In general, which type of nerves stimulate motility and secretion in the gastrointestinal tract?

• A. Sensory nerves
• B. Parasympathetic nerves
• C. Sympathetic nerves
• D. Somatic nerves

Answer: (B)

Verified step by step guidance

1. Understand the role of the autonomic nervous system in regulating the gastrointestinal (GI) tract. The autonomic nervous system is divided into the parasympathetic and sympathetic divisions, which have opposing effects on GI motility and secretion.
2. Learn the function of parasympathetic nerves in the GI tract. Parasympathetic nerves, primarily through the vagus nerve, stimulate motility (movement of food through the GI tract) and secretion (release of digestive enzymes and fluids). This is part of the 'rest and digest' response.
3. Contrast the role of sympathetic nerves. Sympathetic nerves generally inhibit GI motility and secretion, as part of the 'fight or flight' response, redirecting energy away from digestion.
4. Understand the role of sensory nerves. Sensory nerves in the GI tract detect changes such as stretch, chemical composition, and pain, but they do not directly stimulate motility or secretion.
5. Recognize that somatic nerves control voluntary muscles, such as those involved in chewing and swallowing, but they do not regulate the involuntary processes of motility and secretion in the GI tract.