Computational Heat Transfer Modeling of the Artiodactyl Carotid Rete

Cerebral thermoregulation is vital to maintaining functionality of the central nervous system as well as maintaining homeostasis. Because of this, cerebral thermoregulatory structures have a high ecologic and conservation potential. Artiodactyls possess a series of anatomical structures that function to cool blood entering the cranial space. Before entering the brain, the major cerebral arteries split into numerous branches, forming the carotid rete which is surrounded by a venous sinus. The venous sinus contains blood that has been cooled by the nasal cavity. This coupling forms a countercurrent heat exchanger consisting of warm blood from the carotid rete encased by cooled blood from the venous sinus. Following heat transfer, cooler arterial blood flows to the hypothalamus, reducing the physiological need to evaporatively counter heat‐stress and significantly reducing water loss. The efficacy of heat‐exchange should depend on arterial surface area (SA) and volume (V); however, preliminary field‐based, in‐vivo studies do not identify a correlation between brain cooling magnitude and carotid rete height or volume. This contradicts the expected result based on countercurrent heat exchange models. In order to explore the relationship between artiodactyl carotid rete SA and V on heat exchange efficiency, we applied computational fluid dynamic analysis to digital vascular datasets. Anatomical data collection included radiopaque latex vascular injection and CT scanning of a domestic goat, followed by 3D modeling in Avizo (9.5, ThermoFisher) to build digital models of the carotid rete and its surrounding venous sinus. We then simulated countercurrent blood flow for 3 models: the original anatomical SA and V, as well as manipulated higher V / lower SA and lower V / higher SA. We identify a positive relationship between heat exchange and surface area. This suggests that non‐structural factors, such as adrenergic tone, may be responsible for the lack of correlation seen in in‐vivo animals. Support or Funding Information Federal Work‐Study research assistantship to ST and CJ; Oklahoma State University and OSU Center for Health Sciences to DIK and HDO. This abstract is from the Experimental Biology 2019 Meeting. There is no full text article associated with this abstract published in The FASEB Journal .