although tubular complexes have been thought by others to result from ductal proliferation , the following observation indicate that they originate from zymogen-granule-containing cells : a ) there is a continuum of transitional stages between acini and tubules , b ) most tubules decrease in size and are replaced by connective tissue ( evidence of regression rather than proliferation ) , c ) few mitotic figures are seen in tubular complexes , d ) the tubules comprise many cells which have an abundance of rough endoplasmic reticulum , an organelle which is sparce in ducts , and e ) the three-dimensional arrangement of tubules appears identical to the branching , anastomosing arrangement of zymogen-granule-containing cells of the normal rat pancreas .
C0230779
rough endoplasmic
C0007634
cells