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.
As of 2014, the fastest mile run on foot was 3 minutes, 43.13 seconds. Morocco's Hicham El Guerrouj set the mark on July 7, 1999 at Rome's Olympic Stadium. The run broke the previous record of 3 minutes, 44.39 seconds held by Algeria's Noureddine Morceli.