Abstracts - KTH Mechanics

12
Haemodynamics of the embryonic chicken heart.
P. Vennemann ∗ ,R.Lindken ∗ and J. Westerweel ∗
To answer the question whether cardiogenesis is regulated through fluid forces,
detailed knowledge about the velocity distribution in the embryonic heart is required.
The derived wall shear stress distribution can be compared to gene expression patterns
to draw conclusions. Micro Particle Image Velocimetry (µPIV) quantitatively
resolves the instantaneous velocity distribution in vivo. A special polymer coating
makes the fluorescent tracer particles bio-inert. The measurement allows the determination
of the velocity gradient close to the wall. Figure 1 shows the blood velocity
distribution in the central plane of the developing ventricle of a chicken embryo after
three days of incubation. The location of the measurement plane is indicated in the
scanning electron micrograph from Männer 1 . The eccentricity of the flow profile can
be explained by the curvature of the primitive heart tube. Closely following Deans
calculation for a curved tube 2 the velocity peak position is found to be shifted into
the direction of the inner curvature wall for low Reynolds numbers (Figure 1, insets
a and b). Secondary flow is negligibly small (Figure 1, inset c).
∗ Lab. for Aero- and Hydrodynamics, Delft Technical University, The Netherlands.
1 J. Männer, Anat. Rec. 259:248-262 (2000).
2 W.R.Dean,Phil. Mag. Ser. 7 4(20):673-695 (1928).
Figure 1: Particle Image Velocimetry in the embryonic chicken heart. Inset a: theoretical,
axial velocity profile for a curved tube in the plane of coil curvature (r is negative
in the direction of the coil center). Inset b: theoretical, radial velocity peak position
in the plane of coil curvature at varying Reynolds numbers (Rtube/Rcoil = 1/2). Inset
c: theoretical, secondary velocity profile in radial direction.