问题 问答题 简答题

如何评价心泵功能的强弱?

答案

参考答案:

1.常用的评定心泵功能的指标有:

(1)每搏排出量和射血分数。每搏排出量和射血分数均与心肌的收缩力量有关,收缩力量越大,心脏搏出的血量越多,心室内剩余血量越少,射血分数越大。射血分数还和舒张末期容积有关,如耐力运动员尽管会使搏出量增加,但由于心舒末期容积也增加,故射血分数基本不变。

(2)每分输出量和心指数。每分输出量随着机体活动和代谢状况而变化,在肌肉运动、情绪激动、进餐、怀孕等情况下,心输出量增加。研究表明,人在静息时的每分输出量与体重和身高均不成正比,而与体表面积成正比,以每平方米表面积计算的每分输出量称心指数。运动时,由于每分输出量增加,心指数也增加。

(3)心力贮备。心力贮备包括心率贮备、收缩期贮备和舒张期贮备。心率贮备是通过增加心率而使心输出量增加的能力。耐力训练能降低安静心率,故耐力运动员的心率贮备较大。

(4)心脏做功量。血液在血管中循环流动所消耗的能量,是由心脏做功提供的。用心脏做功量来评价心泵功能,较每搏输出量或每分输出量更有意义。因为心脏收缩不仅仅是排出一定的血量,而且使这部分血液具有较高的压强能和较快的流速。故心脏做功量是评价心泵功能的重要指标,心脏做功能力越强,其心泵功能越强。

阅读理解

When 47-year-old volunteer Susan Boyle stepped onto the stage of Britain’s Got Talent and announced she was unemployed, had never been married and “never been kissed, actually”, few in the audience would have wondered why. This Ms Boyle, looking unfashionable, from a village in Scotland, shocked the three judges and the audience with the song I dreamed a dream from the musical Les Miserables on a show of Britain’s Got Talent, one of the hottest reality shows in Britain.

She couldn’t hide the awkwardness when walking to the center of the stage in a housedress, and everyone — including the judges — seemed laughing at her when she said she wanted to be as successful as Elaine Paige. As soon as she began singing, however, everyone in the auditorium fell silent, then rose within seconds to applaud her incredible voice as the celebrity judges sat open-mouthed, and remained standing to the end.

After her performance, one of the judges Piers Morgan said, “Without doubt that was the biggest surprise I’ve had in three years of this show. When you stood there everyone was laughing at you. No one is laughing now. That was amazing.” Actress Amanda Holden followed, “I’m so thrilled because I know that we everybody were against you. I honestly think that we were all being very cynical (愤世嫉俗的) and I think that’s the biggest wake up call ever.”

Susan obviously won over the hearts of millions around the world with sensation spreading across the Atlantic. Hollywood actors Ashton Kutcher and Demi Moore — who between them have nearly 1.5 million followers — speak highly of her. Kutcher posted a link to the video clip (片段). The Scottish talent made her live American debut via satellite connection on CBS’s The Early Show, doing an interview and singing live from her room. And she already accepted an invitation from talk show host Oprah Winfrey.

Now Boyle has become one of the world’s hottest celebrities. The video clip of her performance has been viewed more than 50 million times on Youtube, becoming a hit on the Internet.

小题1: We learn from the passage that Susan Boyle ______.

A.rose from a low social class

B.had an unhappy marriage

C.lived with a dog alone on a farm

D.won the championship in the Britain’s Got Talent show小题2: At the beginning of the show, almost everybody ______.

A.looked forward to her wonderful performance

B.was attracted by her beautiful dress

C.looked down upon her

D.placed great hope on her小题3:We can infer that ______ contributed most to her global popularity.

A.the judges

B.the Internet

C.the newspaper

D.the advertisement小题4:The 4th paragraph intends to tell us ______.

A.how Susan Boyle achieved her success

B.the comment made by American actor Ashton Kutcher

C.Susan Boyle’s influence in the USA

D.Oprah Winfrey’s invitation to Susan Boyle

单项选择题 B1型题