Digestive System Overview

Introduction

• Human body is made up of trillions of cells.
• Food provides nutrients, fuels cells, builds new tissues, repairs damaged tissues, and sustains chemical reactions.
• Digestion is a journey from mouth to anus.
• Digestive tract is one long tube.

Anatomy of the Digestive System

Segments

• Esophagus: Starts as a tube, leading to...
• Stomach: Enlarges from the esophagus, involved in digestion.
• Small Intestine: Comprises duodenum, jejunum, ileum.
  • Not small in length, but in diameter.
  • Increases surface area for absorption by coiling.
• Large Intestine: Follows the small intestine, has specific regions.

Digestion vs Absorption

• Digestion: Breakdown of food into smaller molecules.
• Absorption: Uptake of these molecules into the bloodstream.
• Inside of the digestive tract is technically not "inside" the body.

Process of Digestion

Mouth

• Digestion begins in the mouth.
• Mastication: Chewing, initiates mechanical digestion.
• Saliva: Begins chemical digestion.

Esophagus

• Transports food from mouth to stomach.

Stomach

• Primarily responsible for digestion.
  • Chemical Digestion: Stomach acid denatures proteins.
  • Mechanical Digestion: Muscular movements blend food.
• Converts food into chyme.

Small Intestine

• Duodenum: Continues digestion, starts absorption.
• Jejunum & Ileum: Major absorption sites.
  • Folds and microvilli increase surface area.
  • Absorbs nutrients into bloodstream.

Large Intestine

• Comprises cecum, colon, rectum.
• Function: Absorbs water and salts, stores waste.
• Appendix: Small, can become inflamed (appendicitis).

Digestive System Functions

Digestion

• Enzymes break down carbohydrates, proteins, and fats.

Absorption

• Nutrients absorbed through intestinal walls into the bloodstream.

Waste Elimination

• Collects non-absorbable waste for elimination.
• Involuntary smooth muscle movements push waste through.

Other Highlights

Diseases & Disorders

• Appendicitis: Infection of the appendix can lead to rupture.
• Type 2 Diabetes: Metabolic disorder where cells become insensitive to insulin.

Lifestyle Implications

• Exercise can help manage and improve metabolic conditions like diabetes.
• Importance of hydration and fiber for digestive health.

Conclusion

• The digestive system is crucial for breaking down food and absorbing nutrients.
• Understanding its function helps in recognizing health issues and maintaining well-being.