Exhalation Mechanics and the Evolution of Aspiration Breathing in Tetrapods

四足动物的呼气力学和吸气呼吸的进化

• 批准号: 9419892
• 负责人: Elizabeth Brainerd
• 金额: $ 20.23万
• 依托单位: University of Massachusetts Amherst
• 依托单位国家: 美国
• 项目类别: Standard Grant
• 财政年份: 1995
• 资助国家: 美国
• 起止时间: 1995-04-15 至 1999-03-31
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=9419892&HistoricalAwards=false
• 关键词: Exhalation; Mechanics; Evolution; Aspiration; Breathing

Brainerd 9419892 The mechanism by which complex biological systems with many interacting parts evolve has engaged biologists since Charles Darwin. The goal of this research is to determine how one such complex system, the respiratory pump used for breathing, has changed during vertebrate evolution. Reptiles, birds, and mammals ventilate their lungs with an aspiration pump in which ribs, and in some cases a diaphragm muscle, expand the chest cavity and suck air into the lungs. Air-breathing fish lack the rib and diaphragm structures that are necessary for aspiration breathing. They take air into the mouth cavity and compress it, forcing air into the lungs. Mouth pumps use only muscles of the head region while aspiration pumps use only muscles of the chest and abdominal regions. The transition between the two is a significant change in a complex system. Some amphibians, however, appear to be intermediate, using head muscles for inhalation and body muscles for exhalation. This research will determine whether the use of body muscles for exhalation is common to most species of amphibians, and thus is a probable evolutionary step between mouth pump and aspiration breathing. Pressure transducers, muscle activity transducers, air flow transducers, and x-ray video will be used to determine ventilation patterns in representatives of all three orders of extant amphibians. The results will test the hypothesis that use of body muscles for exhalation is an ancestral character of the amphibians, and hence a probable intermediate stage in the evolution of the aspiration pump. In the long term, this research will aid in identifying the sequence of behavioral, morphological and neural changes that resulted in a reorganization of a complex physiological system for function in a new environment.

Brainerd 9419892 自查尔斯·达尔文以来，生物学家一直关注具有许多相互作用部分的复杂生物系统的进化机制。 这项研究的目的是确定这样一个复杂的系统，即用于呼吸的呼吸泵，在脊椎动物进化过程中是如何变化的。 爬行动物、鸟类和哺乳动物通过吸气泵进行肺部通气，肋骨（有时是膈肌）扩张胸腔并将空气吸入肺部。 呼吸空气的鱼缺乏吸气呼吸所必需的肋骨和隔膜结构。 它们将空气吸入口腔并压缩，迫使空气进入肺部。 口腔泵仅使用头部区域的肌肉，而抽吸泵仅使用胸部和腹部区域的肌肉。 两者之间的转变是复杂系统中的重大变化。 然而，一些两栖动物似乎处于中间状态，使用头部肌肉进行吸气，使用身体肌肉进行呼气。 这项研究将确定大多数两栖动物是否普遍使用身体肌肉呼气，因此这可能是口泵呼吸和吸气呼吸之间的进化步骤。 压力传感器、肌肉活动传感器、气流传感器和 X 射线视频将用于确定现存两栖动物所有三个目代表的通气模式。 研究结果将检验这样的假设：利用身体肌肉呼气是两栖动物的祖先特征，因此可能是吸气泵进化的中间阶段。 从长远来看，这项研究将有助于确定行为、形态和神经变化的顺序，这些变化导致复杂的生理系统在新环境中发挥功能的重组。