Afferent lymph vessel in lymph node (human)

Stain: Azan. Left (A) and right (B): part of the cortex of a lymph node with the capsule (1) and subcapsular (or marginal) sinus (2) filled with lymphocytes. Left (A): (3) show perpendicularly localized reticular cells and fibres (blue) in the sinus. (4) indicate afferent lymph vessel with valves (-->). Below the subcapsular sinus the crescent (5) of a secondary follicle with a germinal centre (6) flanked by intermediate sinuses (or paratrabecular sinuses, 7) filled with many lymphocytes and other cells. Right (B): the entrance of a lymph vessel (4) directly into the subcapsular sinus (2) is marked by the presence of two slender valves with the endothelial lining (-->). Note that reticular fibers are deep-blue stained.