io The Anatomy of the Salivary Glands 



The sublingual gland in the cat is more tubular (Lundberg, 1957) 

 in arrangement; this offers several advantages from the point of 

 view of experimental study. 



The acinar cells are large polygonal cells arranged in the form 

 of an alveolus, which appear tightly packed after the usual fixation 

 procedures, intercellular spaces cannot usually be seen, nor is any 

 lumen prominent in fixed material. The cells may take on a bluish 

 stain with haematoxylin-eosin which may be interpreted as show- 

 ing the presence of mucin or a pinker colour interpreted as serous 

 (albuminous) or non-mucous. Stormont and others have pointed 

 out the fallacies and difficulties of mucin staining particularly in 

 cells apparently intermediate in type. All that can be said with con- 

 fidence is that the presence of basophilic cells in a gland usually 

 correlates with the presence of a viscous saliva (not necessarily very 

 rich in mucoproteins). 



In many glands occasional cells of a different type are seen 

 within an alveolus, and in those glands with a consistently mixed 

 cellular character the acidophil cells are arranged as demilunes. 

 Recent histological interpretations agree in considering a demilune 

 as an evagination of a group of serous cells from the main alveolus. 

 Granulation is not always easily seen in these acinar cells. In 

 general, the tendentious subdivision of the acinar cells into his- 

 tological types previously considered of importance has not proven 

 of value in understanding gland functions. 



The acini lead into intercalated ducts formed of small cuboidal 

 cells almost filled by a large nucleus. The scanty cytoplasm shows 

 no striation nor as a rule any granules (Fig. 2.1). The intercalated 

 ducts are often short and inconspicuous in histological sections, 

 they empty into intralobular ducts which are usually known as 

 " striated " ducts and are composed of dense-looking cells with a 

 markedly striated appearance in their basal one-third and a cen- 

 trally placed nucleus. Occasionally unusual slender cells ("com- 

 pressed cells") may be seen and also basal cells. The basement 

 membrane is often rather prominent. There is a sharp transition 

 into the excretory ducts which are lined by a two-layered epithe- 

 lium composed of a columnar superficial layer and a flattened deep 

 layer. This structural arrangement is continued in the main ducts 

 to near their termination where an abrupt change to a multi- 

 layered stratified squamous epithelium occurs (Fig. 2.3^). These 

 main ducts are very richly vascularized, and Pischinger (1924) has 



