HISTOLOGY. 105 



TH SALIVARY GLANDS. 



The salivary glands are the parotid, submaxillary, 

 sublingual and the pancreas. They are all of a true 

 glandular nature, having a duct, which divides and 

 subdivides until it reaches the alveolus of the gland. 

 The little alveolus is in reality the lumen of the duct 

 lined with glandular epithelial cells. Kach individual 

 alveolus and its basement membrane is called a lobule. 

 Each lobule has an enclosing membrane of white fi- 

 brous tissue separating it from the next lobule. As 

 these duct branches grow larger a second band of 

 white fibrous tissue is thrown around a number of 

 them, forming a lobe. A band of white fibrous tissue 

 is thrown around the whole mass. This band is called 

 a capsule. The whole mass is called a gland. The 

 duct, after leaving the alveolus, is lined with columnar 

 epithelial cells. In some glands it is lined with two 

 layers of cells. The salivary glands are named ac- 

 cording to their secretion: mucous, serous and mixed 

 glands. The glands are richly supplied with blood ves- 

 sels. The artery enters the gland at the point where 

 the duct leaves it, and when it reaches the acini it 

 breaks up into a network of capillaries that reunite to 

 form the veins, which leave the gland, accompanied by 

 the artery. The lymphatics are found with the artery 

 as far as the 'acini. The nerves are of both varieties and 



