four types of chromaffin cell were distinguished largely on the basis of their vesicular content : type i cells contain large , electron-dense vesicles ( 600-7000 a ) and are comparable to noradrenaline-containing cells in the adrenal gland , type ii cells contain large , vesicles ( 600-7000 a ) that are filled with a less electron-dense material than that in type i cells and are comparable to adrenaline-containing cells in the adrenal gland , type iii cells contain smaller vesicles ( 1000-3000 a ) that are incompletely filled with an electron-dense material and may represent cells that have been depleted of their catecholamines by stimulation , type iv cells are clearly different from the other three cell types with respect to the size and appearance of the vesicles ( 1000-1500 a ) , nuclei and rough endoplasmic reticulum and may represent immature sympathetic neurons .
C0028351
noradrenaline
C0014563
adrenaline