The mechanical properties of the dorsal aorta of three cephalopod
mollusks, Nautilus pompilius, Nototodarus sloani, and Sepia latimanus,
were investigated by in vitro inflations of isolated arterial segments. As expected,
all three arteries exhibit nonlinear, J -shaped stress-extension curves, and all are
highly extensible in the circumferential direction. Differences in longitudinal
extensibility appear to be correlated to specific features of the tissue architecture.
The squid, Nototodarus, and to a lesser extent the cuttlefish, Sepia, arteries are
reinforced longitudinally with a dense layer of longitudinally oriented elastic
fibers.
Analysis of the form of the incremental wall stiffness data for Nautilus and
Nototodarus suggests that the in vivo blood pressures for these animals fall in the
ranges 20-60 cm H20 and 100-200 cm H20, respectively. Nautilus has a thinwalled,
low-pressure arterial system that is in keeping with its relatively limited
locomotory capabilities. Nototodarus has a high-pressure, thick-walled circulation
that is required to support the high-speed, aerobic locomotion generally
common in squid. Analysis of pressure wave velocities for these arteries indicates
that the Nautilus circulatory system contains a true Windkessel whereas it
appears possible that wave propogation effects may make a relatively minor
contribution to the hemodynamics of Nototodarus
