Unit VI GI System: Practice Questions (+ Temp regulation)

A) Acetyl coenzyme A (Explanation: beta-oxidation produces acetyl Co-A)

1. Fatty acid degradation in mitochondria produces which two-carbon substance? A) Acetyl coenzyme A B) Carnitine C) Glycerol D) Glycerol 3-phosphate E) Oxaloacetic acid

D) gastric glands of the stomach (Explanation: pepsinogen is the precursor of pepsin which is secreted form the peptic/ chief cells of the gastric gland. Converted to pepsin when it comes in contact with HCL or other Pepsin -> responsible for protein breakdown)

10. The proenzyme pepsinogen is secreted mainly from which of the following structures? A) Acinar cells of the pancreas B) Ductal cells of the pancreas C) Epithelial cells of the duodenum D) Gastric glands of the stomach

A) facilitated diffusion (Explanation: in GI membrane or epithelium of renal tubules = glucose is transported by secondary active sodium co-transport. In all other cell membranes, glucose is transported from higher to lower concentrations by facilitated diffusion made possible by special binding properties of membrane glucose carrier protein)

10. The transport of glucose through the membranes of most tissue cells occurs by what process? A) Facilitated diffusion B) Primary active transport C) Secondary active co-transport D) Secondary active countertransport E) Simple diffusion

B) esophageal varices (Explanation: esophageal varices = dilated submucosal veins in lower 1/3 of esophagus that enlarge with prolonged portal hypertension. The ascites indicates portal hypertension and the varices commonly bleed, lowering the hematocrit. There is no reason to assume cancer, bleeding is uncommon in those with pancreatitis and jaundice & scleral icerus are common i people with cirrhosis.)

11. A 65-year-old woman with hepatic cirrhosis comes to her physician for a checkup. Physical examination shows ascites. The woman's prothrombin time has doubled since her last visit 3 months ago, and her hematocrit is now 30 percent. What is the most likely cause of this low hematocrit? A) Colon cancer B) Esophageal varices C) Jaundice D) Pancreatitis E) Scleral icterus

A) CCK (Explanation: only GI hormone that inhibits gastric emptying to keep the stomach full for a longer time and reduce further eating)

11. Which hormone is released by the presence of fat and protein in the small intestine and has a major effect in decreasing gastric emptying? A) CCK B) GLIP C) Gastrin D) Motilin E) Secretin

C) Potassium (Explanation: saliva contains 7x the amount of potassium compared to plasma, only 3x the amount of bicarb and low concentrations of Na and Cl)

12. Compared with plasma, saliva has the highest relative concentration of which ion under basal conditions? A) Bicarbonate B) Chloride C) Potassium D) Sodium

D) low, low, high (Explanation: under normal conditions such as those described here, the liver has a high blood flow, low vascular resistance and low BP)

12. During resting conditions, about 75 percent of the blood flowing through the liver is from the portal vein, and the remainder is from the hepatic artery. Which option best describes the liver circulation in terms of resistance, pressure, and flow? Resistance, Pressure, Flow A) High, High, High B) High, Low, High C) Low, High, Low D) Low, Low, High E) Low, Low, Low

B) No, no, no, no (Explanation: none of the mechanisms of heat loss are effective when a person is in water with a temperature higher than body temperature. Body will continue to gain heat until it matches the environment)

13. A scuba diver explores an underwater lava flow where the water temperature is 102°F. Which profile best describes the mechanisms of heat loss that are effective in this man? Evaporation, Radiation, Convection, Conduction A) No No No Yes B) No No No No C) Yes Yes No Yes D) No Yes No Yes E) Yes Yes Yes Yes

F) Yes, Yes, Yes, Yes, Yes (Explanation: all can inhibit gastric acid secretion! Gastric acid stimulates somatostatin release which inhibits acid secretion to suppress gastric secretion. Secretin and GLIP inhibit acid secretion by acting directly on parietal cells to decrease gastric secretion. Enterogastrone are unidentified substances released from the duodenum/jejunum that directly inhibit acid secretion and are used if acid enters intestines inappropriately)

13. Which of the following can inhibit gastric acid secretion? Somatostatin, Secretin, GLIP, Enterogastrones, Nervous Reflexes A) No No Yes No Yes B) No Yes No No No C) No Yes No Yes No D) Yes No No Yes Yes E) Yes No Yes No No F) Yes Yes Yes Yes Yes

A) bile pigments (Explanation: low hematocrit indicates a hemolytic disease such as sickle cell which causes premature destruction of RBCs. High bilirubin in plasma due to increase RBC destruction can lead to the development of pigment stones in the gallbladder composed primarily of bilirubin. Cholesterol stones are common but pigment stores are more likeyl because of the decrease in hematocrit Calcium oxylate = common kidney stone composition)

14. A 34-year-old black man is admitted to the hospital because of steadily increasing intense pain in the upper right side of the abdomen. He is nauseated and vomiting. His hematocrit is 30. Ultrasonography shows the presence of gallstones. Which of the following is the most likely major composition of the gallstones in this man? A) Bile pigments B) Calcium carbonate C) Calcium oxalate D) Cholesterol

B) Stimulate, inhibit, no effect, inhibit, no effect (Explanation: Gastrin stimulates acid secretion, secretin and GLIP inhibit it. CCK = no effect at normal concentration but stimulatory effect at higher than normal concentrations and motilin has no effect on gastric acid secretion)

14. The gastrointestinal hormones have physiological effects that can be elicited at normal concentrations, as well as pharmacological effects that require higher than normal concentrations. What is the direct physiological effect of the various hormones on gastric acid secretion? Gastrin, Secretin, Cholecystokinin, GLIP, Motilin A) No effect Stimulate Stimulate No effect No effect B) Stimulate Inhibit No effect Inhibit No effect C) Stimulate Inhibit No effect No effect No effect D) Stimulate Inhibit Inhibit Stimulate Stimulate E) Stimulate Stimulate Inhibit Inhibit No effect

B) Ammonia!

15. Deamination means removal of the amino groups from the amino acids. Which substance is produced when deamination occurs by transamination? A) Acetyl coenzyme A B) Ammonia C) Citrulline D) Ornithine E) α-Ketoglutaric acid

E) Vagotomy (Explanation: cephalic phase of gastric secretion occurs before food enters stomach and is an anticipatory rxn perceived by the brain that tells the stomach to prepare for food. The sensory information responsible for the cephalic phase travels along the vagus nerve therefore a vagotomy can eliminate this response Antacids neutralize gastric acid but do not inhibit gastric secretions, antigastrin antibody would attenuate but not abolish the cephalic phase, atropine would attenuate the cephalic phase by blocking ACH receptors but does not abolish, and H2 blocker would attenuate but not abolish)

15. The cephalic phase of gastric secretion accounts for about 30 percent of the acid response to a meal. Which of the following can completely eliminate the cephalic phase of gastric secretion? A) Antacids (e.g., Rolaids) B) Antigastrin antibody C) Atropine D) Histamine H2 blocker E) Vagotomy F) Sympathectomy

C) Intestinal bacteria (Explanation: MMCs are peristaltic waves of contraction that start in stomach and continue forward to sweep/ clean house, removing undigested food residue and maintaining low bacterial counts. W/o these waves, bacterial would be able to colonize and proliferate unchecked , especially in the upper GI tract. MMCs have no direct effect on mass movements or swallowing)

