Flow diagram and arrangement of organs used for the PBPK model. Each box represents a well-stirred compartment and each arrow is an input or output to the organ. The organ labeled "Portal" includes all organs drained by the portal vein (stomach, small and large intestine, spleen and pancreas). The organ labeled "Other" represents "connective" tissue and its weight is adjusted during the run to so that total weight is equal to that set by the subject's "weight". Adipose tissue is represented by two equal volume adipose compartments with different perfusion rates.