BIO 241 1st EditionExam #4 Study Guide Lectures: 18-22Lecture 18 (March 2)Why do we need a digestive system?Food comes to us in complex molecules so we need to break them down in order to get their nutrients. The fold of the peritoneum that suspend the small intestine from the posterior wall of the abdomen isknown as the mesenteryThe fauces is the:A. Opening from the mouth into the oropharynx.B. Opening of the parotid duct into the mouth opposite the upper second molar.C. Proximal opening of the esophagus.D. Opening into the nasopharynx above the soft palate.E. Distal openings of the small intestine into the large intestine.From the esophagus to the anal canal, the walls of the gastrointestinal tract are made up of the same four basic layers. Arrange them in order from the lumen.A. Muscularis externa, serosa (adventitia), mucosa, submucosaB. Serosa (adventitia), mucosa, submucosa, muscularis externaC. Submucosa, serosa (adventitia), muscularis externa, mucosaD. Muscularis interna, mucosa, muscularis externa, serosa (adventitia)E. Mucosa, submucosa, muscularis externa, serosa (adventitia)When a bolus of chyme is moved into the duodenum, a number of physiologic processes are initiated byboth the nervous system and the endocrine system. List, and then give a brief explanation for each. (10points)(1)stimulation of duodenal enteric nervous system (1/2)increased activity of the duodenum +(1/2)inhibition of the stomach(1)activation of the enterogastric reflex (1/2)decreased activity of the stomach(1)secretion of cholecystokinin (1/2)inhibition of the stomach +(1/2)contraction of the gallbladder +(1/2)relaxation of the sphincter of Oddi +(1/2)stimulation of pancreatic enzyme secretion(1) secretion of secretin (1/2)inhibition of the stomach +(1/2)increased bile secretion by the liver +(1/2)increased pancreatic sodium bicarbonate secretion(1) secretion of gastrin (1/2)increased activity of the stomachLecture 19 (March 4) The purpose of saliva is:A. To cleanse the mouth and dissolve food particles.B. To moisten food and aid in compacting it into a bolus.C. To provide an enzyme that breaks down starchy foods.D. Described by all of the above statements.E. Described by none of the above statements.The secretion of saliva can be stimulated by:A. Chewing. D. All of the above.B. A mental picture of liked food. E. None of the above.C. Presence of food in the mouth.The second phase of deglutition is reflexive and begins in the pharynx.Rugae are longitudinal folds of the gastric mucosa that allow the stomach to fill with food before itstretches.Lecture 20 (March 6)One role of segmentation is to mix chyme with pancreatic juice.Secretion of gastric juice could be inhibited by:1. The intestinal phase of gastric control.2. Inhibition of the vagus nerve.3. Inhibition of local reflexes.A. Only 1 is correct. D. Only 1 and 3 are correct.B. Only 2 is correct. E. All are correct.C. Only 3 is correct.Enterogastric reflex results in decreased activity of the stomach.Which substance begins to break down in the mouth via salivary amylase?Starch  maltoseT/F There is a significant amount of absorption in the stomachLecture 21 (March 16)What is secreted from the pancreas?(Pro)carboxypeptidaseWhat would happen to digestion in the small intestine if the pancreas stopped its secretion of sodium bicarbonate?A. Nothing – other organs would increase their secretions to make up the difference.B. Nothing really, since all digestive organs are capable of all the steps in digestion.C. Digestion started in the stomach would continue until all foodstuffs were completely digested to their absorbable forms.D. Digestion started in the stomach would continue, but foodstuffs would not be completely digested to their absorbable forms.E. Foodstuffs would be absorbed into the liver where hepatocytes would complete the digestive process.Secretin stimulates secretion of pancreatic juice rich in sodium bicarbonate.The ingestion of a fat-rich meal would cause which of the following to occur?A. Severe indigestion caused by a lack of sufficient digestive enzymes.B. Excessive gastrin secretion to offset the high fat content.C. Enough acid secretions from the stomach to ensure the fat digestion.D. Bile would be released from the gallbladder into the duodenum.E. All of the above would occur.Hepatocytes are cells that:1. Secrete digestive enzymes.2. Process newly absorbed nutrients.3. Store fat-soluble vitamins and other substances.4. Detoxify substancesA. 1 and 2 only D. 1, 3, and 4 onlyB. 3 and 4 only E. 2, 3, and 4 onlyC. 1 and 3 onlyLecture 22 (March 18)To store and concentrate bile is the function of the gallbladder.Cholecystokinin stimulates contraction of the gallbladder.Union of the cystic duct and the common hepatic duct form the common bile duct.On the absorptive surface of small intestinal epithelial cells microvilli, which greatly increase the totalsurface area available for absorption.Secretin is a hormone secreted by the duodenal mucosa in response to:A. Irritation of the lining of the stomach.B. Acidic chyme entering the small intestine.C. Distention of the stomach by a meal.D. The enterogastric reflex.E. The gastroileal reflex.Sucrase is secreted by cells of the small intestineThe final products of fat digestion are absorbed into lacteals, vessels located in the villi of the smallintestine.Choose the correct path for an absorbed lipid (via chylomicrons).1. Artery 4. Lacteal2. Thoracic duct 5. Arteriole3. Blood capillary 6. VeinA. 3, 6, 1, 2, 4, 5 D. 3, 5, 1, 6, 2, 4B. 4, 2, 6, 1, 5, 3 E. 2, 4, 1, 5, 3, 6C. 4, 2, 5, 1, 2, 6The outer longitudinal muscle of the large intestine is modified into three bands called the taenia coli.Gastrocolic reflex leads to rapid filling of the rectum and results in mass