Cetaceans have massive vascular plexuses (retia mirabilia) whose function is unknown. All cerebral blood flow passes through these retia, and we hypothesize that they protect cetacean brains from locomotion-generated pulsatile blood pressures. We propose that cetaceans have evolved a pulse-transfer mechanism that minimizes pulsatility in cerebral arterial-to-venous pressure differentials without dampening the pressure pulses themselves. We tested this hypothesis using a computational model based on morphology from 11 species and found that the large arterial capacitance in the retia, coupled with the small extravascular capacitance in the cranium and vertebral canal, could protect the cerebral vasculature from 97% of systemic pulsatility. Evolution of the retial complex in cetaceans-likely linked to the development of dorsoventral fluking-offers a distinctive solution to adverse locomotion-generated vascular pulsatility.
Download full-text PDF |
Source |
|---|---|
| http://dx.doi.org/10.1126/science.abn3315 | DOI Listing |
Publication Analysis
Top Keywords
Similar Publications
Background: A rete mirabile is a rare vascular anomaly, with posterior cerebral artery (PCA) involvement being especially rare. Its pathogenesis has been speculated as a remnant of "distal annexation" between the primitive anterior choroidal artery (AchA) and the PCA at this site, but the exact mechanisms remain unclear.
Observations: A 29-year-old man presented with subarachnoid hemorrhage.
Unilateral rete mirabile in multiple intracranial arteries with ipsilateral agenesis of the internal carotid artery: a case report.
J Med Case Rep
June 2023
Department of Neurosurgery, Shiga University of Medical Science, Seta-Tsukinowa-cho, Otsu, Shiga, 520-2192, Japan.
Background: Rete mirabile of the cerebral artery is a rare anomaly, with most previous cases occurring in the middle cerebral artery or internal carotid artery. Here, we present the first report of unilateral rete mirabile in multiple intracranial arteries with ipsilateral internal carotid artery agenesis.
Case Presentation: A 64-year-old Japanese woman was brought to the emergency department of our hospital in a deep coma.
Retia mirabilia: Protecting the cetacean brain from locomotion-generated blood pressure pulses.
Science
September 2022
Department of Zoology, University of British Columbia, Vancouver, BC, Canada.
Cetaceans have massive vascular plexuses (retia mirabilia) whose function is unknown. All cerebral blood flow passes through these retia, and we hypothesize that they protect cetacean brains from locomotion-generated pulsatile blood pressures. We propose that cetaceans have evolved a pulse-transfer mechanism that minimizes pulsatility in cerebral arterial-to-venous pressure differentials without dampening the pressure pulses themselves.
View Article and Find Full Text PDFExtraordinary grip strength and specialized myology in the hyper-derived hand of Perodicticus potto?
J Anat
November 2019
Department of Biological Sciences, North Carolina State University, Raleigh, NC, USA.
Previous behavioral reports of the African lorisid, Perodicticus potto, have speculated that these animals have an extraordinary grip strength. This ability is hypothesized to be facilitated by a range of anatomical features within the forelimb, ranging from the presence of a retia mirabilia in its wrist to the hyper-abduction of its pollex. Despite numerous behavioral reports, however, this claim of extraordinary grip strength has not been empirically substantiated.
View Article and Find Full Text PDFDynamics of blood circulation during diving in the bottlenose dolphin (): the role of the retia mirabilia.
J Exp Biol
March 2019
Department of Comparative Biomedicine and Food Science, University of Padova, 35020 Legnaro (PD), Italy.
The retia mirabilia are vascular nets composed of small vessels dispersed among numerous veins, allowing blood storage, regulation of flow and pressure damping effects. Here, we investigated their potential role during the diving phase of the bottlenose dolphin (). To this effect, the whole vertebral retia mirabilia of a series of dolphins were removed during post-mortem analysis and examined to assess vessel diameters, and estimate vascular volume and flow rate.
View Article and Find Full Text PDFWant AI Summaries of new PubMed Abstracts delivered to your In-box?
Enter search terms and have AI summaries delivered each week - change queries or unsubscribe any time!