 These three regions are apical, middle cytoplasmic, and basal lamina.The middle cytoplasmic region is the most active of the three due to the concentration of multiple organelles within, such as mitochondria and smooth and rough endoplasmic reticulum, among others.The increase of activity is due to the interlocking labyrinth of the basal lamina creating a crosscurrent activity similar to the mitochondrial-rich cells found in teleost marine fish.