Question 1

Which of the following structural modifications of the small intestine is primarily responsible for increasing the surface area for absorption by 600 times, and what is the main function of this adaptation?

Accepted Answer

Microvilli; they provide a large surface area for absorption and contain brush border enzymes.

Question 2

A patient undergoing chemotherapy develops severe diarrhea. Which of the following best explains this side effect?

Accepted Answer

Chemotherapy damages rapidly dividing cells, including the epithelial lining of the GI tract, impairing absorption.

Question 3

Which of the following best describes the process by which monosaccharides are absorbed in the small intestine?

Accepted Answer

Monosaccharides are cotransported with Na+ across the apical membrane by secondary active transport and exit via facilitated diffusion.

Question 4

Which of the following statements about the motility of the small intestine is correct?

Accepted Answer

Segmentation is most common after a meal and is initiated by intrinsic pacemaker cells.

Question 5

A patient presents with bloating, flatulence, and diarrhea after consuming dairy products. Which enzyme deficiency is most likely responsible, and what is the physiological consequence?

Accepted Answer

Lactase deficiency; undigested lactose creates an osmotic gradient, preventing water absorption.

Question 6

Which of the following best describes the absorption of vitamin B12 in the digestive tract?

Accepted Answer

Vitamin B12 binds with intrinsic factor and is absorbed by endocytosis in the ileum.

Question 7

Which of the following is a unique feature of the large intestine not found elsewhere in the digestive tract?

Accepted Answer

Teniae coli

Question 8

A patient with a low-fiber diet develops diverticulosis. Which of the following best explains the pathophysiology?

Accepted Answer

Low-fiber diet narrows the colon and increases pressure, leading to mucosal herniations (diverticula).

Question 9

Which of the following best describes the process of fat absorption in the small intestine?

Accepted Answer

Chylomicrons are formed in enterocytes and transported into lymphatic lacteals before entering the bloodstream.

Question 10

Which of the following is true regarding the role of bacterial flora in the large intestine?

Accepted Answer

They ferment indigestible carbohydrates, synthesize some B vitamins and vitamin K, and help suppress pathogenic bacteria.

Question 11

Which of the following mechanisms is responsible for the absorption of most water in the digestive tract?

Accepted Answer

Osmosis in the small intestine

Question 12

A patient has a blockage at the ileocecal valve. Which of the following is most likely to occur?

Accepted Answer

Chyme will not enter the large intestine, leading to malabsorption and possible bacterial overgrowth in the ileum.

Question 13

Which of the following best describes the function of Paneth cells in the small intestine?

Accepted Answer

They secrete antimicrobial agents such as defensins and lysozyme to fortify intestinal defenses.

Question 14

Which of the following statements about the absorption of iron and calcium in the small intestine is correct?

Accepted Answer

Iron is stored in mucosal cells with ferritin and transported in blood by transferrin when needed; calcium absorption is regulated by vitamin D and parathyroid hormone.

Question 15

Which of the following is the correct sequence of events during the defecation reflex?

Accepted Answer

Distension of the rectum, activation of stretch receptors, parasympathetic stimulation, relaxation of the internal anal sphincter

Question 16

Which of the following best explains why a patient with celiac disease experiences malabsorption?

Accepted Answer

Gluten damages the intestinal villi and brush border, reducing the surface area for absorption.

Question 17

Which of the following is a function of Peyer’s patches in the small intestine?

Accepted Answer

They are aggregated lymphoid nodules that protect against microorganisms, especially in the distal small intestine.

Question 18

Which of the following best describes the fate of chylomicrons after they are formed in the enterocytes of the small intestine?

Accepted Answer

They are exocytosed into the interstitial fluid and enter lymphatic lacteals.

Question 19

Which of the following is a likely consequence of prolonged diarrhea?

Accepted Answer

Dehydration and electrolyte imbalance, including acidosis and hypokalemia

Study Guide: The Digestive System – Small and Large Intestine, Digestion, and Absorption

Study Guide - Practice Questions

Study Guide - Flashcards