HUMAN NUTRITION

Detailed explanation-1: -Digestion in the tract is done through both physical and chemical digestion. Some type of digestion takes place in almost every part of the digestive tract, but the majority of digestion takes place in the mouth, stomach, and small intestines.

Detailed explanation-2: -Mechanical digestion in the oral cavity consists of grinding of food into smaller pieces by the teeth, a process called mastication. Chemical digestion in the mouth is minor but consists of salivary amylase (ptyalin, or alpha-amylase) and lingual lipase, both contained in the saliva.

Detailed explanation-3: -What changes occur in the mouth and stomach? Your teeth cut, tear, crush, and grind the food into small pieces. This is a physical change.

Detailed explanation-4: -When food is physically changed, mechanical digestion occurs. Food is broken into smaller parts and mixes continually with enzymes and other gastric juices. Mechanical digestion occurs in the mouth, stomach, and small intestine. Food is chemically changed in digestion when new, smaller substances are formed.

Detailed explanation-5: -Mouth. The digestive process starts in your mouth when you chew. Your salivary glands make saliva, a digestive juice, which moistens food so it moves more easily through your esophagus into your stomach. Saliva also has an enzyme that begins to break down starches in your food.