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.
In recognizing Kenyan Geoffrey Mutai's mark of 2:03:02 at the 2011 Boston Marathon as (at the time) the fastest Marathon ever run, the IAAF has noted: Due to the elevation drop and point-to-point measurements of the Boston course, performances [on that course] are not eligible for World record consideration..