DIGESTIONBy

Mahammad javed

rafiq

INTRODUCTION

                                                                                  

Digestion is the breakdown of large insoluble food molecules into small water-soluble food molecules so that they can be absorbed into the watery blood plasma. In certain organisms, these smaller substances are absorbed through the small intestine into the blood stream. Digestion is a form of catabolism that is often divided into two processes based on how food is broken down: mechanical and chemical digestionThe term mechanical digestion refers to the physical breakdown of large pieces of food into smaller pieces which can subsequently be accessed by digestive enzymes. In chemical digestion, enzymes break down food into the small molecules the body can use.

HUMAN DIGESTIVE SYSTEM

PROJECT

EXPLANATIONIn the human digestive system, food enters the mouth and mechanical digestion of the food starts by the action of mastication (chewing), a form of mechanical digestion, and the wetting contact of saliva. Saliva, a liquid secreted by the salivary glands, contains salivary amylase, an enzyme which starts the digestion of starch in the food; the saliva also contains mucus, which lubricates the food, and hydrogen carbonate, which provides the ideal conditions of pH (alkaline) for amylase to work. After undergoing mastication and starch digestion, the food will be in the form of a small, round slurry mass called a bolus. It will then travel down the esophagus and into the stomach by the action of peristalsis. Gastric juice in the stomach starts protein digestion. Gastric juice mainly contains hydrochloric acid and pepsin. As these two chemicals may damage the stomach wall, mucus is secreted by the stomach, providing a slimy layer that acts as a shield against the damaging effects of the chemicals. At the same time protein digestion is occurring, mechanical mixing occurs by peristalsis, which is waves of muscular contractions that move along the stomach wall. This allows the mass of food to further mix with the digestive enzymes.

DIGESTION IN STOMACH

The stomach is a muscular sac that lies between the esophagus and the small intestine in the upper abdomen. The stomach is not the only part of your digestive system that absorbs food but rather is a part of the digestive system and important for churning food into a consistency that is easier to digest for the rest of your intestines.

FUNCTION OF THE STOMACH The stomach is J-shaped and it can expand to temporarily store food. Partial digestion of the food takes place here. The churning action of the stomach muscles physically breaks down the food. The stomach releases acids and enzymes for the chemical breakdown of food. The enzyme pepsin is responsible for protein breakdown. The stomach releases food into the small intestine in a controlled and regulated manner.

LAPAROSCOPIC VIEW OF THE STOMACH

Comparative study about digestion

We can differentiate human digestive system with other animals. Some differences are given below.

Difference between human and rat digestive system

Humans have major differences in the structure of the digestive system with other animals, for example, a rat. A rat digestive system has 2 major differences with that of a human. First, rats do not have a gallbladder. This is because they rarely take in large amount of fatty foods, thereby, making a gallbladder useless. Furthermore, rats have an enlarged large intestine, namely, the cecum. This helps them ferment the grains and seeds they take in, through the help of the bacteria inside thus, breaking down cellulose into nutrients.

DIFFERENCE BETWEEN HUMAN AND FROG DIGESTIVE SYSTEM

Difference between pigeon and Baffallo digestive system

UNITS OF FOOD

The carbohydrate,protein,lipids and vitamins are the parts of food . They are also called the units of food . After digestion carbohydrates are converted into glucose,protein into amino acids,and lipids into fetty acid and glycerol.

Conclustion student should understand and learn the digestion

not only theoretically but practically also , students can do different practicals about digestion like digestion in frog. They can also understand the difference between digestive system through diagram.

student should be able to understand the comparative study of digestive system of different organisms through diagram .

Student should be able to deliver presentation in front of other students,parents,relative etc. Students can make the figures of digestive systems of different organism and then conclude the point about difference in them. Students can understand the difference between good and malnutrition through different charts, figures , theories etc.