Esophageal motor disorders are diagnosed clinically with manometric catheters, multiple small catheters fused into a single assembly with pressure sensors positioned at various levels (see Clinical Focus Box 26.4). They are placed into the esophagus via the nasal cavity. Manometric catheters record a distinctive pattern of motor behavior following a swallow (Fig. 26.23). At the onset of the swallow, the lower
Lower ^^ \ esophageal"""""-^ sphincter J
, Manometric recordings of pressure events in the esophageal body and lower esophageal sphincter following a swallow. The propulsive segment of the peristaltic behavioral complex produces a positive pressure wave at each recording site in succession as it travels down the esophagus. Pressure falls in the lower esophageal sphincter shortly after the onset of the swallow, and the sphincter remains relaxed until the propulsive complex has transported the swallowed material into the stomach.
esophageal sphincter relaxes. This is recorded as a fall in pressure in the sphincter that lasts throughout the swallow and until the esophagus empties its contents into the stomach. Signals for relaxation of the lower esophageal sphincter are transmitted by the vagus nerves. The pressure-sensing ports along the catheter assembly show transient increases in pressure as the segment with the sensing port becomes the propulsive segment of the peristaltic pattern as it passes on its way to the stomach.
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This ebook provides an introductory explanation of the workings of the human body, with an effort to draw connections between the body systems and explain their interdependencies. A framework for the book is homeostasis and how the body maintains balance within each system. This is intended as a first introduction to physiology for a college-level course.