Sio 



A MANUAL OF ANATOMY 



destitute of a fibrous capsule, properly so called, and is invested 

 merely by a thin connective- tissue covering, which readily allows 

 the outline of the lobules to be seen. 



It is composed of a number of lobules, which are loosely held 

 together by ducts and areolar tissue. Each lobule consists of a 

 group of alveoli or acini which are long, tubular, and convoluted, 

 wherein they differ from the saccular alveoli of such a gland as the 

 parotid. From each lobule a duct passes off, which unites with 

 the ducts of adjacent lobules in the left extremity of the gland to 

 form the commencement of the principal duct. Within the lobule 

 the lobular duct divides into junctional ducts, each of which belongs 

 to an acinus, and is lined with flattened cells. 



Islets of Langerbans 



Alveoli 



Fig. 348. — Structure of the Pancreas (highly magnified). 



The alveoli or acini are each composed of a basement membrane, 

 reticular in structure, and lined with secreting columnar epithelium, 

 the basement membrane being continuous with the wall of the 

 junctional duct. The lumen of each acinus is small, and is usually 

 occupied by spindle-shaped cells, known as the centro-acinar cells 

 of Langerhans, which are continuous with the cells of the junctional 

 duct. The connective tissue which covers the pancreas sends ex- 

 pansions inwards between the lobules, along which the bloodvessels 

 are conducted. Further, the interlobular connective tissue pene- 

 trates into the lobules, and so conducts the bloodvessels into their 

 interior. The inter alveolar connective tissue has a loose disposition, 

 and in certain parts contains small groups of epithelium-like cells, 



