1 / 20

The Digestive System

The Digestive System. Structure and function. Two groups of organs. Alimentary canal (GI tract) Mouth to anus Accessory organs Mechanical breaking down food Secretions that chemically break down food. The process of digestion. Ingestion Secretion Mixing and propulsion Digestion

hyman
Download Presentation

The Digestive System

An Image/Link below is provided (as is) to download presentation Download Policy: Content on the Website is provided to you AS IS for your information and personal use and may not be sold / licensed / shared on other websites without getting consent from its author. Content is provided to you AS IS for your information and personal use only. Download presentation by click this link. While downloading, if for some reason you are not able to download a presentation, the publisher may have deleted the file from their server. During download, if you can't get a presentation, the file might be deleted by the publisher.

E N D

Presentation Transcript

  1. The Digestive System Structure and function

  2. Two groups of organs • Alimentary canal (GI tract) • Mouth to anus • Accessory organs • Mechanical breaking down food • Secretions that chemically break down food

  3. The process of digestion • Ingestion • Secretion • Mixing and propulsion • Digestion • Absorption • Excretion (defecation)

  4. Discussion will require a little knowledge of: • Control- nervous and endocrine systems • Transport- circulatory system • Smooth muscle function

  5. Structure of the GI tract (deep to superficial) • Mucosa • Submucosa • Muscularis • Serosa

  6. Mucosa (inner lining) • Several types of epithelium • Stratified squamous in mouth, pharynx, esophagus, anus • Simple columnar epithelium in stomach and intestines • Secretory cells • Mucus, acid, hormones

  7. Mucosa, continued • Lamina propria • Connective tissue • Blood and lymphatic vessels • MALT (immune function) • Muscularis mucosa • Increase surface area for absorption

  8. Submucosa • Connective tissue • Binds mucosa to muscularis • Submucosal plexus (plexus of Meissner) • Secretions and blood supply • Glands and lymphatic tissue

  9. Muscularis- voluntary and involuntary • Skeletal muscle in upper digestive tract and anal sphincter • Smooth muscle in two layers: inner circle and outer longitudinal • Myenteric plexus (plexus of Auerbach) • Muscular contractions

  10. Serosa- superficial membrane • Part of it forms portion of peritoneum (visceral peritoneum) • Covers organs in the peritoneal cavity • Parietal peritoneum lines walls of abdominopelvic cavity

  11. Peritoneum is extensively folded • Folds help hold organs in place • Lots of blood supply and nerves

  12. Peritoneal folds • Greater omentum • Adipose tissue • Immune function • Lesser omentum • Falciform ligament • Attaches liver to anterior abdominal wall and diaphragm • Mesentery • Mesocolon

  13. Peritoneal folds

  14. The mouth- formed by cheeks, hard and soft palates and tongue

  15. Salivary glands • Parotid • Sublingual • Submandibular • Many other minor salivary glands • Saliva lubricates, dissolves and begins to break down food • Amylase • Lipase • Lysozyme • Stimulated by parasympatheitc nervous system

  16. The teeth

  17. Pharynx • Nasopharynx- respiration • Oropharynx • Laryngopharynx- both functions • Contractions propel food into esophagus

  18. Esophagus- posterior to trachea • Transports food without digestive activity • Peristalsis • Upper and lower esophageal sphincters • Delivers food to stomach

  19. GERD (gastroesophageal reflux disease) • Controlled diet • Histamine-2 blockers (Tagamet, Pepcid AC). Good for hearthburn but not inflammation • Antacids- (bicarbonate) • Proton pump inhibitors (Prilosec, Prevacid, Nexium • pro-motility drugs increase action of muscles of digestive system (Reglan) • Foam barriers

  20. On to the stomach

More Related