AP BIOLOGY

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: -Saliva secreted by salivary glands aids the mechanical and chemical process of digestion. Saliva is about 99% water and not only moistens food but cleanses the mouth, dissolves food chemicals so they can be tasted, and contains enzymes that start the chemical breakdown of starchy foods.

Detailed explanation-3: -Most mechanical and some chemical digestion occur in the stomach. Mechanical digestion occurs as layers of muscle in the stomach lining contract to produce a mixing and churning motion. Chemical digestion is carried out by stomach juices that contain enzymes and hydrochloric acid.

Detailed explanation-4: -Mechanical digestion begins in your mouth with chewing, then moves to churning in the stomach and segmentation in the small intestine. Peristalsis is also part of mechanical digestion.

Detailed explanation-5: -Chemical digestion takes place throughout your digestive tract. Chemical digestion begins in your mouth with your saliva. The process continues in your stomach and is completed in your small intestine.