Which of the following is a parasympathetic response in the gastrointestinal (GI) tract?

• A. Relaxation of the bladder
• B. Dilation of the pupils
• C. Decreased blood flow to the GI tract
• D. Increased peristalsis and secretion

Answer: (D)

Verified step by step guidance

1. Understand the role of the parasympathetic nervous system: It is part of the autonomic nervous system responsible for 'rest and digest' activities, promoting functions that conserve energy and enhance digestion.
2. Identify the effects of parasympathetic activation on the gastrointestinal tract: It generally increases digestive activities, including peristalsis (the wave-like muscle contractions that move food through the digestive tract) and secretion of digestive enzymes.
3. Evaluate each option based on parasympathetic effects: Relaxation of the bladder and dilation of the pupils are not typical parasympathetic responses; they are more associated with sympathetic responses. Decreased blood flow to the GI tract is also a sympathetic response.
4. Recognize that increased peristalsis and secretion are consistent with parasympathetic activation, as these actions facilitate digestion and nutrient absorption.
5. Conclude that the correct parasympathetic response in the GI tract is increased peristalsis and secretion, aligning with the 'rest and digest' function of the parasympathetic nervous system.