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Ultrastructure of bovine parotid glands
Author(s) -
Shackleford John M.,
Wilborn Walter H.
Publication year - 1969
Publication title -
journal of morphology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.652
H-Index - 74
eISSN - 1097-4687
pISSN - 0362-2525
DOI - 10.1002/jmor.1051270406
Subject(s) - bone canaliculus , myoepithelial cell , biology , ultrastructure , basal lamina , anatomy , basement membrane , nasal glands , endoplasmic reticulum , epithelium , cytoplasm , microbiology and biotechnology , parotid gland , pathology , immunohistochemistry , mucous membrane of nose , medicine , genetics , immunology
Bovine parotid glands exhibit outstanding structural differences when compared with those of non‐ruminant mammals. The acini are tortuous, branched and lined with cells of different heights, imparting a scalloped appearance to acinar lumina. Numerous microvilli, ca . 1.5 μ in length, extend into the lumina and intercellular canaliculi. Intercellular canaliculi measure ca . 3 μ in diameter and interweave in close association with intercellular tissue spaces. Intercellular tissue spaces are separated from the extraacinar spaces across a basal lamina only, whereas junctional complexes guard canaliculi from direct continuity with tissue spaces and/or extraacinar spaces. Flattened cytoplasmic lamellae extend from adjacent acinar cells and loosely interdigitate with one another across the tissue spaces. Acinar cells contain more mitochondria and less granular endoplasmic reticulum than parotid glands of non‐ruminant mammals. Two types of secretory material, in the form of inclusions which vary in size and electron density, are present in the acinar cells. Intercalated ducts connect acini with striated ducts which in turn, empty into collecting ducts located between gland lobules. In terms of frequency of “basal infoldings” and numbers of mitochondria, striated ducts of calf parotid glands are not as well developed as those of certain other salivary glands. Myoepithelial cells are most often present at junctions of acini and intercalated ducts where they may attach to both acinar and ductal epithelium. Nerve “terminals” were not observed on the epithelial side of basement membranes in relation to the secretory cells.