High Endothelial Venules in a Lymphoid Organ Function To

High endothelial venules in a lymphoid organ function to:

A) Allow the entry of splenic platelets into the bloodstream
B) Attract interstitial macrophages to degenerating red blood cells,as in the spleen
C) Enable the exit of lymphocytes from the bloodstream into the tissue parenchyma
D) Establish a barrier between the bloodstream and the tissue parenchyma,as in the thymus
E) Provide a copious flow of fluid that becomes lymph