$$\text{Na}^+ + \text{K}^+ + \text{ATP} \rightarrow \text{Na}^+_{ECF} + \text{K}^+_{cell} + \text{ADP} + \text{P}_i$$

Question 1

Which of the following best describes the primary mechanism for absorption of di- and tripeptides in the small intestine?

Accepted Answer

H+ cotransport using the oligopeptide transporter (PepT1)

Question 2

A patient with a deficiency in intrinsic factor would most likely have impaired absorption of which vitamin, and where does this absorption occur?

Accepted Answer

Vitamin B12 in the ileum

Question 3

Which hormone is released by S cells in response to acid entering the duodenum and stimulates pancreatic bicarbonate secretion?

Accepted Answer

Secretin

Question 4

During the intestinal phase, which of the following best explains the effect of enterogastrones on gastric motility and secretion?

Accepted Answer

They decrease gastric motility and acid secretion

Question 5

Which of the following equations best represents the osmotic gradient created by nutrient absorption in the small intestine?

Accepted Answer

$$\Delta \pi = RT \left( C_{inside} - C_{outside} \right)$$

Question 6

Iron absorption in the small intestine involves which transporter for non-heme iron, and what is the role of hepcidin?

Accepted Answer

DMT1; hepcidin decreases ferroportin activity

Question 7

Which process is responsible for mixing contents in the intestine without net forward movement?

Accepted Answer

Segmental contractions

Question 8

A newborn infant is more likely to absorb small peptides intact via transcytosis. What is a potential consequence of this process?

Accepted Answer

Stimulation of antibody production and allergic reactions

Question 9

Which of the following best describes the role of CCK in the regulation of bile flow?

Accepted Answer

CCK stimulates contraction of the gallbladder and relaxation of the sphincter of Oddi

Question 10

Which equation best represents the active transport of Na+ out of the intestinal cell into the extracellular fluid?

Accepted Answer

$$	ext{Na}^+ + 	ext{K}^+ + 	ext{ATP} ightarrow 	ext{Na}^+_{ECF} + 	ext{K}^+_{cell} + 	ext{ADP} + 	ext{P}_i$$

Question 11

Which of the following is a primary function of the large intestine?

Accepted Answer

Concentration of waste and absorption of water and ions

Question 12

Which bacterial species is most commonly found in the human colon and plays a role in fermentation of indigestible carbohydrates?

Accepted Answer

Bacteroides fragilis

Question 13

Which of the following best describes the effect of GLP-1 and GIP on gastric function?

Accepted Answer

They inhibit gastric acid secretion and motility

Question 14

During the cephalic phase of pancreatic secretion, which pathway is primarily involved?

Accepted Answer

Vagal pathways

Question 15

Which structure in the large intestine is responsible for creating pouches called haustra?

Accepted Answer

Taenia coli (longitudinal muscle)

Question 16

Which of the following best explains the role of the migrating motor complex (MMC) in the gastrointestinal tract?

Accepted Answer

MMC propels undigested material from the stomach to the large intestine during fasting

Question 17

Which equation best represents the breakdown of a peptide by an endopeptidase?

Accepted Answer

$$	ext{Peptide} + 	ext{H}_2	ext{O} \xrightarrow{	ext{Endopeptidase}} 	ext{Smaller peptides}$$

Question 18

Which of the following is a consequence of the enterogastric reflex?

Accepted Answer

Inhibition of gastric emptying due to distension and acidity in the duodenum

Question 19

Which of the following best describes the absorption of fat-soluble vitamins in the small intestine?

Accepted Answer

Absorbed with fats via micelles

GI Tract 6 - March 13

Study Guide - Practice Questions