16. Migrating motility complexes (MMCs) occur about every 90 minutes between meals and are thought to be stimulated by the gastrointestinal hormone motilin. An absence of MMCs causes an increase in which of the following? A) Duodenal motility B) Gastric emptying C) Intestinal bacteria D) Mass movements E) Swallowing

E) Oxidative phosphorylation (Explanation: 90% of total ATP produced by glucose metabolism is formed during oxidative phosphorylation)

16. Most of the energy released from a glucose molecule occurs as a result of which process? A) Citric acid cycle B) Glycogenesis C) Glycogenolysis D) Glycolysis E) Oxidative phosphorylation

C) Lysine (Explanation: Lysine is an essential AA aka must be included in the diet because we cannot make it. All the other listed amino acids can be made in sufficient quantities by the body. Lysine deficiency is common in poorly designed vegetarian diets)

17. A 29-year-old woman visits her physician because of loss of appetite, fatigue, nausea, and dizziness. Physical examination shows thinning hair. Blood tests show a hematocrit of 32. The woman began following a vegetarian diet suggested by a friend 1 year ago. The physician suspects a dietary deficiently of which substance? A) Alanine B) Glycine C) Lysine D) Serine E) Tyrosine

D) 5.2, 1.8 (Explanation: he has cirrhosis! therefore the rate of bilirubin production is normal and free bilirubin still enters the liver cells to become conjugated. The conjugated bilirubin is mostly returned to the blood so that only small amounts enter bile. This causes elevated levels of direct/ conjugated bilirubin in plasma with normal/near normal unconjugated/ indirect bilirubin)

18. A 45-year-old man is admitted to the emergency department after he was found lying in the street in an inebriated state. He is markedly pale with icteric conjunctivae and skin. His abdomen is distended, and he has shifting dullness, indicating ascites. His liver is enlarged about 5 centimeters below the right costal margin and tender. His spleen cannot be palpated. He has bilateral edema of the legs and feet. Which values of direct and indirect bilirubin (in milligrams per deciliter) are most likely to be present in this man's plasma? Direct, Indirect A) 1.1, 1.2 B) 1.7, 5.4 C) 2.4, 2.5 D) 5.2, 1.8 E) 5.8, 7.2

C) increase, decrease, increase (Explanation: conditions that favor gastric emptying = increased tone of orad stomach which pushes chyme towards pylorus, forceful peristaltic contractions in stomach to move chyme toward pylorus, relaxation of pylorus to allow chyme to pass into duodenum and absence of segmental contraction in the intestine which can impede entry of chyme)

18. Gastric emptying is tightly regulated to ensure that chyme enters the duodenum at an appropriate rate. Which event promotes gastric emptying under normal physiological conditions in a healthy person? Tone of Orad Stomach, Segmentation Contractions in Small Intestine, Tone of Pyloric Sphincter A) Decrease Decrease Decrease B) Decrease Increase Decrease C) Increase Decrease Decrease D) Increase Decrease Increase E) Increase Increase Increase

A) Cyclic adenosine monophosphate (Explanation: cholera toxin causes irreversible increases in cAMP levels in enterocytes in crypts of lieberkuhn of small intestine which opens chloride channels on luminal membrane allowing movement of cl- ions and subsequent na+ and H20 into the lumen -> increased fluid loss = diarrhea)

19. A tropical hurricane hits a Caribbean island, and the people living there are forced to drink unclean water. Within the next several days, a large number of people experience severe diarrhea, and about half of these people die. Samples of drinking water are positive for the bacterium Vibrio cholerae. A toxin from V. cholerae is most likely to stimulate an increase in which of the following in the epithelial cells of the crypts of Lieberkühn in these people? A) Cyclic adenosine monophosphate (cAMP) B) Cyclic guanosine monophosphate (cGMP) C) Chloride absorption D) Sodium absorption

A) duodenocolic (Explanation: mass movements after meals is facilitated by gastrocolic and duodenocolic and result from distention of the stomach and duodenum)

2. A 43-year-old man eats a meal consisting of 40 percent protein, 10 percent fat, and 50 percent carbohydrate. Thirty minutes later the man feels the urge to defecate. Which reflex results in the urge to defecate when the duodenum is stretched? A) Duodenocolic B) Enterogastric C) Intestino-intestinal D) Rectosphincteric

B) 3, 4, 2, 1 (Explanation: pyrogens first raise the set point to higher temperature which activates heat conservation and production mechanism such as vasoconstriction and shivering. Then, once the factor increasing the high temp is removed, the set point is reset to the normal, lower temperature and heat-loss mechanisms, such as sweating and vasodilation, occur.)

2. The following events occurred during the course of a fever in a 12-year-old boy: (1) cutaneous vasodilation and sweating; (2) a return of the set-point temperature to normal; (3) an increase in the set-point temperature to 103°F; and (4) shivering, chills, and cutaneous vasoconstriction. Which of the following best describes the correct temporal order of events during the course of the fever in this boy? A) 4, 3, 2, 1 B) 3, 4, 2, 1 C) 2, 1, 4, 3 D) 4, 2, 1, 3 E) 3, 4, 1, 2 F) 1, 2, 3, 4 G) 2, 3, 1, 4 H) 1, 3, 2, 4

B) Chloride (Explanation: cholera toxin causes irreversible increases in cAMP levels in enterocytes in crypts of lieberkuhn of small intestine which opens chloride channels on luminal membrane allowing movement of cl- ions and subsequent na+ and H20 into the lumen -> increased fluid loss = diarrhea

20. A tropical hurricane hits a Caribbean island, and the people living there are forced to drink unclean water. Within the next several days, a large number of people experience severe diarrhea, and about half of these people die. Samples of drinking water are positive for the bacterium Vibrio cholerae. Which type of ion channel is most likely to be irreversibly opened in the intestinal epithelial cells of these people? A) Calcium B) Chloride C) Magnesium D) Potassium E) Sodium

B) 3 to 6 (Explanation: enterocytes are derived from stem cells in the crypts of lieberkuhn of the small intestine and mature as they migrate upward until they are extruded into the gut lumen. Entire population can be replaced in 3-6 days/ cholera usually runs its course in 3-6 days)

21. A tropical hurricane hits a Caribbean island, and the people living there are forced to drink unclean water. Within the next several days, a large number of people experience severe diarrhea, and about half of these people die. Samples of drinking water are positive for the bacterium Vibrio cholerae. Which range best describes the life span (in days) of an intestinal enterocyte infected with V. cholerae in a person who survives? A) 1 to 3 B) 3 to 6 C) 6 to 9 D) 9 to 12 E) 12 to 15

E) None, none, decrease, none, none (Explanation: CCK is the only GI hormone that INHIBITS gastric emptying by relaxin the orad stomach to increase its compliance and allow the stomach to hold a larger volume of food w/o building pressure. Gastrin, secretin, and GLIP can inhibit emptying at pharmacological doses)

22. The gastrointestinal hormones have physiological effects that can be elicited at normal concentrations as well as pharmacological effects that require higher than normal concentrations. What is the physiological effect of the various hormones on gastric emptying? Gastrin, Secretin, Cholecystokinin, GLIP, Motilin A) Decrease Decrease Decrease Decrease Increase B) Increase Decrease None Decrease Increase C) Increase None None Increase Increase D) None None Decrease Increase Increase E) None None Decrease None None F) None None Increase None None

