Questions tagged [skin]

The skin, part of the integumentary system.

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Can human hair, animal fur and birds feather get cancer?

Hair, fur and feather protect skin from cancer(sun UV light). I am interested can human hair, mammal fur or birds feather get cancer? (Some migration birds like swifts spent 10 months in year in the ...
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129 views

What is the known safety data on phenoxyethanol?

I came across this news article stating that a certain skincare product was declared by FDA to be unsafe for infants due to having chlorphenesin and phenoxyethanol. However, I have been unable to find ...
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Intensity of UVA needed to damage skin and cause ageing

Using a UVA/B measuring device, I was able to determine that approximately $\pu{10 μW/cm^2}$ penetrates a window even when not in direct sunlight. For reference, the intensity of direct sunlight ...
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1 answer
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What is the best way/kit to extract total proteins from biopsy tissue?

I need to extract total protein from 2mm skin biopsies for western blots. I was thinking about miRNeasy Micro Kit (50) Cat. #217084 while it's ok for total RNA ...
-1 votes
1 answer
37 views

Micro-intradermal spasms in the legs after exercise [closed]

Heyo ! When i'm doing physical effort that involves and then rest, I feel small and suddle of what feels like contraction all over my legs (but not feet); It stops by itself after a few minutes and ...
6 votes
3 answers
401 views

How lethal is high dose UV?

I watched a Neil DeGrasse Tyson video about teraforming Mars where he goes over the topic of UV radiation and how our ozone layer protects us. He makes a statement that the UV on earth is actually ...
1 vote
1 answer
28 views

Sequence homology of cytokeratins

I am reading https://www.ncbi.nlm.nih.gov/pmc/articles/PMC7962860/ and do not understand what it means by high sequence homology of cytokeratins in the following text: "Sequence homology of ...
1 vote
1 answer
62 views

Are the lower layers of skin more electrically sensitive as opposed to simply heat sensitive?

Today while surfing I accidentally rubbed the top layer of skin in my fingertips off from friction against the surfboard. I didn't think much of it until later in the day when I was using my laptop. I ...
2 votes
1 answer
940 views

How thick is the residue from a fingerprint?

I am trying to work out the mass added to a small glass sphere when it is picked up with bare fingers.
17 votes
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How hot can a beverage get without burning the tongue?

What is the maximum temperature that a beverage can be without burning the tongue? I suspect there's a maximum temperature that the surface tissue of a tongue can withstand without being damaged (...
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What is my original skin tone i.e. my genetic skin tone with minimal/ subtle sun tan?

When I was younger (about 2-3 year old) I had a lighter skin color and now I have a darker skin color ( currently 19 years old ). Now as a teen I have became conscious about my skin issues ( including ...
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1 answer
228 views

How likely is rabies virus will enter the body through this kind of imperfect human part when you perform this "experiment"?

First, let's not confuse my question with typical skin peel when your body part slip on a road and get that typical red colored skin due to blood. It's not like blood is flowing, but clearly red area ...
-1 votes
1 answer
173 views

Why is African hair different in texture to European or Asian hair?

Most Africans with the exception of Ethiopians and Somalians have relatively kinky/coiled hair. The texture is very different to that of Europeans or Asians. Why is that? I've heard it has to do with ...
1 vote
3 answers
113 views

How can you diagnose albinism in a naturally light-colored person? [closed]

Not all albinos have white hair. There is a type of albinism where the affected person has light yellow hair and the skin color can be the same as a normal North European person. How can you diagnose ...
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Skin tone of a new born just after birth

I have a question. My skin tone is light but the photographs of me as a baby show that when i was just born, i was having an even lighter skin colour for about two years or probably more. As for now ...
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56 views

Why there is swelling when skin doesn't break visibly? [closed]

I had read that swelling occurs as result of blood vessels pouring watery fluid in the affected area to help in fighting the incoming pathogens, when we our skin is cut open. However sometimes like ...
7 votes
1 answer
292 views

Why does hair turn white but not skin?

