Questions tagged [skin]
The skin, part of the integumentary system.
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Why are lips covered with specialized skin?
I found out some interesting facts while studying our lips:
They are covered in glabrous skin, while most of the skin surface is hairy;
The outermost layer (stratum corneum) of the skin is far ...
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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 ...
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Is the skin of feline jungle predators protected against ants?
I was watching a video of a jaguar stalking along a riverbank, killing prey, climbing up the muddy bank, then laying in thick brush to eat. My first thought about this is that there must be tons of ...
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Is the fingerprint regenerated?
Let's say you get a a cut on your finger. Will the fingerprint be regenerated to matched your original fingerprint and if so, how?
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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 ...
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How are animal patterns encoded in the dna?
After seeing the patterns on the feathers of a argusianus argus pheasant (shown below), I am curious where is the information that encodes a pattern for a particular bird, and what form is this ...
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Mammalian scales
Many small mammals have scaly skin on their tails and sometimes limbs. The examples can be found among rodents (rats, degu, scaly-tailed squirrels), insectivores (shrews, desmans), oppossums, musky ...
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Does pain scale with mammal mass?
Some biological features scale with the animal mass (see previous Q&A).
Assuming the same concentration of nociceptors on the skin surface, I'm wondering how painful a 1 cm wound will be ...
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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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Oil absorbed into human skin -- where does it go?
For example, I apply petrolatum to my dry hands twice a day as in winter I am usually in a 20-30% RH environment. Within an hour, the petrolatum seems entirely absorbed.
According to [1], ...
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What is the evolutionary advantage of getting hard nipples when being aroused? Why can they even be stimulated sexually?
I try to understand the evolutionary advantages of the body reactions of nipples and penises/vaginas. I'm confused, because I can explain the evolutionary advantage in a logical & consistent way ...
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What causes the blue color seen in baboons?
Based off of this question from Worldbuilding SE.
In that question, I talked about how the scrotum and buttocks of various animals have a blue color because of thick deposits of collagen in those ...
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How fast can our skin recuperate from sunlight?
Imagine that you get burned in the sun after half an hour. But a quarter and another quarter is also a half hour. So if you go into the sun 15 minutes and after one hour another 15 minutes do you get ...
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Dead skin cell decomposition
What would be the resultant by-products of a completely decomposed dead skin cell?
What would be the size of each of the by-products of a decomposed dead skin cell? How long would it take for a dead ...
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Why does some skin hold perfume longer than others
I was wondering my girlfriend and I used the same perfume for a while and we sprayed the same place. And after a day her skin still smells nice while mine smells normal.
Will different types of ...
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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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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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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 ...
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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 ...
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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:...
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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 ...
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What are the (statistically) normal pH levels in the most-outer part of human sexual organs?
What are the (statistically) normal pH values of the outer skin/epidermis of human sex organs (groin/crotch) in the male and female? e.g male testes, female vulva, male glans, the enveloping epiderm, ...
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Are there wounds which never completely heal?
I have a cut on a knuckle which occasionally opens (usually during winter), to disappear after some time (it is usually fine during the summer). This is going on for years now and yes, I will show ...
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Can skin acclimatize to a the humidity level?
When the outdoor temperature is low, the absolute humidity is low because cold air holds less water. When the heat is turned up indoors the relative humidity decreases and during days with cold ...
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Effect of UV radiation on retinoid (vitamin A) receptors in the skin
The retinoid receptors in the skin (face) can be disabled by UVA sun radiation as these study states : https://www.sciencedaily.com/releases/1999/03/990331063314.htm
In this article it says the same :...
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Has aloe vera been proven to help heal burned skin areas?
I don't like buying into "natural remedy" type things without seeing scientific proof behind them. There's an almost universal belief that aloe vera helps to heal burned skin, and whether that ...
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Do macrophages engulf material in the epidermis?
This question comes from how tattoos work. From what I understand, the ink particles are something like 100 nanometers in size, which is too big for macrophages to remove them in the dermis. What I ...
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How do you identify this particular snake shedding?
Aloha,
Snakes are illegal in the State of Hawaii, with the exception of the Hawaiian Blind Snake (Brahminy Blind Snake (Ramphotyhlops braminus)). I've read through a plethora of articles to no avail....
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Measuring, using and analyzing skin resistance in kohms
What are ballpark ranges of skin resistance in Kohms for average men and their significance (for example 500-1000s = stressed vs 1000+ = fairly relaxed)
What do various skin resistances in kohms say ...
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Why do some macaques have redder faces than others?
I'm watching Monkey Kingdom, and I noticed some of the macaques have redder faces than others.
Specifically the females, and as the social ladder increases, so does the redness.
An alpha female:
...
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metabolic heat generation and exercise intensity
Is there a relationship between bio heat equation (found here) and exercise intensity as described here
That is I am trying to include the effect from exercises to the tempertaure variation in skin. I ...
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What Effect Does Skin Redness Have On Underlying Tissue?
When someone applies a rubefacient ( something that increases blood flow to the skin, turning it red), what effect does this have on the underlying tissue? Is blood supply increased radially from ...
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The skin color of bonobos
Why is that bonobos skin color on the areas not covered by hair are dark throughout life unlike the chimpanzee?
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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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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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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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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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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, ...
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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 ...
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What part of the skin is damaged under sun exposure?
How exactly does extensive sun exposure lead to skin damage and increase cancer risk. In which part of the skin is the sun doing the most damage. Is it in the epidermis or beneath ? I would like to ...
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Is swimming pool water actually a weak topical medication?
I was inspired by this question.
Given that the chlorine levels in swimming pool water are so high that they can seriously harm amphibians, it seems logical that the water should also kill various ...
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What was the first animal having fur?
Did all early mammals have fur? Is it possible to trace the origins, how early animals with fur looked like and how it evolved?
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