physiology 4 Flashcards
1
Q
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
A
A) Duodenocolic
2
Q
- 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 B12 deficiency
A
E) Vitamin B12 deficiency
3
Q
- 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
A
B) Glucose-dependent insulinotropic peptide (GLIP)
4
Q
- 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
A
D) GLIP-induced insulin release
5
Q
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
A
A) CCK
6
Q
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
A
E) Vagotomy
7
Q
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
A
C) Intestinal bacteria
8
Q
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. Use this information to answer Questions 19–21
19. 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
20. 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
21. 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
A
19-A) Cyclic adenosine monophosphate (cAMP)
20-B) Chloride
21-B) 3 to 6
9
Q
- 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
E) 4.0
10
Q
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
A
C) Palatopharyngeal folds
11
Q
- 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
A
C) Somatostatin
12
Q
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. Postinjection 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
A
E) 700
13
Q
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
A
A) Ammonium
14
Q
- 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
A
E. 12
15
Q
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, 4
A
B) 3, 1, 4, 2
16
Q
- 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
B) Chloride
17
Q
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
A
D. Nitric oxide
18
Q
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
A
A) Bowel movements
18
Q
- 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
A
A) Bowel movements
19
Q
- 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
A
E) Vagus nerve
20
Q
- 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
A
C) Duodenum
21
Q
- 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
A
D) Primary esophageal peristalsis
22
Q
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 H2 blocker E) Proton pump inhibitor
A
E) Proton pump inhibitor
23
Q
- 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
A
A) Intrinsic factor
24
Q
- 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
A
C) Fecal fat
25
Q
- 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
A
E) 4, 2, 1, 3
26
Q
- 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
A
B) Enterocolitis
27
Q
- 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
A
A) Endocytosis
28
Q
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
A
C) Autodigestion of pancreas
