Downloaded 11 times
Uploaded byAman Gangwar
Digestive system
The document summarizes the key components and functions of the digestive system. It describes the mechanical and chemical digestion that occurs, the major organs involved including the mouth, esophagus, stomach, small intestine, large intestine, liver, and pancreas. It explains the roles of these organs in ingestion, digestion, absorption, and elimination of waste. Accessory structures like teeth, salivary glands, and the gallbladder are also outlined.
More Related Content
Digestive system
- 1.
- 2. Digestion • Processing offood • Types – Mechanical (physical) • Chew • Tear • Grind • Mash • Mix – Chemical • Catabolic reactions • Enzymatic hydrolysis – Carbohydrate – Protein – Lipid 2
- 3. Digestion • Phases – Ingestion – Movement – Digestion – Absorption – Further digestion 3
- 4. Digestive System Organization •Gastrointestinal (Gl) tract (Alimentary canal) – Tube within a tube – Direct link/path between organs – Structures • Mouth • Oral Cavity • Pharynx • Esophagus • Stomach • Duedenum • Jejenum • kIleum • Cecum • Ascending colon • Transverse colon 4
- 5. Digestive System Organization • Descending colon • Sigmoid colon • Rectum • Anus • Accessory structures – Not in tube path – Organs • Teeth • Tongue • Salivary glands • Liver • Gall bladder • Pancreas 5
- 6. Anatomy of theMouth and Throat 6
- 7. Human Deciduous and Permanent Teeth 7
- 8. Dorsal Surface ofthe Tongue 8
- 9. The Major SalivaryGlands 9
- 10. Deglutition (swallowing) • Sequence – Voluntary stage • Push food to back of mouth – Pharyngeal stage • Raise – Soft palate – Larynx + hyoid – Tongue to soft palate – Esophageal stage • Contract pharyngeal muscles • Open esophagus • Start peristalsis 10
- 11. Deglutition (swallowing) • Control – Nerves • Glossopharyngeal • Vagus • Accessory – Brain stem • Deglutition center – Medulla oblongata – Pons – Disorders • Dysphagia • Aphagia 11
- 12. Esophagus • Usually collapsed(closed) • 3 constrictions – Aortic arch – Left primary bronchus – Diaphragm • Surrounded by – SNS plexus – Blood vessels • Functions – Secrete mucous – Transport food 12
- 13.
- 14. Esophagus • Sphincters – Upper – Lower • Abnormalities – Achalasia – Atresia – Hernia – Barret’s esophagus – Esophageal varices 14
- 15. Stomach • Usually “J”shaped • Left side, anterior to the spleen • Mucous membrane – G cells – make gastrin – Goblet cells – make mucous – Gastric pit – Oxyntic gland – Parietal cells – Make HCl – Chief cells – Zymogenic cells • Pepsin • Gastric lipase 15
- 16. Anatomy of theStomach 16
- 17. Stomach • 3 musclelayers – Oblique – Circular – Longitudinal • Regions – Cardiac sphincter – Fundus – Antrum (pylorus) – Pyloric sphincter • Vascular • Inner surface thrown into folds – Rugae • Contains enzymes that work best at pH 1-2 17
- 18. Stomach • Functions – Absorbs – Mix food • Alcohol – Reservoir • Water – Start digestion of • Lipophilic acid • Protein • Nucleic acids • B 12 • Fats – Activates some enzymes – Destroy some bacteria – Makes intrinsic factor – B 12 absorption – Destroys some bacteria 18
- 19. Small Intestine • Extendsfrom pyloric sphincter ileocecal valve • Regions – Duodenum – Jejenum – Ileum • Movements – Segmentation – Peristalsis 19
- 20. Small Intestine • Histology – Intestinal glands – Intestinal enzymes – Duodenal glands – Alkaline mucous – Paneth cells – Lysozyme – Microvilli – Lacteals – Plica circularis – Smooth muscle – Lymphatic tissue – GALT – Vascular 20
- 21. Small Intestine • Absorbs – Lipids – 80% ingested water • Monoglycerides – Electrolytes • Fatty acids – Vitamins • Micelles – Minerals • Chylomicrons – Carbonates • Active/facilitated transport • Monosaccharides – Proteins • Di-/tripeptides • Amino acids 21
- 22. Structure of theVilli in the Small Intestine 22
- 23. Small Intestine • Secretesdigestive enzymes – Peptidases • Amino- • Di- • Tri- – Sucrases – Maltase – Lactase – Saccharidases • Di- • Tri- – Lipase – Nucleases 23
- 24. Small Intestine • Control •Requires pancreatic enzymes & bile to complete digestion 24
- 25. Large Intestine • Extendsfrom ileocecal valve to anus • Regions – Cecum – Appendix – Colon • Ascending • Transverse • Descending – Rectum – Anal canal 25
- 26. Anatomy of theLarge Intestine 26
- 27. Large Intestine • Histology – No villi – No permanent circular folds – Smooth muscle • Taeniae coli • Haustra – Epiploic appendages – Otherwise like rest of Gl tract 27
- 28. Large Intestine • Functions – Mechanical digestion – Absorbs • Haustral churning •More water • Peristalsis •Vitamins –B • Reflexes –K – Gastroileal – Gastrocolic – Concentrate/eliminate wastes – Chemical digestion – Bacterial digestion • Ferment carbohydrates • Protein/amino acid breakdown 28
- 29. Feces Formation andDefecation • Chyme dehydrated to • Control form feces – Parasympathetic • Feces composition – Water – Voluntary – Inorganic salts – Epithelial cells – Bacteria – Byproducts of digestion • Defecation – Peristalsis pushes feces into rectum – Rectal walls stretch 29
- 30. Liver • Location – R. Hypochondrium – Epigastric region • 4 Lobes – Left – Quadrate – Caudate – Right • Each lobe has lobules – Contains hepatocytes – Surround sinusoids – Feed into central vein 30
- 31. Liver • Functions – Makes bile • Detergent – emulsifies fats • Release promoted by: – Vagus n. – CCK – Secretin • Contains – Water – Bile salts – Bile pigments – Electrolytes – Cholesterol – Lecithin 31
- 32. Liver – Detoxifies/removes • Drugs • Alcohol – Stores • Gycolgen • Vitamins (A, D, E, K) • Fe and other minerals • Cholesterol – Activates vitamin D – Fetal RBC production – Phagocytosis – Metabolizes absorbed food molecules • Carbohydrates • Proteins • Lipids 32
- 33. Liver • Dual bloodsupply – Hepatic portal vein • Direct input from small intestine – Hepatic artery/vein • Direct links to heart 33
- 34. The Duodenum andRelated Organs 34
- 35. The Organs andPositions in the Abdominal Cavity 35
- 36. Structures of theAlimentary Canal 36