Читать книгу The Esophagus - Группа авторов - Страница 115

Several cranial nerves participate in sensory feedback for the oropharyngeal stages of swallowing, including trigeminal (especially maxillary branch), facial, glossopharyngeal, and vagus [8–12]. Sensory initiation of the pharyngeal phase of swallowing occurs through the superior laryngeal nerve (SLN) of the vagus nerve [5, 9]. The pharynx is highly sensitive; as little as 0.5 mL of fluid injected quickly into the pharynx can initiate human swallowing [13–15]. Esophageal feedback occurs via the vagus nerve with its cell bodies in the nodose ganglion, which may also modify cognitive sensation such as pain, acting through higher centers [16]. Afferent information enters the NTS, where subdivisions of the NTS initiate and program sequencing of swallowing, modify ongoing motor activity, and activate reflexes involving the esophagus, esophageal sphincters, and airway [5, 17]. There is viscerotopic organization of the afferent input to the NTS [18, 19]. Although sympathetic nerves entering the spinal cord segments C1 to L3 also carry afferent sensory information from the esophagus [20, 21], their role in modulating SPG activity is unknown.

Oropharyngeal afferents enter primarily into two subnuclei of the NTS: the interstitial (NTS_is) and the intermediate (NTS_im); esophageal afferents enter into the subnucleus centralis (NTS_ce) [5, 6, 18,22–25]. Motor programming of the swallow sequence occurs within these subunits of the DSG [26]. Other NTS subnuclei presumably function in the relay to the VSG and to motor neurons, and in the pathways to affected activities such as respiration.