postcapillary venules

post·cap·il·lar·y ven·ules

the microvasculature immediately following the capillaries, ranging in size from 10-50 mcm, and characterized by investment of pericytes; they are the site of extravasation of blood cells, are particularly sensitive to histamine, and are believed to be important in blood-interstitial fluid exchanges. Synonym(s): pericytic venules

post·cap·il·lar·y ve·nules

(pōst-kap'i-lar-ē ven'yūls) The microvasculature immediately following the capillaries, ranging in size from 10-50 mcm, and characterized by investment of pericytes; they are the site of extravasation of blood cells, are particularly sensitive to histamine, and are believed to be important in blood-interstitial fluid exchanges.
Synonym(s): pericytic venules.