ATI LPN

1. After ingested food is mixed and churned with gastric secretions, the resulting semifluid mass is called:

• A. a bolus.
• B. chyme.
• C. rennin.
• D. glycogen.

Correct Answer: B

Rationale: The correct answer is B: chyme. Chyme is the partially digested food that forms a semifluid mass after mixing with gastric juices. A is incorrect because a bolus refers to a rounded mass of food ready to be swallowed. C, rennin, is an enzyme involved in the digestion of milk proteins and not the term for the semifluid mass after food mixing with gastric secretions. D, glycogen, is a form of stored glucose in the body and is not the term used to describe the partially digested food mass in the stomach.

2. The interrelated network of nerves within the gastrointestinal wall that regulates its muscular action is known as the:

• A. gastric nerve plexus.
• B. biliary nerve plexus.
• C. intramural nerve plexus.
• D. intestinal nerve plexus.

Correct Answer: C

Rationale: The correct answer is C - intramural nerve plexus. This network of nerves regulates the muscular movements within the gastrointestinal wall. The gastric nerve plexus (choice A) specifically relates to the stomach, not the entire gastrointestinal tract. The biliary nerve plexus (choice B) is associated with the bile ducts and gallbladder, not the regulation of muscular action. The intestinal nerve plexus (choice D) is a general term that doesn't specifically refer to the network of nerves within the gastrointestinal wall.

3. The release of gastric secretions is stimulated by nerve and hormonal stimuli and the:

• A. ingestion of water.
• B. swallowing reflex.
• C. presence of food in the stomach.
• D. closing of the pyloric sphincter.

Correct Answer: C

Rationale: The correct answer is C: 'presence of food in the stomach.' Gastric secretions are stimulated when food enters the stomach, triggering nerve and hormonal responses. This process prepares the stomach for digestion. Choices A, B, and D are incorrect because ingesting water, swallowing reflex, and the closing of the pyloric sphincter do not directly stimulate the release of gastric secretions.

4. The lining of the stomach and intestine is protected from self-digestion by:

• A. pepsinogen.
• B. bile.
• C. mucus.
• D. fat.

Correct Answer: C

Rationale: The correct answer is C: mucus. Mucus forms a protective barrier that prevents the stomach and intestine from digesting themselves. Pepsinogen (choice A) is an inactive form of pepsin, a digestive enzyme, and does not protect the stomach lining. Bile (choice B) aids in the digestion and absorption of fats but does not protect the stomach lining. Fat (choice D) is a nutrient and energy source; it does not play a role in protecting the stomach and intestine from self-digestion.

5. What is the term for the action of biting, chewing, and breaking up ingested food into smaller particles?

• A. Peristalsis.
• B. Segmentation.
• C. Metabolism.
• D. Mastication.

Correct Answer: D

Rationale: The correct answer is D, 'Mastication.' Mastication is the mechanical process of chewing that breaks down food into smaller particles. Peristalsis (choice A) is the involuntary constriction and relaxation of muscles in the gastrointestinal tract that moves food along. Segmentation (choice B) is the mixing movement of the digestive system that helps to break down food and mix it with digestive juices. Metabolism (choice C) refers to the chemical processes that occur within a living organism to maintain life.