Question 1

Which of the following correctly lists the four basic layers of the gastrointestinal (GI) tract wall from the lumen outward?

Accepted Answer

Mucosa, submucosa, muscularis externa, serosa

Question 2

A patient presents with difficulty absorbing vitamin B12, leading to anemia. Which stomach cell type is most likely malfunctioning, and what is its key secretion?

Accepted Answer

Parietal cell; intrinsic factor

Question 3

Which of the following best describes the function of the circular folds (plicae circulares) in the small intestine?

Accepted Answer

They increase the time for nutrient absorption by forcing chyme to spiral through the lumen

Question 4

During the process of deglutition (swallowing), which structure prevents food from entering the nasal cavity?

Accepted Answer

Uvula

Question 5

Which of the following is a correct pathway for bile flow from the liver to the duodenum?

Accepted Answer

Right/left hepatic duct → common hepatic duct → common bile duct → duodenum

Question 6

Which of the following best explains why pancreatic proteases are secreted as zymogens (inactive precursors)?

Accepted Answer

To prevent self-digestion of pancreatic tissue

Question 7

A patient with a low-fiber diet develops small pouches in the colon wall. What is the most likely diagnosis?

Accepted Answer

Diverticulosis

Question 8

Which hormone stimulates the gallbladder to contract and release bile in response to fatty chyme in the duodenum?

Accepted Answer

Cholecystokinin (CCK)

Question 9

Which of the following best describes the main function of the large intestine?

Accepted Answer

Absorption of water and electrolytes, and elimination of feces

Question 10

Which of the following is a function of the enteric nervous system (ENS) in the GI tract?

Accepted Answer

Control of GI motility and secretion independent of the central nervous system

Question 11

A patient is unable to digest lactose and experiences bloating and diarrhea after consuming milk. Which enzyme is deficient, and what is the physiological consequence?

Accepted Answer

Lactase; undigested lactose creates an osmotic gradient, drawing water into the intestine

Question 12

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

Accepted Answer

They emulsify fats, increasing the surface area for lipase action

Question 13

Which of the following is the correct equation for the hydrolysis of a disaccharide by a brush border enzyme?

Accepted Answer

$$C_{12}H$$_{22}$$O_{11} + H_2O \rightarrow 2C_6H_{12}O_6$

Question 14

Which of the following best explains why the stomach has an additional oblique muscle layer in its muscularis externa?

Accepted Answer

To allow for more effective churning and mechanical breakdown of food

Question 15

Which of the following statements about the absorption of fats in the small intestine is correct?

Accepted Answer

Short-chain fatty acids are absorbed into blood capillaries, while long-chain fatty acids are packaged into chylomicrons and absorbed into lacteals

Question 16

Which of the following best describes the function of the myenteric plexus in the GI tract?

Accepted Answer

Controls GI tract motility by regulating smooth muscle contraction

Question 17

A patient has a blockage at the hepatopancreatic ampulla. Which of the following would most likely be impaired?

Accepted Answer

Release of bile and pancreatic juice into the duodenum

Question 18

Which of the following is the correct formula for the chemical reaction catalyzed by pancreatic amylase?

Accepted Answer

$$(C_6H_{10}O_5$)_n + H_2O \rightarrow (C_6H_{12}O_6$)_m$$

Question 19

Which of the following best describes the role of the internal and external anal sphincters in defecation?

Accepted Answer

The internal sphincter is smooth muscle (involuntary), and the external sphincter is skeletal muscle (voluntary)

Microscopic Anatomy of the Stomach: Layers and Gastric Glands

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