Bio 202 Exam 4 - Chapter 23

A) rectum B) stomach C) esophagus D) small intestine Answer (D) Small intestine Several areas of the digestive tract are capable of peristalsis, which propels food onward, but only the small intestine undergoes segmentation. The purpose is to mix food with enzymes and bring it close to intestinal walls.

A) Propulsion B) Ingestion C) Digestion D) mechanical breakdown Answer (D) Mechanical breakdown Chewing breaks apart and grinds food and mixes it with saliva.

A) Metabolism comprises all of the chemical reactions preformed within the body while digestion is only the breakdown of food within the GI tract. B) Digestion has a wide variety of chemical reactions while metabolism is restricted to only a few reaction types. C) Digestion requires enzymes for it to take place while metabolism does not necessarily need or use them. D) Digestions must happen first for metabolism to follow it. Answer (A) Metabolism comprises all of the chemical reactions preformed within the body while digestion is only the breakdown of food within the GI tract.

A) Receives blood via the hepatic portal system B) Increases surface area for absorption via villi and microvilli C) Only digestive structure with three muscle layers D) Produces enzymes that break down all categories of foodstuffs E) Bacteria process undigested chyme from the small intestine

A) in the walls of the tract organs B) in the glandular tissue that surround the organ lumen C) in the pons and medulla D) in the oral cavity Answer (A) in the walls of the tract organs

A) spreads directly to the parietal peritoneum B) spreads directly to the retroperitoneal organs C) causes appendicitis D) All of the listed responses are correct. Answer (A) spreads directly to the parietal peritoneum The parietal peritoneum lines the body wall and is separated from the visceral peritoneum by the fluid-filled peritoneal space.

A) mucosa B) serosa C) submucosa D) muscularis externa Answer (D) Muscularis externa Contractions of the circular and longitudinal layers of the muscularis externa produce the effects of peristalsis and segmentation. In the stomach, an additional muscle layer adds a twisting action.

A) muscularis externa B) serosa C) submucosa D) mucosa Answer (C) Submucosa The submucosa layer contains blood and lymphatic vessels, lymphoid follicles, and the submucosal plexus of nerve fibers.

A) pulmonary B) splanchnic C) enterohepatic D) hepatic portal Answer (D) Hepatic Portal The hepatic portal circulation drains all of the blood from the digestive organs and routes that blood through the liver for processing.

A) the rubrospinal tracts B) somatic neurons in the spinal cord C) the reticulospinal and vestibulospinal tracts D) the vagus nerve and enteric plexus Answer (D) The vagus nerve and enteric plexus

A) "down" B) "no" C) "biology" D) All of the listed responses are correct. Answer (D) All of the listed responses are correct

A) Saliva contains enzymes that begin the chemical breakdown of proteins. B) Saliva cleanses the mouth. C) Saliva moistens food and helps compact it into a bolus. D) Saliva dissolves food chemicals so that they can be tasted. Answer (A) Saliva contains enzymes that begin the chemical breakdown of proteins. Saliva contains components with functions ranging from starch breakdown to fighting bacterial infection, but it does not contain any enzymes that digest protein.

A) ingestion of spicy foods B) relaxing after a meal C) being stressed or frightened D) the sight or smell of food Answer (C) being stressed or frightened The sympathetic division of the autonomic nervous system is associated with fight-or-flight responses. Stimulation of the salivary glands by the SNS tends to inhibit flow, as when you are scared or nervous and your mouth "goes dry."

A) 8 B) 16 C) 20 D) 32 Answer (D) 32 There are two incisors (2I), one canine (1C), two premolars (2PM) and three molars (3M) for a total of 8 on each side of each jaw. Multiply by 4 for a total of 32 adult teeth.

A) premolar tooth B) incisor tooth C) canine tooth D) molar tooth Answer (C) Canine tooth

A) detection of nutrients in the esophagus B) peristalsis in the esophagus C) pH changes in the esophagus D) constriction of the upper esophageal sphincter Answer (B) peristalsis in the esophagus As the peristaltic wave triggered by deglutition reaches the stomach, the gastroesophageal sphincter relaxes and allows food into the stomach.

A) body B) fundus C) cardia D) pylorus Answer (D) Pylorus The pylorus is the lowest part of the stomach. It attaches to and empties food into the small intestine via the pyloric sphincter.

