Digestive System Process

Mouth and Esophagus

• Mouth:
  • Mechanical digestion: teeth chew food into smaller pieces
  • Chemical digestion: salivary enzymes (amylase, lipase) break down carbohydrates and fats
  • Mixing of food with saliva forms a bolus
• Esophagus:
  • Muscular tube that uses peristalsis to transport bolus to stomach
  • Food passage takes around 7-10 seconds

Small Intestine Function

• Primary site of nutrient absorption:
  • Walls lined with finger-like projections (villi) for increased surface area
  • Nutrients absorbed into bloodstream and transported to liver for processing
• Enzymes and digestive processes:
  • Pancreatic juices and bile salts break down carbohydrates, proteins, and fats
  • Lactase, sucrase, and maltase break down lactose, sucrose, and maltose

Large Intestine Process

• Water absorption and electrolyte regulation:
  • Water reabsorption from indigestible material
  • Electrolyte regulation for maintaining hydration and pH balance
• Feces formation:
  • Remaining waste material forms feces
  • Feces stored in rectum until elimination through anus

Liver and Pancreas Roles

• Liver:
  • Detoxification: removes toxins from bloodstream
  • Metabolism regulation: regulates glucose, fat, and protein metabolism
  • Production of bile salts for fat emulsification
• Pancreas:
  • Exocrine function: produces digestive enzymes for small intestine
  • Endocrine function: produces hormones (insulin, glucagon) for glucose regulation

Stomach Anatomy

• Layers:
  • Mucosa: innermost layer with rugae (folds) for increased surface area
  • Submucosa: connective tissue layer
  • Muscularis: smooth muscle layer for mixing and churning
• Gastric glands:
  • Produce gastric juices containing pepsin and hydrochloric acid
  • Pepsin breaks down proteins into peptides and amino acids