B) phosphocreatine (Explanation: contains high energy phosphate bonds and is 3-8x as abundant as ATP or ADP in a cell)

22. Which of the following is the most abundant source of high-energy phosphate bonds in the cells? A) ATP B) Phosphocreatine C) ADP D) Creatine E) Creatinine

B) No, Yes, Yes (Explanation: he has heatstroke! is likely not sweating because not only does the hypothalamic-preoptic area tend to overheat, but body is dehydrating so will want to try to conserve fluid)

23. A 54-year-old man is admitted to the emergency department after being found lying in his yard near a running lawnmower on a hot summer day. His body temperature is 106°F, his blood pressure is normal, and his heart rate is 160 beats/min. Which set of changes is most likely to be present in this man? Sweating, Hyperventilation, Vasodilation of Skin A) No No No B) No Yes Yes C) Yes No Yes D) Yes Yes No E) Yes Yes Yes

E) 4.0 (Explanation: pH of gastric juice is lowest immediately before the meal and 4 hours after consumption; lowest pH does not correlate with high acid secretions following a meal)

23. A healthy 12-year-old boy ingests a meal containing 20 percent fats, 50 percent carbohydrates, and 30 percent proteins. The gastric juice is most likely to have the lowest pH in this boy at which time after the meal (in hours)? A) 0.5 B) 1.0 C) 2.0 D) 3.0 E) 4.0

A) not shared, not shared, not shared, not shared (Explanation: gastrin and CCK DO NOT SHARE any effects on GI function at normal conditions)

24. CCK and gastrin share multiple effects at pharmacological concentrations. Which effects do CCK and gastrin share (or not share) at physiological concentrations? Stimulation of Acid Secretion, Inhibition of Gastric Emptying, Stimulation of Gastric Mucosal Growth, Stimulation of Pancreatic Growth A) Not shared Not shared Not shared Not shared B) Not shared Not shared Shared Not shared C) Not shared Shared Not shared Not shared D) Shared Shared Not shared Not shared E) Shared Shared Shared Shared

B) Anaerobic glycolysis (Explanation: release of energy by glycolysis occurs more rapidly than oxidative release but more slowly than the readily present ATP and phosphocreatine already present in cells)

25. Most of the energy for strenuous exercise that lasts for more than 5 to 10 seconds but less than 1 to 2 minutes comes from what source? A) ATP B) Anaerobic glycolysis C) Oxidation of carbohydrates D) Oxidation of lactic acid E) Conversion of lactic acid into pyruvic acid

C) palatopharyngeal folds (Explanation: located on each side of the pharynx and pulled medially together to from a sagittal slit through which a bolus must pass. Slit functions to selectively allow only food that has been masticated sufficiently to pass by impeding the passage of larger objects. Fx of: Soft palate = pulled upward to close posterior nares which prevents food form passing into nasal cavity larynx = pulled upward and anteriorly by neck muscles during swallowing Epiglottis = swing over opening of larynx during swallowing UES - relaxes to allow food to move into upper esophagus )

25. Swallowing is a complex process that involves signaling between the pharynx and swallowing center in the brain stem. Which structure is critical for determining whether a bolus of food is small enough to be swallowed? A) Epiglottis B) Larynx C) Palatopharyngeal folds D) Soft palate E) Upper esophageal sphincter

D) yes, no, yes (Explanation: when feces enters the rectum, distention of the rectal wall initiates signals through myenteric plexus to send peristaltic waves in the colon and rectum to move feces toward anus. At the same time, the internal anal sphincter relaxes to allow the feces to pass. External anal sphincter usually controlled by conscious brain so disruption ex. due to spinal transection, can lead to automatic emptying)

27. The spinal cord of a 60-year-old woman is severed at T6 in an automobile accident. She devises a method to distend the rectum to initiate the rectosphincteric reflex. Rectal distention causes which of the following responses in this woman? Relaxation of the Internal Anal Sphincter, Contraction of the External Anal Sphincter, Contraction of the Rectum A) No No No B) No No Ye s C) No Yes Yes D) Yes No Yes E) Yes Yes No F) Yes Yes Yes

B) gastric acid secretion (Explanation: use of NSAIDS can lead to NSAID-associated gastritis aka peptic ulceration. pentagastrin should produced a less than normal increase in gastric acid secretion due to inflammation of the stomach mucosa.)

28. An 82-year-old woman with upper abdominal pain and blood in the stool has been taking nonsteroidal anti- inflammatory drugs (NSAIDs) for arthritis. Endoscopy reveals patchy gastritis throughout the stomach. Biopsies were negative for Helicobacter pylori. Pentagastrin administered intravenously would lead to a less than normal increase in which of the following? A) Duodenal mucosal growth B) Gastric acid secretion C) Gastrin secretion D) Pancreatic enzyme secretion E) Pancreatic growth

E) yes, yes, yes, no (Explanation: acid, FAs, and hyperosmotic solutions in duodenum/ jejunum -> suppression of acid secretion. Acid -> stimulates secretin secretion -> secretin secretion inhibits acid secretion. Isotonic solutions have no effect on acid secretion.)

29. Which substances have a physiological role in stimulating the release of hormones or stimulating nervous reflexes, which in turn can inhibit gastric acid secretion? Acid, Fatty Acids, Hyperosmotic Solutions, Isotonic Solution A) No No Ye s No B) No No Ye s Ye s C) Yes Yes No Yes D) Yes Yes Yes Yes E) Yes Yes Yes No

B) decreased plasma colloid osmotic pressure (Explanation: He has cirrhosis! fluid accumulation occurs due to decreased plasma colloid osmotic pressure and increased capillary hydrostatic pressure. the decrease in plasma COP is due to decreased albumin being produced in the liver and low plasma COP encourages edema formation in the periphery. Liver parenchymal cells are damaged in people with cirrhosis and replaced with fibrous tissue which impedes the flow of portal blood through the liver. Increased vascular resistance -> increased portal vein pressure -> increased capillary hydrostatic pressure.)

