Digestive System Overview

Overview

• The digestive system is a complex network of organs working together to break down food into absorbable nutrients.
• It's a long, muscular tube that runs from the mouth to the anus.
• Its primary functions are ingestion, digestion, absorption, and elimination.

Ingestion

• The process of taking food into the body.
• Begins in the mouth with chewing and swallowing.
• Mechanical breakdown of food occurs through chewing.
• Salivary enzymes begin chemical digestion.

Digestion

• The process of breaking down large food molecules into smaller, absorbable units.
• Mechanical digestion involves physical breakdown (e.g., chewing, churning).
• Chemical digestion involves enzymes breaking down food into simpler compounds (carbohydrates, proteins, fats).

Absorption

• The process of absorbing the digested nutrients into the bloodstream.
• Takes place primarily in the small intestine.
• Villi and microvilli increase the surface area for absorption.
• Nutrients are transported to various parts of the body for use.

Elimination

• The process of removing undigested food and waste products from the body.
• Occurs in the large intestine.
• Water is reabsorbed.
• Solid waste (feces) is compacted and eliminated through the anus.

Organs of the Digestive System

• Mouth: Ingestion and initial digestion.
• Esophagus: Transports food from the mouth to the stomach.
• Stomach: Stores food, mixes with gastric juices, and continues mechanical and chemical digestion.
• Small intestine: Major site for nutrient absorption.
• Large intestine (colon): Absorbs water and electrolytes, forms feces.
• Rectum: Stores feces.
• Anus: Eliminates feces.

Accessory Organs

• Liver: Produces bile, crucial for fat digestion.
• Gallbladder: Stores and concentrates bile.
• Pancreas: Produces digestive enzymes for the small intestine.

Key Processes

• Peristalsis: Rhythmic muscle contractions that move food through the digestive tract.
• Segmentation: Mixing contractions in the small intestine that further breaks down food.
• Chemical digestion depends on specific enzymes tailored to each type of nutrient.
• Enzymes and other secretions produced by different glands and organs are critical to the digestion process.

Digestive Disorders

• Heartburn: Acid reflux from the stomach.
• Gastritis: Inflammation of the stomach lining.
• Ulcers: Sores in the lining of the stomach or duodenum.
• Irritable bowel syndrome (IBS): A common disorder affecting the large intestine.
• Inflammatory bowel disease (IBD): Chronic inflammation of the digestive tract.
• Celiac disease: Immune response to gluten.

Healthy Digestive Habits

• Eating a balanced diet.
• Maintaining a healthy weight.
• Exercising regularly.
• Avoiding excessive stress.
• Getting enough sleep.