Quiz: Physiology

1. Which of these statements about intrinsic factor is true?

A a) It is secreted by the stomach. B b) It is a polypeptide. C c) It promotes absorption of vitamin B12 in the intestine. D d) All of these are true.

2. Which of these statements about gastric secretion of HCl is false?

A a. HCl is secreted by parietal cells. B b. HCl hydrolyzes peptide bonds. C c. HCl is needed for the conversion of pepsinogen to pepsin. D d. HCl is needed for maximum activity of pepsin.

3. Most digestion occurs in

A a. The mouth B b. The stomach. C c. The small intestine. D d. The large intestine.

4. Which of these statements about trypsin is true?

A a. Trypsin is derived from trypsinogen by the digestive action of pepsin. B b. Active trypsin is secreted into the pancreatic acini. C c. Trypsin is produced in the crypts (of Lieberkühn). D d. Trypsinogen is converted to trypsin by the brush border enzyme enterokinase

5. During the gastric phase, the secretion of HCl and pepsinogen is stimulated by:

A a. Vagus nerve stimulation that originates in the brain. B b. Polypeptides in the gastric lumen and by gastrin secretion. C c. Secretin and cholecystokinin from the duodenum D d. All of these.

6. The secretion of HCl by the stomach mucosa is inhibited by

A a. Neural reflexes from the duodenum. B b. The secretion of an enterogastrone from the duodenum. C c. The lowering of gastric pH. D d. All of these.

7. The first organ to receive the blood borne products of digestion is

A a) The liver. B b) The pancreas. C c) The heart. D d) The brain.

8. Absorption of salt and water is the principal function of which region of the GI tract?

A a) Esophagus B b) Stomach C c) Duodenum D d) Large intestine

9. Cholecystokinin (CCK) is a hormone that stimulates

A a. Bile production. B b. Release of pancreatic enzymes. C c. Contraction of the gallbladder. D d. Both b and c.

10. Which of these statements about vitamin B12 is false?

A a. Lack of this vitamin can produce pernicious anemia B b. Intrinsic factor is needed for absorption of vitamin B12 C c. Damage to the gastric mucosa may lead to a deficiency in vitamin B12. D d. Vitamin B12 is absorbed primarily in the jejunum.

11. Which of these statements about starch digestion is false?

A a. It begins in the mouth. B b. It occurs in the stomach. C c. It requires the action of pancreatic amylase. D d. It requires brush border enzymes for completion.

12. Which of the following hormones stimulates the secretion of histamine from the ECL cells?

A a) Enterogastrone B b) Gastrin C c) Secretin D d) Cholecystokinin

13. Which of the following food types is most effective at provoking the intestinal phase of gastric regulation?

A a) Fat B b) Starch C c) Sugars D d) Proteins

14. Which of the following is true about pepsin?

A a. Most pepsin is released directly from chief cells B b. Pepsin is most active at high pH. C c. Pepsin is essential for protein digestion. D d. Pepsin accelerates protein digestion.

15. Which of the following inhibit/inhibits gastric HCl secretion during a meal?

A a. stimulation of the parasympathetic nerves to the enteric nervous system B b. the sight and smell of food C c. distension of the duodenum D d. presence of peptides in the stomach

17. Which of the following is the primary absorptive process in the large intestine?

A a. active transport of Na+ from the lumen to the blood B b. absorption of water C c. active transport of K+ from the lumen to the blood D d. active absorption of H CO 3− into the blood

1. Bile

A a) Contains enzymes required for the digestion of fat. B b) Contains unconjugated bilirubin. C c) Salts make cholesterol more water-soluble. D d) Pigments contain iron.

2. Saliva

A a) From different salivary glands has a similar composition B b) Contains enzymes essential for the digestion of carbohydrates. C c) Has less than half the ionic calcium level of plasma. D d) Has more than twice the iodide level of plasma.

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