问题 问答题

简述蛛网膜下隙阻滞对生理功能的影响。

答案

参考答案:(1) 对循环的影响:交感神经阻滞,外周容量血管扩张,周围血管阻力下降,使回心血量减少,心排量下降,血压下降,反射性地心率减慢;冠状动脉血流量取决于平均动脉压和心肌耗氧量;(2) 对呼吸的影响:取决于平面的高低,如过高,可引起通气不足;(3) 对胃肠道的影响:交感神经阻断,副交感神经占优势,可使胃蠕动增强,胃液分泌增加,幽门括约肌及Oddi’s括约肌松弛,胆汁反流,可出现恶心呕吐;(4) 对泌尿系统的影响:对肾脏的影响是间接的,主要取决于动脉压;膀胱平滑肌松弛,括约肌不受影响,因此术后尿潴留发生率高。

选择题
阅读理解

US bees operation keeping groups have been attacked seriously by so called Colony Collapse Disorder (蜂群衰竭失调).Almost 1/2 of their worker bees have vanished during the past season.This disorder has also been reported in Israel, Europe and South America.Bees fly away from the hive and never return.Sometimes they are found dead; other times they are never found.Many crops and trees depend on pollination--- by bees to help them grow. 

A new report says a virus may be at least partly responsible for the disorder in honey bee colonies in the United States.This virus is called Israeli acute paralysis virus.It was first found in Israel in 2004.Lan Lipkin at Columbia University in New York and a team reported the new findings in Science Magazine.Doctor Lipkin says the virus may not be the only cause.He says it may work with other causes to produce the collapse disorder.

The team found the virus in colonies with the help of a map of honey bee genes that was published last year.They examined thirty colonies affected by the disorder.They found evidence of the virus in twenty-five of them, and in one healthy colony.The next step is further testing of healthy hives.

The researchers suggested that the United States may have imported the disorder in bees from Australia.They say the bees may carry the virus but not be affected.

The idea is that unlike many American bees, the ability of Australian bees to fight disease has not been hurt by the varroasis mite.This insect attacks honey bees, which could make the disorder more likely to affect a hive.Australian bee producers object to these suspicions.

And some researchers suspect that bee production in the United States is down mainly because of the weather.Honey bees gather nectar from flowers and trees.The sweet liquid gives them food and material to make honey.But cold weather this spring in the Midwest reduced the flow of nectar in many flowers.Many bees may have starved.Dry weather in areas of the country could also be playing apart.

Wayne Esaias is a NASA space agency scientist who keeps bees in his free time.He lives in central Maryland, where he has found that flowers are blooming a month earlier than they did in 1970, which may be partly responsible for the disorder. Wayne Esaias is organizing a group of beekeepers to document nectar flow around the country.

小题1:What is the author’s attitude toward the cause of this disorder?

A.Doubtful

B.Neutral

C.Supportive

D.Negative小题2:The passage is mainly developed by            .

A.presenting the effect and analyzing its causes

B.making comparisons between two countries

C.providing data and examples

D.following the time order小题3:How many possibilities may be involved in the bee disorder according to the passage?

A.Three

B.Four

C.Five

D.Six小题4:From the passage we can infer that           .

A.American bees are more likely to defend themselves against hurt from other insects than Australian ones

B.A collection of plants production in the U.S may be influenced by the bee disorder

C.Israeli acute paralysis virus should be responsible for the disorder

D.The solution to the disorder will be found eventually