Question 1

Which structural modification of the small intestine is primarily responsible for increasing the surface area for nutrient absorption by 600 times, and what is its approximate total surface area?

Accepted Answer

Microvilli; approximately 200 m$$^2$$

Question 2

During carbohydrate digestion in the small intestine, which enzyme is responsible for the final breakdown of disaccharides into monosaccharides, and where is it located?

Accepted Answer

Brush border enzymes; plasma membrane of enterocytes

Question 3

A patient undergoing chemotherapy experiences nausea, vomiting, and diarrhea. Which cellular process in the GI tract is most likely affected by the treatment?

Accepted Answer

Rapid division of stem cells in the villus epithelium

Question 4

Which of the following best describes the mechanism by which glucose and galactose are absorbed in the small intestine?

Accepted Answer

Secondary active transport with Na$$^+$$ across the apical membrane

Question 5

Which hormone initiates peristalsis in the small intestine during fasting, and what is the resulting motility pattern called?

Accepted Answer

Motilin; migrating motor complex (MMC)

Question 6

What is the primary function of Paneth cells in the small intestine?

Accepted Answer

Secretion of antimicrobial agents such as defensins and lysozyme

Question 7

Which of the following statements about the large intestine is correct?

Accepted Answer

It contains abundant deep crypts with many mucus-producing goblet cells

Question 8

A person with lactose intolerance lacks which enzyme, and what is the physiological consequence in the intestine?

Accepted Answer

Lactase; osmotic gradient prevents water absorption, causing diarrhea

Question 9

Which process is responsible for the movement of meal remnants, bacteria, and debris toward the large intestine between meals?

Accepted Answer

Migrating motor complex (MMC)

Question 10

Which of the following is TRUE regarding the absorption of fat-soluble vitamins in the small intestine?

Accepted Answer

They are carried by micelles and diffuse into absorptive cells

Question 11

Which anatomical feature of the large intestine is responsible for its segmented, pocket-like appearance?

Accepted Answer

Haustra

Question 12

What is the main function of the ileocecal valve?

Accepted Answer

To prevent regurgitation of chyme into the ileum

Question 13

Which of the following best describes the absorption of amino acids in the small intestine?

Accepted Answer

Amino acids are cotransported with Na$$^+$$ across the apical membrane

Question 14

Which clinical condition is characterized by inflammation of the appendix due to blockage and can lead to peritonitis if ruptured?

Accepted Answer

Appendicitis

Question 15

Which process is primarily responsible for water absorption in the small intestine?

Accepted Answer

Osmosis

Question 16

Which of the following is a major function of bacterial flora in the large intestine?

Accepted Answer

Fermentation of indigestible carbohydrates and synthesis of vitamin K

Question 17

Which of the following best explains why prolonged diarrhea can lead to acidosis and loss of potassium?

Accepted Answer

Insufficient time for water and electrolyte absorption in the large intestine

Question 18

Which structural modification is NOT found in the large intestine but is present in the small intestine to aid absorption?

Accepted Answer

Villi

Question 19

Which clinical condition is caused by an immune reaction to gluten, resulting in damage to intestinal villi and brush border?

Accepted Answer

Celiac disease

Question 20

Which of the following is TRUE regarding the absorption of iron and calcium in the small intestine?

Accepted Answer

Calcium absorption is regulated by vitamin D and parathyroid hormone (PTH)

Digestion and Absorption in the Small and Large Intestine

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