DIAGRAM: GASTROINTESTINAL: GI: ARTERY: Effects of Hypertension on the Vessel Wall - 1 of 14; A=Intima, B=Media, C=Adventitia, D=Smooth Muscle -- The media is the layer of the artery wall that is comprised of lamellar units of smooth muscle cells that contract to move blood through the vessel. The media makes up most of the thickne