Human Digestive System Processes

Mechanical and Chemical Digestion

• Food breakdown occurs through two primary processes: mechanical and chemical processing.
• Mechanical processing: Involves chewing in the mouth and peristaltic contractions that break food into smaller pieces for easier digestion.
• Chemical processing: Uses enzymes found in saliva, the stomach, and intestines to reduce food into even smaller parts.

Roles of Accessory Organs

• Liver: Responsible for producing bile, which is essential for digesting fats.
• Gallbladder: Acts as a storage site for bile until the body requires it for digestion.
• Pancreas: Releases specific enzymes into the small intestine to target different food groups:
  • $\text{amylase}$: Breaks down carbohydrates.
  • $\text{lipase}$: Breaks down fats.
  • $\text{protease}$: Breaks down proteins.

Nutrient Absorption

• Absorption takes place in the small intestine, where food is reduced to nutrients needed for energy and health.
• Villi: Tiny finger-like structures along the intestinal walls that absorb nutrients and transport them into the bloodstream for distribution throughout the body.

Waste Elimination

• The large intestine is responsible for absorbing water from the leftover food material.
• Residual waste moves through the large intestine and is eliminated from the body via the anus.