SOME ASPECTS OF HEMODYNAMICS IN NAUTILUS-POMPILIUS

Blood pressure recordings from the ventricle, dorsal aorta, dorsal hemocoel, vena cava, afferent and efferent branchial veins show that the Nautilus pompilius cardiovascular system possesses similar functional characteristics to those of the modern coleoid cephalopods. In free swimming animals at 17° C ± 1° the contraction rate of the systemic ventricle varied between 5 and 18 beats per minute. Systolic blood pressure averaged 35 cm H2O while diastolic pressure averaged 16 cm H2O in the dorsal aorta. Peak and low pressures in the afferent branchial vein were 9 cm H2O and 1 cm H2O respectively while the mean pressure in the efferent branchial vein was 2 cm H2O and in the vena cava it was 2.2 cm H2O. The contour of the flow pulse recorded from the dorsal aorta indicated a backflow marking the point of aortic valve closure. Hemodynamics of the Nautilus pompilius cardiovascular system are discussed. Copyright © 1978 Wiley‐Liss, Inc., A Wiley Company