Skin Definition and 157 Threads

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.

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  1. J

    Michael Jackson's Skin Explained

    How did Michael Jackson's skin on his entire body get so pale? What sort of procedure can one do to change one's skin color? Also, has anyone seen Michael Jackon's children? They're also quite pale. Did they get this procedure done as well?
  2. D

    Why do people have different skin colors ?

    Why do people have different skin colors ? Can we change the black into the white ? Thankyou
  3. wasteofo2

    When exposed to the sun, why does your skin darken but your hair lighten?

    I know that when your skin is exposed to a lot of sunlight it turns darker in order to try to absorb some of the light's energy, which can help avoid burns, but why does your hair become blonde?
  4. wasteofo2

    Are antibiotics harmful to human skin cells?

    Just curious if antibiotics you might put on a band-aid over a wound that risks infection could kill/harm the skin cells around it.
  5. D

    Old scar still be there after it heals or will ur skin be new again?

    say u fall off ur bike or something, and cut ur arm, and while the cut is healing, u keep picking the scabs, and thus leaving a scar ok after the scar is there, say u fall down off your bike again, and on the same spot where this scar is, and this time u don't pick the scabs, will the old...
  6. P

    Can water or alcohol be absorbed through the skin with osmosis?

    Can water or alcohol be absorbed through the skin with osmosis? More importantly can it be absorbed into the bloodstream? I know some chemicals can be, what characteristics allow those chemicals to do that? Pan
  7. Nim

    Types of Skin Nerves: 8 Sensory Nerves & CT Network

    How many different kinds of sensory nerves are there present in our skin? I've heard of touch-lightly, touch-pressure, vibration, heat, cold, pain, itch, and tickle. Not to long ago I think a nerve for cuddling was found. Something called the CT Network. Also, are there any official names for...
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