An ==Key Stage 3=====Meaning===[[File:Skin.png|right|300px|thumb|A picture of human [[skin]] with some hairs.]]The [[skin]] is an [[organ]] covering the body. ==Key Stage 3=====Meaning===The [[skin]] is an [[organ]] covering the body used to protect [[Internal Organ|internal organs]] from [[External Conditionsinfection]]. ===About the Skin===: The [[skin]] has pigment called melanin that protects it from harsh sunlight.: The [[skin]] is the largest [[organ]] of the human body. ==Key Stage 4==[[File:SkinDiagram.png|right|300px|thumb|A [[diagram]] showing the features of the [[skin]] involved in [[thermoregulation]].]]===Meaning===The [[skin]] is an [[organ]] covering the body used to protect [[Internal Organ|internal organs]] from [[infection]]. ===About the Skin===: The [[skin]] has pigment called melanin that protects it from harsh sunlight.: The [[skin]] is the largest [[organ]] of the human body.: The [[skin]] is a physical barrier to prevent [[infection]] by [[pathogen]]s.: The [[skin]] is used in [[thermoregulation]].When the [[Body Temperature|body temperature]] is too high:*[[Sweat Gland|Sweat glands]] on the [[skin]] [[secrete]] [[sweat]] which [[evaporate]]s from the [[skin]] cooling it down.*[[Erector Muscle|Erector muscles]] relax allowing the body hairs to lie flat on the [[skin]].*[[Blood Vessel|Blood vessels]] near the surface of the [[skin]] [[Vasodilation|dilate]] to allow more of the warm [[blood]] to pass its [[Thermal Energy Store|thermal energy]] on to the [[skin]]. When the [[Body Temperature|external conditionsbody temperature]]is too low:*[[Sweat Gland|Sweat glands]] stop [[secrete|secreting]] [[sweat]] and the [[skin]] becomes dry.*[[Erector Muscle|Erector muscles]] contract causing body hairs to stand on end. This creates a pocket of trapped air under the hairs which insulates the body.*[[Blood Vessel|Blood vessels]] near the surface of the [[skin]] [[Vasoconstriction|constrict]] reducing [[blood]] flow close to the [[skin]] preventing [[Thermal Energy Store|thermal energy]] being lost to the [[skin]]. ===References=======AQA==== :[https://www.amazon.co.uk/gp/product/0198359373/ref=as_li_tl?ie=UTF8&camp=1634&creative=6738&creativeASIN=0198359373&linkCode=as2&tag=nrjc-21&linkId=952a73bbb09d222ecc4b50d200679849 ''Skin, page 90, GCSE Biology; Third Edition, Oxford University Press, AQA '']:[https://www.amazon.co.uk/gp/product/0008158754/ref=as_li_tl?ie=UTF8&camp=1634&creative=6738&creativeASIN=0008158754&linkCode=as2&tag=nrjc-21&linkId=27ad53b0283feeff7fc5ae04a9e205f511 ''Skin, pages 106-7, 148, 189, GCSE Biology; Student Book, Collins, AQA '']:[https://www.amazon.co.uk/gp/product/1471851338/ref=as_li_tl?ie=UTF8&camp=1634&creative=6738&creativeASIN=1471851338&linkCode=as2&tag=nrjc-21&linkId=425855d5890466e47189e1c21b67a1ea ''Skin, pages 85-6, GCSE Biology, Hodder, AQA ''] ====OCR====:[https://www.amazon.co.uk/gp/product/0198359810/ref=as_li_tl?ie=UTF8&camp=1634&creative=6738&creativeASIN=0198359810&linkCode=as2&tag=nrjc-21&linkId=d768d99f1a06f7c12fab40e5aef85a55 ''Skin, pages 222-223, Gateway GCSE Biology, Oxford, OCR ''] ==Beyond the Curriculum=={{#ev:youtube|https://www.youtube.com/watch?v=OxPlCkTKhzY}}