Physical and computational fluid dynamics models for the hemodynamics of the artiodactyl carotid rete

Haley O'Brien, Jason Bourke

Research output: Contribution to journalArticle

7 Citations (Scopus)

Abstract

In the mammalian order Artiodactyla, the majority of arterial blood entering the intracranial cavity is supplied by a large arterial meshwork called the carotid rete. This vascular structure functionally replaces the internal carotid artery. Extensive experimentation has demonstrated that the artiodactyl carotid rete drives one of the most effective selective brain cooling mechanisms among terrestrial vertebrates. Less well understood is the impact that the unique morphology of the carotid rete may have on the hemodynamics of blood flow to the cerebrum. It has been hypothesized that, relative to the tubular internal carotid arteries of most other vertebrates, the highly convoluted morphology of the carotid rete may increase resistance to flow during extreme changes in cerebral blood pressure, essentially protecting the brain by acting as a resistor. We test this hypothesis by employing 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 analog. The extensive branching of the rete equates to a parallel circuit that is bound in series by single tubular arteries, both upstream and downstream. This method calculated a near-zero increase in resistance across the rete. Because basic equations do not incorporate drag, shear-stress, and turbulence, we used computational fluid dynamics to simulate the impact of these computationally intensive factors on resistance. Ultimately, both simple and complex models demonstrated negligible changes in resistance and blood pressure across the arterial meshwork. We further tested the resistive potential of the carotid rete by simulating blood pressures known to occur in giraffes. Based on these models, we found resistance (and blood pressure mitigation as a whole) to be an unlikely function for the artiodactyl carotid rete.

Original languageEnglish
Pages (from-to)122-131
Number of pages10
JournalJournal of Theoretical Biology
Volume386
DOIs
StatePublished - 7 Dec 2015

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Hemodynamics
Blood pressure
Fluid Model
Hydrodynamics
hemodynamics
Computational Fluid Dynamics
dynamic models
blood pressure
Dynamic models
Dynamic Model
Computational fluid dynamics
fluid mechanics
Blood Pressure
Internal Carotid Artery
Goats
Vertebrates
carotid arteries
Artiodactyla
Arteries
Brain

Keywords

  • Artiodactyla
  • Carotid rete
  • Computational fluid dynamics
  • Hagen-Poiseuille's equation
  • Hemodynamics

Cite this

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title = "Physical and computational fluid dynamics models for the hemodynamics of the artiodactyl carotid rete",
abstract = "In the mammalian order Artiodactyla, the majority of arterial blood entering the intracranial cavity is supplied by a large arterial meshwork called the carotid rete. This vascular structure functionally replaces the internal carotid artery. Extensive experimentation has demonstrated that the artiodactyl carotid rete drives one of the most effective selective brain cooling mechanisms among terrestrial vertebrates. Less well understood is the impact that the unique morphology of the carotid rete may have on the hemodynamics of blood flow to the cerebrum. It has been hypothesized that, relative to the tubular internal carotid arteries of most other vertebrates, the highly convoluted morphology of the carotid rete may increase resistance to flow during extreme changes in cerebral blood pressure, essentially protecting the brain by acting as a resistor. We test this hypothesis by employing 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 analog. The extensive branching of the rete equates to a parallel circuit that is bound in series by single tubular arteries, both upstream and downstream. This method calculated a near-zero increase in resistance across the rete. Because basic equations do not incorporate drag, shear-stress, and turbulence, we used computational fluid dynamics to simulate the impact of these computationally intensive factors on resistance. Ultimately, both simple and complex models demonstrated negligible changes in resistance and blood pressure across the arterial meshwork. We further tested the resistive potential of the carotid rete by simulating blood pressures known to occur in giraffes. Based on these models, we found resistance (and blood pressure mitigation as a whole) to be an unlikely function for the artiodactyl carotid rete.",
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Physical and computational fluid dynamics models for the hemodynamics of the artiodactyl carotid rete. / O'Brien, Haley; Bourke, Jason.

In: Journal of Theoretical Biology, Vol. 386, 07.12.2015, p. 122-131.

Research output: Contribution to journalArticle

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