Affects capillaries, venules, or arterioles. Unlike most capillary beds, the glomerular capillaries exit into efferent arterioles rather than venules. The bulbar conjunctival microvasculature contains arterioles, meta-arterioles, venules, capillaries, and communicating vessels. Arteries, arterioles, capillaries, venules, and veins make up the vasculature. Systemic vasculitis of medium and small arteries, including venules and arterioles. They may be composed of abnormal aggregations of arterioles, capillaries or venules. Paired arterioles are generally smaller than corresponding venules. The arterioles supply capillaries, which in turn empty into venules. The microvessels include terminal arterioles, metarterioles, capillaries, and venules. Capillaries merge into venules, which merge into veins. Broken venules or arterioles often result in a deep blue or dark red bruise, respectively. Then they penetrate the mucosa and submucosa and enter venules or lymphatics. Lymphocytes enter the lymph nodes through specialised high endothelial venules found in the paracortex. Addressin is an extracellular protein of the endothelium of venules. The splenic vein is formed from small venules that leave the spleen.