Illustrated section of pancreas of dog. X 250. (Alveolus labeled at center top.)
An acinus (//) (plural, acini; adjective, acinar [//] or acinous) refers to any cluster of cells that resembles a many-lobed berry, such as a raspberry (acinus is Latin for "berry"). The berry-shaped termination of an exocrine gland, where the secretion is produced, is acinar in form, as is the alveolar sac containing multiple alveoli in the lungs.
Acinar exocrine glands are found in many organs, including:
- the stomach
- the sebaceous gland of the scalp
- the salivary glands of the tongue
- the liver
- the lacrimal glands
- the mammary glands
- the pancreas
- the bulbourethral (Cowper's) glands
The thyroid follicles can also be considered of acinar formation but in this case the follicles, being part of an endocrine gland, act as a hormonal deposit rather than to facilitate secretion.
Mucous acini usually stain pale, while serous acini usually stain dark.
The term "acinus" is considered synonymous with alveolus by some sources, but not all.
|Look up acinus in Wiktionary, the free dictionary.|
- Histology at OU 51_07 - pyloric stomach
- Histology at OU 46_03 - sublingual gland
- BU Histology Learning System: 10405loa
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