Digestive System - PowerPoint PPT Presentation

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Digestive System

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  1. Digestive System Azami PHD

  2. Digestive System Anatomy • Digestive tract • Alimentary tract or canal • GI tract • Accessory organs • Primarily glands • Regions • Mouth or oral cavity • Pharynx • Esophagus • Stomach • Small intestine • Large intestine • Anus

  3. Oral Cavity • Mouth or oral cavity • Vestibule: Space between lips or cheeks and alveolar processes • Oral cavity proper • Lips (labia) and cheeks • Palate: Oral cavity roof • Hard and soft • Palatine tonsils • Tongue: Involved in speech, taste, mastication, swallowing

  4. Salivary Glands • Produce saliva • Prevents bacterial infection • Lubrication • Contains salivary amylase • Breaks down Starch • Three pairs • Parotid: Largest • Submandibular • Sublingual: Smallest

  5. Teeth • Two sets • Primary, deciduous, milk: Childhood • Permanent or secondary: Adult (32) • Types • Incisors, canine, premolar and molars

  6. Tooth structure:

  7. Pharynx Nasopharynx Oropharynx: Transmits food Laryngopharynx: Transmits food Esophagus Transports food from pharynx to stomach Passes through esophageal hiatus (opening) of diaphragm and ends at stomach Pharynx and Esophagus

  8. (Swallowing) • Three phases • Voluntary • Pharyngeal • Reflex • Esophageal • Reflex

  9. Digestive Tract Histology

  10. Nervous regulation Involves enteric nervous system Types of neurons: sensory, motor, interneurons Coordinates peristalsis and regulates local reflexes Chemical regulation Production of hormones Production of paracrine chemicals Digestive System Regulation

  11. Digestive Tract Anatomy

  12. serous membranes

  13. Peritoneum • Peritoneum • Visceral: Covers organs • Parietal: Covers interior surface of body wall • Retroperitoneal: Behind peritoneum as kidneys, pancreas, duodenum Retroperitoneal

  14. Mesenteries • Routes which vessels and nerves pass from body wall to organs

  15. Mesenteries • Mesenteries • Routes which vessels and nerves pass from body wall to organs

  16. Mesenteries

  17. Mesenteries

  18. Lesser omentum from ventral mesentery

  19. Lesser omentum from ventral mesentery

  20. greater omentum from dorsal mesentery

  21. greater omentum from dorsal mesentery

  22. greater omentum

  23. Greater sac Lesser sac

  24. Stomach Anatomy • Openings • Gastroesophageal: To esophagus • Pyloric: To duodenum • Regions • Cardiac • Fundus • Body • Pyloric

  25. Stomach Histology: • Layers • Serosa or visceral peritoneum: Outermost • Muscularis: Three layers • Outer longitudinal • Middle circular • Inner oblique • Submucosa • Mucosa

  26. Stomach Histology • Rugae: Folds in stomach when empty • Gastric pits: Openings for gastric glands • Contain cells

  27. Small Intestine anatomy and Histology • Site of greatest amount of digestion and absorption • Divisions • Duodenum • Jejunum • Ileum: Peyer’s patches or lymph nodules • Modifications • Circular folds or plicaecirculares, villi, microvilli • Cells of mucosa • Absorptive, goblet, granular, endocrine

  28. Small Intestine Secretions • Mucus • Protects against digestive enzymes and stomach acids • Digestive enzymes • Disaccharidases: Break down disaccharides to monosaccharides • Peptidases: Hydrolyze peptide bonds • Nucleases: Break down nucleic acids • Duodenal glands • Stimulated by vagusnerve, secretinsecretinincreases water and bicarbonate secretion from duodenal (Brunner's) glands

  29. Duodenum