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.
Justin Gatlin was the fastest sprinter in first round of the 100m. Usain Bolt raced for the first at the 2016 Olympics and won his opening round 100m heat in 10.07 seconds. Bolt is attempting to become the first man to win three consecutive Olympic 100m gold medals.