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.
Usain Bolt is a phenomenal athlete. Heâs the fastest man in the World. Heâs the fastest person who has ever lived (according to all records we have). He currently holds the World Record for the 100m sprint at just 9.58 seconds (achieved in Berlin in 2009, beating his own previous record of 9.69 seconds at the 2008 Olympic Games in Beijing).