Elastic membranes in arteries. Do they reduce intimal tension?

Computerized morphometric measurements have been made of the circumference of the internal (IEM) and external elastic membranes (EEM) and the area of the tunica media on cross-sectioned muscular arteries in kidneys of rat and man. The IEM circumference exceeded that of the EEM significantly. The interrupted elastic membranes of the media revealed corrugations similar to the EEM. It is concluded that the elastic membranes peripheral to IEM resist flattening out of the IEM. Even in vessels normally distended, the internal elastic membrane may not be fully stretched and retains its folds.