Chapter 3 Digestion: From Meals to MoleculesChapter 3 Learning ObjectivesSlide 3Slide 4Organs and organ systemsOrgan systemsSlide 7Slide 8Slide 9PowerPoint PresentationDigestion vs. absorptionDigestive system secretions: chemical digestionDigestive enzymesDigestion in the MouthPharnyxThe esophagus to the stomach….The Stomach……Slide 18StomachSlide 20Slide 21The Small IntestineStructure of the Small IntestineSmall intestinesAccessory organs involved in digestion in SISmall intestine secretionsSlide 27Small intestines chemical digestionTransport across membranesAnatomy of the Large Intestine: ~5 ft longLarge intestinesWhat a scientist seesDigestive system summaryThe Digestive System (fig. 3.3)AbsorptionDigestive & cardiovascular systemsLiver & portal systemCardiovascular systemRemoval of wastesMetabolismMetabolism example: cellular respirationSlide 42Digestive system &immune systemDigestive system & immune systemFood allergiesSlide 46Celiac diseaseSlide 48Digestive disordersSlide 50Slide 51GallstonesSlide 53Slide 54End of Chapter 3Chapter 3Digestion: From Meals to MoleculesChapter 3 Learning Objectives1. Define the following terms: digestion, absorption, mucus, hormones, enzymes, epiglottis2. Identify the organ systems that assist with digestion and absorption of nutrients and those that assist with the elimination of metabolic waste products.3. List the organs that make up the digestive system, including the accessory organs.4. Describe how each of the organs involved with the digestion system assists with digestion and absorption.5. List the 3 sphincters associated with the gastrointestinal tract (GIT) discussed in this lecture and describe where they are located.6. Distinguish between mechanical digestion and chemical digestion.Copyright 2010, John Wiley & Sons, Inc.Chapter 3 Learning Objectives7. Explain the roles of saliva, mucus, enzymes, bicarbonate, hormones, and hydrochloric acid in digestion. 8. Identify the enzyme or group of enzymes responsible for digestion of the macronutrients.9. Explain how the structure of the lumen of the small intestine aids in the function of the small intestine.10. Outline the process of digestion and absorption, from the mouth to the anus.11. Discuss the methods of the absorption of nutrients from the small intestine. 12. Describe the role of the cardiovascular system and lymphatic system in distributing nutrients and oxygen to the cells in the body and in the elimination of waste.13. Explain how the GIT protects us from infectionCopyright 2010, John Wiley & Sons, Inc.Chapter 3 Learning Objectives13. Discuss the role of the microflora (gut flora) in maintaining health, including their function in metabolism of nutrients.14. Define prebiotics and probiotics.15. Describe the causes of food allergies.16. Describe celiac disease. 17. Identify food groups that those with celiac disease may consume and food groups that need to be avoided.18. Define GERD, why it occurs, and identify complications associated with it if left untreated.19. Define peptic ulcer and discuss its major cause.20. Describe diarrhea, constipation, and diverticula.21. Identify primary causes for constipation and diarrhea.Copyright 2010, John Wiley & Sons, Inc.Organs and organ systemsDefinitions:Organ:A structure that is made up of more than one tissue that performs a specialized functionOrgan system:A group of organs that work together to perform a specific taskMultiple organ systems in the bodyCopyright 2010, John Wiley & Sons, Inc.© 2012 John Wiley & Sons, Inc. All rights reserved.Organ systems© 2012 John Wiley & Sons, Inc. All rights reserved.Organ systems© 2012 John Wiley & Sons, Inc. All rights reserved.Organ systems© 2012 John Wiley & Sons, Inc. All rights reserved.Organ systemsDigestion vs. absorptionWhat is the definition of digestion?What is the difference between mechanical digestion and chemical digestion?What is the definition of absorption?Which comes first?© 2012 John Wiley & Sons, Inc. All rights reserved.Digestive system secretions: chemical digestionMucus is secreted from mucosal cells lining the digestive tract.  moistens, lubricates and protects the digestive systemEnzymes speed up reactions.  for digestion, help breakdown larger molecules into smaller onesHormones: chemicals secreted from cells which travel through the bloodstream to signal cells in another part of the body.© 2012 John Wiley & Sons, Inc. All rights reserved.Digestive enzymes© 2012 John Wiley & Sons, Inc. All rights reserved.Digestion in the MouthMechanical and chemical digestion begins.Saliva secreted from salivary glands after the sight, smell, or presence of food. Contains lubricants, enzymes and other substances.Teethbreak down food particles.Taste buds detect food chemicals. Tongue helps mix food and aids chewing. Bolus formed© 2012 John Wiley & Sons, Inc. All rights reserved.PharnyxPart of digestive and respiratory systems.Epiglottis blocks food from entering the trachea (windpipe) and lungs during swallowingCopyright 2010, John Wiley & Sons, Inc.The esophagus to the stomach….Peristalsis:Lower esophageal sphincter:The Stomach……Pyloric SphincterThought, smell, sight of food starts gastric motility and increase gastric secretionsFood enters stomach, stimulates release: Gastrin Increases secretion of gastric juices© 2012 John Wiley & Sons, Inc. All rights reserved.StomachTemporary storage of foodStomach lining produces gastric juice containing:WaterPepsinogenactivated into the digestive enzyme pepsin Digestive enzyme for protein (precursor)Hydrochloric acid Kills micro-organism Unfolds proteins activates pepsin Inhibits amylaseMucus© 2012 John Wiley & Sons, Inc. All rights reserved.StomachChurning of stomach muscles to mix foodLittle absorption: water, alcohol, aspirin, acetaminophen (Tylenol) are absorbedEnd result: chymeleaves the stomach to enter the small intestine through a sphincter Stomach emptying is regulated by signals from the small intestines and is affected by meal size and compositionFood enters small intestine, stretches it: decrease stomach motility  decrease gastric juice secretionThe Small IntestineNarrow tube that is approximately 20 ft longMain site for digestion, absorptionDivided into three segmentsDuodenumJejunumIleumCopyright 2010, John Wiley & Sons, Inc.Copyright