Large Intestine

Nutrition in animals of Class 7

Small intestine opens into large intestine from where the undigested food material is passed to anus through rectum.

large intestinedivided into three parts:

(i) Caecum

(ii) Colon

(iii) Rectum

The large intestine or colon leads into the rectum. The external opening of rectum is called anus which is kept closed by a ring of muscles called the anal sphincter. It opens only during defaecation.

Digestive Glands:

  • Salivary glands: 3 pairs of salivary glands are found in mouth cavity. It helps in chemical digestion. They secret an enzyme called salivary amylase or ptyalin. It helps in digestion of starch. These glands secrete saliva which performs two functions:

1. It moistens dry food and facilitates swallowing by a lubricating action. Since water evaporates slowly from saliva it prevents desiccation of the oral mucosa.

2. It provides an enzyme called salivary amylase or ptyalin for the digestion of starch.

  • Gastric glands: Present in stomach. They secrete hydrochloric acid, protein digesting enzymes and mucus.


It is the largest gland, secretes bile into the small intestine. Bile contains bile juice and bile pigments. Bile is alkaline in nature and it is temporarily stored in gall bladder and helps in digestion of fats, it also helps in absorption of fats.


It lies parallel to and below the stomach. It secretes pancreatic juice into small intestine. Pancreatic juice contains trypsin and pancreatic amylase. Besides these 2 enzymes pancreas secretes 2 hormones also i.e. insulin and glucagon so it has both exocrine as well as endocrine functions. Both bile and pancreatic juice are released into the duodenum by a common duct.

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