Interaction of Ventilation and Perfusion with Diffusion in Cutaneous Gas Exchange

拟议的研究将继续进行分析， 脊椎动物的皮肤气体交换以及 可以进行调节。 一个关键问题是， 血液流动的变化可以调节皮肤气体 交换;解决这个问题需要一个精确的 大量血液流动的变化与 皮肤可能表现在微循环水平。 皮肤微循环的变化，（2）试管红细胞压积， (3)毛细血管募集;（4）毛细血管募集的间隔 毛细血管，和/或（5）1- 4.这五个变量将首先被量化， 在分离的灌注皮肤制备物中测量摄取;这 准备工作将产生关于实验变异如何 在这五个变量是相关的皮肤的大小 气体交换 一项补充研究将描述这五个 在体内的变量，以确定它们实际上如何变化， 完整的动物。 另一个关键问题涉及到 扩散边界层的皮肤在水中：是他们的 电阻大，可忽略不计，或介于两者之间？ 第二 一系列的实验将直接检验 氧扩散边界层可限制皮肤气体交换 与不同水流状态的动物一起生活。 处于试验 准备，皮肤的绝对和相对电阻 并且氧扩散边界层将被量化。 这些问题很重要，因为虽然皮肤是 脊椎动物的主要气体交换器， 皮肤的气体交换还太粗略， 以及对脊椎动物气体交换的全面了解。

The proposed research will continue an ongoing analysis of cutaneous gas exchange in vertebrates and the means by which it may be regulated. One critical question concerns how effective changes in blood flow can be in regulating cutaneous gas exchange; resolution of this question requires a precise distinction among the ways in which changes in bulk blood flow to the skin might be manifested at the microcirculatory level. Variation in cutaneous microcirculation, (2) tube hematocrit, (3), capillary recruitment, (4) the spacing of recruited capillaries, and/or (5) spatial and temporal heterogeneity in 1- 4. These five variables will first be quantified while oxygen uptake is measured in an isolated perfused skin preparation; this preparation will yield information on how experimental variation in these five variables is related to the magnitude of cutaneous gas exchange. A complementary study will characterize the five variables in vivo to determine how they actually vary in an intact animal. Another critical question concerns the resistance of diffusion boundary layers about skin in water: Is their resistance large, negligible, or somewhere in between? A second series of experiments will directly examine the extent to which oxygen diffusion boundary layers may limit cutaneous gas exchange with animals of different flow regimes. In an experimental preparation, the absolute and relative resistances of the skin and the oxygen diffusion boundary layer will be quantified. These issues are important ones because, although skin is one of the primary gas exchangers of vertebrates, our knowledge of cutaneous gas exchange is as yet too sketchy to achieve a general and comprehensive understanding of vertebrate gas exchange.