alveolar gland alveolar gland alveolar glands, also called saccular glands are glands with a saclike secretory portion, in contrast with tubular glands. they typically have an enlarged lumen (cavity), hence the name: they have a shape similar to alveoli, the very small air sacs in the lungs. alveolar glandsection of pancreas of dog. x 250.identifiersthh2.00.02.0.03028 anatomical terminology look up alveolar in wiktionary, the free dictionary. look up tubuloalveolar in wiktionary, the free dictionary. some sources draw a clear distinction between acinar and alveolar glands, based upon the size of the lumen. a further complication in the case of the alveolar glands may occur in the form of still smaller saccular diverticuli growing out from the main sacculi. the term "racemose gland" is used to describe a "compound alveolar gland" or "compound acinar gland." branched alveolar glands are classified as follows: type description location simple branched acinar thyroid glands tubuloalveolaror tubulo-alveolaror tubulo-acinaror compound tubulo-acinaror compound tubuloalveolar glands that start out as simple branched tubular, and branch further to terminate in alveoli salivary glands,esophagusmammary glands additional images alveoli of lacrimal gland. human submaxillary gland. at the right is a group of mucous alveoli, at the left a group of serous alveoli. section of portion of mamma.