1. Online Counseling Resource YCMOU ELearning Drive… School of Architecture, Science and Technology Yashwantrao Chavan Maharashtra Open University, Nashik – 422222, India

2. OC-SEP033-CP01-03 Introduction Programmes and Courses  SEP – SBT033 – Unit 01  SEP – SBI033 – Unit 01  SEP – SGS033 – Unit 01

3. School of Science and Technology, Online Counseling Resource… © 2007, YCMOU. All Rights Reserved.3 Credits  Academic Inputs by Arun Punaji More. M.Sc. (Microbiology) Experience: 11 Years.  arunmesh@hotmail.com

4. School of Science and Technology, Online Counseling Resource… © 2007, YCMOU. All Rights Reserved.4 How to Use This Resource  Counselor at each study center should use this presentation to deliver lecture of 40-60 minutes during Face-To-Face counseling.  Discussion about students difficulties or tutorial with assignments should follow the lecture for about 40-60 minutes.  Handouts (with 6 slides on each A4 size page) of this presentation should be provided to each student.  Each student should discuss on the discussion forum all the terms which could not be understood. This will improve his writing skills and enhance knowledge level about topics, which shall be immensely useful for end exam.  Appear several times, for all the Self-Tests, available for this course.  Student can use handouts for last minutes preparation just before end exam.

5. School of Science and Technology, Online Counseling Resource… © 2007, YCMOU. All Rights Reserved.5 Learning Objectives  After studying this module, you should be able to: Describe digestion of fats. Describe various digestive end products of fats. Describe various digestive enzymes involve in digestion of fats. Explain the action of various digestive enzymes.

6. School of Science and Technology, Online Counseling Resource… © 2007, YCMOU. All Rights Reserved.6 Introduction-1  Dietary fats are presents in forms of neutral fats which are also known as triglycerides.  Triglycerides are macromolecules made up of three fatty acid molecules and one molecule of glycerol.  The other fats present in human diet is in forms of phosphilipids, cholesterols and cholesterol esters.  In this presentation let us see how fats are digested in stomach and small intestine and the mechanism of their absorption into blood.

7. School of Science and Technology, Online Counseling Resource… © 2007, YCMOU. All Rights Reserved.7 Introduction - 2  Digestion of fat involve number of process such as: Emulsification of fats by bile released from gallbladder. The bile is released in response to the hormone cholecystokinin secreted by duodenum when partially digested foob enter into duodenum.

8. School of Science and Technology, Online Counseling Resource… © 2007, YCMOU. All Rights Reserved.8 Digestion of Fats-1  Fats are digested in stomach by the enzyme lingual lipase to fatty acids.  The enzyme lingual lipase is secreted by lingual glands in the mouth and is swallowed with saliva.  Lingual lipase is responsible of digestion of 10% fats in stomach.

9. School of Science and Technology, Online Counseling Resource… © 2007, YCMOU. All Rights Reserved.9 Digestion of Fats -2  The complete digestion of fats occur in small intestine.  The biomolecules responsible for fats digestion in small intestine are:  Bile acids,  Lecithin,  Pancreas lipase.  The bile acids and lecithin bring about the emulsification of fats.  The bile is released in response to the hormone cholecystokinin secreted by duodenum when partially digested foob enter into duodenum.

10. School of Science and Technology, Online Counseling Resource… © 2007, YCMOU. All Rights Reserved.10 Emulsification of Fats

11. School of Science and Technology, Online Counseling Resource… © 2007, YCMOU. All Rights Reserved.11 Digestion of Fats -3  Emulsification is process of breaking down the large fat globules into very smaller globules of 3 to 4 nanometer in size.  Emulsification increases the surface area of fat globules 1000 time.  Thus emulsification make available large surface area of fat globules to the action of lipase enzymes.  Let us see how the bile acids and lecithin bring about the emulsification of large fat globules.

