THE SPLEEN 



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The fibromuscular layer (tunica albuginea) forms the framework of the spleen. It is com- 

 posed of white fibrous connective tissue containing smooth muscle cells and elastic fibres, and 

 it invests the organ as a capsule, and at the hilum is reflected inward upon the vessels in the form 

 of sheaths. From these sheaths, as well as from the inner surface of the fibromuscular layer, 



FIG. 1203. Transverse section of the spleen, showing the trabecular tissue and the splenic vein 



and its tributaries. 



numerous small fibrous bands, trabeculse (trabeculae lienis} (Figs. 1203 and 1204), are given 

 off in all directions; these uniting with the bands from the vessel sheaths constitute the frame- 

 work of the spleen. This framework resembles a sponge-like material, consisting of a number 

 of small spaces or areolse. The spaces of the areolse contain the lymphoid material known 

 as splenic pulp (pulpa lienis}. 



FIG 1204 Transverse section of the human spleen, showing the distribution of the splenic artery 



and its branches. 



Within the capsule is the parenchyma, consisting of the splenic pulp and splenic (Malpighian) 

 corpuscles The splenic pulp is dark reddish brown in color and consists of a delicate retieulum , 

 upon the fibres of which are seen stellate connective-tissue cells. In the meshes of the reticulum 

 arc diffuse lymphoid tissue, erythrocytes, erythroblasts, disintegrating erythrocytes pigment 

 granules, branched cells, and certain large polynuclear elements, splenic cells. 

 tissue consists of leukocytes, mainly lymphocytes, and hyaline cells scattered throughout the 



