The thermoelastic behavior of isolated aortic strips of the dog.

A detailed thermodynamic study of isolated strips of dog aorta is basic to the interpretation of the nonlinear and apparently rubber-like elastic behavior of such specimens. Experimental data indicate that the retractile force in isolated aortic strips of the dog is entropic. Volume changes with elongation in such strips are negligible. However, a large negative internal energy contribution to the total force is present at small elongations. Studies of aortic strips extracted with alkali suggest that the latter force arises from the elastic tissue itself.