Class 1 digestion and absorption of carbohydrate
•
24 likes•5,033 views
Dr. Dhiraj J. Trivedi presenting Lecture on Carbohydrate metabolism for medical students. Professor, SDM College of Medical Sciences, Dharwad, Karnataka, India
Recommended
More Related Content
What's hot
What's hot (20)
Viewers also liked
Viewers also liked (20)
Similar to Class 1 digestion and absorption of carbohydrate
Similar to Class 1 digestion and absorption of carbohydrate (20)
More from Dhiraj Trivedi
More from Dhiraj Trivedi (20)
Recently uploaded
Recently uploaded (20)
Class 1 digestion and absorption of carbohydrate
- 1. Digestion and absorption of carbohydrates Dr. Dhiraj J. Trivedi
- 3. Breaking down of complex macromolecules to simple, absorbable and assimilable molecules. Digestion – Digestion apparatus – MOUTH STOMACH SMALL INTESTINE LARGE INTESTINE Let us recall
- 4. Dietary Carbohydrates Starch/ Dextrin – cereals, potato, rice, corn, bread Glycogen – animal liver and muscle Maltose – malt , Lactose – milk and milk products Sucrose – table sugar and desserts Fructose – fruits, Sucrose and honey Glucose – grape, honey, fruits, Starch Cellulose, hemicellulose, pectin, Gum – cereals, fruits, vegetables
- 5. Digestive Enzymes Carbohydrase Salivary Amylase – From Salivary glands Pancreatic Amylase – From Pancreas Enzymes of Intestinal mucosal cell - Isomaltase, Maltase, Lactase, Sucrase Dextrimax
- 6. Digestion in Mouth Salivary Amylase Carbohydrate digestion begins in buccal cavity Salivary Amylase – From Salivary glands Acts on cooked Starch or glycogen Random acting, endocarbohydrase Product: Dextrin, Limit dextrin, maltose, isomaltose Activator – Chloride ion Starch / Glycogen Dextrin, Limit Dextrin Maltose, Maltotriose H2O Cl S.Amylase
- 8. Digestion in Intestinal Lumen Pancreatic Amylase Pancreatic Amylase – From pancreas Acts on cooked or uncooked Starch or glycogen Hydrolyses α 1—4 and α 1—6 Glycosidic bonds Exocarbohydrase Product -- Maltose, Isomaltose , Trisaccharides Activator – Chloride ion, Alkaline pH Limit dextrin, Oligosaccharides – digested by glycosidase Starch / Glycogen Limit dextrin, O S, Maltose, Isomaltose H2O Cl Pancreatic Amylase
- 9. Starch Amylo dextrin Erythro dextrin Achro dextrin Malto triose Maltose & Isomaltose Hydrolysis Blue colour Purple blue colour Red Colour No Colour No Colour No Colour Colour with Iodine Hydrolytic products of starch
- 10. Digestion in small intestine Main digestion takes place in the small intestine by pancreatic amylase, Dextrimax & disaccharidases Starch / Glycogen Digestion is completed by pancreatic amylase because food stays for a looong time.
