Comprehensive Osteopathic Medical Licensing Examination (COMLEX USA) Practice

Which effect is associated with the parasympathetic nervous system on the stomach and intestines?

1. Decreases motility

2. Increases motility

3. Blocks digestion

4. Stimulates bile production

The correct answer is: Increases motility

The parasympathetic nervous system primarily promotes digestive processes, which includes increasing motility in the stomach and intestines. When the parasympathetic system is activated, typically during rest and digest states, it enhances peristalsis—the wave-like contractions that move food through the gastrointestinal tract. This increased motility aids in the mixing of food with digestive enzymes and facilitates the absorption of nutrients. In addition to enhancing muscle contractions in the digestive tract, the parasympathetic system also stimulates the secretion of digestive juices and enzymes, further promoting digestion. This effect is a contrast to the sympathetic nervous system, which tends to inhibit digestive activity by reducing motility in response to stress or danger, thereby prioritizing blood flow to skeletal muscles over the digestive organs.