The structure of blood vessel walls is important in the regulation of blood flow. The tunica media contains smooth muscle fibers which contract to either dilate or constrict the size of the vessel. These small changes in the vessel lumen can greatly influence blood pressure and blood flow. Therefore, the tunica media plays an important role in maintaining blood pressure and continuous blood circulation.
Update Date 2/24/2016
Updated by: Michael A. Chen, MD, PhD, Associate Professor of Medicine, Division of Cardiology, Harborview Medical Center, University of Washington Medical School, Seattle, WA. Also reviewed by David Zieve, MD, MHA, Isla Ogilvie, PhD, and the A.D.A.M. Editorial team.