Читать книгу The Esophagus - Группа авторов - Страница 139

Central control and peripheral neural and myogenic mechanisms must integrate effectively to direct peristalsis in the smooth muscle segment. Which mechanism is dominant under normal circumstances is not established. The esophagus ordinarily is both mechanically and electrically silent, and for a contraction to occur, some form of stimulus is required. With a swallow, the central mechanism controls and initiates contractions in the striated muscles of the oropharyngeal stage and in the upper striated muscle portion of the esophagus. For initiation of a contraction in the smooth muscle portion, the excitatory cholinergic neuron must be adequately stimulated by central and/or peripheral neural input. The threshold for muscle contraction, timing in the peristaltic sequence, and contraction amplitude are determined by the balance between excitatory and inhibitory influences at the muscle level.