Scanning electron microscopic features of spleen in the rat and human: a comparative study.

The marginal zone, white pulp and red pulp of rat and human spleen were studied by scanning electron microscopy and were compared. The marginal zone was observed in both species. The arterial termination in the marginal zone was quite different between both species. The follicular arteries terminated at the boundary of the white pulp and formed a vascular net regarded as the marginal sinus in rat. On the other hand, numerous arterial termini of the follicular and sheathed arteries were scatteringly found in the marginal zone in man. The central artery was surrounded with flat reticular cells in rat and human spleen. In the red pulp of rat, the arterial termini were funnel-shaped or tubular. The sheath of the sheathed arteries of man revealed a circumferential lamellar structure consisting of flat reticular cells, and most free cells of the sheath were washed away by perfusion.