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BIOL 204 Lab For Week 12 Digestive System Anatomy Microscopic Anatomy of the GI Tract The GI tract consists of a tube that extends from the mouth to the anus. It has four tissue layers (tunics): Another, detailed view of GI tract tunics There are structural modifications of the tunics in various areas of the GI tract Gross Anatomy of the GI Tract The GI Tract: Mouth The Esophagus The Esophagus Gastroesophageal Junction Gastric pit The Esophagus The Stomach Microscopic anatomy of the stomach. B. The Liver Gross View of the Liver The Duodenum of the Small Intestine Receives the Ducts of the Liver, Gall Bladder and Pancreas Liver Microscopic Anatomy Pancreas Gross Anatomy Microscopic View of the Pancreas: Islet Cells: endocrine; secrete insulin and glucagon Acinar Cells: exocrine; secrete digestive enzymes Small Intestine Gross Anatomy Histology of the Small Intestine (Duodenum) Intestinal Villus Portions of the Large Intestine Extrinsic Salivary Glands Types of Permanent Teeth Each jaw has: 2 central incisors 2 lateral incisors 2 canines (eyeteeth) 4 premolars 6 molars Internal Anatomy of a Tooth Mesenteries of the abdominal digestive organs. 1. Diaphragm 2. Liver – left lobe 3. Falciform Ligament 4. Liver right lobe 5. Stomach 6. Greater Omentum 7. Ascending Colon 8. Cecum 9. Small Intestine 10. Descending Colon 11. Sigmoid Colon An Appendix, Unfixed Gall Bladder on the Underside of the Liver Liver – Gross View Serosal Surface Human Duodenum, Unfixed Cat Dissection 1. Parotid Gland 2. Sublingual Gland 3. Submandibular Gland 4. Esophagus 5. Tongue 6. Masseter Muscle 7. Larynx 8. Trachea Cat Dissection Abdomen 1. 2. 3. 4. 5. 6. Diaphragm Round Ligament Falciform Ligament Left Lateral Lobe of Liver Left Medial Lobe of Liver Quadrate Lobe of Liver 7. 8. 9. 10. 11. Right Medial Lobe of Liver Right Lateral Lobe of Liver Gall Bladder Spleen Greater Omentum Cat Abdomen – Greater Omentum Removed 1. 2. 3. 4. 5. 6. 7. Cardiac Stomach Fundic Stomach Stomach Body Pyloric Stomach Lesser Omentum Duodenum Pancreas (Ventral) 8. 9. 10. 11. 12. 13. 14. Ascending Colon Ileum Jejunum Sigmoid Colon Spleen Gastrospleenic Ligament Bladder Small and Large Intestine Removed 1. 2. 3. 4. 5. Small Intestine THE Mesentary Ileum Cecum Ascending Colon 6. 7. 8. 9. 10. Transverse Colon Descending Colon Sigmoid Colon Mesocolon Greater Omentum Gall Bladder and Lobes of the Liver BIOL 204 Lab Week 12 Digestive Enzymes Digestive Enzymes: are used in the lumen of the GI tract to break down complex molecules into absorbable subunits Enzymes are biological catalysts which increase the rate of a chemical reaction without themselves becoming part of the product: In this experiment we will observe the activity of three different enzymes: Amylase: digests starch into disaccharides Trypsin: digests proteins into peptides Lipase: digests fats into glycerol and fatty acids Variables tested …… 1. Incubation temperature: How will enzyme activity compare when incubated at O o C and 37 o C? 2. Denaturization of Enzymes How will enzyme activity be altered if the enzyme is denatured by boiling? Activity 1 Trypsin Activity Trypsin an enzyme, secreted by pancreatic acinar cells, that hydrolyzes proteins into small fragments (peptones, peptides and proteoses)” In this experiment, trypsin will act on an artificial substrate to yield a yellow colored product: Trypsin BAPNA + H2O 1. N-benzoyl-L-arginine + p-nitroaniline (yellow) Reaction rate will be compared at these different incubation temperatures: 370 C and 0o C What do you predict will happen? 2. The rate of the reaction will be determined using boiled trypsin. What do you predict will happen? Activity 2 Amylase Activity Amylase is a carbohydrate digesting enzyme, produced by salivary glands and pancreatic acinar cells, that hydrolyzes starch into maltose (disaccharides): Amylase Starch + H2O maltose (disaccharides) Indicators: Starch: IKI (Lugol’s solution) - turns “blue/black” in the presence of starch Benedict’s Solution: turns green/orange/ red/brown in the presence of reducing sugar IKI Test For Starch in a Spot Plate Benedict’s Test for reducing sugar in heat test tubes As in activity one, the reaction will be observed under different conditions: Boiled Enzyme (Amylase) Incubation Temperature: 0oC and 37oC Activity 3 Lipase Activity Lipase is a hydrolytic enzyme, made primarily by pancreatic acinar cells, that hydrolyzes neutral fats into fatty acids and glycerol: Lipase Fat + H2O Fatty Acids + Glycerol Fat Digestion: Indicator: Blue litmus turns pink (red) in the presence of acid (one the products is fatty acids) Bile emulsifies fat…. In this activity, you will examine the effect of: incubation temperature (0oC vs. 37oC) and addition of bile salts on the reaction