By: Bob Woolmer
Posted: 2010-07-05 08:22:53
DEFINITION:The processes in which complex food that contains carbohydrates, protein and fat is converted into simple food particles by the action of certain chemicals so that it can be used by the body to perform various functions.WHY DIGESTION IS NECESSARY?When food is taken, it is not in a form that can be used by the body to perform proper functions so first it must be changed into smaller food molecules before entering in the blood through absorption. The blood then carried it to all parts of the body so that body can use it to build and nourish cells and for the production of energy.COMPARTMENTS OF DIGESTIVE SYSTEM:The digestion is taken place in a long and hollow tube that is packed from mouth to the end, this tube is called as gastrointestinal tract or alimentary canal. It includes mouth, pharynx, esophagus, stomach, small intestine, and large intestine. In the mouth tongue and teeth present that is used for the mechanical breakdown of food. The salivary glands, liver, gallbladder, and pancreas are major accessory organs that play an important role in the digestion.
Figure: organs/components of digestive system.STAGES OF DIGESTIVE SYSTEM:Foods that take mostly consist of carbohydrates, protein and fat which are in form of larger molecules so they must be broken down in smaller molecules. This involves following stages;
1. MOVEMENT: Propulsion of food from one part to another part of the digestive tract.
2. SECRECTION: Release of digestive juices that contain chemicals necessary in the process of digestion.
3. DIGESTION: Break down of food in smaller units that can easily be entered in the cells.
4. ABSORPTION: Passage of smaller food particles into the blood that carried them throughout the body parts.
5. ELIMINATION: Removal of unwanted substances in form of waste.
Three stages that is digestion, absorption and elimination are collectively refers as proper digestion.DIGESTION:Basically digestion is of two types;
• MECHANICAL DIGESTION: In mouth teeth grind the food in smaller particles that can be acted upon by the chemicals. This breaking also takes place in the stomach through its muscles.
• CHEMICAL DIGESTION: In this components of food are acted upon by certain chemicals that change them into further smaller particles. These chemicals increase the rate of chemical reaction.DIGESTIVE JUICES:In the mouth break down of carbohydrate takes place by the action of first releasing chemical from the salivary gland while in the stomach break down of protein takes place by the action of other secretion called gastric juice that is released by the stomach gland. After stomach broken food enters in the small intestine, where final break down of food occurs in the presence of certain chemicals that are released by the pancreas called as pancreatic secretion and liver that are the accessory organs as well as from the wall of intestine. The liver produces another juice called bile that dissolves the fats into small droplets, after that secretion from the pancreas and intestine break it further.ABSORPTION:When all the nutrients mainly carbohydrates, protein and fat are digested they finally enter in the blood by the process of absorption. In this process all components of food converted in such a form that they can easily be utilized by the body.ELIMINATION:It is the final stage in which food particles that can not be digested or absorbed must be removed from the body because if not eliminated they can produce harmful effects on the body.REFERENCES:
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