3. A 72-year-old man with a 25-year history of alcoholism and liver disease visits his physician because of sudden weight gain. One year ago the man had a body mass index (BMI) of 24.9 kg/m 2 ; today his BMI is 28.5 kg/m 2 . Physical examination shows +3 edema in his feet and moderate ascites. Which condition is most likely to have promoted the development of both ascites and peripheral edema in this man? A) Decreased capillary hydrostatic pressure B) Decreased plasma colloid osmotic pressure C) Increased capillary hydrostatic pressure D) Increased plasma colloid osmotic pressure

C) somatostatin (Explanation: when the stomach is empty, pH is at its lowest point and secretion is suppressed because the concentrated H+ in gastric juice stimulate somatostatin release which decrease secretion of gastrin and acid and because the acid itself directly suppresses parietal cells. When a meal is taken in, the buffering effects cause the gastric pH to increase which then decreases somatostatin release. CCK/VIP = no role in regulation of gastric acid secretion)

30. A clinical study is conducted to determine the time course of gastric acid secretion and gastric pH in healthy volunteers after a meal consisting of 10 percent fat, 30 percent protein, and 60 percent carbohydrate. The results show an immediate increase in the pH of the gastric juice after the meal, which is followed several minutes later by a secondary increase in the rate of acid secretion. A decrease in which substance is most likely to facilitate the secondary increase in the rate of acid secretion in these volunteers? A) Gastrin B) Cholecystokinin C) Somatostatin D) Vasoactive intestinal peptide

C) albumin output (Explanation: hepatocyte produce essentially all albumin normally present in the blood)

30. An experimental device containing hepatocytes is developed to provide effective support for patients with hepatic failure pending liver regeneration or liver transplantation. Hepatocyte viability is best documented by an increase in which function? A) Lactate dehydrogenase uptake B) Ethanol output C) Albumin output D) Glucuronic acid uptake E) Oxygen output F) Carbon dioxide uptak

E) Increase, increase, decrease, decrease (Explanation: GH = can increase metabolic rate by stimulating cellular metabolism. Fever increased chemical reactions in the body therefore increasing metabolic rate. Metabolic rate decreases during sleep and prolonged nutrition)

31. The metabolic rate of a person is typically expressed in terms of the rate of heat liberation that results from the chemical reactions of the body. Metabolic rate can be estimated with reasonable accuracy from the oxygen consumption of a person. Which factors tend to increase or decrease a person's metabolic rate? Growth Hormone, Fever, Sleep, Malnutrition A) Decrease, Decrease, Decrease, Decrease B) Decrease, Increase, Decrease, Increase C) Increase, Increase, Increase, Increase D) Increase, Increase, Decrease, Increase E) Increase, Increase, Decrease, Decrease

D) relax, relax, contract, contract (Explanation: vomiting is preceded by anti peristalsis that can begin as far down as the ileum. Distention of upper portion of GI tract, esp. the duodenum = EXCITING FACTOR FOR VOMITING. At onset of vomiting, strong contractions in duodenum and stomach as well as relaxation of LES occur. then, the vomiting act involved a deep breath, relaxation of UES, closure of glottis, strong CONTRACTIONS of abdominal muscle and diaphragm)

31. Vomiting is a complex process that requires coordination of numerous components by the vomiting center located in the medulla. Which of the following occurs during the vomiting act? LES, Upper Esophageal Sphincter, Abdominal Muscles, Diaphragm A) Contract Contract Contract Contract B) Contract Contract Relax Relax C) Relax Contract Contract Relax D) Relax Relax Contract Contract E) Relax Relax Relax Relax

B) gastroileal (Explanation: origin of reflex = "gastro" because initiated by gastric distention and targets ileocecal valve = "ileal". This reflex occurs shortly after eating, causing the ileocecal sphincter to relax)

44. A 65-year-old man eats a healthy meal. Approximately 40 minutes later the ileocecal sphincter relaxes and chyme moves into the cecum. Gastric distention leads to relaxation of the ileocecal sphincter by way of which reflex? A) Enterogastric B) Gastroileal C) Gastrocolic D) Intestino-intestinal E) Rectosphincteric

E) 700 (Explanation: secretin INHIBITS gastrin secretion from normal G cells in antrum and duodenum but STIMULATES gastrin secretion ONLY IN gastrinoma cells. and increase in serum gastrin greater than 110 pg/ml above baseline after administration of secretin is diagnostic.)

32. A 34-year-old woman has a recurrent history of duodenal ulcers associated with diarrhea, steatorrhea, and hypokalemia. Her fasting gastrin level is 550 pg/ml, and basal acid secretion is 18 mmol/hour. Human secretin at a dose of 0.4 μg/kg of body weight is administered intravenously over 1 minute. Post-injection blood samples are collected after 1, 2, 5, 10, and 30 minutes for determination of serum gastrin concentrations. Which serum gastrin concentration is considered diagnostic for gastrinoma in this woman (in pg/ml)? A) 450 B) 500 C) 550 D) 600 E) 700

C) Hartnup's disease (Explanation: condition resembled pellagra from niacin deficiency because it also present with diarrhea, dementia and dermatitis, but is an autosomal recessive trait caused by .a defective gene that codes for an amino acid transporter expressed in the kidney and interstitial epithelium. poor epithelial transport -> poor absorption -> excess amino acid excretion in urine. Is likely due to tryptophan, the precursor of niacin, not being properly transported beriberi = thiamine deficiency Sticklers = group of genetic disorders affecting CT)

32. An 8-year-old girl is taken to the physician because of diarrhea and a red scaly rash. Physical examination shows mild cerebellar ataxia. She is suspected of having pellagra because of these chronic symptoms. However, she appears to be ingesting adequate amounts of niacin in her diet, which is rich in meat. A brother has a similar problem. Urine studies show large amounts of free amino acids. Which diagnosis is most likely? A) Alkaptonuria B) Beriberi C) Hartnup's disease D) Scurvy E) Stickler's syndrome

B) 0.7 (Explanation: lack of insulin -> little carbs used by body's cells -> respiratory quotient remains near that for fat = 0.70 Carbs = 1.0 Proteins = 0.8)

33. In a person with type 1 diabetes who is not receiving insulin therapy and who has a fasting blood glucose of 400 mg/100 ml, what would the respiratory quotient likely be 2 hours after eating a light meal containing 60 percent carbohydrates, 20 percent protein, and 20 percent fat? A) 0.5 B) 0.7 C) 0.9 D) 1.0 E) 1.

E) Yes, Yes, Yes (Explanation: enterokinase activates trypsinogen to become trypsin, trypsin then catalyzes formation of additional trypsin from trypsinogen and pepsin, although first secreted as pepsinogen, is activated by HCL and then turns around and activates other pepsinogens to become pepsin)

33. Various proteolytic enzymes are secreted in an inactive form into the lumen of the gastrointestinal tract. Which of the following substances are important for activating one or more proteolytic enzymes, converting them to an active form? Trypsin, Enterokinase, Pepsin A) No No No B) No No Yes C) No Yes No D) Yes Yes No E) Yes Yes Yes

C) a mutation that produces a non-functional melanocortin-4 receptor protein (Explanation: mutations producing nonfunctional melanocortin-4 receptor proteins cause extreme obesity. excessive stimulation of POMC neurons, excessive secretion of leptin and NPY formation in hypothalamic neuron would cause decreased food intake or increased energy expenditure)

34. A 3-year-old white boy is extremely obese (weight of 37.5 kg), and his parents report that he has a voracious appetite. What is the most likely cause of his hyperphagia and obesity? A) A lesion/destruction of the lateral hypothalamus B) Excessive stimulation of the ventromedial nuclei of the hypothalamus C) A mutation that produces nonfunctional melanocortin-4 receptor protein D) Excessive stimulation of pro-opiomelanocortin (POMC) neurons E) Excessive secretion of leptin F) A mutation that prevents neuropeptide Y (NPY) formation in hypothalamic neuron

B) Yes, no, no (Explanation: plasma gastrin and acid secretion rate are not diagnostic although patients with duodenal ulcers do generally appear with increased rate of acid secretion and decreased plasma gastrin. Endoscopy, however, is diagnostic.)

