Definition of acinus in English:



  • 1A small sac-like cavity in a gland, surrounded by secretory cells.

    • ‘In cases with moderate or advanced changes, marked immunoreactivity was observed in the interlobular area and in the area surrounding both the acini and intralobular ducts.’
    • ‘The lesion displayed unremarkable pancreatic lobules with acini, ducts, and islets of Langerhans cells.’
    • ‘Small residual ducts and islands of intact salivary gland acini predominantly composed of serous-type glandular epithelium were present.’
    • ‘The mass also contained cystic spaces lined by columnar epithelium, sebaceous glands, cartilage, smooth muscle, and pancreatic acini.’
    • ‘The airway wall is composed of many interrelated structural components such as epithelium, connective tissue, vessels, muscle, and mucus-secreting gland acini.’
    bag, pouch, bladder, blister
    View synonyms
  • 2A region of the lung supplied with air from one of the terminal bronchioles.

    • ‘A spectrum of airborne organic particulate matter, appropriately sized to reach pulmonary acini, produces this disease.’
    • ‘The acinus or primary pulmonary lobule (the basic unit of gas exchange) consists of one terminal bronchiole, two to five generations of respiratory bronchioles, alveolar ducts, alveolar sacs, and alveoli.’
    • ‘Primary bronchiolar disorders are separated from diseases primarily affecting more distal components of the pulmonary acinus and large airway diseases in which prominent secondary bronchiolar changes may be seen.’
    • ‘Panlobular emphysema, also referred to as panacinar emphysema, affects the acinus of the entire secondary lobule.’
    • ‘Emphysema is classified into three subtypes based on the portion of the acinus that is involved.’


Mid 18th century: Latin, literally a kernel.