Fig. 4.
Representative illustration of the MTM of ‘Model 10’ that consists of a body and antrum in series and a bypass compartment that can transfer the phenol red solution directly to the antrum. Duodenum and jejunum reactors are connected in series with the stomach compartment. Ca0 stands for the initial concentration of phenol red present in the glass of water; Q0 stands for input water flow i.e., 250 mL in 2 min; RwD and RwJ stands for the secretion rate constants in the duodenum and jejunum, respectively; Kaw represents the water absorption rate constants, present in the duodenum and jejunum; KtD and KtJ are the first-order transit rate constants in the duodenum and jejunum, respectively.