AEMCA Practice Exam

What role do muscarinic M1 receptors play in the parasympathetic system?

1. Regulate heart rate and anxiety

2. Stimulate gastric acid secretion and salivary glands

3. Cause pupil dilation and blood vessel constriction

4. Manage bladder relaxation and bowel movements

The correct answer is: Stimulate gastric acid secretion and salivary glands

Muscarinic M1 receptors play a crucial role in the function of the parasympathetic nervous system, particularly in the stimulation of gastric acid secretion and the activation of salivary glands. When these receptors are stimulated by acetylcholine, they help facilitate digestive processes by increasing gastric acid production, which is essential for breaking down food in the stomach. Additionally, the activation of these receptors leads to increased saliva production, which is necessary for digestion and oral health. This specific action highlights the importance of the M1 receptors in enhancing digestive functions and supports the overall role of the parasympathetic nervous system in promoting rest-and-digest activities. Other receptor types serve different functions within the autonomic nervous system, which is why the activities associated with M1 receptors are distinct and specialized.