Anatomy
Summary
The glossopharyngeal nerve, or cranial nerve IX, begins in the medulla and exits the cranium through the jugular foramen, along with cranial nerves X and XI. The glossopharyngeal nerve innervates one muscle, the stylopharyngeus, which elevates the pharynx and larynx during swallowing. In addition, the glossopharyngeal nerve carries sensory information from areas of the pharynx, as well as from the inner surface of the tympanic membrane. And it carries somatic and taste sensation from the posterior one-third of the tongue. The glossopharyngeal nerve also acts as the afferent limb of the gag reflex.
Another function of the glossopharyngeal nerve is conveying sensory information from the carotid body (chemoreceptors) and carotid sinus (baroreceptors) which sense changes in blood chemical composition and pressure, respectively. Hence, the glossopharyngeal nerve is involved in the carotid sinus reflex. Finally, the glossopharyngeal nerve carries parasympathetic innervation to the parotid gland to produce saliva. Dysfunction of the glossopharyngeal nerve could result in the loss of these functions.
Lesson Outline
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FAQs
The glossopharyngeal nerve (cranial nerve IX) innervates the stylopharyngeus muscle. This muscle, which is positioned in the lateral wall of the pharynx, elevates the larynx and pharynx and aids in swallowing.
The glossopharyngeal nerve is responsible for transmitting sensory information from the posterior third of the tongue. This includes both general sensation and the special sensory information of taste.
The glossopharyngeal nerve conveys sensory information from the carotid sinus which consists of baroreceptors that sense changes in blood pressure. Hence, the glossopharyngeal nerve is involved in the carotid sinus reflex.
The glossopharyngeal nerve, or cranial nerve IX, conveys sensory innervation including from areas of the pharynx and the posterior third of the tongue (along with taste from this third). It also supplies parasympathetic fibers to the parotid gland, one of the major salivary glands. It is involved in the gag reflex and in the carotid sinus reflex. In addition, the glossopharyngeal nerve innervates the stylopharyngeus muscle.
