Question

Name any three glands associated with digestion in humans.Write the names of enzymes secreted by them.

Answer 1

Hint: The glands which secrete digestive juices for the digestion of food are called associated glands. They are:- salivary glands, gastric glands, liver, pancreas etc.

Complete answer:
Salivary glands look like clusters of grapes.The function of salivary gland is to secrete saliva.The salivary gland secretion is very rich in salivary amylase, a starch splitting enzyme. About 99.5% of saliva is water.It contains two important enzymes, amylase and lysozyme. Amylase is a starch digesting enzyme which breaks starch into maltose and triose. Lysozyme causes lysis of several common bacteria that may be present in the mouth. Mucin in saliva helps to lubricate the food for swallowing. The saliva helps to wash out bacteria of the mouth, aids in speech.

Pancreas is a gland partly exocrine and partly endocrine, but the main bulk is constituted by the exocrine part. The exocrine pancreas secretes enzymes that play a very important role in the digestion of carbohydrates, proteins and fats. The endocrine part of the pancreas is in the form of numerous rounded collections of cells. These collections of cells are called Islets of langerhans. They can be distinguished as three main types:
I.The alpha cells secrete the hormone glucagon.
II.Beta cells secrete the hormone insulin which breakdowns glucose.
III.Delta cells secrete hormones gastrin and somatostatin.

Intestinal glands:They are present in the mucosa of the small intestine and are of two types:
I. Crypts of Lieberkuhn: These are simple tubular glands, opening into the lumen of the small intestine. They are lined by the columnar epithelial cells, and contain some mucus secreting goblet cells. The juice produced by these glands is known as succus entericus. It is a thin watery juice containing various enzymes like enterokinase etc..
II. Brunners glands: These are compound tubular glands which are found only in the submucosa of the duodenum and open in the spaces in between the villi. These glands secrete alkaline mucus rich juice.

Note: Liver and gastric glands also play an important role in digestion as they secrete important gastric juices. Pancreas secrete pancreatic amylase, pancreatic protease and liver secretes bile juice.