Skin is the layer of usually soft, flexible outer tissue covering the body of a vertebrate animal, with three main functions: protection, regulation, and sensation.Other animal coverings, such as the arthropod exoskeleton, have different developmental origin, structure and chemical composition. The adjective cutaneous means "of the skin" (from Latin cutis 'skin'). In mammals, the skin is an organ of the integumentary system made up of multiple layers of ectodermal tissue, and guards the underlying muscles, bones, ligaments and internal organs. Skin of a different nature exists in amphibians, reptiles, and birds. Skin (including cutaneous and subcutaneous tissues) plays crucial roles in formation, structure and function of extra-skeletal apparatus such as horns of bovids [e.g. cattle] and rhinos, cervids' antlers, giraffids' ossicones, armadillos' osteoderm, and os penis/ os clitoris.All mammals have some hair on their skin, even marine mammals like whales, dolphins, and porpoises which appear to be hairless.
The skin interfaces with the environment and is the first line of defense from external factors. For example, the skin plays a key role in protecting the body against pathogens and excessive water loss. Its other functions are insulation, temperature regulation, sensation, and the production of vitamin D folates. Severely damaged skin may heal by forming scar tissue. This is sometimes discoloured and depigmented. The thickness of skin also varies from location to location on an organism. In humans for example, the skin located under the eyes and around the eyelids is the thinnest skin in the body at 0.5 mm thick, and is one of the first areas to show signs of aging such as "crows feet" and wrinkles. The skin on the palms and the soles of the feet is 4 mm thick and is the thickest skin on the body. The speed and quality of wound healing in skin is promoted by the reception of estrogen.Fur is dense hair. Primarily, fur augments the insulation the skin provides but can also serve as a secondary sexual characteristic or as camouflage. On some animals, the skin is very hard and thick, and can be processed to create leather. Reptiles and most fish have hard protective scales on their skin for protection, and birds have hard feathers, all made of tough beta-keratins. Amphibian skin is not a strong barrier, especially regarding the passage of chemicals via skin and is often subject to osmosis and diffusive forces. For example, a frog sitting in an anesthetic solution would be sedated quickly, as the chemical diffuses through its skin. Amphibian skin plays key roles in everyday survival and their ability to exploit a wide range of habitats and ecological conditions.
http://www.elastoplast.com.au/media/11/12276804863360/schnittwunde_03.jpg
If your skin is cut deeply, meaning a cut to dermis why is that we can see scar tissue. I mean if the cut region in the dermis would be replace by scar tissue, but the epidermis region above that would have normal...
References are available to calculate skin effect, RAC/RDC given wire gauge and frequency. But my problem is a complication of this simple calculation.
Say I have a 1 Amp RMS AC current component and a selected wire size that gives me a skin effect of 7X the DC resistance. But I also have a...
Does skin that is perpendicular to the sun’s rays burns faster than skin that is closer to parallel to the sun’s rays? I was certain that it does but a very smart friend/engineer is certain that it doesn’t and was incredulous that I thought it did.
I really would like to know the physics...
Hi All,
I know that the environment is responsible for people of African descent having black skin and people of Scandinavian descent have white skin but I cannot figure out the logic behind this.
I thought it had to do with the absorption of Vitamin D from the sun and the Scandinavian...
Hi all! This is my first post :D
I came across skin effect which blocks propagation of an em-wave within a conductor...
But doesn't the energy generated at an electric plant reach our house through conductors flowing for over a 1000 miles sometimes?
If I have to consider it just as an...
wiki-A dermatome is an area of skin that is mainly supplied by a single spinal nerve. There are eight cervical nerves, twelve thoracic nerves, five lumbar nerves and five sacral nerves. Each of these nerves relays sensation (including pain) from a particular region of skin to the brain.
My...
I remember this hilarious argument on Curb Your Enthusiasm. Who has a more refined palette? Someone who is overweight because he has eaten a lot of food in his life or the skinny person because they enjoy the smaller quantities of food?
DISCUSS!
Homework Statement
'Briefly explain the importance of skin depth in the context of radio communications.'
Homework Equations
The Attempt at a Solution
A guess would be that, the frequencies of the radio transmissions should be kept small so that the signal has a large skin depth...
Does putting oil on the skin helps to reduce the dry skin? Or, it just looks better because under oil, the dry skin is temporarily invisible? What is baby oil for?
I placed a cellphone in 2 half-spheres that i closed afterwards to create a metal cavity (aliminium 1mm) and called it (with another cellphone). The phone rang even if it wasn't supposed to considering the skin effect (wavelenght were about 0,04m and i couldn't see any holes). Anyone has a clue why?
There's a lot of advertising out here for laser treatments for all types of skin problems (acne, discoloration, wrinkles, etc). Here's one of the places that does these treatments:
http://www.laserhq.com/1/index.html
Do you think laser treatments work? How do lasers fix so many different...
I searched up NaOH and saw that it's irritating at 0,05 to 0,5 mol/l. So I guess at a pH of 12,7 you will burn your skin. Is that true?
I'm going to do an experiment with 5% NaOH. I thought it was a very small concentration but actually you could burn quite a bit with this solution after a...
hi there, I am stuck on this question can some give me a hint on how to solve the question:
the question is:
Calculate the skin depth for copper at 1.0 GHz . σ = 5.8x10^7 S/m, εr=1, μr=1.
the formula i think that i need to use is
tan δ = σ / (ω)(ε0)(εr)
ω = 2nf = 2 x n x 1 x 10^9...