34. A 71-year-old man with hematemesis and melena has a cresenteric ulcer in the duodenum. Lavage dislodged the clot, revealing an underlying raised blood vessel, which was successfully eradicated via cautery with a bipolar gold probe. Which of the following factors are diagnostic for duodenal ulcer? Endoscopy, Plasma Gastrin Levels, Rate of Acid Secretion A) No No No B) Yes No No C) Yes No Yes D) Yes Yes No E) Yes Yes Yes

C) 25, 15 (Explanation: histamine potentiates the effects of gastrin and ACH and H2 blockers weaken the secretory responses to both ACH and gastrin. ACH potentiates the effects of gastrin and histamine and atropine weakens the secretory effects of histamine and gastrin. So here, the stimulation of acid secretion by pentagastrin is weakened by the H2 blocker)

35. A clinical study is conducted in which gastric acid secretion is stimulated using pentagastrin before and after treatment with a histamine H2 blocker. Which rates of gastric acid secretion (in mEq/hr) are most likely to have occurred in this experiment? Pentagastrin Alone, Pentagastrin + H 2 Blocker A) 15 15 B) 25 25 C) 25 15 D) 26 28 E) 40 45

E) Yes, Yes, Yes, Yes (Explanation: all are secreted after a meal and all have physiological effects gastrin = protein cck = protein and fat glip = all 3 secretin = ??)

36. A 23-year-old medical student consumes a cheeseburger, fries, and chocolate shake. Which of the following hormones produce physiological effects at some point during the next several hours? Gastrin, Secretin, Cholecystokinin, GLIP A) No Yes Yes Yes B) Yes No Yes Yes C) Yes Yes No Yes D) Yes Yes Yes Yes E) Yes Yes Yes Yes

A) increased NPY in hypothalamus (Explanation: NPY is orexigenic = stimulates feeding = increased during food deprivation leptin, PYY, CCK POMC activating = all reduced by fasting Ghrelin = increased by fasting)

36. Which changes would be expected to stimulate hunger in a person who has not eaten for 24 hours? A) Increased NPY in the hypothalamus B) Increased leptin secretion C) Increased peptide YY (PYY) secretion D) Decreased ghrelin secretion E) Activation of hypothalamic POMC neurons F) Increased cholecystokinin secretion

A) Release of CCK by the duodenum (Explanation: CCK is mainly released in response to fat or proteins entering the duodenum -> sends sensory afferents via vagal that contribute to satiation and meal cessation all others --> increase food intake)

37. Which of the following would be most important in contributing to satiety after eating a large meal containing carbohydrates (50 percent), fat (40 percent), and protein (10 percent)? A) Release of cholecystokinin by the duodenum B) Decreased leptin secretion C) Increased release of endorphins D) Increased ghrelin release by the stomach E) Decreased release of PYY by the intestine

A) Ammonium (Explanation: H. pylori is present in 95% of patients with duodenal ulcer and close to 100% of patients with gastric ulcers not due to NSAIDs. Characterized by high urease activity -> metabolizes urea to ammonia/ ammonium which allows the organism to withstand the acidic environment. Ammonium directly damages epithelial cells causing increased permeability of mucosal barriers. Bile salts, gastrin, NSAIDs and pepsin can all damage the mucosa but are not associated with H. Pylori)

39. A 68-year-old woman with hematemesis has heartburn and stomach pain. An endoscopy shows inflammation involving the gastric body and antrum as well as a small gastric ulcer. Biopsies were positive for H. pylori. H. pylori damages the gastric mucosa primarily by increasing mucosal levels of which of the following? A) Ammonium B) Bile salts C) Gastrin D) NSAIDs E) Pepsin

B) Thiamine (vitamin B1)

39. Deficiency of which vitamin is the main cause of beri- beri? A) Vitamin A B) Thiamine (vitamin B1) C) Riboflavin (vitamin B2) D) Vitamin B12 E) Pyridoxine (vitamin B6)

D) Evaporation (Explanation: is the only mechanism of head loss form the body when the environmental temp is greater than body temp)

4. A 24-year-old student goes hiking in the Mojave Desert during spring break. The environmental temperature is 105°F and the relative humidity is 20 percent. Which option best describes the major mechanism of heat loss in this student? A) Conduction to air B) Conduction to objects C) Convection D) Evaporation E) Radiation

E) Vitamin B12 deficiency (Explanation: Vit B12 is absorbed in the ileum. absorption requires IF secreted by parietal cells of stomach which binds to dietary b12 and attached it to the brush border in the ileum. likely to cause diarrhea not constipation)

4. The ileum and distal jejunum of a 34-year-old man are ruptured in an automobile accident. The entire ileum and a portion of the jejunum are resected. What is most likely to occur in this man? A) Atrophic gastritis B) Constipation C) Gastric ulcer D) Gastroesophageal reflux disease (GERD) E) Vitamin B 12 deficiency

B) 10, 0 (Explanation: Slow wave frequency is relatively unaffected by ANS or hormones/ stays relatively constant. When a slow wave reaches a threshold value, a calcium spike potential/action potential occurs -> C2+ enter smooth muscle cell -> contraction. Norep hyperpolarizes smooth muscle cells aka threshold is less likely to be reached -> does not affect basal slow wave frequency but lowers contraction frequency to 0)

40. A physiology experiment is conducted in an isolated rat small intestine. The intestine is bathed with all essential nutrients, ions, and gases in a glass dish maintained at a temperature of 37°C. The proximal jejunum is observed to contract at a frequency of five contractions per minute. A glass micropipette is then inserted into an interstitial cell of Cajal (pacemaker cell) at the same location in the jejunum, and a slow-wave frequency of 10 contractions per minute is recorded. Norepinephrine is then added to the bathing solution. Which of the following best describes the most likely slow-wave frequency and contraction frequency after treatment with norepinephrine (in occurrences per minute)? Slow-Wave Frequency, Contraction Frequency A) 0 0 B) 10 0 C) 10 10 D) 10 5 E) 5 10

C) increased release of PYY by the intestine (Explanation: PYY released in response to food intake. Increased levels have been show to decrease food intake)

40. Which of the following would tend to decrease hunger? A) Increased release of endorphins B) Increased ghrelin release by the stomach C) Increased release of PYY by the intestine D) Increased release of NPY by the hypothalamus E) Increased release of cortisol by the adrenals

E) Yes, Yes, Yes (Explanation: defecation reflex occurs when mass movement forces feces into rectum which contracts reflexively to move feces toward anus via relaxation of internal anal sphincter. External anal sphincter is voluntarily controlled and contracted when defecation is not wanted.)

