Richardson B S
Department of Obstetrics and Gynaecology, University of Western Ontario, London.
Clin Invest Med. 1993 Apr;16(2):103-14.
The fetal environment is well suited for normal brain growth and development with oxygen availability well in excess of oxidative needs. With impairments in blood gas exchange, cerebral oxidative metabolism is initially maintained by an increase in cerebral blood flow, thus protecting the 'oxygen margin of safety', and, when this response becomes limited, by an increase in the brain's fractional extraction of oxygen. Additional adaptive mechanisms involve substrate alterations and a decrease in energy consuming processes, including growth restriction and behavioural state alterations. Although protective insofar as essential metabolic functions are maintained, pathologic change may become evident as the 'oxygen margin of safety' becomes limited or energy conserving measures give rise to abnormal growth and development.
胎儿环境非常适合正常的大脑生长和发育，氧气供应量远超过氧化需求。在血气交换受损的情况下，大脑氧化代谢最初通过脑血流量增加来维持，从而保护“氧气安全边际”，当这种反应受到限制时，则通过大脑对氧气的分数提取增加来维持。其他适应性机制包括底物改变和能量消耗过程的减少，包括生长受限和行为状态改变。尽管在维持基本代谢功能方面具有保护作用，但当“氧气安全边际”受到限制或节能措施导致异常生长和发育时，病理变化可能会变得明显。
