after classification of the specific endocrine cell types according to the ultrastructural morphology of secretory granules , the volume densities of ecl , p and d cells ( 30 +/- 9 % , 24 +/- 7 % , and 22 +/- 4 % of the entire endocrine cell mass , respectively ) were higher than those of other endocrine cell types .
C0886515
secretory granules
C0007634
cell