part_of part of part of cortex of kidney nephron tubule descending limb of loop of Henle proximal straight tubule Portion of the renal tubule which is just posterior to the proximal convoluted tubule.[TAO] FMA:17716 UBERON:0001290 pars recta TAO:0005291 segment 3 of proximal tubule MA:0002614 pars recta tubuli renalis thick descending limb of proximal tubule EMAPA:29661 ZFA:0005291 BTO:0000055 Wikipedia:Proximal_straight_tubule EMAPA:29669 UBERON:0005166 proximal tubule segment 3 tubulus rectus proximalis S3 The proximal straight tubule is the part of the descending limb that extends from the proximal convoluted tubule to the descending thin tubule. TODO - is S3 exactly coincident with PST? todo - ensure relationships work across species (loop of Henle) proximal tubule kidney pyramid