A) intrinsic factor B) pepsinogen C) hydrochloric acid D) Vasoactive intestinal peptide (VIP) Answer (A) intrinsic factor Without the production of intrinsic factor by gastric parietal cells, the body would not be able to absorb vitamin B12 in the small intestine.

A) deglutition B) absorption C) defecation D) mechanical breakdown Answer (D) mechanical breakdown Mechanical breakdown occurs in the stomach by churning.

A) Many potentially harmful bacteria will be prevented entry to the small intestine by stomach acid. B) Stomach acid denatures proteins making the polypeptide chain more accessible to pepsin digestive enzymes. C) The stomach's acid catabolically breaks down food stuffs in preparation for absorption. D) Low pH converts pepsinogen to its active form of pepsin, preventing the protease enzyme from digesting the cells that produce it. Answer (C) The stomach's acid catabolically breaks down food stuffs in preparation for absorption.

A) parietal cells B) surface epithelial cells C) chief cells D) mucous neck cells Answer (A) parietal cells

A) decrease the activities of the accessory digestive organs B) increase the release of digestive enzymes and bile C) increase stomach emptying D) increase the force of stomach contractions Answer (B) increase the release of digestive enzymes and bile

A) It would reduce the symptoms of heartburn. B) It would raise the pH of the stomach. C) It would cause the release of secretin and cholecystokinin. D) It would lower the activity of parietal cells. Answer (C) It would cause the release of secretin and cholecystokinin.

A) goblet cells of the small intestine B) parietal cells of the stomach C) Brunner's glands in the duodenum D) chief cells of the stomach Answer (D) chief cells of the stomach

A) This type of food would cause secretion of gastrin to cease, resulting in faster gastric emptying. B) Bile would be released from the gallbladder to emulsify the fat in the duodenum. C) Increased production of trypsinogen. D) The acid secretions from the stomach would be sufficient to digest this food but may cause heartburn. Answer (B) Bile would be released from the gallbladder to emulsify the fat in the duodenum.

A) distention B) carbohydrates C) low acidity D) peptides Answer (B) carbohydrates

A) inferior vena cava B) hepatic portal vein C) central vein D) hepatic vein Answer (B) Hepatic portal vein All blood from the digestive organs as well as the spleen is delivered to the liver in the hepatic portal vein before being returned to the general circulation.

A) chymotrypsin B) enteropeptidase C) carboxypeptidase D) amylase Answer (B) enteropeptidase Enteropeptidase is a protein produced by and bound to the membranes of intestinal cells. Contact with this protein converts trypsinogen to trypsin, the active form of the enzyme.

A) secreting hormones that help digest food in the duodenum B) neutralizing chyme entering the small intestine from the stomach C) acidifying the contents of the small intestine D) emulsifying fats by breaking them into smaller pieces Answer (B) neutralizing chyme entering the small intestine from the stomach Pancreatic juice contains bicarbonate (as baking soda does) that can neutralize the pH of acidic chyme coming from the stomach.

A) eating a low to no carb diet B) eating fewer, but larger meals C) eating foods that are low in fat D) increasing unsaturated fats while eliminating trans fats in their diets Answer (C) eating foods that are low in fat

A) carbohydrates B) proteins C) starches D) lipids Answer (D) lipids

A) Bile is both an excretory product and a digestive secretion. B) Bile functions to emulsify fats. C) Bile functions to carry bilirubin formed from breakdown of worn-out RBCs. D) Bile contains enzymes for digestion. Answer (D) Bile contains enzymes for digestion.

A) process nutrients B) produce digestive enzymes C) detoxify toxic chemicals D) store fat-soluble vitamins Answer (B) produce digestive enzymes

A) villi B) intestinal crypts C) microvilli D) circular folds Answer (D) circular folds The circular folds of the small intestine help slow the progress of food through the intestine so that it can be digested and absorbed more effectively. These folds also increase surface area and help mix chyme.

A) Paneth cells B) enteroendocrine cells C) absorptive cells D) goblet cells Answer (D) goblet cells Goblet cells, which secrete mucus and are found in several areas of the digestive tract, are located on the villi of the small intestine.

A) special blood capillaries in the villi designed for absorbing food effectively B) a lymphatic vessel designed to help introduce fats to the blood C) a deep pocket in the intestinal wall where endocrine and antimicrobial cells are located D) a projection of the small intestine wall designed to increase surface area Answer (B) a lymphatic vessel designed to help introduce fats to the blood Lacteals are lymphatic vessels located in the intestinal villi. Their ability to accept large materials makes them helpful in transporting large fat particles (called chylomicrons) into the lymph for eventual transport to the bloodstream.

