234 



THE LYMPHATIC SYSTEM 



lymph nodules, and in the thymus, where we may consider the lohule 

 of the organ as being the structural equivalent of a lymph nodule. 



The lymph nodule consists of a mass of lymphoid tissue, usually of 

 ovoid form, which is surrounded by or embedded in connective tissue. In 

 those locations where it exists independently the nodule is completely 



FIG. 241. A LYMPH NODULE, SOLITARY FOLLICLE, FROM THE LARGE INTESTINE OF 



MAN. 



In the upper part of the figure the edge of the intestinal mucosa is shown; it con- 

 tains many secreting tubules which have been cut in transverse or oblique section 

 and are lined by columnar epithelium and goblet cells. Photo. X 80. 



surrounded by the connective tissue in which it lies. In other places, 

 as in the lymph nodes, the nodule is only partially surrounded by the 

 connective tissue trabeculae of the organ. Not only do fine branches 

 from the surrounding connective tissue bundles penetrate the periphery 

 of the nodule, but the reticulum of the nodule is continuous with these 

 trabeculae, thus forming a supporting stroma in which the lymphocytes 

 are embedded. 



