Digestive System IB 6.1

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  • 1. The Digestive System02/26/13 16:09 cottingham
  • 2. Digestion• W is digestion? hat • Breaking food down into smaller molecules. • This can be done by physically pounding the molecules, or chemically breaking the molecules apart.• W is the m hat edical term for anything digestive? – GAS O TR• W sort of m hat olecules help with chemical digestion? – Enzymes• W kind of gland aids in digestion? hat – Exocrine • Not hormone produced/ be both. can• W hich reaction is involved in digestion, hydrolysis or dehydration synthesis? – Hydrolysis 02/26/13 16:09 cottingham
  • 3. Five Stages of Food Processing1. Ingestion2. Digestion (enzymatic hydrolysis)3. Absorption – into the blood4. Assimilation – into the body5. Egestion02/26/13 16:09 cottingham
  • 4. Mammalian Digestion• Physical digestion – caused by movement• Chemical Digestion – enzymes, water, acids• Accessory glands: – Salivary glands – Pancreas – Liver – Gallbladder 02/26/13 16:09 cottingham
  • 5. 02/26/13 16:09 cottingham
  • 6. 02/26/13 16:09 cottingham
  • 7. Oral Cavity• Organs Includes: – Tongue – mixes/ moves chewed food – Teeth – breaks food down – Enzymes: • Salivary Amylase – begins digestion of polysaccharides (starch). Starch to maltose (pH – 7) – Chewed and swallowed food: Bolus02/26/13 16:09 cottingham
  • 8. 02/26/13 16:09 cottingham
  • 9. Teeth02/26/13 16:09 cottingham Thank you Rebecca Lieberman!
  • 10. Esophagus• Muscular tube…connects mouth to stomach. (epiglottis)• PERISTALSIS – (rhythmic) muscular movement of food thru the digestive tract after swallowing.• No chemical action. No digestion.02/26/13 16:09 cottingham
  • 11. 02/26/13 16:09 cottingham
  • 12. StomachThe Basics:• J – shaped muscular organ. Thick walled• Chemical and physical digestion• Sphincter – cardiac and pyloric• Stores food• Begins protein digestion…. 02/26/13 16:09 cottingham
  • 13. Stomach• Stomach lining:• Contains Gastric Glands:• Have three kinds of cells – Parietal: Secretes HCl – activates pepsinogen; kills bacteria. – Chief: Secretes Pepsinogen; activates to PEPSIN (gastric protease) begins protein digestion. pH – 2. – Neck: Releases mucous; provides protection• Stomach processes food in 2-6 hours• Semisolid food: chyme. 02/26/13 16:09 cottingham
  • 14. Small Intestine02/26/13 16:09 cottingham
  • 15. Small Intestine02/26/13 16:09 cottingham
  • 16. Small Intestine• Small diameter….6 meters long• Some physical; mostly chemical digestion.• Receives secretions from the liver and pancreas.• 3 sections: duodenum (digestion), jejunum (digestion and absorption) and ileum (for absorption)• Absorption of nutrients begins in the lining of the small intestine.02/26/13 16:09 cottingham
  • 17. Enzymes02/26/13 16:09 cottingham
  • 18. Small Intestine - Enzymes• Bicarbonate – from pancreas to neutralize acid (not an enzyme)• Protein – • Trypsin - (pancreas) continues protein digestion. (pH 8) • Peptid - (small intestine) completes protein digestion – to amino acids (pH – 7.5)• Fat – • B – (liver) not an enzym B ile e. reaks down large fat molecules • Lipase – (pancreas) digests fats. (pH – 8)• Carbohydrates • Amylase (pancreas) continues starch digestion (maltose) (pH 7) • Maltase - (small intestine) = (maltose into glucose). (pH 7) • Sucrase – glucose and fructose (pH – 7) • Lactase – glucose and galactose (pH – 7) 02/26/13 16:09 cottingham
