Large intestine

This a short tube of a wider diameter than the small intestine. Each part has a similar structure to that of the small intestine. However, in the lumen, there arc no villi and no digestive glands, but there are more goblet cells.

Caecum - a short, blind-ending lube joining the ileum al its junction with the ascending colon: this is the Ueocaecal junction (Fig. 9.2). In the carnivore it has no significant function.

Colon - divided into the ascending. transverse and descending colon (Fig. 9.1) according to the relative position in the peritoneal cavity, but all are a continuation of the same organ. Thedescending colon is held close to the dorsal body wall by the

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mesocolon. Within Ihecolon waler, vitamins and electrolytes are absorbed ensuring that the bsegmentation.

■ Digestion occurs by the action of enzymes, each of which is specific to a particular food type.

■ Digestive juices containing enzymes are secreted by intrinsic exocrine glands in the stomach and small intestine and by extrinsic glands such as the pancreas and gall bladder.

■ Digestion results in the production of soluble molecules that can pass through the epithelium of the small intestine into the blood capillaries (amino acids and monosaccharides) or Iacteals (fatty acids and glycerol).

■ The products of digestion are carried around the body where they are metabolised and used by the tissues.

■ Any unwanted or indigestible food remains are excreted in the faeces.