AEMCA Practice Exam

What is the primary role of cranial nerve 9?

1. To stimulate salivary glands

2. To manage swallowing and blood pressure

3. To control facial expressions

4. To regulate heart rate

The correct answer is: To manage swallowing and blood pressure

The primary role of cranial nerve 9, also known as the glossopharyngeal nerve, encompasses several key functions, with a significant focus on managing swallowing and regulating blood pressure. This nerve is responsible for providing sensory innervation to the oropharynx and tonsils, and it plays an essential role in the swallowing reflex by facilitating the movement of food from the mouth into the esophagus. Additionally, cranial nerve 9 is involved in the autonomic regulation of blood pressure through its sensory function in detecting changes in blood pressure via baroreceptors located in the carotid sinus. By relaying these changes to the brain, it assists in modulating cardiovascular functions and ensuring proper blood pressure levels. In contrast, while stimulating salivary glands is an important function, it is typically associated more with cranial nerve 7 (the facial nerve), which directly innervates these glands. Control of facial expressions is primarily governed by cranial nerve 7 as well, and the regulation of heart rate is managed mainly by the vagus nerve, which is cranial nerve 10. Thus, the correct understanding of the functions of cranial nerve 9 highlights its primary roles in swallowing and blood pressure management.