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.
Yâall do know that Usain Bolt is the fastest man in the worldâ¦ Height having nothing to do with speedâ¦ Randy Moss was fast as hellâ¦ Over 6 feetâ¦ Lebron James is 6â8 or 6â9 and runs a 4.3 â¦ No one can see Usain in the 40.