问题 问答题 简答题

蛛网膜下隙出血后脑血管痉挛(cerebrovascularspasm,CVS)机制。

答案

参考答案:

发生机理主要涉及:

(1)血液对血管壁的机械性刺激。

(2)血管活性物质的作用,如5-HT、儿茶酚胺、血红蛋白及花生四烯酸代谢产物等。研究发现,血红蛋白和NO之间的相互作用是CVS的重要因素之一。其中氧合血红蛋白氧化成高铁血红蛋白并释放氧自由基,也起重要作用。

(3)包裹血块压迫、血管营养障碍等引致血管壁结构的破坏。

(4)血管壁炎症和免疫反应等因素的影响。

(5)SAH后由于颅内压增高,临床上过量的脱水治疗而不及时补充血容量也是引起CVS的原因。

单项选择题

阅读下面短文,从短文后各题所给的四个选项(A、B、C和D)中,选出可以填入空白处的最佳选项,并在答题卡上将该项涂黑。学科&网

Hundreds of people have formed impressions of you through that little device(装置) on your desk. And they’ve never actually   41   you. Everything they know about you   42   through this device, sometimes from hundreds of miles away.   43   they feel they can know you   44   from the sound of your voice. That’s how powerful the   45   is.

Powerful, yes, but not always   46  . For years I dealt with my travel agent only by phone. Rani, my faceless agent whom I’d never met   47  , got me rock-bottom prices on airfares, cars, and hotels. But her cold voice really   48   me. I sometimes wished to   49   another agent.

One morning, I had to   50   an immediate flight home for a family emergency. I ran into Rani’s office   51  . The woman sitting at the desk,   52   my madness, sympathetically jumped up. She gave me a   53   smile, nodded while listening patiently, and then printed out the   54   immediately. “What a wonderful lady!” I thought.

Rushing out   55   I called out over my shoulder, “By the way, what’s your name?” “I’m Rani,” she said. I turned around and saw a   56   woman with a big smile on her face waving to wish me a safe trip. I was   57  ! Why had I thought she was cold? Rani was, well, so   58  .

Sitting back in the car on the way to the airport, I figured it all out. Rani’s   59  ---her warm smile, her nods, her ‘I’m here for you’   60  ---were all silent signals that didn’t travel through wires.

43()

A. Thus

B. Yet

C. Then

D. Indeed

填空题