from ultraviolet radiation.
The number of melanocyte cells is about the same in all humans, but there are 2 main types of melanin produced by these cells; eumelanin and pheomelanin. Darker skinned individuals produce more eumelanin and lighter skinned individuals produce more pheomelanin. Heredity is the key factor in the type of melanin produced by cells. In some individuals the melanocyte cells cannot produce melanin, resulting in a condition called albinism. Albino persons have the absence of pigment in their skin, hair and eyes.
Sunlight, or exposure to ultraviolet radiation in sunlight triggers the melanocytes to produce more melanin resulting in a darkening of the skin color or tanning of the skin. Again this is done as a method to protect DNA in the nucleus of cells. Consistent overexposure to UV radiation can also influence overproduction of melanin causing dark “age spots” on the skin.
The skin can sometimes appear reddish or pinkish, such as during exercise, because blood vessels in the dermis vasodilate, or increase in diameter, allowing more blood to flow through them. The red tones of hemoglobin in red blood cells are more visible making the skin appear reddish or pinkish.
Freckles are another skin coloration. Freckles are yellowish brown spots that occur on certain areas of the body. They appear as a result of increased melanocyte cell activity and their pigmentation depends on heredity and exposure to the sun.
A yellow orange pigment from beta-carotene may alter skin color. The body can convert beta-carotene to vitamin A, which contributes to healthy skin, and it is found in carrots, corn and sweet potatoes. So, extremely high consumption of beta-carotene foods can cause a yellow-orange coloration of the skin.
A bruise can also alter skin color. Bruises can occur from some sort of trauma to the body such as a bump or a fall, where blood vessels get damaged and tear. This causes blood to leak into tissues beneath the skin causing a reddish color due to the red color of red blood cells containing hemoglobin.
As the body heals itself and breaks down the hemoglobin, the bruise color may take on a bluish purple tone. And as the area continues to heal, the bruise may take on a yellowish color and finally once the bruise has completely healed the skin will return to its normal color.
Tattoo’s also change the color of the skin. Tattoo’s are made as a machine with a needle punctures holes through the epidermis, or outer layer of the skin, into the dermis or deeper layer of the skin and deposits the ink. The dermis, which is comprised of connective tissue that is very stable, allows the ink to stay in place with slight fading or spreading out over time. One note though, the body does respond to the puncturing of the skin by sending in white blood cells to the area, and they do remove some of the ink bringing it to lymph nodes.
Timestamps
0:00 Skin color and melanin
0:28 Eumelanin and pheomelanin
0:45 Albinism
0:56 Sunlight exposure produces more melanin
1:19 Skin color and exercise
1:35 Freckles
1:49 Beta-carotene and skin color
2:08 Bruises
2:39 Tattoo's
