Answer: A digestive system can be defined as a system which is made up of the alimentary canal and the associated glands and organs which produce some of the enzyme- rich secretions that bring about digestion. The process of digestion of food Hanan are, is discussed below.
Step-by-step explanation:
The food taken by Hanan consist of carbohydrates (rice, potatoes ), protein( fish, dal) , fats and oil( fish, fried potatoes). The digestion of the food taken passess through a long tube ( alimentary canal) which stretches from the mouth through oesophagus to stomach, intestines and down to the anus.
In the MOUTH, the following occurs:
--> The food is cut and grinded into smaller pieces by the help of the teeth.
--> the enzyme ptyalin acts on the carbohydrate part of the food converting it to complex sugar.
--> the food is mixed with saliva, with the help of the tongue, is rolled into a bolus which is then swallowed.
At the STOMACH, food enters through the peristaltic movements of the oesophagus, The following occurs:
--> The muscular walls of the stomach contract and relax forcefully, thus churning the food.
--> Gastric juice( consists of pepsin, renin and dilute hydrochloric acid). Dilute hydrochloric acid activates pepsinogen to pepsin which digests proteins to polypeptides.
--> Food remains in the stomach for three to four hours. By this time, it is a thick, creamy fluid called chyme which them moves to the duodenum (small intestine).
At the SMALL INTESTINE, digestion occurs at the first part called the duodenum, and later part called the ILEUM.
--> Several substances are secreted into the duodenum from the pancreas( pancreatic juice) and liver( bile), the accessory organs of digestion.
--> pancreatic juice contains three important enzymes whose activities include:
• Amylopsin: Breaks down complex sugar to maltose
• Trypsin: breaks down protein into peptides
• Lipase: Breaks down fat into carboxylic acids and glycerol (end product of digestion of fat).
--> Bile from the liver, adds water to the chyme, emulsifies fat and neutralise the action of dilute hydrochloric.
At the ILEUM, intestinal juice is produced by special cells of the small intestine. Their actions include:
• maltase: this acts on maltose converting it to glucose( which is the end product of carbohydrate digestion).
• erepsin: This acts on peptides converting it to amino acids( which is the end product of protein digestion).
Absorption takes place at the small intestine.