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.
Fastest menâs time: Kenyaâs Geoffrey Mutai ran the Boston Marathon in 2 hours, three minutes, and two seconds in 2011. At the time, it was a world-record pace. Fastest womenâs time: Kenyaâs Rita Jeptoo ran the race in 2 hours, 18 minutes, and 57 seconds in the 2014 Boston Marathon, and set the womenâs course record.