A) jejunum B) duodenum C) ileum D) colon Answer (B) Duodenum This is the first segment of the small intestine.

A) circular folds B) villi C) rugae D) microvilli Answer (C) rugae Rugae are a structural modification that allow expansion of the stomach wall. Three structural modifications of the small intestine—circular folds, villi, and microvilli—amplify its absorptive surface enormously (by a factor of more than 600 times). The result is an intestinal surface area equal to about 200 square meters, the size of a singles tennis court!

A) stomach and duodenum B) descending and sigmoid colon C) jejunum and ileum D) cecum and ascending colon Answer (C) jejunum and ileum The majority of nutrients are absorbed as digesting foods make their way through the jejunum (~8 feet long) and ileum (~12 feet long) of the small intestine. Although absorption begins in the duodenum, it is too short (~12 inches long) to account for the majority of nutrient absorption.

A) arge intestine B) pancreas C) stomach D) mouth Answer (C) stomach As the stomach releases its contents into the small intestines, enterogastric reflexes and gastrin released by the stomach affect the motility of the small intestine.

A) secrete enzymes that kill bacteria B) secrete hormones C) secrete digestive enzymes D) secrete bicarbonate ions Answer (A) secrete enzymes that kill bateria

A) enterocytes B) microvilli C) the muscularis layer of the intestine D) mucosal stem cells Answer (C) the muscularis layer of the intestine The muscularis is a smooth muscle bilayer. Smooth muscle has a relatively slower rate of mitosis.

A) atrophy of the muscularis externa B) atrophy of the mucosa C) weakening of the colon's submucosa D) thickening of the serosa Answer (C) weakening of the colon's submucosa The submucosa is composed of dense connective tissue containing elastic fibers, blood and lymphatic vessels, lymph nodes, and nerves.

A) increases the activity of the longitudinal layer of the muscularis B) increases the activity of the parasympathetic division of the ANS C) inhibits muscle tone in the anal sphincters D) inhibits the activity of the myenteric nerve plexus Answer (D) inhibits the activity of the myenteric nerve plexus The myenteric nerve plexus is the major nerve supply that controls gastrointestinal tract motility.

A) haustral contractions B) mass movement C) Valsalva's maneuver D) defecation reflex Answer (B) Mass movement Mass movement propels food residue over large areas of the colon three to four times a day. The defecation reflex occurs when the rectal wall stretches as mass movements force feces into it.

A) primary digestion of food B) mechanical breakdown of food C) nutrient absorption D) water absorption and feces elimination Answer (D) water absorption and feces elimination Though most water is absorbed in the small intestine, the absorption of most remaining water and the elimination of feces are the primary physiological functions of the large intestine. The large intestine also provides a transport route and a surface for healthful bacteria.

A) absorption of electrolytes B) absorption of water C) synthesis of intrinsic factor D) synthesis of vitamins Answer (C) synthesis of intrinsic factor Intrinsic factor is produced in the stomach; it is required for absorption of vitamin B12 in the small intestine.

A) amylases B) nuclease C) proteases D) trypsin Answer (A) amylases Amylases hydrolyze carbohydrate chains.

A) in the form of chylomicrons B) in the form of micelles C) in the form of glycerol D) in the form of fatty acids and glycerol Answer (A) in the form of chylomicrons Within enterocytes, fats are combined with phospholipids and cholesterol, and coated with proteins to form water-soluble lipoprotein droplets called chylomicrons. Chylomicrons are secreted first into lymphatic vessels where they are eventually emptied into the bloodstream.

A) lipid emulsification B) lipid digestion C) lipid absorption D) lipid ingestion Answer (A) lipid emulsification

A) is accomplished by cotransporters that use the concentration gradient of Na+ outside of the cells B) requires vesicular, active transport of the relatively large fatty acids and monoglyceride C) requires enzymes attached to the brush border to further breakdown the fats D) occurs by simple diffusion because lipids are able to penetrate the hydrophobic fatty acid tails within the plasma membrane Answer (D) occurs by simple diffusion because lipids are able to penetrate the hydrophobic fatty acid tails within the plasma membrane

A) pepsin B) amylase C) chymotrypsin D) lipase Answer (D) Lipase