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.

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.

Diaphragm Liver – left lobe Falciform Ligament Liver right lobe Stomach Greater Omentum Ascending Colon Cecum Small Intestine Descending Colon Sigmoid Colon

An Appendix, Unfixed

Gall Bladder on the Underside of the Liver

Liver – Gross View Serosal Surface

Human Duodenum, Unfixed

Cat Dissection Parotid Gland Sublingual Gland Submandibular Gland Esophagus Tongue Masseter Muscle Larynx Trachea                                        1. Parotid gland   2. Sublingual gland   3. Submandibular gland   4. Esophagus   5. Tongue   6. Masseter muscle   7. Larynx   8. Trachea

Cat Dissection Abdomen 1. Diaphragm 7. Right Medial Lobe of Liver 2. Round Ligament 8. Right Lateral Lobe of Liver 3. Falciform Ligament 9. Gall Bladder 4. Left Lateral Lobe of Liver 10. Spleen 5. Left Medial Lobe of Liver 11. Greater Omentum 6. Quadrate Lobe of Liver

Cat Abdomen – Greater Omentum Removed 1. Cardiac Stomach 8. Ascending Colon 2. Fundic Stomach 9. Ileum 3. Stomach Body 10. Jejunum 4. Pyloric Stomach 11. Sigmoid Colon 5. Lesser Omentum 12. Spleen 6. Duodenum 13. Gastrospleenic Ligament 7. Pancreas (Ventral) 14. Bladder

Small and Large Intestine Removed

1. Small Intestine 6. Transverse Colon 2. THE Mesentary 7. Descending Colon 3. Ileum 8. Sigmoid Colon 4. Cecum 9. Mesocolon 5. Ascending Colon 10. 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:

Amylase: digests starch into disaccharides 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 …… Incubation temperature: How will enzyme activity compare when incubated at O o C and 37 o C? 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)”

What do you predict will happen? In this experiment, trypsin will act on an artificial substrate to yield a yellow colored product: Trypsin BAPNA + H2O N-benzoyl-L-arginine + p-nitroaniline (yellow) 1. 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?

Starch + H2O maltose (disaccharides) 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….

incubation temperature (0oC vs. 37oC) In this activity, you will examine the effect of: incubation temperature (0oC vs. 37oC) and addition of bile salts on the reaction