41. A healthy 21-year-old woman eats a big meal and then takes a 3-hour ride on a bus that does not have a bathroom. Twenty minutes after eating, the woman feels a strong urge to defecate, but manages to hold it. Which mechanisms have occurred in this woman? Relaxation of the Internal Anal Sphincter, Contraction of the External Anal Sphincter, Contraction of the Rectum A) No No No B) No Yes Yes C) Yes No Yes D) Yes No No E) Yes Yes Yes

D) melanocortin-4 receptor antagonist (Explanation: antagonists of melanocortin-4 receptors have been shown to markedly attenuate anorexia by blocking hypothalamic melanocortin receptors)

41. Which substance might be most useful in stimulating appetite in a patient with cancer who has anorexia/cachexia? A) Leptin Β) α-Melanocyte-stimulating hormone C) PYY D) Melanocortin-4 receptor antagonist E) Ghrelin antagonist F) Neuropeptide YY antagonist

E) 12 (Explanation: adenosine dilates the villus artery -> increased blood flow to villus tip -> decreased resistance time for blood in artery -> greater amount of O2 reaching villus tip)

42. A physiology experiment is conducted in an anesthetized rat. The distal duodenum is opened without disturbing its blood supply, and an oxygen-recording micropipette is inserted into the tip of a villus that is submerged in inert oil. An oxygen value of 10 mm Hg is recorded. The distal duodenum at the same location is then treated with the vasodilator adenosine. Which value of oxygen is most likely in the tip of the villus within 2 minutes after treatment with adenosine (in mm Hg)? A) 0 B) 5 C) 7 D) 10 E) 12

E) Yes, Yes, Yes, No, No (Explanation: Gastrin = stimulates mucosal growth throughout GI tract and stimulates pancreatic growth Secretin & CCK = stimulate growth of the exocrine pancreas GLIP & Motilin = no trophic actions on GI tract)

43. One of the following hormones can stimulate growth of the intestinal mucosa, and two other hormones can stimulate pancreatic growth. Which three hormones are these? Gastrin, Secretin, Cholecystokinin, GLIP, Motilin A) No Yes Yes Yes No B) Yes No Yes No Yes C) Yes No Yes Yes No D) Yes No Yes Yes No E) Yes Yes Yes No No

B) 17.6 (Explanation: rate of protein metabolism can be estimated by the nitrogen in the urine + 10% )

43. Urinary nitrogen excretion measured in a patient is 16.0 grams in 24 hours. What is the approximate amount of protein breakdown in this patient for 24 hours in grams? A) 16.0 B) 17.6 C) 100 D) 110 E) 120

C) protein (Explanation: Achlorhydria = stomach cannot secrete HCl. when acid is not secreted, pepsin is also not secreted and function decreases as it requires an acid medium for activity)

8. Digestion of which of the following is impaired to the greatest extent in patients with achlorhydria? A) Carbohydrate B) Fat C) Protein

D) weaken, strengthen, weaken, weaken, strengthen, weaken (Explanation: damage to mucosa causes back leak of H+ ions; mucus and gastrin strengthen gastric mucosal barrier by impeding the influx of hydrogen ions and stimulating mucosal growth, respectively. certain prostaglandins may stimulate mucus secretion and act as protective factors as well)

45. The gastric mucosal barrier has a physiological and an anatomical basis to prevent back-leak of hydrogen ions into the mucosa. Some factors are known to strengthen the integrity of the gastric mucosal barrier, whereas other factors can weaken the barrier. Which factors strengthen or weaken the barrier? Bile Salts, Mucous, Aspirin, NSAIDs, Gastrin, Ethanol A) Strengthen Strengthen Weaken Weaken Strengthen Strengthen B) Strengthen Strengthen Weaken Weaken Weaken Strengthen C) Weaken Strengthen Strengthen Weaken Strengthen Weaken D) Weaken Strengthen Weaken Weaken Strengthen Weaken E) Weaken Weaken Weaken Strengthen Strengthen Weaken

B) 3, 1, 4, 2 (Explanation: fat entering small intestine is first emulsified into smaller globules by bile -> digested by pancreatic lipase/co-lipase = triglycerides -> monoglycerides/FFAs -> become surrounded by bile salts to form micelles (water-soluble) -> makes contact w/ enterocyte and monoglycerides/FFAs diffuse into enterocyte -> form new triglycerides in enterocyte -> packaged by enterocyte golgi into chylomicrons -> exocytosed)

46. The assimilation of fats includes (1) micelle formation, (2) secretion of chylomicrons, (3) emulsification of fat, and (4) absorption of fat by enterocytes. Which sequence best describes the correct temporal order of these events? A) 4, 3, 2, 1 B) 3, 1, 4, 2 C) 3, 4, 1, 2 D) 2, 1, 4, 3 E) 4, 2, 1, 3 F) 2, 4, 1, 3 G) 1, 2, 3, 4 H) 1, 3, 2,

C) Yes, No, Yes, Yes (Explanation: PPIs = bond and irreversibly inhibit H+/K+ ATPase pump H2 Blockers = directed at histamine release and block H2 receptors on parietal cells Abx = can eradicate the H. pylori infection NSAIDs = cause damage to gastric mucosal barrier!)

47. A 62-year-old man with dyspepsia and a history of chronic gastric ulcer has abdominal pain. Endoscopy shows a large ulcer in the proximal gastric body. Biopsies were positive for H. pylori. Which substances are used clinically for treatment of gastric ulcers of various etiologies? Antibiotics, NSAIDs, H2 Blockers, Proton Pump Inhibitors A) No No Yes Yes B) Yes No No Yes C) Yes No Yes Yes D) Yes Yes Yes Yes E) No Yes Yes Yes

B) Chloride (Explanation: the movement of chloride ions out of the cell leads to fluid secretion by cells therefore without the additional fluids being released from the cells, the mucus secreted is too thick)

48. Cystic fibrosis (CF) is an inherited disorder of the exocrine glands affecting children and young people. Mucus in the exocrine glands becomes thick and sticky and eventually blocks the ducts of these glands (especially in the pancreas, lungs, and liver), forming cysts. A primary disruption in the transfer of which ion across cell membranes occurs in CF, leading to decreased secretion of fluid? A) Calcium B) Chloride C) Phosphate D) Potassium E) Sodium

A) Back-leak of hydrogen ions (Explanation: H+ ions leak into the mucosa when damaged, accumulate, saturate intracellular buffers -> decrease pH of cells -> injury/cell death. H+ also damages mast cells causing them to inappropriately release histamine, further damaing the mucosa and capillaries. Results in focal ischemia, hypoxia and vascular stasis if untreated. PPIs = treatments mucus secretion = protective tight jxns = prevent H+ backflow vagotomy = crushing vagus nerve decreases gastic acid secretion)

49. A 45-year-old man presents with abdominal pain and hematemesis. An abdominal examination was relatively benign, and abdominal radiographs were suggestive of a perforated viscus. Endoscopy revealed a chronically perforated gastric ulcer, through which the liver was visible. Which mechanism is a forerunner to gastric ulcer formation? A) Back-leak of hydrogen ions B) Mucus secretion C) Proton pump inhibition D) Tight junctions between cells E) Vagotomy

C) protein (Explanation: metabolic rate increases after a meal because of chemical reactions associated with digestion, absorption and storage of food aka the thermogenic effects of food. After a meal containing mostly carbs and fats, the metabolic rate usually increases by 4% but a high -protein meal can increased metabolic rate by as much as 30 for 3-12 hours after the meal = specific dynamic action of proteins)

5. A 32-year-old student consumes a meal containing 10 percent fat, 50 percent carbohydrate, and 40 percent protein. Four hours later the metabolic rate has increased by about 30 percent, even though the student is sitting at rest. Which substance is most likely to cause the greatest increase in metabolic rate in this student 4 hours after consuming the meal? A) Carbohydrate B) Fat C) Protein

A) bicarbonate (Explanation: potassium is increased in saliva compared to plasma but bicarbonate concentration is higher)

