BIOL 252 Module 6 (2026) Exam Prep: Digestive
System Questions & Correct Answers | 100 Verified
MCQs With Rationales Already Graded A+
Ace BIOL 252 Module 6 with 100 high-yield MCQs covering the entire Digestive System! Each
question includes a detailed Rationale explaining the correct answer—so you learn the
WHY, not just the WHAT. Master gastric phases, pancreatic enzymes, bile function,
histology, and GI hormones tested on every A&P II exam. Perfect for UNC, Duke, NC State,
USC & Texas A&M. Save hours of study time and boost your exam score with this
comprehensive, professor-approved Q&A guide!
,1. Which of the following correctly lists the four tunics of the alimentary canal from the
lumen outward?
A) Serosa, muscularis externa, submucosa, mucosa
B) Mucosa, muscularis externa, submucosa, serosa
C) Muscularis externa, mucosa, serosa, submucosa
D) Mucosa, submucosa, muscularis externa, serosa
Rationale: The correct order from innermost (lining the lumen) to outermost is mucosa,
submucosa, muscularis externa, and serosa (or adventitia). This layered organization is
consistent throughout most of the GI tract.
2. Which digestive process involves the wave-like contraction of smooth muscle to move
food along the esophagus?
A) Segmentation
B) Peristalsis
C) Haustral churning
D) Mass movement
Rationale: Peristalsis is the coordinated sequential contraction of circular and
longitudinal muscle layers that propels food distally through the GI tract.
Segmentation primarily mixes chyme, while haustral churning and mass movements
occur in the large intestine.
3. The cephalic phase of gastric secretion is triggered by which of the following?
A) The presence of chyme in the duodenum
B) Distension of the stomach and presence of proteins
C) Sight, smell, or thought of food
D) Low pH in the stomach lumen
Rationale: The cephalic phase is a neural reflex initiated by cerebral cortex input—such
as seeing, smelling, or thinking about food—that stimulates vagal nerve activation of
gastric glands, even before food enters the stomach.
4. Which component of saliva functions primarily as a lubricant and protects oral tissues?
A) Salivary amylase
, B) Lysozyme
C) Mucin
D) Electrolytes
Rationale: Mucin is a glycoprotein that forms mucus when mixed with water, providing
lubrication for food bolus formation and protecting the oral mucosa from mechanical
and chemical damage.
5. The intestinal phase of gastric regulation is primarily initiated by:
A) Vagal nerve stimulation from the brain
B) Chyme entering the duodenum
C) Gastrin release from G cells
D) Distension of the stomach
Rationale: The intestinal phase begins when chyme enters the duodenum. This triggers
both excitatory (gastrin release) and inhibitory (enterogastric reflex and hormones like
secretin and CCK) responses that regulate gastric emptying and secretion.
6. Which histological feature of the small intestine dramatically increases surface area for
absorption?
A) Rugae
B) Gastric pits
C) Villi and microvilli
D) Plicae circulares only
Rationale: Villi are finger-like projections of the mucosa, and microvilli form the brush
border on the apical surface of enterocytes. Together, they amplify the absorptive
surface area tremendously, with plicae circulares providing additional macroscopic
folding.
7. Bile is produced by the liver and stored in the gallbladder. What is the primary digestive
function of bile salts?
A) Hydrolyzing proteins into amino acids
B) Emulsifying fats into smaller lipid droplets
C) Neutralizing acidic chyme
D) Activating pancreatic proteases
Rationale: Bile salts are amphipathic molecules that act as detergents to emulsify
System Questions & Correct Answers | 100 Verified
MCQs With Rationales Already Graded A+
Ace BIOL 252 Module 6 with 100 high-yield MCQs covering the entire Digestive System! Each
question includes a detailed Rationale explaining the correct answer—so you learn the
WHY, not just the WHAT. Master gastric phases, pancreatic enzymes, bile function,
histology, and GI hormones tested on every A&P II exam. Perfect for UNC, Duke, NC State,
USC & Texas A&M. Save hours of study time and boost your exam score with this
comprehensive, professor-approved Q&A guide!
,1. Which of the following correctly lists the four tunics of the alimentary canal from the
lumen outward?
A) Serosa, muscularis externa, submucosa, mucosa
B) Mucosa, muscularis externa, submucosa, serosa
C) Muscularis externa, mucosa, serosa, submucosa
D) Mucosa, submucosa, muscularis externa, serosa
Rationale: The correct order from innermost (lining the lumen) to outermost is mucosa,
submucosa, muscularis externa, and serosa (or adventitia). This layered organization is
consistent throughout most of the GI tract.
2. Which digestive process involves the wave-like contraction of smooth muscle to move
food along the esophagus?
A) Segmentation
B) Peristalsis
C) Haustral churning
D) Mass movement
Rationale: Peristalsis is the coordinated sequential contraction of circular and
longitudinal muscle layers that propels food distally through the GI tract.
Segmentation primarily mixes chyme, while haustral churning and mass movements
occur in the large intestine.
3. The cephalic phase of gastric secretion is triggered by which of the following?
A) The presence of chyme in the duodenum
B) Distension of the stomach and presence of proteins
C) Sight, smell, or thought of food
D) Low pH in the stomach lumen
Rationale: The cephalic phase is a neural reflex initiated by cerebral cortex input—such
as seeing, smelling, or thinking about food—that stimulates vagal nerve activation of
gastric glands, even before food enters the stomach.
4. Which component of saliva functions primarily as a lubricant and protects oral tissues?
A) Salivary amylase
, B) Lysozyme
C) Mucin
D) Electrolytes
Rationale: Mucin is a glycoprotein that forms mucus when mixed with water, providing
lubrication for food bolus formation and protecting the oral mucosa from mechanical
and chemical damage.
5. The intestinal phase of gastric regulation is primarily initiated by:
A) Vagal nerve stimulation from the brain
B) Chyme entering the duodenum
C) Gastrin release from G cells
D) Distension of the stomach
Rationale: The intestinal phase begins when chyme enters the duodenum. This triggers
both excitatory (gastrin release) and inhibitory (enterogastric reflex and hormones like
secretin and CCK) responses that regulate gastric emptying and secretion.
6. Which histological feature of the small intestine dramatically increases surface area for
absorption?
A) Rugae
B) Gastric pits
C) Villi and microvilli
D) Plicae circulares only
Rationale: Villi are finger-like projections of the mucosa, and microvilli form the brush
border on the apical surface of enterocytes. Together, they amplify the absorptive
surface area tremendously, with plicae circulares providing additional macroscopic
folding.
7. Bile is produced by the liver and stored in the gallbladder. What is the primary digestive
function of bile salts?
A) Hydrolyzing proteins into amino acids
B) Emulsifying fats into smaller lipid droplets
C) Neutralizing acidic chyme
D) Activating pancreatic proteases
Rationale: Bile salts are amphipathic molecules that act as detergents to emulsify