- 11. Disaccharidases Present in the brush border epithelium of intestinal mucosal cells They act on disaccharides Different disaccharidases are 1. Maltase – act on maltose 2. Isomaltase – act on Isomaltose 3. Sucrase – digest sucrose 4. Lactase – hydrolyses lactose 5. Di and Trisaccharidases
- 12. Digestion in Intestinal Lumen Maltase & Isomaltase Maltose (1—4) Glucose + Glucose H2O Intestinal Maltase Isomaltose (1—6) Glucose + Glucose H2O Intestinal Isomaltase Hydrolysis of α 1 – 4 linkage from straight chain Hydrolysis of α 1 – 6 linkage present at branch point
- 13. Digestion in Intestinal Lumen Lactase & Sucrase Lactose Glucose + Galactose H2O Intestinal Lactase Sucrose Glucose + Fructose H2O Intestinal Sucrase Hydrolysis of β 1 – 4 linkage Hydrolysis of α1 – β2 linkage Di and Trisaccharides Glucose
- 14. End product of Digestion Glucose --- (80%) Fructose Galactose Non digestible carbohydrates Dietary fiber Cellulose, Hemicellulose Pectin, Inulin Due to lack of enzymes
- 15. In short Site Digestive juice pH Source Enzyme Substrate End product Mouth Saliva 6.8 Salivary gland S Amylase (ptylin) Starch / Glycogen Dextrins Duodenum Pancreatic juice 7.5 – 8.3 Pancreas P Amylase (Amylopsin) Starch / Glycogen Dextrins, Oligosaccharides Small Intestine Intestinal juice 7.5 – 8.0 Intestinal - EC brush border Dextrimax Maltase Isomaltase Lactase Sucrase Di –Tri saccharidase Dextin Maltose Isomaltose Lactose Sucrose Di & Tri saccharides Glucose, Fructose, Galactose Undigested carbohydrates – food fibers
- 16. Galactose > 110 Glucose > 100 Fructose > 43 Xylose > 15 Arabinose > 09 Absorption of Monosaccharides Absorbed from proximal Jejunum , By 1] Facilitated 2] Active and Sodium dependant , Rate of absorption depend on type of MS
- 17. 1 2 3 SGLUT – 1 Glucose and Galactose GLUT – 2 Glucose , Fructose and Galactose GLUT – 5 Fructose
- 18. Intestinal Lumen Cytoplasmic side of Epithelial cell Carrier mediated Facilitated diffusion
- 20. Glu Glu Glu Na Na Na Na K Na NaNa K K K ATP ADP Active transport Primary activeSecondary active SGLUT Symport Antiport Sodium dependent secondary active transport
- 21. GLUT type Km value of Glucose Tissue distribution Significance of distribution 1, 3, 5 Low Brain, RBC Use only glucose 2 High Liver, Intestine, Kidney, Panaceas Handling high glucose load 4 Intermediate Heart & Skeletal muscle, Adipose Insulin dependent Types of glucose transporters
- 22. Abnormal Carbohydrate digestion / absorption Lactose intolerance Maltase- Sucrase combined deficiency
- 23. Lactose Intolerance o Commonest Disaccharidase deficiency o Either complete absence of Lactase o Or low concentration of Lactase (non inducible enzyme)
- 24. •Develops over a time •No congenital absence of lactase •But low enzyme synthesis and precipitate in adult •Very common in Asian population •There is intolerance to milk and dairy products Primary lactase deficiency Fine/ good OK Oh ! NO
- 25. Secondary lactase deficiency Occurs because of mucosal damage or from medications resulting from certain gastrointestinal diseases Exposure of gastrointesinal parasites like Giardia lamblia [giardiasis]. Production of lactase disturbed Temporary lactose intolerance Another form is due to lactose over load
- 26. Clinical manifestations *Osmotic effect Form of abdominal cramps, distensions, diarrhea, constipation, flatulence upon ingestion of milk or dairy products Dislike towards milk and milk product
- 27. Biochemical basis of the disease Undigested lactose in lumen is acted upon by intestinal bacteria and forms CO2, H2, and 2-C and 3-C compounds which remain undigested CO2 and H2 causes Distension and flatulence Lactose + 2C & 3C are somatically active They withdraw water from intestinal mucosal cell and cause osmotic diarrhea or constipation because of undigested milk
- 28. Diagnosis Stool analysis Reducing sugar present , Acid stool Urine test shows positive Benedict’s test LACTOSURIA Mucosal biopsy confirms diagnosis
- 29. Lactose intolerance Cause: • Primary severe Lactase deficiency – newborn • Primary low lactase deficiency – Adult • Secondary low lactase deficiency – both adult and children Features: • Diarrhea (osmotic effect) • Flatulence (fermentation of lactose) Diagnosis: • Reducing sugar in stool sample Management: • Avoid milk in diet, • Use preparation of live lactobacilli (Curd)
- 30. Not so common Sucrase , Isomaltase deficiency Rare but create problem