  • 19. Enzymes…the need for?• At body temperature (37°C in mammals), reaction rates are too slow to be efficient during hydrolysis of large food molecules• Hydrolytic reactions in the digestion of large food molecules, are EXERGONIC, but occur very slowly due to high activation energies• Enzymes lower activation energy, catalyzing hydrolysis reactions of large food molecules into their monomers.02/26/13 16:09 cottingham
  • 20. 02/26/13 16:09 cottingham
  • 21. Small Intestine - Food Absorption • W of the small intestine has circular folds with fingerlike all projections, called VIL I. L • Each Villus contain: – Blood vessels(capillary): amino acid and glucose absorption in O2 poor blood. – Lacteals: fat absorption: triglycerides reform, coated with protein and are absorbed • The epithelial cells of each villus have extensions called microvilli. – Function: • increase the small intestines surface area for nutrient absorption. • Absorbed food travels to the liver for assimilation. 02/26/13 16:09 cottingham
  • 22. Villus02/26/13 16:09 cottingham
  • 23. Assimilation• Taking molecules to cells to become part of the body: – Carbohydrates: produce ATP, DNA, RNA, Cell membrane – Fat: Adipose tissue, phospholipids, mitochondrial membranes, hormones – Amino acids: cells=proteins. Excessive amino acids are deaminated by the liver to form urea02/26/13 16:09 cottingham
  • 24. Large Intestine• Larger diameter…shorter tube (1.5m)• Sections: cecum, colon (main), rectum• Functions: – Reabsorbs water. – Mutualistic bacteria (E. coli): synthesize vitamin K – Elimination (egestion) of W aste (Feces)02/26/13 16:09 cottingham
  • 25. Main Components of Feces• CELLULOSE• LIGNIN• BILE PIGMENTS• BACTERIA• INTESTINAL CELLS02/26/13 16:09 cottingham
  • 26. Large Intestine02/26/13 16:09 cottingham
  • 27. Colonoscopy02/26/13 16:09 cottingham
  • 28. I think this selection will just about say it all!02/26/13 16:09 cottingham
  • 29. Accessory Organs - LIVER Largest gland in the body – 2 lobes• Functions: – Filters blood of “poisons” – Maintains blood glucose levels (glycogen) – Produces bile02/26/13 16:09 cottingham
  • 30. 02/26/13 16:09 cottingham
  • 31. Accessory Organs – Gall Bladder• Attached to liver.• Stores bile02/26/13 16:09 cottingham
  • 32. Accessory Organs - Pancreas• Produces enzymes and hormones• Enzymes for all major food groups• Enzymes travel to Sm. Intestine through ducts. 02/26/13 16:09 cottingham
  • 33. DRAW!02/26/13 16:09 cottingham
  • 34. END02/26/13 16:09 cottingham
  • 35. Disorders of the Digestive System02/26/13 16:09 cottingham
  • 36. Diarrhea and Constipation• Constipation – condition by which feces is eliminated infrequently and with difficulty. • Excess removal of water • Slow peristalsis• Diarrhea – occurs when too little water is removed • Often associated with infection • Can result in severe dehydration02/26/13 16:09 cottingham
  • 37. Ulcer• Open sores on the interior wall of the digestive tract.• Usually in the stomach or small intestine.• Usually associated with the over-production of gastric juices. 02/26/13 16:09 cottingham
  • 38. Appendicitis• Infection of the appendix• Sometimes caused by a small blockage of feces which causes a bacteria buildup.• An infected appendix that bursts can be fatal>>>>>>>>>>>>>>>>>>>>>> >02/26/13 16:09 cottingham
  • 39. Gall Stones• Small, hard particles of cholesterol that block the bile duct (in the gall bladder.)02/26/13 16:09 cottingham
  • 40. Let’s Diagram• Mouth• Esophagus• Stomach - sphincters• Small intestine – duodenum• Pancreas/ gall bladder/ liver• Large Intestine – colon/rectum/ anus 02/26/13 16:09 cottingham