Tridimensional Architecture of Elastic Tissue in the Rat Aorta and Femoral Artery—A Scanning Electron Microscope Study

Overall tridimensional architecture of the elastic tissue in the rat aorta (elastic type artery) and femoral artery (muscular type artery) has been studied by scanning electron microscopy after hot-formic acid extraction followed by freeze-drying method. In the aorta the elastic tissue is composed to 6–7 concentric plate-like laminae interconnected by radially oriented interlaminar elastic fibers, whereas in the femoral artery it is composed of two distinct inner and outer sheet-like laminae bridged by a dense continuous interlaminar network of elastic fibers. The internal elastic lamina has numerous fenes-trations which considerably differ in size, shape and structure between the two types of arteries. Tunnel-like compartments free of elastic tissue extend helically into the medial wall of both types of arteries. These findings are discussed in relation to conventional transmission electron microscopic information and some new functional roles of arterial elastic tissue are proposed.