Carotid Sinus Baroreceptors and Their Neural Pathway

The carotid sinus contains stretch-sensitive baroreceptors that monitor arterial blood pressure. Changes in pressure cause these baroreceptors to send afferent signals to the brainstem to help regulate cardiovascular function.

Location of Neuronal Cell Bodies

• The afferent fibers carrying signals from the carotid sinus baroreceptors travel via the carotid sinus nerve, which is a branch of the glossopharyngeal nerve (cranial nerve IX).

• The cell bodies of these sensory neurons reside in the petrosal ganglion, which is the sensory (afferent) ganglion of the glossopharyngeal nerve.

• This ganglion contains the pseudounipolar neurons whose peripheral processes innervate the carotid sinus baroreceptors and central processes project to the brainstem cardiovascular centers.kenhub+2

Answer

The correct answer is:

(3) petrosal ganglion

Brief Explanation of Other Options

• Nodose ganglion (1): Houses sensory neurons for the vagus nerve (cranial nerve X), associated with the aortic arch baroreceptors.

• Geniculate ganglion (2): Sensory ganglion of the facial nerve, not involved in baroreceptor afferents.

• Spiral ganglion (4): Contains sensory neurons for the cochlea (hearing); unrelated to baroreceptors.

Summary Table

Conclusion

The sensory neurons conveying pressure information from the carotid sinus baroreceptors have their cell bodies in the petrosal ganglion of the glossopharyngeal nerve.

Understanding this anatomy supports further insights into cardiovascular reflexes and the neural control of blood pressure.