Arterial walls resist stretch: animals
The arterial walls of many animals resist stretch disproportionately by incorporating non-stretchy collagen fibers in a particular arrangement.
"In effect, Laplace's law rules out the use of ordinary elastic materials for arterial walls, requiring that an appropriate material fight back against stretch, not in direct proportion to how much it's stretched, but disproportionately as stretch increases. Which, again in obedience to the dictates of the real world, our arterial walls do--aneurysms, fortunately, remain rare and pathological. We accomplish the trick first, by incorporating fibers of a non-stretchy material, collagen, in those walls, and second, by arranging those fibers in a particular way. Thus, as the wall expands outward, more and more of these inextensible fibers are stretched out to their full lengths and add their resistance to stretch to that of the wall as a whole." (Vogel 2003:7-8)
Learn more about this functional adaptation.
- Steven Vogel. 2003. Comparative Biomechanics: Life's Physical World. Princeton: Princeton University Press. 580 p.