Oregon Certified Nursing Assistant State Practice Exam

What defines peristalsis in the digestive system?

1. Involuntary muscle contractions that move food through the digestive tract

2. Active chewing and grinding of food

3. Release of digestive enzymes into the stomach

4. Absorption of nutrients through the intestinal wall

The correct answer is: Involuntary muscle contractions that move food through the digestive tract

Peristalsis is defined as involuntary muscle contractions that facilitate the movement of food through the digestive tract. This process is essential for digestion, as it ensures that food is pushed along the esophagus, stomach, and intestines, allowing for proper processing and breakdown. The rhythmic contractions of the muscles in the digestive organs create a wave-like motion that helps mix food with digestive juices and efficiently move it towards elimination. The other options describe different aspects of the digestive process, but they do not encompass the specific definition of peristalsis. Chewing and grinding of food refers to a mechanical process, while the release of digestive enzymes relates to chemical digestion. Absorption of nutrients is a separate function that occurs after digestion, utilizing the walls of the intestines to transfer nutrients into the bloodstream. Each of these plays a role in digestion, but it is the involuntary contractions that specifically characterize peristalsis.