Meeting Abstract
In the mammalian order Artiodactyla, the majority of arterial blood entering the cranial cavity is supplied by a large arterial meshwork, the carotid rete, which functionally replaces the internal carotid artery. Extensive experimentation demonstrates that the artiodactyl carotid rete drives one of the most effective selective brain-cooling mechanisms recorded for vertebrates. Additionally, the unique morphology of the rete may have a beneficial impact on the hemodynamics of blood flow to the cerebrum. It has been hypothesized that the numerous interdigitating segments protect the brain from extreme changes in blood pressure by increasing resistance to blood flow. We test this hypothesis by applying simple and complex physical models to a 3D surface rendering of the carotid rete of the domestic goat, Capra hircus. First, we modeled the potential for increased resistance across the carotid rete using an electrical circuit analogy, wherein extensive branching of the rete equates to a parallel circuit linked proximally and distally to single arteries in series. This method calculates a near-zero increase in resistance across the rete. These basic equations do not incorporate drag, shear-stress, or turbulence, so computational fluid dynamics simulation was used to model the impact of more complex factors on resistance. Multiple-grid simulations of blood flow through the rete during both the high and low pressure portions of the cardiac cycle revealed negligible changes in pressure within the rete (a decrease of ~0.94 mmHg). Because both simple and complex models demonstrated minute changes in resistance and blood pressure across the arterial meshwork, we find blood pressure mitigation to be an unlikely function for the artiodactyl carotid rete.
