Q: Which equation represents the breakdown of starch by salivary amylase in the mouth?

$$\text{Starch} + \text{H}_2\text{O} \xrightarrow{\text{amylase}} \text{Maltose}$$

Question 1

Which layer of the gut wall contains the submucosal plexus, and what is its primary function?

Accepted Answer

Submucosa; regulates secretion by GI epithelial cells and muscularis mucosae

Question 2

A patient presents with dumping syndrome, characterized by rapid passage of unabsorbed chyme into the large intestine. Which gastric function is most likely impaired?

Accepted Answer

Receptive relaxation and regulation of gastric emptying

Question 3

Which of the following statements about GI motility is correct?

Accepted Answer

Slow wave potentials originate from interstitial cells of Cajal and regulate smooth muscle contractions

Question 4

During the gastric phase, which cell type secretes a hormone that stimulates acid release, and what is the hormone?

Accepted Answer

G cells; gastrin

Question 5

Which equation best represents the neutralization of acidic chyme by pancreatic bicarbonate in the small intestine?

Accepted Answer

$$\mathrm{$$HCO_3$$^-} + \mathrm{H^+} \rightarrow \mathrm{H_2O} + \mathrm{CO_2$}$$

Question 6

Which process is primarily responsible for moving food remnants and bacteria from the upper GI tract into the large intestine between meals?

Accepted Answer

Migrating motor complex

Question 7

A patient with decreased lactase activity is likely to experience which condition, and what is the underlying mechanism?

Accepted Answer

Lactose intolerance; inability to digest lactose into monosaccharides

Question 8

Which of the following best describes the absorption pathway for dietary fats?

Accepted Answer

Absorbed into lymphatic vessels in the villi and transported via the lymphatic system

Question 9

Which GI hormone is released by G cells and promotes acid secretion, and what is its effect on parietal cells?

Accepted Answer

Gastrin; stimulates HCl release

Question 10

Which of the following is a function of mucus in the GI tract?

Accepted Answer

Forms a protective coating and lubricates gut contents

Question 11

A patient is unable to absorb vitamin B12 despite normal dietary intake. Which gastric secretion is most likely deficient?

Accepted Answer

Intrinsic factor

Question 12

Which of the following best explains why most digestive enzymes are secreted in an inactive form?

Accepted Answer

To avoid damaging GI tract cells before activation

Question 13

Which equation represents the breakdown of starch by salivary amylase in the mouth?

Accepted Answer

$$	ext{Starch} + 	ext{H}_2	ext{O} \xrightarrow{	ext{amylase}} 	ext{Maltose}$$

Question 14

Which of the following is TRUE regarding the hepatic portal system?

Accepted Answer

It carries blood from the digestive system to the liver for metabolism and detoxification

Question 15

Which pattern of contraction is responsible for mixing intestinal contents and keeping them in contact with the intestinal wall?

Accepted Answer

Segmental contractions

Question 16

Which cell type in the stomach secretes somatostatin, and what is its effect?

Accepted Answer

D cells; inhibits acid production and pepsinogen secretion

Question 17

Which of the following best describes the role of bile salts in fat digestion?

Accepted Answer

They emulsify large fat droplets into smaller ones, increasing surface area for lipases

Question 18

Which equation best represents the enzymatic breakdown of proteins in the stomach?

Accepted Answer

$$	ext{Protein} + 	ext{H}_2	ext{O} \xrightarrow{	ext{pepsin}} 	ext{Peptides}$$

Question 19

Which of the following is a consequence of diarrhea in terms of fluid balance?

Accepted Answer

Dehydration due to excessive loss of water in feces

Question 20

Which GI peptide is produced by the intestine, enhances satiety, and also acts as a neurotransmitter in the brain?

Accepted Answer

Cholecystokinin (CCK)

Advanced Physiology: The Digestive System

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