Splenic Nodules (#1 and #2) - clusters of B lymphocytes located on central arterioles
Central Arterioles (#1 and #2) - branches of trabecular arteries coated by PALS and adjacent to nodules
Red Pulp - filters and degrades red blood cells (RBCs)
Splenic Sinusoids - vascular spaces lined by specialized endothelial cells that filter RBCs
Splenic Cords (of Billroth) - loose connective tissue that contains macrophages, plasma cells, and lymphocytes
Pulp Arterioles (#1 and #2) - they are not surrounded by lymphocytes like central arterioles in white pulp
The spleen is one of the organs that has a framework (or stroma) of reticular fibers.
Reticular fibers are composed of thin and delicately woven strands of type III collagen. They do not stain with hematoxylin & eosin (H&E), but are specifically stained by silver. This renders them black and makes them easily distinguishable from type I collagen fibers that are stained red/brown.