Biology Stack Exchange
Biology Stack Exchange

Questions tagged [skin]

The skin, part of the integumentary system.

For questions about the skin, part of the integumentary system (skin, hair, feathers, nails, scales, hooves). The role of the system is to protect, detect, help regulate, and is a site of vitamin D synthesis.

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Why do tattoos persist if body cells are regularly renewed?

I am not quite sure if it is true, but I read somewhere that within 7 years all the body's cells are replaced with new ones. I am not quite sure if it is cells or atoms. If it is then why do tattoos persist for so long? If the cells which were…
vfclists
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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 threshold within spectrum at which electromagnetic…
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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 (causing the burning feeling that lasts even after the…
J.Todd
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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 absorption spectrum goes to almost zero for…
cinico
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Why does having cold hands hurt?

(1). Why does having cold hands create a painful sensation? Is it a physical effect, maybe a protection mechanism from evolution? (2). Why, if one's hands are cold, does it feel as if they are more susceptible to pain? Note: I have (2) as a separate…
User 17670
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If cells regularly renew, why do we have scars?

Question may sound bit poetic but I have a pretty basic question here: Often we get a minor wound and cells renew and quickly "cover" it. But when we have deeper wounds, often they leave behind scars. Why does it happen? I was researching around…
Failed Scientist
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Why did humans evolved the scratch reflex?

I've been wondering about this for some time, and I can't come to an answer... Everybody keeps telling me that scratching one's own skin is bad. It damages the epidermis, creates the hazard of malicious bacteria getting past the skin barrier, and…
gaazkam
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Do humans perceive temperature or heat-flux? (or both?)

The general understanding is that when I touch an object, I perceive its (relative) temperature. A metal object at room temperature, however, will often feel cool to the touch. This leads me to believe that the skin senses heat flux in addition to,…
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How can haired mammals synthesize vitamin D?

The human body can synthesize vitamin D in the skin from cholesterol, when sun exposure is adequate. But how can haired mammals do it? Do not they need it?
cesargastonec
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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.
Failed Scientist
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How and why do skin tags develop?

WebMD writes: Skin tags are small, soft pieces of skin that stick out on a thin stem. They most often appear on the neck, armpits, upper trunk, and body folds. The cause of skin tags is not known. Do we really know nothing about why they appear?…
Christian
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Why can good music raise goosebumps?

Listening to really good music right now, I was wondering why it raises goosebumps. Is there any physiological reason for this reaction to specific wavelengths or something? EDIT: Due sometimes strong vibration, roadwork for example, raise…
jawo
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Why doesn't the human skin grow back exactly how it was before being damaged?

Very simple: Why (and how) is regenerated skin different from original ? As we know we lose skin cells that becomes the dust in out homes and it always grows back to full thickness right ? So when I have a cut, I imagined it to heal provisionally…
Leck
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Why does the sweat of children not smell like adults?

My kids sweat plenty in this hot heat, but they don't smell afterward. I on the other hand need all kinds of deodorant. Why doesn't kid sweat smell?
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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 body is injured and needs repair, or does the brain…
wim
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