Deck 35: Gastrointestinal Function

Question 1

Suppose there is a need to differentiate a situation of true malabsorption due to damage to intestinal mucosa from maldigestion due to pancreatic insufficiency.Given that one of these two situations is suspected, the patient is given a 25-gram dose of D-xylose dissolved in 300 mL of water.A blood sample is obtained 2 hours after the D-xylose administration, and a 5-hour urine is collected.The results of the D-xylose analysis are: blood xylose = 400 mg/L; urine xylose = 7 g/5 hr.These results provide laboratory evidence of:

A)malabsorption due to damage to the intestinal mucosa
B)maldigestion due to pancreatic insufficiency
C)both malabsorption and maldigestion
D)The D-xylose test alone cannot evaluate for either malabsorption or maldigestion.

Answer 1

maldigestion due to pancreatic insufficiency

Question 2

The following statements are true of what major intestinal hormone?
1)It has 22 amino acids.
2)It is produced by the upper small intestine.
3)Its stimulating factor is a high-fat meal and duodenal acidification.
4)Its function is to stimulate motility of the small intestine.

A)glucagon
B)motilin
C)gastrin
D)secretin

Answer 2

motilin

Question 3

Which of the following laboratory test results is not consistent with a diagnosis of carcinoid syndrome?

A)increased fecal fat
B)negative stool occult blood
C)normal lactose tolerance
D)increased 5-hydroxyindoleacetic acid (5-HIAA)

Answer 3

increased fecal fat

Question 4

What analyte is measured in a lactose tolerance test?

A)lactose
B)lactase
C)D-xylose
D)glucose

Question 5

Given the following laboratory information, what is the most probable laboratory diagnosis?
Fecal fat - increased
Stool examination - foul smelling
Lactose intolerance test - normal
Serum carotene and serum vitamin A - decreased
Serum vitamin B₁₂ and serum folate - normal to decreased
Schilling test - abnormal
D-Xylose absorption - abnormal
Stool occult blood - negative
Carcinoembryonic antigen - normal
Gluten antibodies - negative

A)carcinoid syndrome
B)bowel carcinoma
C)steatorrhea
D)celiac disease

Question 6

Which of the following statements are true of gut hormone structure and functions?
1)Gut hormones regulate digestion and absorption.
2)Gut hormones are released in response to nutrients in the lumen of the GI tract and stimulate the release of acid, bicarbonate, and enzymes for the digestion of food.
3)Secretin, cholecystokinin, vasoactive intestinal polypeptide, and pancreatic polypeptide are involved in regulating insulin and glucagon production.
4)Glucagon-like peptide 1 (GLP-1) and glucose-dependent insulinotropic polypeptide (GIP) control exocrine pancreatic function.

A)1, 2, 3, 4
B)1, 3, 4
C)2, 4
D)1, 2

Question 7

Which of the following explains an increased prothrombin time in patients with malabsorption syndrome?

A)decreased intestinal absorption of thrombin
B)decreased intestinal absorption of vitamin K
C)decreased intestinal absorption of carbohydrates
D)decreased intestinal absorption of electrolytes

Question 8

Which of the following hormones is produced by the mucosa of the upper small intestine and functions to stimulate gall bladder and stomach contraction?

A)cholecystokinin
B)gastrin
C)secretin
D)motilin

Question 9

Which of the following statements are true of the D-xylose absorption test?
1)The amount of D-xylose excreted over a 5-hour period is closely correlated with the amount absorbed in the GI tract.
2)Most persons demonstrate plasma levels greater than 300 mg/L in one of the samples collected.
3)Low levels of urine or plasma D-xylose are suggestive of an absorptive defect in the jejunum.
4)High levels of D-xylose are seen in ascites, vomiting, delayed gastric emptying, improper urine collection, and high-dose aspirin therapy.

A)1, 2, 3, 4
B)1, 2, 3
C)1, 3, 4
D)2, 3, 4

Question 10

Which of the following is a function of parietal cells?

A)to produce hydrochloric acid and intrinsic factor
B)to produce the proenzyme pepsinogen
C)to secrete a protective layer of mucus to protect stomach mucosa from attack by acid and enzymes
D)to produce the hormone gastrin

Question 11

Which of the following is a function of chief cells?

A)to produce hydrochloric acid and intrinsic factor
B)to produce the proenzyme pepsinogen
C)to secrete a protective layer of mucus to protect stomach mucosa from attack by acid and enzymes
D)to produce the hormone gastrin

Question 12

The breath test and the CLO test used to determine the presence of Helicobacter pylori are based on H.pylori's production of what substance?

A)excess hydrochloric acid
B)carcinoembryonic antigen (CEA)
C)bombesin
D)urease

Question 13

Crohn's disease:
1)presents with abdominal pain, diarrhea, and malabsorption.
2)affects the small intestine.
3)produces antibodies to Saccharomyces cerevisiae.
4)produces perinuclear antineutrophil cytoplasmic antibodies.

A)1, 2, 3, 4
B)1, 2, 3
C)1, 2, 4
D)2, 3, 4

Question 14

Which of the following vitamins are not water soluble and must be absorbed with lipids?
1)Vitamin A
2)Vitamin C
3)Vitamin D
4)Vitamin K

A)1, 2, 3, 4
B)1, 2, 3
C)1, 3, 4
D)2, 3, 4

Question 15

When considering the lactose tolerance test, a healthy person will demonstrate a glucose of ______, but those with lactase deficiency will exhibit a peak plasma glucose of ______.

A)> 2000 mg/L over the baseline sample, < 1000 mg/L
B)< 2000 mg/L over the baseline sample, > 1000 mg/L
C)> 1000 mg/L over the baseline sample, < 2000 mg/L
D)< 1000 mg/L over the baseline sample, > 2000 mg/L

Question 16

Which of the following is not a function of gastrin?

A)stimulates stomach acid secretion
B)stimulates stomach contraction
C)stimulates intestinal motility
D)stimulates growth of small bowel mucosa

Question 17

Which of the following processes occurs in the large intestine?

A)Selective water and electrolyte absorption occur.
B)Pancreatic secretions enter the intestine.
C)Components of micelles are absorbed.
D)All of the above