SALIVARY GLANDS. 



153 



THE SALIVARY GLANDS. PANCREAS. 

 PLAN OF GLAND STRUCTURE. 



GLANDS. 



A gland is an organ frequently subsidiary to and located within 

 other organs whose cells manufacture from the blood products to be 

 utilized in the maintenance of physiological integrity. 



Glands are tubes or cavities, with connective-tissue walls lined with 

 cells of a columnar type. Around, and in close proximity to the lin- 

 ing, is spread a plexus of blood capillaries. 



The essential parts of a gland are, therefore: 



1. A duct) or efferent conduit for the secretion. 



2. Parenchyma, cells engaged in secretion. 



3. A blood-vascular supply. 



TUBULAR GLANDS. 



The simplest gland structure is presented in the form of a tube. 

 Ci-lands are, frequently, little more than tubular depressions in mucous 



FIG. 102. DIAGRAM. SIMPLE TUBULAR GLAND. 



A. Lining cells parenchyma. 



B. Capillary plexus, supplying the parenchyma. 



C. Connective tissue supporting capillaries. 



D. Arterial supply. 



