A scanning electron microscopic study of microcirculation of rabbit and human lymph nodes

Corrosion casts of rabbit and human lymph nodes were observed by SEM. Casts showed a broad bean appearance. On the outer surface of casts, the afferent and efferent vessels and the vessels of the capsule were seen. Cross-sectioned surfaces of the casts showed a marked difference between the architecture of the cortex and the medulla. The casts of primary nodules appeared as small roundish capillary networks. The casts of secondary nodules formed spheres, inside of which there were poor capillaries. Secondary nodules showed many transitions. Pseudo-nodules appeared as egg-like, large capillary networks and included secondary nodules. The capillaries in diffuse lymphoid tissue anastomosed with the PCV. The PCV, which ran deeply into the cortex, anastomosed with the veins of the medulla in the cortico-medullary junction. The capillaries of medulla anastomosed directly with the veins of the medulla. Basically, the elements and arrangements of the vascular casts of the rabbit lymph node were similar to those of the human lymph node.