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Digestive System

Digestive System. Two K ey F unctions : Digestion - breaking down food into smaller molecules (nutrients). Absorbing these nutrients into the bloodstream. TYPES OF DIGESTION. MECHANICAL. CHEMICAL. Digestive System. Parts Mouth Pharynx Esophagus Stomach small intestine Liver

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Digestive System

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  1. Digestive System • Two Key Functions: • Digestion - breaking down food into smaller molecules (nutrients). • Absorbing these nutrients into the bloodstream

  2. TYPES OF DIGESTION MECHANICAL CHEMICAL

  3. Digestive System • Parts • Mouth • Pharynx • Esophagus • Stomach • small intestine • Liver • Gallbladder • Pancreas • large intestine • Rectum

  4. Mouth • Mechanical Digestion • Tongue and teeth work together to break down food mechanically • Chemical Digestion • Amylase - enzyme in saliva that breaks the carbohydrates • Starch Simple Sugars

  5. Esophagus • No digestion • Food is directed from mouth to stomach using peristalsis • Epiglottis – flap of cartilage • Ensures food travels to esophagus and not wind pipe (larynx)

  6. Stomach • Large muscular sac that continues digestion • Acidic pH – 2-3 on the pH scale • Cardiac sphincter – circular muscle that keeps food in stomach • Mechanical Digestion - • Peristalsis • Chemical Digestion – protein digestion begins here • HCL and Pepsin - pepsin (enzyme) and hydrochloric acid begins protein digestion. • HCL changes inactive enzyme, pepsinogen active pepsin • Chyme- mixture of stomach fluids and food produced in the stomach by contracting stomach muscles

  7. STOMACH

  8. REVERSE PERISTALSIS

  9. Small Intestine • Digestion is completed and nutrients are absorbed here. • Small in diameter, not in length (> 6m) • Chemical Digestion completed here. • Digestion • Intestinal Enzymes • Pancreatic amylases – starch • Peptidases (trypsin, chymotrypsin) – proteins  amino acids • Nucleases – nucleic acids  nucleotides • Lipases – break down fat • Nutrient Absorption – Villi(villus-singular) – millions of fingerlike projections (latter portion of small intestine) • Increase surface area

  10. Villi and the Small Intestive

  11. Liver • Liver - large organ just above the stomach that produces bile, a fluid loaded with lipids and salts • Produces bile that digests fat • Sends bile to gallbladder for storage

  12. Gallbladder and Pancreas • Gallbladder • Stores bile • Cholesterol Deposits (gallstones) • Pancreas • Secretes peptidases – protein digestive enzymes

  13. Large Intestine or Colon • large intestine • No digestion • 2major functions • Egestion – removal of undigested waste • Rectum – stores feces for release • Anus – Releases feces • Reabsorption • Water is absorbed

  14. Digestive Disorders • Belching / Burping • swallowed air, eat fast, improperly fitted dentures, & chewing gum • Intestinal gas • foods rich in fiber, starches, & sugar • beans, dairy, some vegetables • bacteria in the GI • fat substitutes • GERD - gastroesophageal reflux disease • painful, persistent heartburn (acid in esophagus) • cause: hiatal hernia,cigarette smoking, alcohol, overweight, pregnancy, chocolate, citrus, spicy or fried foods, large high-fat meal

  15. DIGESTIVE PROBLEMS/DISORDERS

  16. Digestive Disorders • Peptic ulcers • areas of GI eroded by HCL & pepsin • Helicobacter pylori – bacteria contributes to production of gastric & duodenal ulcers • Food allergy • hypersensitivity reaction of immune system • Food intolerance • GI gas, pain, diarrhea, or constipation

  17. Digestive Disorders • Celiac disease (celiac sprue) • genetic disorder • inability to absorb gluten - protein in wheat, rye, & barley • Immune cells damage the small intestine • leads to poor nutrient absorption • requires a diet lacking wheat, rye, & barley • early diagnosis avoids delayed growth & malnutrition • Crohn’s disease • inflammatory bowel can affect any area of the GI tract • possible immune system reaction to a virus or bacteria • diarrhea, abdominal pain, rectal bleeding • weight loss, fever, anemia • children can experience delayed growth

  18. Digestive Disorders • Ulcerative colitis • chronic disease of the colon • inflammation & ulceration of inner most lining • possible immune response to a virus or bacteria • symptoms are similar to Crohn’s disease • not caused by food • patients may avoid foods that cause discomfort • Diarrhea • frequent passage of loose, watery stools • Infection, stress, food intolerances • reactions to medications, or bowel disorders • can lead to severe dehydration • more dangerous for children & the elderly

  19. Digestive Disorders • Constipation • infrequent hard, small, difficult to pass stools • prevention includes fiber-rich foods & regular exercise • Irritable bowel syndrome (IBS) • interferes with normal colon function • abdominal cramps & bloating • diarrhea or constipation • stress, caffeine, large meals, chocolate, alcohol, dairy, wheat • more common in women • treatment includes stress management, high fiber diet, fluids, avoiding offending foods

  20. A blast from the past

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