12. School of Science and Technology, Online Counseling Resource… © 2007, YCMOU. All Rights Reserved.12 Digestion of Fats-4  The bile acid and lecithin molecules which is phospholipids have polar ends and non polar ends or sterol nucleus of bile acids.  The polar ends of these molecules interact with water thus making them soluble in water.  Whereas the non polar ends interact with the fat globules; thus in no polar regions of these molecules fats are soluble.  The dual interaction of molecules of bile acids and lecithin molecules with water as well as with fats reduces interfacial tension of fats with that of water.

13. School of Science and Technology, Online Counseling Resource… © 2007, YCMOU. All Rights Reserved.13 Digestion of Fats-5  Thus the reduced interfacial tension with water facilitate the breaking down of large globules of fats into smaller one remaining associated with the bile acids and lecithin molecules on agitation in small intestine.  The emulsification of fats increases the action of lipase interaction with large number of molecules on the surfaces of minutes fat globules of diameter of 3 to 6 nanometer in size facilitating the increased digestion of fats in small intestine.

14. School of Science and Technology, Online Counseling Resource… © 2007, YCMOU. All Rights Reserved.14 Digestion of Fats-6  The pancreas lipase break down the fat molecules into free fatty acids and 2- monoglycerides molecules on the surfaces of minutes fat globules.  The free fatty acids and 2-monoglycerides thus formed accumulate on the outer surface of the minutes fat globules; this stop the further hydrolysis of triglycerides.  Therefore the accumulated newly formed free fatty acids and 2-monoglycerides have to be removed immediately from the minute fat globules.

15. School of Science and Technology, Online Counseling Resource… © 2007, YCMOU. All Rights Reserved.15 Digestion of Fats-7  The sterol nucleus of free bile acid molecules surround the newly formed free fatty acid molecules and removed them from the surface of minute fat globules.  The free fatty acid molecules associated with the sterol nucleus of bile acid molecules when come in vicinity of epithelial cells of small intestine, they are absorbed into the epithelial cells making free the associated bile acid molecules to re associate with another free fatty acid and monoglyceride molecules on the surface of minute fat globules.

16. School of Science and Technology, Online Counseling Resource… © 2007, YCMOU. All Rights Reserved.16 Absorption of Fatty Acids  Once the free fatty acids and monoglycerides entered into the epithelial cells of small intestine by diffusion, they are taken up by smooth endoplasmic reticulum of the cells and converted into new triglycerides which are subsequently released in forms of chylomicrons through the base of epithelial cell into the thoracic duct from where they enter into blood circulation.  The short chain triglycerides are directly absorbed into portal blood.

17. School of Science and Technology, Online Counseling Resource… © 2007, YCMOU. All Rights Reserved.17 Absorption of Fatty Acids

18. School of Science and Technology, Online Counseling Resource… © 2007, YCMOU. All Rights Reserved.18 What We Learn…..  Digestion of fat in small intestine.  Digestive enzymes involved in digestion of fats.  End products of fat digestion.  Absorption mechanism of end products of fats digestion.

19. School of Science and Technology, Online Counseling Resource… © 2007, YCMOU. All Rights Reserved.19 Critical Thinking Question  Why it is said that the fat diet is most energy efficient diet?

20. School of Science and Technology, Online Counseling Resource… © 2007, YCMOU. All Rights Reserved.20 Tips for Critical Thinking Question  Energy expenditure for fat digestion.  Energy content fat diet.

21. School of Science and Technology, Online Counseling Resource… © 2007, YCMOU. All Rights Reserved.21 Study Tips  Book Title:Textbook of medical physiology. Dr. Arthur C. Guyton, John E. Hall. Author: Dr. Arthur C. Guyton, John E. Hall. Publication: Elsevier India Private Limited.  Book Human Physiology Title: Human Physiology C. C. Chattergy. Author: C. C. Chattergy.

22. End of the Presentation Thank You!