Arteries elastic modulus

In addition to intimal thickening, the arterial wall properties also change with age. Most measurements suggest that arterial elastic modulus increases with age (hardening of the arteries) however, in some cases arteries to become more compliant (inverse of elasticity) [Learoyd and Taylor, 1966]. Local weakening of the wall may also occur, particularly in the descending aorta, giving rise to an aneurysm, which, if ruptures, can cause sudden death. 

Although Moens [1878] and Korteweg [1878] are credited with this formulation, Fung [ 1984, p. 107] has pointed out that the formula was first derived much earher [Young, 1808]. Wave speeds in arterial blood vessels from several species are given in Table 56.3. In general, wave speeds increase toward the periphery as vessel radius decreases and are considerably lower in the main pulmonary artery than in the aorta owing primarily to the lower pressure and consequently lower elastic modulus. 

Table B6.13 presents the circumferential incremental elastic modulus of human arterial walls from young adults (< 35 years) at a transmural pressure of 100 mmHg.

The structure of the venous walls is basically similar to that of the arterial walls. The main difference is that they contain less muscle and elastic tissue than the arterial walls, which raises the static elastic modulus two to fourfold [49]. Because the venous walls are much thinner than the arterial wall, they are easily collapsible when they are subject to external compressions. 

Table B6.19 lists the static incremental elastic moduli of the canine jugular vein and human saphenous vein. For the purpose of comparison, the static increment elastic modulus of the canine carotid artery segments are also presented in the table. This comparison is of interest because in some arterial reconstructive surgeries, a vein is used as a substitute for an artery.

Extension ratio Incremental venous elastic modulus Carotid artery Incremental modulus ... 

Mechanical properties of the arteries from human and various animals have been extensively studied. However, literature on lymphatic vessels is very scarce. The data on the circumferential elastic modulus of the lymphatic vessels obtained by Ohhashi et al [53, 54] seem to be too low considering that the lymphatics are originating from the veins. 

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