in contrast , b-type cells had few filopodia , numerous smooth micropinocytotic vesicles , few coated micropinocytotic vesicles , a well-developed golgi apparatus and rough endoplasmic reticulum , mitochondria that were longer and had a denser matrix than that of a cell mitochondria , and surprisingly , only few maturing or fully formed secretory granules .
C0026237
mitochondria
C1510421
matrix