Certified Neuroscience Registered Nurse (CNRN) Practice Exam

Which gastric secretions are primarily responsible for breaking down food?

1. Insulin, glucagon, and bile

2. Pepsin, hydrochloric acid, and gastrin hormone

3. Sodium bicarbonate and mucus

4. Amylase, lipase, and protease

The correct answer is: Pepsin, hydrochloric acid, and gastrin hormone

The gastric secretions that play a crucial role in the breakdown of food include pepsin, hydrochloric acid, and gastrin hormone. Pepsin is an enzyme that specifically targets proteins, breaking them down into smaller peptides, which is essential for efficient digestion. Hydrochloric acid creates an acidic environment in the stomach that not only aids the activation of pepsin from its inactive form, pepsinogen, but also helps denature proteins and provides a barrier to pathogens. Gastrin is a hormone that stimulates the secretion of hydrochloric acid and promotes gastric motility, ensuring that the digestive process is effective. Together, these secretions facilitate the chemical digestion of food, particularly proteins, making them critical for overall digestive health. In contrast, the other options contain substances that do not primarily function in the stomach for breaking down food. Insulin and glucagon are involved in glucose metabolism, bile aids in the emulsification of fats but is produced in the liver and stored in the gallbladder, sodium bicarbonate mainly neutralizes stomach acid in the small intestine, and mucus serves to protect the stomach lining from acid but does not contribute to digestion. Amylase, lipase, and protease are digestive enzymes found in saliva and