glossary

acinus

Definition acinus

acinus

acinus n. (pl. acini) 1. a small sac or cavity surrounded by the secretory cells of a gland. Some authorities regard the term as synonymous with *alveolus, but others distinguis an acinus by the possession of a narrow passage (lumen) leading from the sac. 2. (in the lung) the tissue supplied with air by one terminal *bronchiole. *Emphysema is classified by the part of the acinus involved (i.e. centracinar, paracinar, or periacinar) -acinous adj.