19,994
edits
Changes
no edit summary
==Key Stage 3==
[[File:KidneyClipart.png|right|300px200px|thumb|A drawing of a [[kidney]].]]
===Meaning===
[[Kidney]]s are [[organ]]s in the [[Excretory System|excretory system]] that removes [[urea]] and excess [[water]] from the [[blood]].
==Key Stage 4==
[[File:KidneyDiagramKS4.png|right|300px|thumb|A [[diagram]] of a [[kidney]] showing the [[nephron]]s.]]
===Meaning===
[[Kidney]]s are [[organ]]s in the [[Excretory System|excretory system]] that removes [[urea]] and excess [[water]] from the [[blood]].
===About the Kidneys===
: The [[kidney]]s are responsible for [[osmoregulation]] as well as the removal of [[urea]] from the [[blood]].
: As [[blood]] passes through the [[kidney]]s [[water]], [[urea]], [[glucose]] and [[salt]]s [[Diffusion|diffuse]] into the kidney tubules. [[Glucose]] is completely reabsorbed into the [[blood]] while [[water]] is selectively reabsorbed depending on the [[water]] [[concentration]] in the [[blood]].
: The selective re-absorption of [[water]] is affected by [[Anti-diuretic Hormone|anti-diuretic hormone]]. When the levels of [[Anti-diuretic Hormone|anti-diuretic hormone]] are high most of the [[water]] is reabsorbed into the [[blood]]. When the levels of [[Anti-diuretic Hormone|anti-diuretic hormone]] are low the [[water]] is not re-absorbed and is passed down the [[ureter]]s to the [[bladder]].