Tubuloacinar

Tubuloacinar describes a type of secretory gland architecture in which the secretory portions consist of both tubular and acinar units. In tubuloacinar glands, secretory endpieces may be tubular, acinar, or mixed, arranged in lobules and draining through a duct system. The combination yields a histological pattern in which tubular segments feed into or surround acinar clusters; mucous glands often show tubules with serous demilunes, giving a seromucinous appearance.

Common examples include the exocrine pancreas, and several salivary glands such as the submandibular and sublingual glands, which display serous and mucous cells in a mixed tubuloacinar organization. By contrast, the parotid gland is typically described as a purely serous acinar gland, not as tubuloacinar.

Functionally, tubuloacinar glands produce secretions that are delivered via ducts; the acinar portions typically generate the enzyme-rich or mucous components, while ductal portions modify and transport the secretions.

In summary, tubuloacinar is a structural descriptor used in histology to characterize glands whose secretory units combine tubular and acinar elements, providing versatility in the composition of secretions and in glandular function.