Scanning electron microscopic study of the red pulp of ferret spleen.

Scanning electron microscopy of the red pulp of ferret spleen showed areas of relatively wide splenic cord and rather poorly developed splenic sinuses of two different types. The inner aspect of most sinuses was covered with rod-shaped cells running in the longitudinal direction of the sinus. Stomata of these sinuses were recognized between the rod-like cells in a relatively regular lattice-like arrangement. The lining of other sinuses showed characteristics of the poorly differentiated sinuses, having a remarkable irregularity in form, size, and distribution of the lining cells and the stomata. The outer surface of the splenic sinuses was covered with attenuated reticular cell processes supporting the sinus. Sheathed capillaries which have a well-developed sheath structure were frequently found in the cordal area. Cordal capillaries were exclusively open into labyrinthine reticular tissue space of the cord with a funnel-shaped or a perforated saccular or ampullar terminal.