one is a radial microtubule system in which the microtubules run radially from the basal to the apical cytoplasm and in which fibroin globules ( secretory granules of fibroin ) and mitochondria are arranged along these microtubules , thus composing a `` '' canal system '' '' which is assumed to be responsible for the intracellular transport of fibroin globules .
C0010834
cytoplasm
C0886515
secretory granules