Plasma Cell

Plasma cell from submucosa of a rat. Note the clumps of peripheral heterochromatin (ch) alternating with clear areas of euchromatin and large central nucleolus in the nucleus (N). The zones of euchromatin extend to the pores (P) in the nuclear envelope (NuE), while the heterochromatin is confined to the interpore areas. There is extensive RER and the Golgi region (G ) is well developed. This cells is largely transcribing and processing a single immunoglobulin. (PM, plasma membrane).
Porter, KR and Bonneville, MA, Fine Structure of Cells and Tissues, 4th ed., Lea & Febiger, Philadelphia, 1973, p. 2.

Red Pulp of Spleen

Scanning electron micrograph of red pulp of spleen. Sinusoids (s) are lined by elongated endothelial cells (ec). There are macrophages (m) both within the cords and in the sinusoids. There are also reticular cells (r) within the cords.
Cormack, D.H. Ham’s Histology, 9th ed., Lippincott, Philadelphia, 1987, p. 260.