Which one of the following statements regarding the regulation of gastrointestinal function is true?

**Core Concept**
The regulation of gastrointestinal (GI) function is a complex process involving the coordination of the enteric nervous system, hormonal signals, and neural inputs from the central nervous system. The enteric nervous system, often referred to as the "little brain," plays a crucial role in maintaining GI homeostasis.

**Why the Correct Answer is Right**
The correct answer involves the understanding of the enteric nervous system and its role in regulating GI function. The enteric nervous system contains over 100 million neurons, which are more than the number of neurons in the spinal cord or the brainstem. These neurons release various neurotransmitters and hormones that regulate GI motility, secretion, and blood flow. The enteric nervous system can function independently of the central nervous system, although it can be influenced by neural inputs from the brain and spinal cord.

**Why Each Wrong Option is Incorrect**
**Option A:** This option suggests that the regulation of GI function is solely dependent on the central nervous system. However, the enteric nervous system is capable of functioning independently, and its dysfunction can lead to various GI disorders.
**Option B:** This option implies that the release of gastrin is the primary regulator of GI function. While gastrin does play a role in regulating gastric acid secretion, it is not the primary regulator of overall GI function.
**Option C:** This option suggests that the regulation of GI function is solely dependent on hormonal signals. However, the enteric nervous system plays a crucial role in regulating GI function, and neural inputs from the central nervous system can also influence GI function.

**Clinical Pearl / High-Yield Fact**
The enteric nervous system is often referred to as the "little brain" due to its ability to function independently of the central nervous system. Dysfunction of the enteric nervous system can lead to various GI disorders, including irritable bowel syndrome (IBS), gastroparesis, and intestinal pseudo-obstruction.

**Correct Answer: C. The enteric nervous system plays a crucial role in regulating gastrointestinal function.**

✓ Correct Answer: C. Salivary secretion is stimulated by both branches of the autonomic nervous system, although not to the same degree.