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Biologische Systeme und Medizin Vortrag: Fr., 09:40–10:00 F-V55
Synchrotron x-ray-videography and -tomograpy combined with physiological
measurements for analysis of circulation and respiration dynamics in
insects (Drosophila and Calliphora).
Lutz Thilo Wasserthal 1 , Peter Cloetens 3 , Rainer Fink 2
1 Universität Erlangen, Lehrstuhl für Zoologie I, Staudtstr. 5, D-91058 Erlangen –
2 Universität Erlangen, Lehrstuhl für Physikalische Chemie II, Egerlandstr. 3, D-91058
Erlangen – 3 ESRF, 6 rue Jules Horowitz, F-38043 Grenoble
Despite their small size, higher flies (fruitflies and blowflies) have a sophisticated respiratory
gas exchange system based not only on diffusion as generally assumed - but
also on mechanical ventilation of the tracheal system [1]. The mechanism has largely
been ignored, as the ventilatory movements are invisble from outside. The periodic
volume changes of the air sacs and of heart pulses are visualised by x-ray videos in
Drosophila and Calliphora respectively. Intratracheal pressure pulses measured in the
mesothorax coincide with pulsations of the air sacs in the head and with anterograde
pulses of the heart shown in x-ray-videos. Parallel measurements of pressure pulses
with x-ray videos of heart pulsations reveal that the enlarged conical heart chamber in
the anterior abdomen is the main motor of periodic hemolymph shift between anterior
body and abdomen. It works as a pressure pump during forward (anterograde) pulsations
and as a suction pump during backward (retrograde) pulses.
[1] L.T.Wasserthal, Int. J. Insect Morph. and Embryol. 28 (1999) 111-129.