Digestive System

• Functions of the Digestive System

  • Ingestion
  • Movement of food
  • Digestion
  • Absorption
  • Defecation
• Parts of the Digestive System

  • Mouth
  • Pharynx
  • Oesophagus
  • Stomach
  • Small intestine
  • Large intestine
  • Rectum
  • Anus
• Mouth


  • Chewing, mixing food with saliva, swallowing
• Teeth


  • Mastication (chewing)
• Salivary Glands


  • Produce saliva containing amylase to break down starches
• Pharynx


  • Passage for food from mouth to esophagus
• Esophagus


  • Transports food to the stomach via peristalsis
• Stomach


  • Mixes food with gastric juices; begins protein digestion
• Regions of the Stomach

  • Cardiac
  • Fundus
  • Body
  • Pyloric
• Cells in the Stomach

  • Mucus Cells
  • Parietal Cells
  • Chief Cells
  • G-Cells
• Pancreas


  • Secretes digestive enzymes and bicarbonate to neutralize stomach acid
• Enzymes secreted by the Pancreas

  • Amylase
  • Lipase
  • Trypsin
  • Chymotrypsin
  • Carboxypeptidase
  • Nucleases
• Liver


  • Produces bile, processes nutrients, detoxifies blood
• Functions of the Liver

  • Glycogen storage
  • Metabolism of fats and proteins
  • Detoxification
• Gallbladder


  • Stores and concentrates bile for fat digestion
• Small Intestine


  • Major site of digestion and nutrient absorption
• Parts of the Small Intestine

  • Duodenum
  • Jejunum
  • Ileum
• Enzymes in the Small Intestine


  • Peptidase
  • Sucrase
  • Maltase
  • Lactase
  • Lipase
• Large Intestine


  • Absorbs water and electrolytes, forms feces
• Parts of the Large Intestine


  • Caecum
  • Appendix
  • Ascending colon
  • Transverse colon
  • Descending colon
  • Sigmoid colon
• Functions of the Large Intestine


  • Houses gut flora, secretes mucus, defecation
• Digestion and Absorption in the Mouth

  1. Mastication

  2. Saliva mixing

  3. Starch breakdown by amylase
• Digestion and Absorption in the Stomach

  1. Gastric Secretions: Pepsinogen, HCl, mucus, intrinsic factor

  2. Phases: Cephalic, Gastric, Intestinal
• Digestion and Absorption in the Small Intestine

  1. Secretions: Peptidase, sucrase, maltase, lactase, lipase, enterokinase, somatostatin, cholecystokinin, secretin

  2. Absorption: Through villi for monosaccharides, amino acids, fatty acids, glycerol, electrolytes, and water
• Disorders and Diseases


  • Gastritis
  • Peptic Ulcer Disease
  • Ulcerative Colitis
  • Crohn's Disease
  • Hepatitis
• Gastritis

  Inflammation of the stomach lining
• Risk Factors for Gastritis

  • NSAIDs
  • Corticosteroids
  • Alcohol
  • Major surgery
  • Kidney/liver failure
• Peptic Ulcer Disease


  Ulcers in the stomach or duodenum
• Causes of Peptic Ulcer Disease


  • H. Pylori
  • NSAIDs
  • Stress
  • Smoking
  • Alcohol
  • Genetics
• Ulcerative Colitis


  Affects entire large intestine
• Crohn's Disease


  Can affect any part of the digestive tract
• Hepatitis


  Inflammation of the liver, often viral
• Types of Hepatitis


  • Hepatitis A
  • Hepatitis B
  • Hepatitis C
  • Hepatitis D
  • Hepatitis E
  • Hepatitis F
  • Hepatitis G
• Symptoms of Hepatitis


  • Headache
  • Low fever
  • Fatigue
  • Vomiting
  • Rash
  • Foamy urine
  • Pale feces
  • Jaundice
  • Pain