140 



NORMAL HISTOLOGY. 



at certain stages of their activity, are so crowded with granules that 

 the nuclei are obscured. These granules are the accumulated mate- 

 rial from which the secretion is formed, and when the gland has 

 been functionally active for some time they diminish in number, 



Fig. US. 



Section of an acinus of the human submaxillary gland. (Krause.) The lumen is surrounded 

 by mucous cells, containing globules of mucigen. Two groups of Gianuzzi's crescents are 

 represented, with the intracellular channels conveying the serous secretion to the lumen. 



and the nuclei then come into view. At the same time the cells 

 become smaller, and the lumen within the acinus, which at first was 

 barely distinguishable, becomes more obvious. 



The epithelium lining the acini of all the salivary glands rests 



Fig. 119. 



Diagrammatic representation of a portion of a human submaxillary gland. (Krause.) a, duct, 

 lined with columnar cells, striated at their bases and passing into a more cubical epithe- 

 lium without such striation ; b, mucous cells; c, serous cells; d, crescent; abasement. 

 membrane. In this figure the convoluted course of the ducts and tubular acini has been 

 ignored, and they have been represented as though lying in a single plane. 



upon a modified connective tissue, called the " basement-membrane," 

 which consists of flattened cells arranged to form a broad, mem- 

 branous reticulum, the meshes of which are filled with cement. 

 Outside of this basement-membrane there is a small amount of 



