Читать книгу The Esophagus - Группа авторов - Страница 71

The medulla oblongata houses paired swallowing centers responsible for processing afferent sensory signals and programming the motor swallowing sequences [46–48]. These centers are poorly defined areas and comprise the NTS, ventromedial reticular formation (VMRF), and nucleus ambiguus (NA) [49]. There is increasing evidence that cortical structures have a significant influence on the brainstem swallowing centers [50]. Cortical areas in the preorbital gyrus and lateral precentral gyrus have been implicated in modulation of deglutition. Cortical projections have been found connecting the cortical and medullary swallowing centers. Although poorly understood, experimental evidence suggests the presence of a close functional, structural, and physiologic interaction between deglutitive and respiratory centers and their afferent and efferent inputs.

Figure 3.2 Sequence of events during primary swallows. (A–D) The primary swallow resulted in bolus transport from the mouth into the pharynx and esophagus. Straight arrows indicate pharyngeal lumen. (A, E) Bolus of 5 mL of barium is held in the oral cavity immediately before the onset of swallowing. Tongue base and soft palate are in contact (curved arrow), segregating the oral bolus from the pharyngeal cavity. (B, F) Tongue base is depressed and soft palate has elevated and is in contact with the posterior pharyngeal wall. This resulted in closing off the nasopharynx and allowing the bolus to enter the pharynx. (C, G). Bolus transferring to the pharynx while the nasopharynx and oral cavity are sealed off by approximation of the soft palate and posterior pharyngeal wall, and apposition of the tongue base and soft palate, respectively. The hyoid bone has moved upward and forward. (D, H) The barium bolus has cleared the pharynx, the oral cavity and nasopharynx are open, and the larynx and hyoid bone have returned to the resting position. B, barium bolus; H, hyoid bone.

Source: Shaker et al. [37] with permission of Elsevier.