connective The outer layer of a blood vessel (artery or vein) is called the tunica externa or tunica adventitia.See http://training.seer.cancer.gov/module_anatomy/unit7_3_ca â¦ rdvasc_blood1_classification.html pericardium is the layer of the blood vessel that is made of tough  connective tissue.onnective The outer layer of a blood vessel (artery or vein) is called the tunica externa or tunica adventitia.
As of June 2000, the fastest running human is Michael Johnson, the American track and field star who on August 1, 1996 set the world record of running 200 meters in 19.32 seconds.
, August 1, 2016. The six-time Olympic gold medalist Usain Bolt, who set a hundred-metre world record of 9.58 seconds, in 2009. Photograph by Sandra Mailer / REX / AP. Three minutes, forty-three seconds, and thirteen hundredths of a second is the fastest that a human has ever run a mile, as far as we know.