CHAPTER IX 

 THE LYMPHATIC SYSTEM 



THE lymphatic system includes primarily the 

 tissues or lymph spaces, the lymph and blood capil- 

 laries; secondarily, the lymphatic vessels, and lymph 

 nodes or lymphatic glands, and the veins which sub- 

 sequently receive the lymph through the large right 

 and thoracic ducts. 



The lymphatic system is supposed to be a closed 

 system in relation with the tissues. The lymph reaches 

 the lymphatic vessels by transudation through the 

 endothelial lining of the vessels; this also occurs in 

 the serous membranes, and is not due to the lymph 

 passing by permanent openings between the cells 

 (stomata), as was once held. 



The Tissues or Lymph Spaces. These are located 

 in practically every tissue and organ of the body. 

 They are found between cells (intercellular), around 

 bloodvessels (peri vascular), and around nerves (peri- 

 neural); these spaces are not lined by endothelial 

 cells; the cells are nourished as demonstrated above, 

 by a transudation through the capillary walls, and 

 the lymph -comes in contact with the cells in the 

 lymph spaces. The spaces in the cranial cavity, the 

 subdural and subarachnoid, also the serous cavities, 

 as the pericardial, pleural, peritoneal, and synovial 

 bursse, are lined by endothelial cells, and the lymph 

 transudes or passes through the membranes by 

 osmosis. The ventricles of the brain and the central 

 canal of the spinal cord contain lymph from the blood 

 capillaries of these parts, and communicate with the 

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