问题 选择题

右图表示血液流经肾脏形成尿液的过程中几种成分(蛋白质、葡萄糖、尿酸和尿素)在各种液体中百分含量的变化,字母表示肾脏的有关结构,下列说法错误的是(  )

A.曲线甲、乙所示物质分别是蛋白质、葡萄糖

B.[B]内的液体是原尿

C.图中表示有重吸收功能的是[C]

D.[D]内的液体主要有水、无机盐和尿素

答案

血液经过肾小球和肾小囊壁时血液中的大分子的物质如血细胞、蛋白质外,其余的如水、无机盐、葡萄糖和尿素经过过滤形成原尿;然后原尿在经过肾小管时,在肾小管的重吸收作用下把全部葡萄糖、部分水还有部分无机盐重新吸收.那么剩下的水和无机盐、尿素等就会形成尿液,所以原尿、尿液中都不含有蛋白质而含有葡萄糖和尿素;原尿流经肾小管时,重吸收了全部葡萄糖,导致尿液中不含有的物质是葡萄糖.故乙是葡萄糖;由于肾小管重吸收了大部分水,而不重吸收尿素,因此,尿素浓度升高.图中甲浓度升高,乙浓度减少,因此,甲是尿素,乙是葡萄糖.
据图可知:在肾小管的重吸收作用下全部葡萄糖被吸收,所以C是肾小管;B是肾小囊腔,里面的液体是原尿;D内的液体是尿液,主要有水、无机盐和尿素.

故选:A

阅读理解

Many of us believe that a person’s mind becomes less active as he grows older. But this is not true, according to Dr Jarvik, professor of psychiatry at the University of California. She has studied the mental functioning of aging persons for several years. For example, one of her studies concerns 136 pairs of twins (双胞胎), who were first examined when they were already 60 years old. As Dr Jarvik continued the study of the twins into their 70s and 80s, their minds did not generally decline (衰弱) as was expected.

  However, there was some decline in their psycho-motor speed. This means that it took them longer to finish mental tasks than it used to. But when speed was not a factor, they lost very little intellectual (智力的) ability over the years. In general, Dr Jarvik’s studies have shown that there is no decline in knowledge or reasoning ability. This is true not only with those in their 30s and 40s, but with those in their 60s and 70s as well.

  It is true that older people themselves often complain that their memory is not as good as it once was. However, much of what we call “loss of memory” is not that at all. There usually was incomplete learning in the first place. For example, the older person perhaps had trouble hearing, or poor vision, or was trying to learn the new thing at too fast a speed. In the cases where the older person’s mind really seems to get worse, it is not necessarily a sign of decline due to old age. Often it is simply a sign of a sad emotional state. 

小题1: This passage is mainly about _______.

A.what caused mental decline

B.a new discovery about mental decline

C.the difference between middle-aged and older persons

D.how Dr Jarvik studied mental functioning of the twins小题2:The word “psychiatry” in paragraph 1 most probably means _______.

A.the study of diseases of the mind

B.the study of physical diseases

C.the study of twins’ growth

D.the study of human behavior小题3:More often than not, what we call mental decline is actually a sign of _______.

A.a worsening state of health

B.old age

C.nervous tension

D.a state of unhappiness

单项选择题