5. Which ion has the highest concentration in saliva under basal conditions? A) Bicarbonate B) Chloride C) Potassium D) Sodium

D) Nitric oxide (Explanation: fundus of stomach and LES normally relax during a swallow through food is higher in the esophagus = "receptive relaxation'. Mediated by NO. Gastrin and histamine = no significant effects on smooth muscle contraction/relaxation Norep = decreases smooth muscle contraction but not involved in receptive relaxation)

50. A 10-year-old boy consumes a glass of milk and two cookies. His LES and fundus relax while the food is still in the esophagus. Which substance is most likely to cause relaxation of the LES and fundus in this boy? A) Gastrin B) Histamine C) Motilin D) Nitric oxide E) Norepinephrine

B) Gastrin only (Explanation: gastrin is critical in stimulating mucosal growth throughout the GI system

51. A 19-year-old man is fed intravenously for several weeks after a severe automobile accident. The intravenous feeding leads to atrophy of the gastrointestinal mucosa, most likely because the blood level of which of the following hormones is reduced? A) Cholecystokinin only B) Gastrin only C) Secretin only D) Gastrin and cholecystokinin E) Gastrin and secretin F) Secretin and cholecystokinin

A) bowel movements (Explanation: mass movements force feces into rectum -> wall of rectum stretched -> defecation reflex initiated -> bowel movement when convenient. No effect of mass movements on esophageal contractions or pharyngeal peristalsis)

52. Mass movements are often stimulated after a meal by distention of the stomach (gastrocolic reflex) and distention of the duodenum (duodenocolic reflex). Mass movements often lead to which of the following? A) Bowel movements B) Gastric movements C) Haustrations D) Esophageal contractions E) Pharyngeal peristalsis

E) vagus nerve (Explanation: gastroparesis = delayed gastric emptying = disorder that slows or stops movement of chyme from stomach to duodenum MOST COMMONLY CAUSED BY DM . high blood glucose os thought to damage the vagus nerve and delay gastric emptying)

53. A 45-year-old woman with type 1 diabetes has an early feeling of fullness when eating. She is often nauseous after a meal and vomits about once each week after eating. Glucose-induced damage to which structure is most likely to explain her gastrointestinal problem? A) Celiac ganglia B) Enteric nervous system C) Esophagus D) Stomach E) Vagus nerve

C) Acid, Somatostatin (Explanation: acid acts directly on somatostatin cells to stimulate somatostatin release -> somatostatin release = decreased activity of gastric secretion from G cells in antrum. Acid is also a weak stimulus for CCK release but CCK does not act on gastrin release.)

54. Which stimulus-mediator pair normally inhibits gastrin release? Stimulus, Mediator A) Acid, CCK B) Acid, GLIP C) Acid, Somatostatin D) Fatty acid Motilin E) Fatty acid Somatostatin

C) duodenum (Explanation: all 5 gastrointestinal hormones are released from BOTH the duodenum and jejunum. Only gastrin is also released from the antrum and small amounts of CCK and secretin are released from the ileum. no GI hormones are released from the colon or esophagus.)

55. A 55-year-old man consumes a meal consisting of 20 percent fat, 50 percent carbohydrate, and 30 percent protein. The following gastrointestinal hormones are released at various times during the next 6 hours: gastrin, secretin, motilin, glucose-dependent insulinotropic peptide, and cholecystokinin. Which structure is most likely to release all five hormones in this man? A) Antrum B) Colon C) Duodenum D) Esophagus E) Ileum

D) primary esophageal peristalsis (Explanation: visceral somatic fibers in the vagus nerves directly innervate smooth muscles fibers of the pharynx and upper esophagus which coordinate pharyngeal peristalsis and indirectly primary peristalsis of the esophagus. Secondary esophageal persitalsis = Esophageal contractions occur independently of vagal stimulation by a local stretch reflex initiated by the food bolus itself. vagus nerve can stimulate gastrin acid secretion, gastrin release and pancreatic bicarb secretion but these processes are activated by other mechanisms as well and therefore wouldn't be eliminated if there were no vagal stimulation)

56. An 89-year-old man has a cerebrovascular accident (stroke) in the medulla and pons that completely eliminates all vagal output to the gastrointestinal tract. Which function is most likely to be totally eliminated in this man? A) Gastric acid secretion B) Gastrin release C) Pancreatic bicarbonate secretion D) Primary esophageal peristalsis E) Secondary esophageal peristalsis F) None of the above

D) Increased, Increased, Decreased (Explanation: patients with duodenal ulcers tend to have twice as may parietal cells as unaffected individuals. Plasma gastrin levels are inversely related to acid secretion therefore if acid is increased then plasma gastrin will be decreased)

57. An 84-year-old man with hematemesis and melena is diagnosed with a duodenal ulcer. A patient diagnosed with a duodenal ulcer is likely to exhibit which of the following? Parietal Cell Density, Acid Secretion, Plasma Gastrin A) Decreased Decreased Decreased B) Decreased Increased Decreased C) Increased Decreased Increased D) Increased Increased Decreased E) Increased Increased Increased

C) Atropine (Explanation: atropine weakens the effects of gastrin. gastrin, ACh and histamine directly stimulate parietal cells to secrete acid. inhibition of one reduces the effectiveness of the remaining two.)

58. The gastric phase of gastric secretion accounts for about 60 percent of the acid response to a meal. Which substance can virtually eliminate the secretion of acid during the gastric phase? A) Antacids (e.g., Rolaids) B) Antigastrin antibodies C) Atropine D) Histamine H 2 blocker E) Proton pump inhibitor

A) intrinsic factor (Explanation: IF is secreted from parietal cells for the absorption of B12. Acid and IF are both secreted by parietal cells therefore a diminished capacity to secrete acid is usually associated with a diminished capacity to produce IF ptyalin = salivary amylase; not affected by gastritis rennin = chymosin = proteolytic enzyme synthesized by chief cells in stomach and responsible for milk digestion saliva secretion = not affected by gastritis trypsin = proteolytic enzyme secreted by pancreas)

59. A 71-year-old man with upper abdominal pain and blood in the stool takes NSAIDs for the pain and washes it down with whiskey. Pentagastrin administration produced lower than predicted levels of gastric acid secretion. Secretion of which substance is most likely to be diminished in this patient with gastritis? A) Intrinsic factor B) Ptyalin C) Rennin D) Saliva E) Trypsin

B) Glucose-dependent insulinotropic peptide (GLIP) (Explanation: is the only GI hormone released in response to all three major foodstuffs! fat and protein only= stimulate CCK release protein in stomach antrum = stimulates gastrin release fat has minor effect on motilin or secretin secretion and neither is released by presence of protein or carbs in the GI tract!)

