Digestive System Overview

General Statistics

• Humans consume between 1 and 2.7 kg of food daily.
• Annually, this adds up to 365 kg, and over a lifetime, more than 28,800 kg.

Digestive System Components

• Gastrointestinal Tract: A twisting channel with an internal surface area of 30-40 square meters.
• Pancreas, Gallbladder, and Liver: Organs producing juices to break down food.
• Enzymes, Hormones, Nerves, and Blood: Work together to modulate digestion and transport nutrients.
• Mesentery: Tissue supporting and positioning digestive organs.

Digestive Process

1. Preparation Stage

   • Anticipation of food stimulates saliva production (1.5 liters/day).
   • Saliva begins starch breakdown.

2. Mouth to Esophagus

   • Chewing and saliva form a bolus.
   • Bolus is transported via the esophagus through peristalsis.

3. Stomach

   • Muscular walls break the bolus into chunks.
   • Release of acids and enzymes begins protein breakdown.
   • Hormones signal pancreas, liver, and gallbladder to prepare for digestion.
   • After 3 hours, bolus becomes chyme.

4. Small Intestine

   • Duodenum: Bile dissolves fats, pancreatic and intestinal juices digest them.
   • Enzymes continue to break down proteins to amino acids and carbohydrates to glucose.
   • Jejunum and Ileum: Villi aid in nutrient absorption into the bloodstream.

5. Large Intestine (Colon)

   • Absorbs remaining fluids, forms stool.
   • Stool stored in the rectum until excretion.

Final Stage

• Stool exits the body through the anus.
• Digestion duration varies with food type.

Summary

• The digestive process involves a complex interaction of organs and biological substances to transform food into essential nutrients and energy.