Arteriovenous oxygen diffusion shunt is negligible in resting and working gracilis muscles.
Arteriovenous oxygen diffusion shunt is negligible in resting and working gracilis muscles.
复制标题
动静脉氧扩散分流在静止和工作的股薄肌中可以忽略不计。
DOI：
10.1152/ajpheart.1991.261.6.h2031
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发表时间：
1991
期刊：
影响因子：
--
通讯作者：
Clark,PA
中科院分区：
文献类型：
--
作者：
Honig,CR;Gayeski,TE;ClarkJr,A;Clark,PA
本文用低温分光光度法测定了狗和大鼠股薄肌中微动脉和微静脉内及微动脉和微静脉之间的氧分布。即使血流异常低，40微米小动脉的饱和度与主动脉的饱和度也没有明显差异。大于40微米的小动脉平行于小静脉。测量和数学模型表明，对于小动脉和小静脉之间的典型分离距离，扩散分流可以忽略不计。大多数分离距离大于30微米。在距离小动脉小于15微米的一些小静脉段中，面向小动脉的壁的10微米内的饱和度高于小静脉内的其他位置。然而，在人口的小静脉的饱和度并没有增加与小静脉直径，平均小静脉饱和度是没有不同的饱和度流出的血液。我们得出以下结论：1）姿势肌中存在小的动静脉扩散O2通量; 2）该通量对O2质量平衡的贡献可以忽略不计; 3）体内小动脉壁和周围组织的O2扩散率不能远高于体外测定的O2扩散率; 4）流出物PO 2非常接近平均毛细血管末端PO 2。
Distribution of O2 within and among arterioles and venules was determined in dog and rat gracilis muscles with a cryospectrophotometric method. Saturation in 40-microns arterioles was not demonstrably different from saturation in the aorta even when flow was abnormally low. Arterioles greater than 40 microns ran parallel to venules. Measurements and a mathematical model indicate that diffusive shunting is negligible for typical separation distances between arterioles and venules. Most separation distances were greater than 30 microns. In some venule segments less than 15 microns from an arteriole, saturation within 10 microns of the wall facing the arteriole was higher than at other locations within the venule. However, saturation in the population of venules did not increase with venule diameter, and mean venular saturation was not different from saturation in effluent blood. We make the following conclusions: 1) a small arteriovenous diffusive O2 flux exists in postural muscles; 2) contribution of this flux to O2 mass balance is negligible; 3) O2 diffusivity of the arteriolar wall and surrounding tissue in vivo cannot be much higher than O2 diffusivity determined in vitro; and 4) effluent PO2 closely approximates mean end-capillary PO2.