Integrative Biomechanics of Marine Mammals; Adaptations for Feeding, Diving, and Hearing in Whales

我们从工程学和物理学的角度研究动物是如何工作的。新的工作将集中在海洋哺乳动物上，主要是短须鲸。经过几十年的商业开发和无数的研究机会，它们的解剖学和生物力学细节直到最近还不清楚。在最近成功的基础上，我们的发现研究试图加深我们对支持它们水生生活方式的解剖、生理和生物力学适应的理解。我们将使用解剖学、组织生物力学以及计算机和数字建模来推断四个关键领域的生理功能：*冲刺进食流体力学，能量学。将根据过去对鱼尾的研究方法，利用灵活的、按比例制作的大鼠尾吸虫模型的水动力学性能来改进吞噬的水动力学和代谢模型。将结果与计算流体力学相结合，将通过增加不同物体大小和速度的流体动力阻力的实际成本，从而形成数学能量预算模型。*循环系统设计，以适应游泳和跳水过程中压力的快速变化。通过一个合作项目的现场测量心率数据，我们将重温我们旧的中心循环血流动力学模型，看看在潜水过程中血流是如何优化的。我们将研究身体胸部和颅骨血管的力学特性和3D结构，然后使用数学模型来测试在内压快速变化时RETIA如何保护大脑免受血流瞬变的影响的假说。*呼吸系统设计与肺深度塌陷。我们将讨论鼻塞和气孔如何保护上呼吸道免受水的入侵，以及特殊的咽部结构如何在吞咽过程中保护正常的上呼吸道免受食物的侵袭。我们将继续对许多物种的下呼吸道结构的形态和力学进行比较研究，使用肺部充气、CT扫描的3D肺和气管解剖，以及显微镜和肺泡的成分来确定肺如何在呼吸中排空和深度塌陷。在高压CT扫描的基础上，我们将创建一个胸部压缩的有限元模型，以了解胸壁和横隔膜变形如何在深度压缩肺部，并在胸腔与胸骨和颅底之间转移血量。*内耳结构和听力。我们现在知道如何对耳蜗毛细胞成像，并制作了第一张鲸鱼(白鲸)耳蜗的空间频率图，目的是将搁浅伤亡中看到的损害与特定的声源联系起来。我们计划在其他物种上开展类似的工作，包括听力未知的流浪鼠。*我们的鲸鱼生物力学研究计划将对大鲸的游泳、潜水和进食，以及它们特定于这些功能的解剖和生理适应进行最全面和定量的研究。**

We study how animals work from an engineering and physics perspective. New work will focus on marine mammals, principally rorqual baleen whales. After decades of commercial exploitation with countless opportunities for study, details of their anatomy and biomechanics remained obscure until lately. Building on recent successes, our discovery research seeks to further our understanding of anatomical, physiological, and biomechanical adaptations that support their aquatic lifestyle. We will use anatomy, tissue biomechanics, and computer and digital modelling to infer physiological function in four key areas: *** Lunge feeding hydrodynamics, energetics. Hydrodynamic and metabolic models of engulfment will be refined with quantified hydrodynamic performance of flexible, scaled models of rorqual tail flukes, following methods from past studies of fish tails. Combining results with computational fluid dynamics will inform mathematical energy budget models by adding realistic costs of hydrodynamic drag forces for different body sizes and speeds. *** Circulatory system design for rapid pressure changes during swimming and diving. With field measured heart rate data from a collaboration, we will revisit our old hemodynamic model of the central circulation to see how flow is optimized during a dive. We will study the mechanical properties and 3D structure of thoracic and cranial vascular retia from post-mortem cases, and then use mathematical modelling to test hypotheses of how retia protect the brain from flow transients during rapid changes in internal pressures. *** Respiratory system design and lung collapse at depth. We will address how nasal plugs and blowhole protect the upper airway from water incursion and how special pharyngeal structures protect the rorqual upper airway from food during swallowing. We will continue a comparative study of morphology and mechanics of lower airway structures in numerous species, using lung inflations, 3D lung and trachea anatomy from CT scans, and microscopy and composition of alveolae to determine how lungs empty in respiration and collapse at depth. Based on a hyperbaric CT scan, we will create a finite element model of thoracic compression to see how thoracic wall and diaphragm deformation compress the lungs at depth and shift blood volumes between the thorax and the thoracic and cranial retia. *** *Inner ear structure and hearing. We now know how to image cochlea hair cells, and have made the first spatial frequency map of a whale (beluga) cochlea with the aim of linking damage seen in stranded casualties to specific sound sources. We plan similar work on additional species, including rorquals, whose hearing capacities are unknown. ******Our research program on whale biomechanics will produce the most comprehensive and quantitative study of swimming, diving and feeding in the great whales, and their anatomical and physiological adaptations specific to these functions.**