Chorda tympani nerve

The chorda tympani is a branch of the facial nerve that originates from the taste buds in the front of the tongue, runs through the middle ear, and carries taste messages to the brain. It joins the facial nerve (cranial nerve VII) inside the facial canal, at the level where the facial nerve exits the skull via the stylomastoid foramen.Mandible of human embryo 24 mm. long. Outer aspect.Distribution of the maxillary and mandibular nerves, and the submaxillary ganglion.Plan of the facial and intermediate nerves and their communication with other nerves.The course and connections of the facial nerve in the temporal bone.Sympathetic connections of the submaxillary and superior cervical ganglia.View of the inner wall of the tympanum (enlarged.)Dissection of chorda tympani nerveLateral head anatomy detail.Facial nerve dissection. The chorda tympani is a branch of the facial nerve that originates from the taste buds in the front of the tongue, runs through the middle ear, and carries taste messages to the brain. It joins the facial nerve (cranial nerve VII) inside the facial canal, at the level where the facial nerve exits the skull via the stylomastoid foramen. The chorda tympani is part of one of three cranial nerves that are involved in taste. The taste system involves a complicated feedback loop, with each nerve acting to inhibit the signals of other nerves. The chorda tympani exits the cranial cavity through the internal acoustic meatus along with the facial nerve, then it travels through the middle ear, where it runs from posterior to anterior across the tympanic membrane. It passes between the malleus and the incus, on the medial surface of the neck of the malleus. The nerve continues through the petrotympanic fissure, after which it emerges from the skull into the infratemporal fossa. It soon joins the pathway of the larger lingual nerve, a branch of the mandibular nerve. The fibers of the chorda tympani travel with the lingual nerve to the submandibular ganglion. Here, the preganglionic fibers of the chorda tympani synapse with postganglionic fibers which go on to innervate the submandibular and sublingual salivary glands. Special sensory (taste) fibers also extend from the chorda tympani to the anterior 2/3 of the tongue via the lingual nerve. The chorda tympani carries two types of nerve fibers from their origin with the facial nerve to the lingual nerve that carries them to their destinations: There are similarities between the tastes the chorda tympani picks up in sweeteners between mice and primates, but not rats. Relating research results to humans is therefore not always consistent.Sodium chloride is detected and recognized most by the chorda tympani nerve. The recognition and responses to sodium chloride in the chorda tympani is mediated by amiloride-sensitive sodium channels. The chorda tympani has a relatively low response to quinine and varied responses to hydrochloride. The chorda tympani is less responsive to sucrose than is the greater superficial petrosal nerve.