1. Chapter 19.5-Stomach

2. Four Regions 1)Cardia 2)Fundus 3)Body 4)Pylorus -Pyloric sphincter CARDIA BODY FUNDUS PYLORUS Pyloric sphincter Rugae of mucosa

3. Gastric Glands -The rugae is covered is lined with gastric pits -Gastric pits contain epithelial secretory cells called gastric glands -Mucous surface and neck cells: secrete mucous into lumen -Chief cells: secrete inactive enzyme pepsinogen -Parietal cells: Secrete HCl; turns pepsinogen -> pepsin -All of these secretions are called gastric juice -G Cells secrete gastrin into blood stream

4. Gastric pits Surface mucous cell Mucous neck cell Parietal cell Chief cell G cell

5. Digestion and Absorption in Stomach -HCl secretions trigger nerve impulses that initiate mixing waves -Produces chyme -Forces a small amount of chyme through pyloric sphincter -Different food types spend different amounts of time in stomach

6. Digestion and Absorption in Stomach -Protein digestion begins in the stomach -Pepsin breaks peptide bonds between amino acids -Stomach cells protected by mucous lining -Triglycerides broken down into fatty acids by lingual lipase -Very little absorption takes place in stomach

7. Chapter 19.6- Pancreas

8. Structure of the Pancreas -Lies behind the stomach -Connected to the small intestines via hepatopancreatic duct -Pancreatic duct combined with common bile duct from liver -Epithelial cells secrete pancreatic juice -Mixture of fluid and digestive enzymes -Other cells secrete hormones Left hepatic duct Right hepatic duct Gallbladder Hepatopancreatic duct to duodenum Pancreatic duct Common bile duct Pancreas

9. Pancreatic Juice -Consists of water, salts, sodium bicarbonate, and enzymes -Bicarbonate (pH=7.1-8.2) makes the juice basic -Digestive Enzymes: -Pancreatic amylase -> starch -Trypsin (activated by enterokinase) -> protein -Chymotrypsin (activated by trypsin) -> protein -Carboxypeptidase (activated by trypsin) -> protein -Pancreatic lipase -> fats -Ribonuclease and deoxyribonuclease -> nucleic acids