| Serous demilune | |
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| Section of submaxillary gland of kitten. Duct semidiagrammatic. (Demilune labeled at center bottom.) | |
| Gray's | subject #242 1136 |
A serous demilune is a cap in the shape of a half-moon (hence the name, "demilune") on some salivary glands.
Serous demilunes are the serous cells at the distal end of mucous tubuloalveolar secretory unit of certain salivary glands (submandibular and sublingual). These demilune cells secrete mucus which contains the enzyme lysozyme that degrades the cell walls of bacteria. In this way, lysozyme confers antimicrobial activity to mucus.
The serous demilune is an artifact from traditional methods of preparing samples. Samples are traditionally preserved and fixed in formaldehyde. When samples were preserved by quick-freezing in liquid nitrogen and then fixed with osmium tetraoxide in acetone, no demilunes are found. Examination showed that the serous cells and mucosal cells were aligned in the acinus. The traditional preparation caused serous cells to swell during fixation, and they popped out of their alignment. After sectioning the cells resembled the common demilune shape, and were so named. [1]
When the gland has this demilunar structure, it produces both serous and mucous secretions, and is thus classified as "mixed".
External links
- serous+demilune at eMedicine Dictionary
- Histology at OU 13_05 - "Trachea"
- Physiology at MCG 6/6ch4/s6ch4_4
- Slide at cytochemistry.net
- MedEd at Loyola Histo/HistoImages/hl9-21.jpg
Please make the following corrections: 1.It is the mucous cells which swell after fixation in formaldehyde. 2.Serous cells secrete the proteins and not mucous.
Notes
- ^ Ross, Michael (2003). Histology: A Text and Atlas. Lippincott Williams & Wilkins. pp. 434–474. ISBN 0781751241.
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