An ==Key Stage 2=====Meaning===The '''small intestine''' is part of the [[Digestive System|digestive system]]. ==Key Stage 3=====Meaning===[[File:SmallIntestine.png|right|300px|thumb|A computer generated image showing the [[Small Intestine|small intestine]], [[Large Intestine|large intestine]], [[rectum]] and [[anus]].]]The '''small intestine''' is an [[organ]] in the [[Digestive System|digestive system]] which [[Absorb(Biology)|absorbs]] [[Nutrient|nutrients]] into the [[blood]] and . ===Adaptations of The Small Intestine===: The '''small intestine''' is a very long tube to give a large surface area to [[Absorb (Biology)|absorb]] [[nutrient]]s.: There is part around 1kg of [[Bacteria in Digestion|bacteria]] inside the '''small intestine''' which helps [[digestion|digest]] the food.: There are [[Digestive Enzyme|digestive enzyme]]s in the '''small intestine''' which break down large [[molecule]]s into smaller [[molecule]]s.: Only small [[molecule]]s can be [[Absorb (Biology)|absorb]]ed into the blood through the wall of the '''small intestine'''. ==Key Stage 4=====Meaning===The '''small intestine''' is an [[organ]] in the [[Digestive System|digestive system]] which [[Absorb (Biology)|absorbs]] [[Nutrient|nutrients]] into the [[blood]]. ===About The Small Intestine===: The [[Small Intestine]] is where food is broken down by [[Digestive Enzyme|digestive enzymes]] including [[amylase]], [[protease]] and [[lipase]] before being [[Absorb (Biology)|absorbed]] into the [[blood]].: The [[Small Intestine]] produces some of its own [[Digestive Enzyme|digestive enzymes]] including [[amylase]] and [[peptidase]] but also takes some [[Digestive Enzyme|digestive enzymes]] from the [[pancreas]] including [[Pancreatic Amylase|pancreatic amylase]], [[trypsin]] and [[lipase]].: The [[Small Intestine]] is long and folded to increase the [[Surface Area|surface area]].: The [[Small Intestine]] has structures called [[Villi]] which are extra folds in the surface to increase the [[Surface Area|surface area]].: The [[blood]] supply to the [[villi]] in the [[Small Intestine]] is very good in order to constantly supply enough fresh [[blood]] with few [[nutrients]] keeping a high [[Concentration Gradient|concentration gradient]] between the food and the [[blood]].: There is around 1kg of [[Bacteria in Digestion|bacteria]] inside the '''small intestine''' which helps [[digestion|digest]] the food.: Only small [[molecule]]s can be [[Absorb (Biology)|absorb]]ed into the [[blood]] through the wall of the '''small intestine'''. ===References=======AQA==== :[https://www.amazon.co.uk/gp/product/1782945563/ref=as_li_tl?ie=UTF8&camp=1634&creative=6738&creativeASIN=1782945563&linkCode=as2&tag=nrjc-21&linkId=9a1d023a374038e6072f33c4f3cf808b ''Small intestine, page 31, GCSE Biology; The Revision Guide, CGP, AQA '']:[https://www.amazon.co.uk/gp/product/1471851354/ref=as_li_tl?ie=UTF8&camp=1634&creative=6738&creativeASIN=1471851354&linkCode=as2&tag=nrjc-21&linkId=9012a0d354024419214fb3ad5ac44ba0 ''Small intestine, page 45, GCSE Combined Science Trilogy 1, Hodder, 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=27ad53b0283feeff7fc5ae04a9e205f512 ''Small intestine, pages 93, 100-1, 103, GCSE Biology; Student Book, Collins, 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 ''Small intestine, pages 59, 63, 73, Gateway GCSE Biology, Oxford, OCR '']