|
| |
|
|
|
|
||||
| Home Help Feedback Subscriptions Archive Search Table of Contents | ||||
|
Fig. 4. Analytical modeling of spiracle function. (A) Schematics of the diffusive
model, as used in the present study. CO2 flux into and out of the
tracheal system depends on the pressure difference
(PMCO2–PTCO2
and
PTCO2–PACO2)
multiplied by the conductance for CO2 through the cytoplasm and the
spiracle opening, GC and GS,
respectively. IFM, indirect flight muscle;
M, metabolic rate of the
flight muscle; T, temporal
flux of CO2 molecules entering the tracheoles of the tracheal
system; S, gas flux through
the spiracle. More details are given in the Materials and methods. (B) Example
of simulated instantaneous tracheal partial pressure of CO2 as
controlled by a single model spiracle. Switching opening behavior of the model
spiracle stabilizes PTCO2 near a
threshold value Ts (red, left scale). Temporal sum of
T is shown in blue (right
scale). (C) Example of simulated total release rate of CO2 of four
autonomously working model spiracles, as shown in B. Due to temporal beat, the
four modeled spiracle openings may synchronize (oscillatory gas release, blue)
or may work out of phase (non-oscillatory release, gray). (D) Relative
amplitude of Fast-Fourier Transformation (FFT) analysis of simulated data
traces. Location of peak (black) indicates the principle frequency component
of the FFT spectrum. Model parameters are: Ts=1.0,
Gc=1.0, GS,max=0.1,
PMCO2=1.05. Gray area in D shows
S.D. of mean value (black) obtained from 20 different randomly
distributed starting values for
PTCO2. t=total length of normalized
time domain (0–1).
|
