Illustration of the histological analysis processing stages in an ovine descending aorta. (b) Characteristic colors of the histological preparations, from left to right: elastin, smooth muscle, collagen, and the original image, where the three integrated constituents can be visualized throughout the arterial wall. (a) Similar discrimination with assigned fictional colors that allow a clearer visualization of the location of each wall constituent. Note the increase in the amount of smooth muscle and collagen with respect to the ascending aorta (Figure 3).