ABSTRACT
On visual inspection, blood vessels appear to be fairly homogeneous and distinct from the surrounding connective tissue. The inhomogeneity of the vascular wall is realized when one examines the tissue under a low-power microscope, where one can easily identify two distinct structures: the media and adventitia. For this reason, the assumption of vessel wall homogeneity is applied cautiously. Such an assumption may be valid only within distinct macroscopic structures. Although physiologic systems are nonideal, much understanding of vascular mechanics has been gained through the use of methods based upon these ideal assumptions. Experimental measurement of wall compressibility of 0.06% at 270 cm of H2O indicates that the vessel can be considered incompressible when subjected to physiologic pressure and load. Therefore, vascular compressibility may be important to understand other physiologic processes related to blood vessels, such as the transport of interstitial fluid.
