They are about 5-10 Î 1\/4 ms big , which connect arterioles and venules , and enable the moving of water , oxygen , carbon dioxide , and many other nutrient and waste chemical between blood and surrounding tissues . These microvessels , measuring 5-10 Î 1\/4 m in diameter , connect arterioles and venules , and enable the exchange of water , oxygen , carbon dioxide , and many other nutrient and waste chemical substances between blood and surrounding tissues .