ISSN:
0003-276X
Keywords:
Life and Medical Sciences
;
Cell & Developmental Biology
Source:
Wiley InterScience Backfile Collection 1832-2000
Topics:
Medicine
Notes:
Splenic tissue from the dog, monkey, guinea pig, and rat were fixed in OsO4, embedded in maraglas, and examined by electron microscopy. The red pulp is composed of sinuses, the walls of which are formed by littoral cells (macrophages and fixed reticulum cells) resting on a framework of reticulum. The pulp cords (Billroth cords) are formed by sinuses containing bands of reticulum which compartmentalize the cord. Interlocked littoral cells and entrapped formed elements of the blood are found in the cords. The stroma of the white pulp is composed of two types of fixed reticular cells (fixed reticular cells, type A; and fixed reticular cells, type B), macrophages, and cell types intermediate between macrophages and fixed reticular cells. The reticulum of the white pulp is similar to that of the red pulp. With PTA staining the extracellular connective tissue (reticulum) is found to be composed of a homogeneous substance with fibrillar elements, namely (1) fibrils 50 mμ in diameter with a 640 Å axial periodicity, (2) fibrils of similar diameter without periodicity, and (3) non-periodic, closely packed undulating, parallel fibrils ca. 70 Å in diameter. The reticulum is, in general, enclosed by cytoplasm of littoral cells or sandwiched between cells; rarely, however, the reticulum appears to be in contact with the blood in the sinus. The junction of capillary and sinus is abrupt and the terminal capillary endothelium is surrounded by litoral cells.
Additional Material:
1 Ill.
Type of Medium:
Electronic Resource
URL:
http://dx.doi.org/10.1002/ar.1091470105
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