Small intestine : It is the longest part of alimentary canal which measures between 4.5 to 7 m in length. The term small intestine is used because this part of the alimentary canal has narrowest diameter. Small intestine lies coiled in the abdomen. Internally, it possess two types of ingrowths circular folds and villi. Circular folds are also called plicae circulares. They slow down the movement of food through the intestine. Consequently, the food remains for longer time in the small intestine for digestion and absorption.
Large Intestine: It is the hindermost part of alimentary canal which opens to the outside through the anus. The larger intestine is called large because it has a wider diameter(4-6 cm) as compared to small intestine(3.5-4.5 cm). The length of large intestine is about 1.5 m. It has 4 regions: caecum, colon, rectum and anal canal.
|It is quite long, 4.5 - 7.0 m.||It is comparatively shorter, 1.5 m|
|It is narrow, 3.5-4.5 cm in width.||It is comparatively broader, 4-6 cm in diameter.|
|Small intestine. has three parts: duodenum, jejunum and ileum.||It has four parts: caecum, colon, rectum and anal canal.|
|Internal surfaces has circular folds or plicae circulares.||Circular folds are absent.|
|Villi are present.||Villi are absent.|
|Peyer’s patches are present in a part of small intestine.||Peyer’s patches are absent.|
|The surface does not contain longitudinal bands called taeniae coli.||Taeniae coli are present|
|Haustra are absent.||Haustra are present.|
|It does not contain epiploic appendages.||Epiploic appendages are present.|
|Digestion is complicated in small intestine.||It has no role in digestion.|
|It secrets a number of hormones.||Hormone secretion is absent.|
|It absorbs the digested nutrients.||It takes part in absorption of water from the indigestible residue.|
|It shows small movements in the abdominal activity.||It is largely fixed. Mobility is little.|