THORAX ABDOMEN AND PELVIS

Detailed explanation-1: -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-2: -Only about five percent of starches are broken down in the mouth. (This is a good thing as more glucose in the mouth would lead to more tooth decay.) When carbohydrates reach the stomach no further chemical breakdown occurs because the amylase enzyme does not function in the acidic conditions of the stomach.

Detailed explanation-3: -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.

Detailed explanation-4: -The teeth aid in mechanical digestion by masticating (chewing) food. Mastication permits easier deglutition (swallowing) and faster chemical breakdown in the digestive tract. During mastication, salivary glands secrete saliva to soften the food into a bolus (semi-solid lump).