On the basis of a fully coupled active musculomechanical model for esophageal transport, we aimed to find the roles of @entity121 ( @entity121 ) contraction and longitudinal muscle (LM) shortening in esophageal transport, and the influence of their coordination. Two groups of studies were conducted using a computational model. In the first group, bolus transport with only @entity2472 , only LM shortening, or both was simulated. Overall features and detailed information on pressure and the cross-sectional area (CSA) of mucosal and the two muscle layers were analyzed. In the second group, bolus transport with varying delay in @entity2472 or LM shortening was simulated. The effect of delay on esophageal transport was studied. For cases showing abnormal transport, pressure and CSA were further analyzed. @entity2472 by itself was sufficient to transport bolus, but LM shortening by itself was not. @entity2472 decreased the CSA and the radius of the muscle layer locally, but LM shortening increased the CSA. Synchronized @entity2472 and LM shortening led to overlapping of muscle CSA and pressure peaks. Advancing LM shortening adversely influenced bolus transport, whereas lagging LM shortening was irrelevant to bolus transport. In conclusion, @entity2472 generates high squeezing pressure, which plays a primary role in esophageal transport. LM shortening increases muscle CSA, which helps to strengthen @entity2472 . Advancing LM shortening decreases esophageal distensibility in the bolus region. Lagging LM shortening no longer helps esophageal transport. Synchronized @entity2472 and LM shortening seems to be most effective for esophageal transport.

Simulation studies of @entity121 contraction, XXXX , and their coordination in esophageal transport.

@entity121 :: ('MESH:D009135', 'Disease') :: ['circular muscle', 'CM'] @entity2472 :: ('MESH:C536214', 'Disease') :: ['CM contraction']
@entity121 :: (MESH:D009135,Disease) :: ['longitudinal muscle shortening']
