Question 1

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

Accepted Answer

It controls the involuntary movement of digestive materials through peristalsis and segmentation.

Question 2

During the process of swallowing (deglutition), which phase is the ONLY one that can be consciously controlled?

Accepted Answer

Buccal phase

Question 3

Which of the following is NOT a function of the oral cavity?

Accepted Answer

Absorption of nutrients into the bloodstream

Question 4

What is the main role of parietal cells in the gastric glands?

Accepted Answer

Secretion of hydrochloric acid (HCl) and intrinsic factor

Question 5

Which equation correctly represents the chemical reaction for the secretion of hydrochloric acid (HCl) by parietal cells?

Accepted Answer

$$CO_2 + H_2O$$ \rightarrow H_2CO_3 \rightarrow H^+ + Cl^- \rightarrow HCl$$

Question 6

Which structure in the small intestine is primarily responsible for increasing the surface area for absorption?

Accepted Answer

Villi and plicae circulares

Question 7

Which of the following statements about segmentation in the digestive tract is correct?

Accepted Answer

Segmentation is a mixing action that churns and breaks up material without propulsion.

Question 8

Which hormone is released in response to acidic chyme entering the duodenum and stimulates the pancreas to release alkaline secretions?

Accepted Answer

Secretin

Question 9

Which of the following is TRUE regarding nutrient absorption in the stomach?

Accepted Answer

No nutrients are absorbed in the stomach because the mucosa lacks transport mechanisms.

Question 10

Which pancreatic enzyme is responsible for the breakdown of proteins, and how is it activated?

Accepted Answer

Pancreatic proteases (e.g., trypsin); secreted as inactive proenzymes and activated in the small intestine

Question 11

Which of the following best explains the role of bile in digestion?

Accepted Answer

Bile emulsifies fats, increasing their surface area for enzymatic breakdown.

Question 12

What is the correct sequence of events during the three phases of gastric activity?

Accepted Answer

Cephalic phase → Gastric phase → Intestinal phase

Question 13

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

Accepted Answer

Reabsorption of water and bile salts

Question 14

Which process is responsible for the movement of small organic molecules, electrolytes, and water across the digestive epithelium into the interstitial fluid?

Accepted Answer

Absorption

Question 15

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

Accepted Answer

They transport triglycerides from the intestinal cells into the lymphatic system.

Question 16

Which of the following is a correct comparison between the digestion of carbohydrates, lipids, and proteins?

Accepted Answer

Proteins begin digestion in the stomach, carbohydrates in the mouth, and lipids in both the mouth and small intestine.

Question 17

Which hormone is produced by adipose tissue and acts as an 'adiposity signal' to inhibit food intake?

Accepted Answer

Leptin

Question 18

Which of the following is a plausible consequence of long-term bile storage in the gallbladder?

Accepted Answer

Formation of gallstones due to dehydration of bile

Question 19

Which of the following best describes the role of the liver in digestion?

Accepted Answer

It detoxifies blood, stores nutrients, and produces bile salts for fat digestion.

Question 20

Which of the following equations correctly represents the facilitated diffusion of glucose across the intestinal epithelium?

Accepted Answer

$$Glucose_{lumen} \xrightarrow{facilitated\ diffusion} Glucose_{epithelial\ cell}$$

Digestive System: Structure, Function, and Processes

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