Homework Statement
If 4.0 g of boiling water at 100.0°C was splashed onto a burn victim’s skin, and if it cooled to 45.0°C on the 37.0°C skin, (a) how much heat is given up by the water? (b) How much tissue mass, originally at 37.0°C, was involved in cooling the water?
Homework Equations...
Hi PF,
Why when we listen to some music we can have the chicken skin? What is occurring to the brain when we listen to a music creating chicken skin? Is it because of the emotions? But it seems that when we have other emotions we don't have chicken skin. Is it because music can create...
Hello All,
I am wondering if when a sharp pulse is injected into a piece of wire, if that piece of wire produces a radially directed external electric whose magnitude is proportional to the skin depth of the current into the wire and the voltage potential of the input pulse.
To elaborate...
Can anybody explain the skin effect more clearly-
why does the current tries to concentrate more closely to the surface of
the conductor at high frequencies?
what is happpening inside the conductor?
thanks
At least, it's the only thing I can think of that could be causing the burning sensation.
I chopped some jalapenos last night, then washed my hands as usual. I woke up during the night with the palm and fingers of my hand burning. These weren't hot jalapenos, and it's only affecting one...
hi all
i run into some contradictions while studing electromagnetics.
you know skin depth decreases when frequency increases.It ans that waves of higher frequencies have lower skin depth.
ok
and every one of us knows that X-ray have higher frequencies than other waves for example radio...
Ultraviolet light can kill skin cells but infrared light only warms skin cells even though both types of lights are from the sun. Why is this, explain using the photon theory...?
1. Can HIV attach itself to a muscle cell or a skin cell?
It seems that HIV attacks the immune system mainly by damaging the CD4 (also known as T4 or T-helper) cells which help the body fight off diseases.
But I don't think that is the correct answer to this question. Theoretically...
Has anyone heared about a a substance called l glutathione that is used for skin lightening?
like this one:
<Link Removed>
Does it work? And is it as safe as they say it is?
I am looking for an explanation about a simple physics phenomen.
When washing plates and ustensils, I would manipulate knives and, from times to times, would cut myself a bit. Does it matter if your hands are wet or dry and what does the water do on the surface of the skin that can influence...
Hello, I have some question I want to ask.
1) Let's say there identical twins marry identical twins, and they have baby's would the baby's of the two families share the same DNA as if they were brothers?
If someone didn't understand I mean: male and female which have identical brother or...
ive been searching through many biophysics and physiology books lately... but i haven't found anything useful... i want to find some explanations of the structure of the skin - but not the ones you'd get from biology books - i want equations that describe the impedance of each layer of the skin...
Greetings,
Does anyone know how a Chameleon physiologically changes the color of its skin? I'm guessing the mechanism has to do with proteins in their epidermis that contain chromophores which can be controlled to vary their skin pigment. If anyone knows the details, please show me the...
I was just reading about "Morgellons Disease". At first I thought this was a psychotic symptom. I've definitely heard of similar crawling sensations experienced by schizophrenia sufferers.
But it sounds like there might actually be a strange dermatological condition that these people are...
I heard and read that mercury and some of its compounds can get absorbed through the skin how could it do that ?
Aren't our skins soposed to be waterproof ? I don't think that while washing our hands with water the water pases through the epidermis.
http://www.nytimes.com/2005/12/16/science/16gene.html
Yesterday's issue of Science magazine, and this article in the 16 December NY Times report that a major determinant of skin color is a single gene which has been located
reportedly 99 pecent of European caucasians have one allele, one...
There are some hints of this with insiders claiming that two camps have formed within the WH: One supporting Libby and the other supporting Rove. This comes from the CNN WH reporter today. The title of this thread is something that struck me as possible when there were reported flurries of...
Okay I have one area with skin irritation...could somebody give advice on how to diminish/destroy the skin irritation? I've heard irritated skin on my hands before from for example washing my hands too much...but that's not a problem anymore...
anyways thanks
Steve Harris, M.D.
The above doctor's quote suggests that Cyanoacrylate adhesives (Super Glue, Krazy Glue) may be used to cover cuts. He suggests that it is non-toxic, but I am skeptical.
I heard of this before and wanted to recommend this to someone who cut their finger and plays a...
Ok, I'm drinking a whisky (a rather fine Islay blend too) and I'm increasingly noticing that the feeling in my upper lip is vanishing where the drink passes over it. I can only assume that I'm directly absorbing the alcohol through my skin, and the neurones in there are blind drunk. Am I right...
Do you know why people say, the white, the black, the yellow... ?
What about people who is not white, not yellow, not black ?
I know sunlight can burn ou skin to bright black. Why some people's heads are pink like just using some cosmetics ?
Thanks
What kind of foods, hygene (sp) habits, etc etc are good for the skin? What can I eat? A certain time to sleep? Sleep in general? Lotion? Prevention of the sun's UV? Any suggestions?
Is there a way that you can fix/tighten loose skin? Like if somebody had liposuction and as a result they had loose skin, or if somebody had a bump somewhere (like a hemmorhoid) and when it disappeared loose skin was left, could they fix it somehow? I mean, they can sort of fix wrinkles and...
Two cases:
1. A #12 solid copper wire is rated for 20a and a #12 stranded wire is rated
for 25a the reason given for greater ampacity is increased surface area
of the stranded wire called skin effect.
2. Does/is skin effect a consideration when current passes through a liquid or...
This is sort of an unusual question (and I'm not even sure this is the right forum for it) but here goes. I'm doing a project where theoretically a human would be kept immersed in a liquid for long periods of time and I'm wondering what liquid would be the best for this. The most obvious...