From my understanding melanocyte stem cells (McSCs) stop being produced and we have a finite reserve that gets depleted with time. They're at the origin of melanocytes that create hair and skin ...
4 votes
1 answer
230 views

Can anti-aging cream work?

I have a friend who told me that anti-aging cream cannot work to reduce wrinkles as it only penetrates x amount of skin layers and can never make a long term effect. Me not knowing much about how ...
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2 answers
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Is there any difference between fascia and skin ?Are both the different names of the same thing?

Skin is the outermost layer of the body ,and it consists of two layers; epidermis and the second layer the dermis .There is another layer the (third layer) beneath the dermis called superficial fascia ...
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Why Do Healing Wounds Feel Warmer To The Touch?

I fell over on my bicycle trying to avoid running over a rattlesnake, and ended up badly skinning my knee. It immediately began to bleed, but soon clotted. It has been 2 days now and it has formed a ...
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3 answers
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Why can silicone reduce keloid?

I heard people use silicone sheet for reducing raised scars (i.e., keloids). I was wondering what is the rational behind it, and whether it actually works.
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1 answer
70 views

How can botox cure wrinkels?

How can botox cure wrinkels? Do wrinkles caused by tension of some muscles in the skin? Can these muscles be relaxed by hypnosis or training?
5 votes
2 answers
863 views

Why Is The Toughness Of Skin Different On Different Parts Of The Body?

My cat was licking my arm with his sandpaper like tongue. It hurt and the area he was licking was slightly smarting afterwards. However, when he licks the palm of my hand the feeling is rather ...
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1 answer
114 views

What is the effect of anti-fungal soap?

As I understand, most popular anti fungal soap/shampoo has Ketoconazole as an active ingredient. Ketoconazole stops the growth of fungi, but as it does not kill it, but halts division, how can soap/...
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1 answer
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How do viruses attacking the outside of the body invade if the upper strata of the epithelial layer is metabolically inactive?

The top two layers of the epithelia, the layer of skin on the outside of the body, are the stratum corneum and the stratum lucidum. Both of these layers are metabolically inactive, in other words they ...
1 vote
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Why does more melanin means harder vitamin D production if melanocytes lie deeper in the skin than keratinocytes?

From my Googling, I understand that keratinocytes are primarily responsible for generating vitamin D from UV rays, and melanocytes are for producing melanin to block UV rays. However in lots of skin ...
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Are dark skinned natives of Central America dark skinned due to the same genes as people of African heritage?

I'm trying to understand how strong the evolutionary pressure on genes for skin color happens to be. Was it fast enough that the humans that migrated through the Bering Strait had lighter skin color ...
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How does expansion of the skin via mitosis influence the density of its specialised nerve endings

I found a reddit question Do nerves & nerve endings expand with skin or does skin expansion causes loss of nerve density where a user references the study Assessment of Epidermal Nerve Fibers: A ...
20 votes
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2k views

Why does UV radiation from the Sun cause skin cancer?

What is the specific mechanism makes non-ionizing UVA and UVB radiation carcinogenic? Can lower energy light, like visible light, be carcinogenic because of this mechanism, or is there some kind of ...
1 vote
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86 views

Why are many skin depigmenting agents toxic to the body?

Coming from a developing country, I know many people who regularly use these creams to lighten their skin and some of them have developed liver and kidney problems as a result. I know that many ...
2 votes
1 answer
572 views

Why are all human beings not black in color?

Archaeologists and historians strongly claim human beings originated from the African continent, where the default color is black for humans. Why are all human beings not black in color?
2 votes
1 answer
49 views

How do humans detect temperature differentials on the skin?

I just read this question on Physics SE about how the body detects cold or warm surfaces. As someone who already understands how heat flux devices like thin film gauges and thermocouples work (by ...
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27 views

How do Human Skin Creases Vary?

