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.
, Boston Marathon qualifier. In 1983 Mike Boit of Kenya ran a mile in 3:28.36. As far as I know, no one has ever covered the distance faster. This was on a downhill road course so it isn't recognized by IAAF but it's still the fastest mile ever run by a human. Views Â· View Upvotes.