Melanocyte; The Cell Responsible for Color Pigment
Skin colour is one subject that people have argued a little bit about. Some say it arises from genetics, others say it could be due to location and the nearness to the sun. While some are dark-skinned, some are white, some are red, and we have other people with different colour of skins. If location is a factor, then I see so many whites who come as expatriates to my country and give birth here, and their children do not change skin colour due to a change in geographical location. I remember a time someone was saying that people who are light skin do not have melanin in their skin. That is one thing I cannot say for now, but as you go on with this post, you would know if white people have melanin or not. I will be looking at skin colour, what you should know about, and how the colour of our skin is determined
The skin belongs to the integumentary system which is made up of the skin (epidermis, dermis, and hypodermis), hair, nails and the glands. The upper layer of the skin is known as the epidermis, which is a thin layer of the skin at the outermost part of the skin. Some part of the epidermis are thicker like the parm, while most part of the epidermis is thin. The Dermis, which is the majority of the skin diameter. It is the next part of the skin after the epidermis, followed by the hypodermis or the subcutaneous layer, which is made up of Adipose tissue. It is the least part of the skin. The epidermis is for energy storing insulation.
The human skin pigment is found in the epidermis, which means the colour of your skin is determined by the outer part of the skin. The epidermis is made of up of strata of cells. The button pattern of the epidermis is known as the stratum basal, followed by the stratum spinodum. The stratum basal are mitotically active, causing them to divide and go upwards until they reach the uppermost part of the epidermis, then they flake off. Majority of the cells in the epidermis are keratinocytes. It is important to know that the kerotinocyte doesn't make up the skin coloration, the Melanocyte is the cell which produces melanin, which is responsible for the coloration of the skin. The melanocyte is made up of the melanin granule, dendrites, melanosome, golgi apparatus, nucleus, mithochondrium, and rough endoplasmic reticulum. They deposit melanin to the kerotinocyte in the epidermis, causing the kerotinocyte to have color. The more the melanin being produced by an active melanocyte, the more darker the skin becomes. Other cells in the epidermis are Langerhans’ cells, and Merkel’s cell.
In Africa, we tell ourselves that when we go do activities outside, where the sun is scuching, we tend to get darker. Well, this isn't a lie, as the sun activates the melanocytes to produce more melanin to the keratinocytes. But the melanin does protect the DNA from damage and mutation from ultraviolet ray. So people with darker skins are less likely to have skin cancer or burns, as they are more protected from the UV light compared to people with light skin.
It is important to know that the epidermis is an Avascular tissue, so blood doesn't flow into it, so it gets blood from the dermis. It is important that we do not forget the Stratum granulosum, which serves as a water protective layer, preventing water from getting into the skin. Also, the Stratum Corneum are cells that are flattened out that, and are more thick in the parm of the hands and the soles of the feet. Also on the parm of the hand and sole of the feet, is another layer just between the granulosum and the corneum which is the Stratum Lucidum.
Conclusion
At the end of this post, it is important to know that the epidermis is responsible for the color of our skins, and everyone has the melanocyte cell which is responsible for producing melanin in their epidermis. Melanin performs the function of coloration and preventing the DNA from ultravoilent rays of light which could damage the DNA and the cause diseases.
- National Library of Medicine - Physiology, Integument
- Physiopedia - The Integumentary System
- National Library of Medicine - Melanin reduces ultraviolet-induced DNA damage formation and killing rate in cultured human melanoma cells
- National Library of Medicine - Anatomy, Skin (Integument), Epidermis
- Cleveland clinic - Epidermis
- National Library of Medicine - The Protective Role of Melanin Against UV Damage in Human Skin
- National Library of Medicine -Biochemistry, Melanin
I suspect that there is a relation between Vitamin D and skin color.
The effect takes place on an evolutionary scale and not on an individual scale.
The UVB rays from the sun turns 7-dehydrocholesterol into Vitamin D3. The kidney turns this into Vitamin D2. These vitamins control a variety of things including the absorbtion of calcium by the bones and the immune system.
This is serious stuff. People who don't get enough vitamin D often fail to reproduce or die.
UVB rays are the first rays filtered by the sky. UVB doesn't pass through glass.
Since thick atmosphere filters vitamin D, people living in temperate climates don't get enough vitamin D in the winter.
Vitamin D deficiencies lead to poor immune systems and are likely to die from colds and flus. Children with vitamin D deficiences develop rickets.
Too much UVB is problematic as UVB rays cause skin cancer.
The situation is that people who get too much sun are more likely to die of cancer. People who don't get enough sun are apt to get rickets and have bad immune systems.
Populations that live in tropical climates have sun exposure all year round. It is an evolutionary advantage to have dark skin.
People in temperate climates don't get enough vitamin D in the winter. People in these climates have skin that turns white in the winter and tans during the summer.
Skin color appears to be an example of evolution in action.
NOTE: people in northern climates learned that fortifying milk with vitamin D could reduce problems with vitamin D deficiency; so we can counter the problem with science.
Sadly, the mortality rate of COVID was higher for African Americans in the United States than for people of European or Native American heritage. Studies show that African Americans tend to suffer vitamin D deficiencies.
I think people are scared of discussing this important topic.
I wish the CDC would scream from the roof tops that vitamin D reduces the severity of COVID. I have no idea why they won't do it.
You have a very good point here, I was starting to look at Vitamin D as responsible for skin colour, but actually, vitamin D has has other functions such as absorb and retain calcium and phosphorus , and it helps to absorb ultraviolet ray into the skin..
I will love to see the CDC come out with this.
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