Acinus

An acinus is a small, specialized cluster of cells in certain organs, such as the lungs and salivary glands, where the production or secretion of substances occurs. In the lungs, alveolar acini contain tiny air sacs called alveoli, which are essential for gas exchange—oxygen in, carbon dioxide out. These acini are important organizational units that help carry out specific functions efficiently. Essentially, think of an acinus as a tiny, functional building block within larger organs, playing a crucial role in processes like breathing or secretion.