THE SPLEEN. 173 



THE SPLEEN. 



The spleen presents no regular subdivision of parts which may be 

 studied separately and combined afterward, as we are able to do 

 with organs like the lung, liver, etc. The spleen is a ductless organ 

 or so-called gland, and the plan or scheme may, perhaps, be best 

 comprehended by following the blood distribution. 



The splenic artery enters the organ, supported by a considerable 

 amount of connective tissue, and rapidly breaks into smaller branches, 

 from which the arterioles leave at right angles. The arterioles 

 quickly merge into capillaries, which form plexuses throughout the 



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Artery 



FIG. 115. DIAGRAM. SHOWING THE COURSE OF BLOOD IN THE SPLEEN. 



different portions of the organ. Here we meet with an anomalous 

 structure. 



The capillaries, instead of uniting to form venules as in the usual 

 vascular plan, empty their contents into small chambers or sponge-UJce 

 cavities the venous spaces. The blood, after filtering through these 

 venous interstices, is collected in larger, irregular, vein-like channels, 

 which finally conduct the blood into the veins proper and out of the 

 spleen. 



The tissue, containing the vascular arrangement described in the 

 last paragraph, is called spleen pulp. 



