An important support for understanding the difference between artery and vein histology. In this single-piece model one artery and two veins are represented in great detail. One vein is longitudinally sectioned to show the closed and open venous valves; the artery and the right vein are cross-sectioned so the different layers, such as tunica media, elastic membrane and tunica adventitia, can be easily recognized. 20X life size.