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.
Who was the man who won the Boston Marathon in the fastest time ever in all sports history? Geoffrey Mutai of Kenya set the course record in April 2011. His world best time of 2:03:02 is not considered the World Record by IAAF, as the legendary Boston Marathon course â¦ does not conform to WR layout standards.