问题 单项选择题

下图是人体局部内环境示意图。有关叙述正确的是()

A.结构1和结构2中的细胞所处的具体内环境相同

B.当人体发生花粉过敏反应时,C液会减少

C.当组织细胞产生的代谢产物大量累积在C液中时,B液会增加

D.当人进食l小时后,A液中的胰高血糖素含量会迅速升高

答案

参考答案:C

解析:

A液为血浆,B液为淋巴,C液为组织液,1毛细血管壁细胞所处内环境为组织液和血浆,2毛细淋巴管壁细胞的内环境为淋巴和组织液,两者不同;人体发生过敏反应时毛细血管壁通透性增加,血浆蛋白渗入组织液,组织液增加;当细胞产生的代谢产物大量积累在组织液中时,使组织液渗透压升高而从周围吸收水分导致B液减少;当人进食1小时后,淀粉被分解成葡萄糖吸收进入血液,使血糖浓度升高,为了维持血糖浓度的恒定,胰岛素分泌增加

考点:内环境、稳态调节

实验题
单项选择题

Questions 53 to 57 are based on the following passage:The Internet can make the news more democratic, giving the public a chance to ask questions and seek out facts behind stories and candidates, according to the head of the largest US on-line service.’But the greatest potential for public participation is still in the future,’ Steven Case, chairman of America On-line, told a recent meeting on Journalism and the Internet sponsored by The Freedom Forum, though some other speakers say the new technology of computers is changing the face of journalism, giving reporters access to more information and their readers a chance to ask questions and turn to different sources.’You don’t have to buy a newspaper and be confined to the four comers of that paper anymore.’ Sam Meddis, on-line technology editor at USA Today, observed about the variety of information available to computer users.But the speakers noted the easy access to the internet also means anyone can post information for others to see.’Anyone can say anything they want, whether it’s right or wrong.’ said Case. Readers have to determine for themselves who to trust. ’In a world of almost infinite voices, respected journalists and respected brand names will probably become more important, not less,’ Case said.’The internet today is about where radio was 80 years ago, or television 50 years ago or cable 25 years ago, ’he said. But it is growing rapidly because it provides people fast access to news and a chance to comment on it.

Which of the following statements is true

A.Only respected journalists can post information on the internet for others to see.

B.Respected journalists will probably become more important than before.

C.When people read newspapers, they have to stay in the comers of the street.

D.The greatest potential of public participation of the internet is in the near future.