① acinus: a serous acinus structure. pyramidal or cuboidal ound basally-located N apical: zymogen granule-acidophilic e basal: basophilic-RER, ribosome function: secret salivary amylase① acinus: a. serous acinus: structure: pyramidal or cuboidal round basally-located N apical: zymogen granule-acidophilic basal: basophilic-RER, ribosome function: secret salivary amylase