Recent in vivo experiments have illustrated the importance of understanding the haemodynamics of heart morphogenesis. In particular, ventricular trabeculation is governed by a delicate interaction between haemodynamic forces, myocardial activity, and morphogen gradients, all of which are coupled to genetic regulatory networks. The underlying haemodynamics at the stage of development in which the trabeculae form is particularly complex, given the balance between inertial and viscous forces. Small perturbations in the geometry, scale, and steadiness of the flow can lead to changes in the overall flow structures and chemical morphogen gradients, including the local direction of flow, the transport of morphogens, and the formation of vortices. The immersed boundary method was used to solve the two-dimensional fluid-structure interaction problem of fluid flow moving through a two chambered heart of a zebrafish (Danio rerio), with a trabeculated ventricle, at 96 hours post fertilization (hpf). Trabeculae heights and hematocrit were varied, and simulations were conducted for two orders of magnitude of Womersley number, extending beyond the biologically relevant range (0.2-12.0). Both intracardial and intertrabecular vortices formed in the ventricle for biologically relevant parameter values. The bifurcation from smooth streaming flow to vortical flow depends upon the trabeculae geometry, hematocrit, and Womersley number, $Wo$. This work shows the importance of hematocrit and geometry in determining the bulk flow patterns in the heart at this stage of development.

中文翻译：

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心脏发育中的流体动力学：血细胞比容和小梁形成的影响。


最近的体内实验说明了了解心脏形态发生的血流动力学的重要性。特别是，心室小梁由血流动力学、心肌活动和形态发生素梯度之间微妙的相互作用控制，所有这些都与遗传调控网络耦合。鉴于惯性力和粘性力之间的平衡，小梁形式特别复杂的发育阶段的基本血液动力学。流动的几何形状、规模和稳定性的小扰动可能导致整体流动结构和化学形态素梯度的变化，包括流动的局部方向、形态素的传输和涡流的形成。浸入边界法用于解决受精后 96 小时 (hpf) 流体流过斑马鱼 (Danio rerio) 两室心脏（具有小梁心室）的二维流固耦合问题。小梁高度和血细胞比容各不相同，并且对沃默斯利数的两个数量级进行了模拟，超出了生物学相关范围 (0.2-12.0)。心室内和小梁间涡流均在心室内形成，以获得生物学相关的参数值。从平滑流到涡流的分叉取决于小梁几何形状、血细胞比容和沃默斯利数 $Wo$。这项工作表明了血细胞比容和几何形状在确定心脏在此发育阶段的整体流动模式方面的重要性。