Lume.22 The hyoid and larynx move superiorly and anteriorly even though the epiglottis folds backwards sealing the laryngeal vestibule. These motion helps guard the airway.23 The vocal folds close the glottis 24-26 and interrupt breathing for 0.4-1.0 seconds to prevent aspiration.27, 28 The upper esophageal sphincter (UES) opens by a combination of cricopharyngeus relaxation (UES is held closed by its active contraction), suprahyoid muscle contraction, along with the force of gravity generated by the down-moving bolus. 23,NIH-PA Author Manuscript NIH-PA Author Manuscript NIH-PA Author Manuscript3. four. 5.Esophageal Phase As soon as the bolus passes via the UES, peristalsis and gravity move it down for the reduce esophageal sphincter by way of which meals reaches the stomach.Neural Manage of SwallowingNormal control of swallowing requires suitable function of the brain stem, the basal ganglia, the thalamus, the limbic technique, the cerebellum, and also the motor and sensory cortices (Table 1). These systems control afferent and efferent, anticipatory and preparatory, voluntary and automatic processes. More than 30 muscles are involved in swallowing and are coordinated by a complex neural network that may be not fully understood. The central pattern generator (CPG) for swallowing is positioned in the region in the nucleus tractus solitarius (NTS), the reticular formation, and nucleus ambiguus (NA) in the rostral and ventrolateral medulla.30-32 Its interneuronal network controls timing in the deglutition phases and integrates sensory and supramedullary afferent with efferent processes.30 Sensory input from mechanoreceptors, chemoreceptors and thermoreceptors in the oral cavity, pharynx and larynx towards the CPG has been shown to affect swallowing initiation, facilitation and airway protection.31-34 The oral cavity sensory neurons synapse within the trigeminal sensory nuclei, even though pharyngeal and laryngeal sensory neurons travel in branches of CN IX, X and XI to synapse inside the NTS.35 The ventral CPG premotor neurons connect with CN V, VII and XII and CN IX and X inside the NA.31 Timing of motor outputs varies with bolus traits.36 Functionally, these peripheral connections coordinate unique phases of deglutition. As an illustration, peripheral feedback inhibits the esophageal swallow throughout the pharyngeal swallow. It is probably that the trigeminal nucleus and reticular formation control the oral phase.6-Methoxy-5-nitropicolinic acid web The NTS regulates the sensation and pattern-generation, using the NA and dorsal motor nucleus controlling motor efferents for pharyngeal and esophageal phases.Eugenol acetate Data Sheet 37 The ventromedial nucleus on the NTS may possibly be accountable for coupling the pharyngeal and esophageal phases.PMID:23833812 37 Considering the fact that these locations are essential for pattern generation a lateral medullary stroke (Wallenberg’s Syndrome) canCurr Phys Med Rehabil Rep. Author manuscript; readily available in PMC 2014 September 01.Gonz ez-Fern dez et al.Pageresult in dysphagia that is definitely generally serious and outcomes in aspiration.34, 38 This lesion impacts the CPG as well as the CNs involved in swallowing; paralyzes or weakens the ipsilateral pharynx, larynx along with the soft palate; and initiates and coordinates the pharyngeal stage of deglutition. Notably, electrophysiological studies demonstrate that the acute disconnection of contralateral swallowing centers also requires spot.34 Quite a few supratentorial structures are related with swallowing. In stroke, the size with the unaffected swallowing cortical region predicts dysphagia symptoms.39 Voluntary initiation of deglutition re.
