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Heart activity and high-pressure circulation in cirripedia
Science (New York, N.Y.)
|May 4, 1973
Summary
Pacific gooseneck barnacles exhibit high hemolymph pressures, suggesting a functional heart circulates blood. This rhythmic pulsation is temperature-dependent, offering insights into invertebrate circulatory systems.
Area of Science:
- Marine Biology
- Invertebrate Physiology
- Comparative Physiology
Background:
- Invertebrates often have less understood circulatory systems compared to vertebrates.
- The Pacific gooseneck barnacle (Pollicipes polymerus) is a unique marine invertebrate.
Purpose of the Study:
- To investigate the hemolymph pressure dynamics in the Pacific gooseneck barnacle.
- To determine the mechanism behind hemolymph circulation in this species.
Main Methods:
- Direct measurement of hemolymph pressures within the barnacle.
- Observation of pulsation patterns and their relationship with environmental temperature.
Main Results:
- Hemolymph pressures of significant magnitude were recorded, with mean pressures around 250 cm H2O.
- Pulse pressures reached up to 70 cm H2O, exhibiting distinct, rhythmical pulsations.
- Pulsation rate showed a strong dependence on ambient temperature.
Conclusions:
- The observed high and rhythmic hemolymph pulsations strongly indicate the presence of a functional heart.
- Muscular contractions of this heart are the likely mechanism for hemolymph circulation in cirripeds.
- This finding contributes to understanding circulatory mechanisms in marine invertebrates.
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