BIOD 151 Module 3 Exam - Digestive System 2026/2027 UPDATE
1. Which layer of the GI tract is responsible for peristalsis and segmentation?
A. Mucosa
B. Muscularis externa
C. Submucosa
D. Serosa
Answer: B
Rationale: The muscularis externa consists of circular and longitudinal smooth muscle
layers that contract to move and mix food.
2. Which cells in the stomach secrete hydrochloric acid (HCl)?
A. Parietal cells
B. Chief cells
C. G cells
D. Mucous neck cells
Answer: A
Rationale: Parietal cells produce HCl and intrinsic factor, whereas chief cells produce
pepsinogen.
3. What is the primary function of the gallbladder?
A. Production of bile
B. Secretions of insulin
C. Digestion of proteins
D. Storage and concentration of bile
Answer: D
,Rationale: The liver produces bile, but the gallbladder stores and concentrates it until it is
needed in the duodenum.
4. Which enzyme is responsible for the initial breakdown of starches in the
mouth?
A. Salivary amylase
B. Pancreatic amylase
C. Lingual lipase
D. Pepsin
Answer: A
Rationale: Salivary amylase, secreted by salivary glands, begins the chemical digestion of
carbohydrates in the oral cavity.
5. The ‘S-shaped’ portion of the large intestine that leads to the rectum is called
the:
A. Ascending colon
B. Transverse colon
C. Sigmoid colon
D. Descending colon
Answer: C
Rationale: The sigmoid colon is the fourth segment of the colon, characterized by its S-
shape before connecting to the rectum.
6. Which hormone stimulates the release of bile and pancreatic enzymes?
A. Cholecystokinin (CCK)
B. Secretin
C. Gastrin
D. Insulin
Answer: A
, Rationale: CCK is released by the duodenum in response to fats and proteins, triggering
gallbladder contraction and pancreatic secretion.
7. Where does the majority of nutrient absorption occur in the digestive
system?
A. Small intestine
B. Stomach
C. Large intestine
D. Esophagus
Answer: A
Rationale: The small intestine, especially the jejunum, is the primary site for nutrient
absorption due to its large surface area.
8. Which of the following is an example of mechanical digestion?
A. Hydrolysis of proteins
B. Mastication
C. Action of pepsin
D. Emulsification by bile
Answer: B
Rationale: Mastication (chewing) physically breaks down food into smaller pieces, which
is a mechanical process.
9. What is the role of intrinsic factor?
A. Digestion of lipids
B. Absorption of Vitamin B12
C. Activation of trypsinogen
D. Neutralization of stomach acid
Answer: B
Rationale: Intrinsic factor, secreted by parietal cells, is essential for the absorption of
Vitamin B12 in the ileum.
1. Which layer of the GI tract is responsible for peristalsis and segmentation?
A. Mucosa
B. Muscularis externa
C. Submucosa
D. Serosa
Answer: B
Rationale: The muscularis externa consists of circular and longitudinal smooth muscle
layers that contract to move and mix food.
2. Which cells in the stomach secrete hydrochloric acid (HCl)?
A. Parietal cells
B. Chief cells
C. G cells
D. Mucous neck cells
Answer: A
Rationale: Parietal cells produce HCl and intrinsic factor, whereas chief cells produce
pepsinogen.
3. What is the primary function of the gallbladder?
A. Production of bile
B. Secretions of insulin
C. Digestion of proteins
D. Storage and concentration of bile
Answer: D
,Rationale: The liver produces bile, but the gallbladder stores and concentrates it until it is
needed in the duodenum.
4. Which enzyme is responsible for the initial breakdown of starches in the
mouth?
A. Salivary amylase
B. Pancreatic amylase
C. Lingual lipase
D. Pepsin
Answer: A
Rationale: Salivary amylase, secreted by salivary glands, begins the chemical digestion of
carbohydrates in the oral cavity.
5. The ‘S-shaped’ portion of the large intestine that leads to the rectum is called
the:
A. Ascending colon
B. Transverse colon
C. Sigmoid colon
D. Descending colon
Answer: C
Rationale: The sigmoid colon is the fourth segment of the colon, characterized by its S-
shape before connecting to the rectum.
6. Which hormone stimulates the release of bile and pancreatic enzymes?
A. Cholecystokinin (CCK)
B. Secretin
C. Gastrin
D. Insulin
Answer: A
, Rationale: CCK is released by the duodenum in response to fats and proteins, triggering
gallbladder contraction and pancreatic secretion.
7. Where does the majority of nutrient absorption occur in the digestive
system?
A. Small intestine
B. Stomach
C. Large intestine
D. Esophagus
Answer: A
Rationale: The small intestine, especially the jejunum, is the primary site for nutrient
absorption due to its large surface area.
8. Which of the following is an example of mechanical digestion?
A. Hydrolysis of proteins
B. Mastication
C. Action of pepsin
D. Emulsification by bile
Answer: B
Rationale: Mastication (chewing) physically breaks down food into smaller pieces, which
is a mechanical process.
9. What is the role of intrinsic factor?
A. Digestion of lipids
B. Absorption of Vitamin B12
C. Activation of trypsinogen
D. Neutralization of stomach acid
Answer: B
Rationale: Intrinsic factor, secreted by parietal cells, is essential for the absorption of
Vitamin B12 in the ileum.
