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.

中文翻译：

---

Retia mirabilia：保护鲸类大脑免受运动产生的血压脉冲的影响

鲸目动物有大量的血管丛（retia mirabilia），其功能未知。所有的脑血流都通过这些视网膜，我们假设它们可以保护鲸目动物的大脑免受运动产生的脉动血压的影响。我们建议鲸类动物已经进化出一种脉冲传递机制，可以在不抑制压力脉冲本身的情况下最大限度地减少脑动脉 - 静脉压差中的搏动。我们使用基于 11 个物种的形态学的计算模型验证了这一假设，发现视网膜中的大动脉电容，加上颅骨和椎管中的小血管外电容，可以保护脑血管系统免受 97% 的全身搏动。