Elastic arteries in a primitive vertebrate: mechanics of the lamprey ventral aorta

Lampreys exhibit important structural and biochemical differences in their connective tissues relative to higher vertebrates. The lamprey ventral aorta wall, for example, is composed principally of microfibrils, not elastin and collagen as in higher vertebrates. Our working hypothesis was that this arrangement of microfibrils is primitive, but provides sufficient elastic behaviour to function as aortae in higher vertebrates. To support this hypothesis, we measured the mechanical properties of the ventral aorta wall of the lamprey, and showed that the architecture provides a mechanical structure that does produce functional mechanical properties similar to aortae in higher vertebrates.