Question 1

Which of the following best describes the primary function of peristalsis in the digestive tract?

Accepted Answer

Moving food distally along the alimentary canal by coordinated contraction and relaxation of longitudinal muscles

Question 2

During the cephalic phase of gastric secretion, which neural pathway is primarily responsible for stimulating gastric glands?

Accepted Answer

Vagus nerve releasing acetylcholine (AcH)

Question 3

A patient has a mutation that prevents the release of histamine from enteroendocrine cells in the stomach. Which of the following is the most likely consequence?

Accepted Answer

Decreased secretion of HCl by parietal cells

Question 4

Which hormone is released in response to acidic chyme entering the duodenum and acts to inhibit gastric gland secretion and motility?

Accepted Answer

Secretin

Question 5

Which of the following best explains why glucose absorption in the small intestine is dependent on sodium ions?

Accepted Answer

Glucose is actively transported into the epithelial cell by a sodium-glucose symporter (SGLT)

Question 6

A patient is unable to produce bile. Which of the following digestive processes would be most directly impaired?

Accepted Answer

Emulsification and absorption of dietary lipids

Question 7

Which of the following best describes the process of segmentation in the small intestine?

Accepted Answer

Nonadjacent segments contract and relax, mixing and breaking down food without net movement

Question 8

Which of the following equations correctly represents the chemical reaction catalyzed by carbonic anhydrase in parietal cells for HCl production?

Accepted Answer

$$\mathrm{CO_2$ + H_2O \xrightarrow{carbonic\ anhydrase} H_2CO_3 \rightarrow H^+ + $$HCO_3$$^-}$$

Question 9

Which of the following is the correct order of events for the absorption of dietary lipids in the small intestine?

Accepted Answer

Emulsification by bile → formation of micelles → diffusion into epithelial cells → packaging into chylomicrons → absorption into lacteals

Question 10

A patient has a defect in the sodium-glucose transport protein (SGLT) in the small intestine. Which of the following would most likely occur?

Accepted Answer

Decreased absorption of glucose and galactose

Question 11

Which of the following best explains why pepsin is inactivated in the duodenum?

Accepted Answer

The pH in the duodenum is increased to around 8.0 by pancreatic bicarbonate

Question 12

Which of the following is a direct effect of the enterogastric reflex?

Accepted Answer

Decreased force of stomach contractions and inhibition of gastric emptying

Question 13

Which of the following best describes the role of chylomicrons in lipid absorption?

Accepted Answer

They transport triglycerides from intestinal epithelial cells into lymphatic lacteals

Question 14

Which of the following is the correct pathway for the movement of food through the digestive tract?

Accepted Answer

Mouth → pharynx → esophagus → stomach → small intestine → large intestine → rectum → anus

Question 15

Which of the following best explains why water is absorbed along with glucose in the small intestine?

Accepted Answer

Glucose increases the osmolarity of the extracellular fluid, drawing water through leaky tight junctions

Question 16

A patient has a deficiency in brush border enzymes. Which of the following would most likely be impaired?

Accepted Answer

Final breakdown of carbohydrates into monosaccharides

Question 17

Which of the following best describes the function of goblet cells in the stomach?

Accepted Answer

They secrete mucus to protect the mucosal lining from stomach acid

Question 18

Which of the following is a direct result of the activation of stretch receptors in the rectal wall?

Accepted Answer

Initiation of the parasympathetic visceral spinal reflex leading to contraction of the sigmoid colon and rectum

Digestive System: Structure, Function, and Nutrient Absorption

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