Spleen with central artery in lymphatic nodule (human)

Stain: Azan. A longitudinally cut central artery (1) of a lymphatic nodule or follicle, (white pulp) is invested by a distinct lymphatic sheath (PALS) composed of concentric layered T lymphocytes) (2). The red pulp consists of open venous sinusoids (4) and splenic cords (5, Billroth) with macrophage-sheathed capillaries. (3) pulpa arteriole, arrows indicate penicillar arterioles