48 



VETERINARY STUDIES 



Lymphatic System 



Parts.— The lymphatic system consists of vessels and glands. 

 Lymphatic vessels. — These have thin transparent walls and 



are found in most of the body 

 tissues. They have valves like 

 the veins and carry lymph, or, 

 in the lacteals, chyle. The cur- 

 rent in the lymph vessels is like 

 that in the veins in that it flows 

 toward the heart and is very slug- 

 gish. The lacteals are lymphatic 

 vessels which drain the digestive 

 canal, chiefly the small intestines. 

 There are two main vessels : the 

 thoracic and right lymphatic. 



The thoracic is situated near 

 the vertebral column within the 

 abdomen and thorax, on the right 

 side, near the heads of the ribs 

 and discharges its lymph into the 

 anterior vena cava. Its opening 

 in the vein is protected by a valve 

 in order that blood may not get 

 into the duct. This duct drains 

 all the body except the right side 

 of the face, head, and neck, the 

 right shoulder, and the right 

 front limb. 



The right lymphatic duct is 

 not always present in typical 

 form. When present it is a very 

 short vessel into which empty 

 all the vessels that drain these 

 latter regions. It discharges into 

 the anterior vena cava with or 

 near the thoracic duct. 

 Lymph glands. — The lymph glands serve in part to remove 



from the lymph fluid disease germs and other harmful bodies. 



Their structure and function is something like that of a sponge 



filter. 



Pig. 26. — The Lymphatic Sys- 

 tem. Human. (Eddy.) 



a, Union of left jugular and 

 subclavian veins, and point of 

 union with the thoracic duct; 

 b, thoracic duct; c, right jugular 

 and subclavian veins, and point 

 of union of right lymphatic sys- 

 tem; d, receptacle for food ab- 

 sorbed from the intestine; the 

 oval bodies are glands. 