I am studying human gross anatomy in order to produce an anatomically correct CGI model of the human body. As part of this, I'm attempting to understand the different features that define the ...
2 votes
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33 views

Constitutive Dark Skin vs Facultative Tanned Skin

Most can easily spot the difference between a tanned and dark person. But from my research, the only difference is in the size and concentration of melanin (Jablonski). But this continues to increase ...
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1 answer
425 views

How is boiling oil tolerated by some people?

There are people who can withstand exposure to extreme heat with no apparent side effects. One such person is Kann Trichan, a Thai street vendor who dips his bare hands in hot oil. An old TV show ...
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How does salicylic acid work on acne?

There are claims that salicylic acid has an effect on acne. I have done preliminary research and found multiple sources saying: "Salicylic acid [can] help prevent future breakouts." - https:...
1 vote
1 answer
83 views

By what physiological mechanism do we not feel microbes (bacteria, etc.) living on our skin?

Background I know our bodies have a handful of ways to threshold our awareness of sensory stimuli: Neural density Sensory acuity I assume really tiny stimuli could fit between receptors e.g., ...
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1 answer
127 views

How far can free radicals from UV radiation diffuse through the skin?

UV radiation damages DNA through two separate mechanisms. Direct damage occurs when a photon is absorbed by DNA. Indirect damage occurs when a photon is absorbed by a chromophore, and the excited ...
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Are facial 'cleansing' products 'effective' on human skin, and if so, what is their mechanism of action? [closed]

All major supermarkets and beauty stores stock some form of facial cleansing products. They come in the form of scrubs, gels, and lotions which vary in application (from in shower, to apply daily ...
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107 views

Do we as humans develop tolerance to deodorants or antiperspirants?

Do we as humans develop tolerance to deodorants or antiperspirants? In particular when they contain isobutane, isopropyl, palmitate, isododecane, dimethicone, coconut oil, magnesium oxide, allantoin, ...
8 votes
1 answer
977 views

How does skin healing work?

I stacked my bike and split my head right open. About three weeks later the scab falls off and the skin is sealed over, like magic! How does it all work? How does the brain know that part of the ...
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Do pyrocalciferol and isopyrocalciferol form in vertebrate skin?

I heard that pyrocalciferol and isopyrocalciferol can only be formed above 100°C/212°F, yet some images in the web depict them as forming in vertebrate skin. So, I wonder if pyrocalciferol and ...
5 votes
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3k views

Why do we like to touch fluffy things?

I read this article but it didn't explain much. Is the fact people like to cuddle pets with fur connected anyhow with our past when our ancestors had fur as well - and therefore could evolve an ...
9 votes
3 answers
14k views

Why are bald heads so "shiny"?

Why do males with baldness have shiny skin on their head, whereas we don't experience such "shiny skin" in other parts of body without hair.
14 votes
2 answers
2k views

Can UV radiation be safe for the skin?

It is well known that UV radiation can damage the DNA and generally harm our skin. We also know that UV radiation helps on the production of melanin and Vitamin D. From what I could find, the DNA ...
5 votes
1 answer
5k views

Can viruses pass through sweat pores?

I have read somewhere that viruses and other microbes can not penetrate skin but what about sweat pores? Can viruses pass through these pores?
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How hot water burn works?

At age of 6 I accidentally dipped my hand into a boiling indian curry(Sambar) which was in a large pot. I got a Boiling Water Burn(Just like in the picture but with a little more radius) in my hand ...
3 votes
1 answer
761 views

Why hand washing causes skin to dry?

This seems counter intuitive: dry hands mean low humidity, so why when humidity is increased, by washing hands, they become even more dry, eventually? In particular, why such hand dryness is usually ...
1 vote
1 answer
13k views

Consequence of touching Formaldehyde

I accidently touched formaldehyde some days ago. Skin on my hand got dehydrated as if I had placed it in salt solution. I washed it with water and it returned to normal state after 5 minutes. But now ...
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Evolution of scratching

Is scratching (aka the scratching reflex) thought to be inherited from a single vertebrate ancestor or is it something that evolved several times e.g. in birds, mammals etc., i.e. is it a case of ...