Assertion: esophagus | /r/HasAspect | closing mechanisms
Facets:
Source sentences:
text: The esophagus possesses closing mechanisms at both its upper and lower ends which are called the upper esophageal sphincter (UOS) and the lower esophageal sphincter (LOS).
text: The esophagus possesses a closing mechanism at both its upper and lower end, called the upper (UOS) and lower esophageal sphincter (LOS).