Elastic environment of the capillary bed.

To determine the degree to which the capillary blood vessels in vivo are supported by the elasticity of the surrounding tissue, a study was made of the elastic properties of the mesentery of the rabbit. A torsion test was made on a circular membrane of the avascular region of the mesentery, by applying a graded static torque and measuring the resulting deformation. The mesentery was found to have a modulus of rigidity in the same category as that of larger arteries and veins. It has a nonlinear stress-strain relationship with a tendency to harden at larger strains. In torsion experiments, the shear modulus G can be reduced to the following form