The digestive system is made up of thealimentary canal and the other abdominal organs that play a part in digestion, such as the liver and pancreas. The alimentary canal (also called thedigestive tract/ gut) is the long tube of organs - including the esophagus, stomach, and intestines - that runs from the mouth to the anus. An adult's digestive tract is about 30 feet (about 9 meters) long.
Digestive System’s main purpose is to break down, or digest, the food we eat. The food is a combination of carbohydrates, proteins and fats. Hence, every morsel of food eaten has to be broken down into nutrients that can be absorbed by the body. In humans, protein must be broken down into amino acids, starches into simple sugars, and fats into fatty acids and glycerol.
Digestion generally involves two phases: a mechanical phase and a chemical phase. In the mechanical phase, teeth or other structures physically break down large pieces of food into smaller pieces. In the chemical phase, digestive chemicals called enzymes break apart individual molecules of food to yield molecules that can be absorbed and distributed throughout the body. These enzymes are secreted (produced and released) by glands in the body.
Digestion begins in the mouth,where both mechanical and chemical digestion occurs. tear and chop the food increasing the surface area for enzyme action and saliva moistens it for easy swallowing. A digestive enzyme called amylaseis found in saliva,which hydrolysissome of the carbohydrates (starches and sugars) to maltose, before it leaves the mouth. Saliva also contains mineral salts (e.g. sodium hydrogen carbonate) that help to maintain a pH of around 6.5-7.5 which is the optimum for the action of salivary amylase............
