A&P Test 2 (2)

the plasma membranes of endothelial cells form a continuous tube that is interrupted only by intercellular clefts

small pores (holes) ranging from 70 to 100 nm in diameter

have very large intercellular clefts that allow proteins and in some cases even blood cells to pass from a tissue into the bloodstream.

drain the capillary blood and begin the return flow of blood back toward the heart

They are the smallest venules, measuring 10 um to 50 um in diameter, and have loosely organized intercellular junctions

sites of exchange of nutrients and wastes and white blood cell emigration

very thin walls relative to their total diameter. They range in size from 0.5 mm in diameter

Return blood to heart, facilitated by valves in limb veins.