Nutrition in Animals Notes

• Digestion begins in the mouth where food is cut and ground by teeth.
• This makes food easier to dissolve and provides a greater surface area for various fluids to act upon.

• The swallowed food passes into the foodpipe or oesophagus.
• The foodpipe runs along the neck and the chest.

Movement of food in alimentary canal

• The walls of the esophagus contain muscles (involuntary muscles) that contract in successive waves, a process called peristalsis.

• The stomach is a thick-walled bag. Its shape is like a flattened U.
• It is the widest part of the alimentary canal.
• The inner lining of the stomach secretes mucous, hydrochloric acid (HCl) and digestive juices.

• The acid kills many bacteria that enter along with the food and makes the medium in the stomach acidic.
• Once in the stomach, food gets churned into a paste-like material and is mixed with gastric juices.
• Eventually this is called chyme (semi-digested food).