FETAL HEAT PRODUCTION AND TEMPERATURE REGULATION

胎儿生活在一个异常热稳定的环境中 可能会出现挑战胎儿体温调节的特殊情况 能力。其中包括母体发热和运动引起的体温过高， 极端寒冷暴露的体温过低，以及可变的，更冷 出生后的体温，此时体温调节可能变得至关重要 为了新生儿的生存。胎儿体温的调节机制 在子宫内的生产和消除在很大程度上仍然是未知的。因此，我们， 建议继续我们的研究，沿着三条线调查，以 更好地理解生理学的这一方面。我们将完成这项研究 差示量热法测定胎儿产热量及其相关性 结果与耗氧量；2)测量胎儿的受热分数 通过各种排泄途径输给母亲，包括 胎盘、皮肤、脐带、羊水和子宫壁；以及3)探索 胎儿和新生儿做出的各种体温调节反应以维持 恒温。这些反应包括热量产生的变化， 热传导性，以及可能稳定温度的脐带流。 将在开发期间的不同时间进行调查，以 研究反应的成熟度。实验旨在提供新的 了解胎儿产热和体温控制，以及如何 在整个妊娠过程中这些变化并评估它们的生理 重要性。

The fetus lives in an environment that is exceptionally theromstable but special situations may arise that challenge fetal thermoregulatory capability. These include the hyperthermia of maternal fever and exercise, the hypothermia of extreme cold exposure, and the variable, colder temperatures after birth, when temperature regulation may become critical for survival of the newborn. The mechanisms regulating fetal heat production and elimination in-utero remain largely unknown. We, therefore, propose to continue our studies along three lines of investigation to better understand this aspect of physiology. We will 1) complete the study of fetal heat production using differential calorimetry and correlate its results with oxygen consumption; 2) measure the fraction of heat the fetus loses to the mother through various excretory pathways including the placenta, skin, cord, amniotic fluid, and uterine wall; and 3) explore the various thermoregulatory responses the fetus and newborn make to maintain a constant temperature. These responses include changes in heat production, heat conductance, and umbilical flow that might stabilize temperature. Investigations will be performed at various times during development to study maturation of responses. Experiments are designed to give new understanding of fetal heat production and temperature control, and how these change throughout gestation and to assess their physiologic importance.