1. Which layer of the gastrointestinal (GI) tract is responsible for

peristalsis and segmentation?

A. Mucosa

B. Submucosa

C. Muscularis

D. Serosa

Answer: C. Muscularis

Rationale: The muscularis layer is responsible for the involuntary

movements of peristalsis and segmentation that propel and mix food along

the GI tract.

2. The enteric nervous system primarily controls which of the following

functions in the GI tract?

A. Blood flow regulation

B. Digestive enzyme secretion

C. Motility and secretion

D. Nutrient absorption

Answer: C. Motility and secretion

Rationale: The enteric nervous system is a network of neurons that

governs the function of the GI tract, including motility and secretion,

independently of the central nervous system.

3. What is the primary function of the stomach's pyloric sphincter?

A. To prevent backflow of food from the small intestine

B. To regulate the release of stomach contents into the duodenum

C. To mix food with gastric juices

D. To initiate protein digestion

Answer: B. To regulate the release of stomach contents into the duodenum

Rationale: The pyloric sphincter controls the passage of chyme from the

stomach to the small intestine, ensuring a regulated and gradual release.

4. Which cells in the stomach are responsible for secreting hydrochloric

acid (HCl)?

A. Chief cells

B. Parietal cells

C. Goblet cells

D. Enteroendocrine cells

Answer: B. Parietal cells