Digestion Quiz: Mechanics and Processes

Digestion

• Digestion breaks down food into smaller molecules the body can absorb and use.
• There are two types of digestion: mechanical and chemical.
• Mechanical Digestion physically breaks down food into smaller pieces.
  • Examples: chewing, mashing, grinding food with teeth and tongue.
• Chemical Digestion involves chemical reactions that break down food into smaller molecules.

The Mouth

• Mechanical digestion starts in the mouth.
• Muscles in the jaw chew food.
• Saliva breaks down carbohydrates and neutralizes acidic foods before chewing.

The Esophagus

• After swallowing, food enters the esophagus.
• The esophagus connects the mouth to the stomach.
• It's a muscular tube and food moves through via muscle contractions called peristalsis.

Peristalsis

• Peristalsis means squeezing a tube of toothpaste with muscles.
• The muscles in the esophagus contract and relax, moving partially digested food down the esophagus and into the stomach.

The Stomach

• Partially digested food goes from the esophagus to the stomach.
• The stomach is a large, hollow organ that stores food temporarily and aids in chemical digestion.
• Gastric juice, an acidic fluid in the stomach, helps break down plant and animal cell structures.

The Small Intestine

• The small intestine is a long tube attached to the stomach.
• Most chemical digestion occurs here.
• Nutrient absorption also occurs in the small intestine.
• The folds of the small intestine are covered with villi.
• Each villus contains small blood vessels – nutrients enter the bloodstream through these vessels.

The Large Intestine

• Most water from food and liquid is absorbed in the small intestine.
• More water is absorbed in the large intestine.
• Waste products of digestion pass through the large intestine.
• Excess water is absorbed, creating more solid waste.
• Semisolid waste is eliminated from the body.