6. A 10-year-old boy consumes a cheeseburger, fries, and chocolate shake. The meal stimulates the release of several gastrointestinal hormones. The presence of fat, carbohydrate, or protein in the duodenum stimulates the release of which hormone from the duodenal mucosa? A) Cholecystokinin (CCK) B) Glucose-dependent insulinotropic peptide (GLIP) C) Gastrin D) Motilin E) Secretin

E) Sweating (Explanation: he has heatstroke! when the body temp rises to 105-108, heat loss mechanisms are overwhelmed by metabolic production of heat/ excessive environmental heat. Usually accompanied with dehydration which can produce the the headache, nausea and hypotension. hypothalamic-preoptic area of the brain normally responsible for sweating is usually compromised at these high temperatures)

6. A 70-year-old man is found sitting in his yard, vomiting on a hot summer day with the lawnmower running. The man is confused and dizzy. He is admitted to the hospital as an emergency patient. His body temperature is 105°F, his heart rate is 110 beats/min, and his skin turgor is poor. Which symptom is unlikely in this man? A) Headache B) Hot skin C) Hypotension D) Nausea E) Sweating

E) Yes, Yes, No, Yes (Explanation: parietal cell has receptors for gastrin, ACH and histamine therefore these factors may directly inhibit secretion. antigastrin antibodies, atropine and Histamine H2 blockers can reduce secretion but do not have direct action)

60. Gastric acid is secreted when a meal is consumed. Which factors have a direct action on the parietal cell to stimulate acid secretion? Gastrin, Somatostatin, Acetylcholine, Histamine A) No No Yes Yes B) Yes No No Yes C) Yes No Yes Yes D) Yes Yes Yes Yes E) Yes Yes No Yes

C) fecal fat (Explanation: she has celiacs! disease that interferes with absorption of nutrients from food. ingestion of gluten from wheat, and in some cases rye and barley, causes an immunologically mediated inflammatory response to the gliadin in gluten -> malabsorption and maldigestion at brush border. Malabsorption increases the stool concentration of carbs, fat, and nitrogen)

61. A 45-year-old woman adds high-fiber wheat and bran foods to her diet to reduce her serum cholesterol levels. She had avoided eating foods containing wheat or rye since she was a child because her mother said they would make her sick. The woman loses 25 pounds on her new diet but has frequent stomach cramps, gas, and diarrhea. She has also become weaker, finding it difficult to complete her morning walks. What is most likely to be increased in this woman? A) Blood hemoglobin concentration B) Carbohydrate absorption C) Fecal fat D) Protein absorption E) Serum calcium

E) 4, 2, 1, 3 (Explanation: after a meal, the pH of gastric contents increases because the food buffers the acid in the stomach. the increase in pH = suppressed release of somatostatin from delta cells -> increased secretion of gastrin and gastric acid -> decreased pH of gastric contents -> decrease d rate of acid secretion with falling pH)

62. The control of gastric acid secretion in response to a meal involves several events that take place over a 4- or 5-hour period after the meal. These events include (1) a decrease in the pH of the gastric contents, (2) an increase in the rate of acid secretion, (3) a decrease in the rate of acid secretion, and (4) an increase in the pH of the gastric contents. Which sequence best describes the correct temporal order of events over a 4- or 5-hour period after a meal? A) 4, 3, 2, 1 B) 3, 1, 4, 2 C) 3, 4, 1, 2 D) 2, 1, 4, 3 E) 4, 2, 1, 3 F) 1, 2, 3, 4 G) 2, 3, 1, 4 H) 1, 3, 2, 4

B) Enterocolitis (Explanation: symptoms indicate Hirschsprung's disease = characterized by absence of ganglion cells in distal colon at birth causing functional dysfunction. Fecal stasis can lead to enterocolitis and full thickness necrosis or perforation can occur achalasia = LES fails to relax during swallowing Halitosis = bad breath, can occur in Hirschprung's but is not severe peptic ulcer and pancreatitis = not common in people with Hirschsprung's disease)

63. A newborn boy does not pass meconium within 48 hours of delivery. His abdomen is distended, and he begins vomiting. A suction biopsy of a distally narrowed segment of the colon shows a lack of ganglionic nerve cells. This newborn is at risk for developing which condition? A) Achalasia B) Enterocolitis C) Halitosis D) Pancreatitis E) Peptic ulcer

C) 5.0, 1.7 (Explanation: post-hepatic problems ex. gall stones can cause an increase in conjugated/ direct bilirubin)

64. A 43-year-old obese woman with a history of gall - stones is admitted to the emergency department because of excruciating pain in the upper right quadrant. The woman is jaundiced, and a radiograph suggests obstruction of the common bile duct. Which values of direct and indirect bilirubin are most likely to be present in the plasma of this woman (in milligrams per deciliter)? Direct, Indirect A) 1.0 1.3 B) 2.3 2.4 C) 5.0 1.7 D) 1.8 6.4 E) 6.8 7.5

A) endocytosis (Explanation: intestinal absorption of immunoglobulins (ex. present in colostrum) during early infancy can occur during endocytosis. The other are all normal transport processes in adult and infant enterocytes)

65. Which mechanism for transport of substances across the luminal cell membrane of an enterocyte is present in newborns and infants but not in adults? A) Endocytosis B) Facilitated diffusion C) Passive diffusion D) Primary active transport E) Secondary active transport

D) H. pylori (Explanation: ammonium produced damages gastric mucosal barrier by damaging epithelial cells and H pylori also increases gastric secretions, potentially by increasing parietal cell mass. This combination promotes the development of gastric ulcers. Bile salts = can damage gastric mucosal barrier but have no clinically significant effect on acid secretion. All other answer option strengthen the gastric mucosal barrier)

66. Damage to the gastric mucosal barrier is a forerunner of a gastric ulcer. Which substance can both damage the gastric mucosal barrier and stimulate gastric acid secretion? A) Bile salts B) Epidermal growth factor C) Gastrin D) H. pylori E) Mucus

C) Autodigestion of pancreas (Explanation: reduced secretion of fluid into pancreatic ducts cause the digestive enzymes to accumulate in the ducts, become activated and begin to "digest" the pancreas -> inflammation, cysts internal bleeding, etc.)

67. CF is the most common cause of pancreatitis in children. Which option best explains the mechanism of CF-induced pancreatitis? A) Activation of enterokinase B) Activation of trypsin inhibitor C) Autodigestion of pancreas D) Excessive secretion of CCK E) Gallstone obstruction

E) Radiation (Explanation: most head loss from the body occurs by radiation in the form of heat waves. The reflective surface of the mylar blanket prevents heat loss by reflecting the heat waves produced by the body back onto the body. At room temp, 60% of head loss occurs by radiation)

7. A 22-year-old woman on a camping trip has underestimated the cool evening temperatures, so she wraps herself in a thin sheet of polyester film with a reflective surface (Mylar), also known as an emergency blanket or space blanket. She feels warm immediately. Which heat loss mechanism most likely accounts for the effectiveness of this paper-thin, reflective Mylar blanket? A) Conduction to air B) Conduction to objects C) Convection D) Evaporation E) Radiation

D) GLIP-induced insulin release (Explanation: GLIP is released in the presence of fat, carbs and protein in the GI tract and is a strong stimulator of insulin release. an oral glucose load releases more insulin due to GLIP activity because IV glucose does not stimulate GLIP ** neither CCK nor VIP stimulate insulin release!)

7. A clinical experiment is conducted in which one group of subjects is given 50 grams of glucose intravenously and another group is given 50 grams of glucose orally. Which factor can explain why the oral glucose load is cleared from the blood at a faster rate compared with the intravenous glucose load? A) CCK-induced insulin release B) CCK-induced vasoactive intestinal peptide (VIP) release C) GLIP-induced glucagon release D) GLIP-induced insulin release E) VIP-induced GLIP release