Principles of Decentralized Pumping in Biological Systems

Jellyfish are interesting sea creatures that provide insight into the evolution of cardiovascular networks; while vertebrates are characterized by a centralized heart that allows the distribution of resources in the body through pulsatile pumping, jellyfish lack such a centralization. However, they also have complex vascular structures, with gastrovascular canals that extend throughout their bodies from their open mouths to their stomach pouches and back in 4-fold symmetrical fractal branching patterns that increase in complexity as they age and develop. Flow through these networks is generated through swimming motion, involving a muscle contraction leading to deformations of these canal networks. While previous work has focused on the interaction of jellyfish with the fluids in their environments, studies providing a quantitative understanding of the flows within the jellyfish gastrovascular system are limited. Here, we build a mathematical model using fluid dynamics and network theory principles to simulate the flow through these networks during contraction, looking at three different variations of swimming motions. Future directions include comparing the flow generated through simulation to experimental data, increasing the biological accuracy and complexity of the model, and incorporating the effects of cilia on the flow in our model. An understanding of these flow mechanisms can lead to further discoveries about other aspects of these organisms as a whole, as well as broader discoveries about the evolution of circulatory systems across different life forms.