ADAPTATIONS TO HYPOXIA

该计划项目旨在检查氧气的每一种成分 从肺的通风开始的运输系统在控制下 呼吸(项目A)。在肺内，空气的分布应该是 与血液分布相匹配，即肺的控制 传阅(项目B)。氧气的实际转移发生在肺泡处 毛细血管血流的控制是最重要的，也是研究的重点。 肺微循环研究(项目C)。一旦充氧，血液就会 循环由心脏和全身循环的功能决定。 最后，氧气的实际输送取决于两个血液中的氧气 内容物和血流量。氧含量与氧含量直接相关。 血液的携带能力，即血红蛋白浓度和红细胞压积， 而血流量与红细胞压积(粘度)成反比。这些 相互关系和相关因素决定全身供氧 (新项目D)。因为氧气输送系统必须对 无论是氧气的供应还是需求，了解其特殊性都很重要 对高原慢性缺氧的适应(项目E)。那么，这些， 是本计划项目中的五个主要调查领域。这个 低毒和高碳酸血症呼吸机驱动在控制呼吸中的作用 在睡眠和运动中的呼吸衰竭，正在被研究。 大量二氧化碳流入肺将被检查为高呼吸的主要刺激因素。 在锻炼的时候。组胺、前列腺素、血管周围肥大细胞和 低氧对肺血管的直接影响正在调查中。 控制力。由此引起的血管张力的变化改变了毛细血管的动力学 血液流动。导致肺毛细血管复张作为一种手段的因素 加强气体交换的研究。所有这些机制都将是相关的 对高原的适应和适应不良，包括怀孕、慢性 高原反应，高原肺水肿，氧气运输， 尤其是在存在红细胞增多症的情况下。

This Program Project is structured to examine each component of the oxygen transport system which begins with ventilation of the lung under the Control of Breathing (Project A). Within the lung, the distribution of air should be matched by the distribution of blood, i.e. the Control of the Pulmonary Circulation (Project B). Actual transfer of oxygen occurs at the alveolus where control of capillary perfusion is of prime importance, and is the focus of study of the Pulmonary Microcirculation (Project C). Once oxygenated, blood circulation is determined by function of the heart and systemic circulation. Finally, the actual delivery of oxygen is dependent upon both blood oxygen content and blood flow. Oxygen content is directly related to the oxygen carrying capacity of the blood, i.e., hemoglobin concentration and hematocrit, whereas blood flow is inversely related to hematocrit (visocosity). These interrelationships and associated factors determine Systemic Oxygen Delivery (new Project D). Since the oxygen transport system must respond to changes in both oxygen supply and demand, it is of importance to understand the special adaptations to the chronic hypoxia of High Altitude (Project E). These, then, are the five major areas of investigation within this Program Project. The roles of hypotoxic and hypercapnic ventilatory drives in controlling breathing in respiratory failure, during sleep, and during exercise, are being studied. Bulk flow of CO2 to the lung will be examined as a major stimulus to hyperpnea during exercise. Histamine, prostaglandins, perivascular mast cells, and the direct effects of hypoxia are under investigation relative to pulmonary vascular control. Resulting changes in vascular tone alter the dynamics of capillary blood flow. Factors causing pulmonary capillary recruitment as a means of enhancing gas exchange will be studied. All of these mechanisms will be related to adaptation and maladaptation to High Altitude, including pregnancy, chronic mountain sickness, high altitude pulmonary edema, and oxygen transport, particularly in the presence of polycythemia.