Stages of Digestion Four Stages of Digestion Ingesting
- Slides: 8
Stages of Digestion
Four Stages of Digestion • • Ingesting Digesting Absorbing Eliminating
Stage 1: Ingesting • The starting point of the digestion process.
Stage 2: Digesting • Mouth: Mechanical and Chemical digestion begins. • Mechanical digestion is the chewing and breaking food down into smaller pieces • Each small piece of food is a bolus • Saliva lubricates the food, and contains an enzyme, called amylase. • Chemical digestion occurs when amylase begins to break down complex carbohydrates.
• Esophagus: as food passes through the pharynx, the epiglottis covers the airway tube. • The food moves on to the esophagus. • The esophagus is a tube that connects the pharynx and the stomach.
• The esophagus is long and muscular • The bolus is pushed through the esophagus in a process called peristalsis.
Stomach • Your stomach is like a stretchable muscular bag. • Inside the stomach is gastric juice, which is very acidic. • The stomach walls are lined with mucus, that protects the tissue. • Pepsin is an enzyme which breaks down protein, and needs an acidic environment. • The bolus breaks down into a liquid called chyme.
Small Intestine • Once the chyme leaves the stomach, it empties into the small intestine. • The first metre is called the duodenum. Digestion is complete after foods leaves. • Within the first 30 cm are ducts that connect to other organs. • Pancreas: produces enzymes • Liver: produces bile.
