Respiratory and neurovascular adaptation to physiological stress

心脏、循环系统、肺和胸壁以高度协调的方式共同作用。虽然单独研究每个系统可以提供有价值的信息，但检查这些系统如何协同工作可以更全面地了解基本生理学。我的项目旨在通过人体模型进一步了解这些系统之间的解剖和生理关系。在探索心肺相互作用时很少考虑生理性别，然而，现在已经确定了重要的差异。例如，骨骼肌的疲劳程度在两性之间是不同的。在单肢收缩过程中，女性通常比男性更不容易疲劳，但人们对呼吸肌肉组织疲劳程度的性别差异知之甚少。我项目的长期目标是了解心血管和呼吸系统如何相互作用并适应生理挑战。我的短期目标建立在最近四个具体目标的进展基础上。目的1旨在了解呼吸肌如何竞争氧气输送。参与者将在进行运动的同时，用一种独特的呼吸机实验性地控制呼吸肌肉组织，并直接测量运动肢体的血流量。目的2将确定在运动过程中，呼吸肌运动对交感血管收缩素流出和血压的影响。将获得神经活动的连续测量，以提供对呼吸的神经后果的理解。目的3将使用新的成像方法来量化男性和女性气道。在运动过程中，将体内气道测量与肺力学相结合，可以全面评估气道结构与生理功能之间的关系。目标4将确定呼吸肌疲劳是否因性别而异。为了评估呼吸肌收缩的独立影响，参与者将对高气道阻力进行高强度的膈肌收缩。膈肌疲劳将通过磁刺激膈神经来评估。每个目标的设计都为HQP从本科生到博士后提供了重要的培训机会。新的方法和综合实验方法将提供人类呼吸系统如何影响心血管控制的机制知识-这种关系尚未得到很好的理解。

The heart, circulation, lungs, and chest wall act together in a highly coordinated fashion. While studying each system in isolation can provide valuable information, examining how these systems work together provides a more comprehensive understanding of basic physiology. My program seeks to further our understanding of the anatomic and physiological relationships between these systems using a human model. Biological sex has been rarely considered when exploring cardiorespiratory interactions however, important differences have now been identified. For example, skeletal muscle fatigability differs between the sexes. Women are usually less fatigable than men during single-limb contractions but little is known about sex differences in the fatigability of the respiratory musculature. The LONG-TERM OBJECTIVE of my program is to understand how the cardiovascular and respiratory systems interact and adapt to physiological challenges. My SHORT-TERM OBJECTIVES build upon recent progress along four specific aims. Aim 1 seeks to understand how the respiratory muscles compete for oxygen delivery. Participants will perform exercise while the respiratory musculature is manipulated experimentally with a unique ventilator and blood flow to the exercising limbs will be measured directly. Aim 2 will determine the effect of respiratory muscle work on sympathetic vasoconstrictor outflow and blood pressure during exercise. Continuous measures of nerve activity will be acquired to provide an understanding of the neural consequences of breathing. Aim 3 will use novel imaging methodologies to quantify male and female airways. Coupling in vivo airway measures with lung mechanics during exercise permits a comprehensive assessment of the relationship between airway structure and physiological function. Aim 4 will determine if respiratory muscle fatigue differs between the sexes. To assess the independent effect of respiratory muscle contraction participants will perform high intensity contractions of the diaphragm against high airway resistance. Diaphragm fatigue will be assessed using magnetic stimulation of the phrenic nerves. Each aim is designed such that they provide a significant training opportunity for HQP ranging from undergraduates to postdoctoral fellows. Novel methods and integrative experimental approaches will provide mechanistic knowledge of how the human respiratory system influences cardiovascular control – a relationship that is not well understood.