下列是对人体的血液循环的相关叙述，不正确的是（） A．经_爱下问搜题

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问题选择题

下列是对人体的血液循环的相关叙述，不正确的是（　　）

A．经肺流出的血一定是动脉血，而经心脏后不一定是动脉血

B．肺循环和体循环都是由心室→动脉→毛细血管→静脉→心房

C．在医院做“DNA”亲子鉴定时抽取血液，仅仅只用到血细胞中的白细胞

D．某人腿部受伤，吃药后，药物到达受伤部位至少经过2次体循环和2次肺循环

答案

A、血液通过肺动脉流经肺部的毛细血管时，由于吸入肺泡内的空气中，氧的含量比血液中的多，而二氧化碳的含量比血液中的少，因此肺泡内的氧气扩散到血液里，血液中的二氧化碳扩散到肺泡里，这样，血液由含二氧化碳较多的静脉血变成了含氧气较多、二氧化碳较少的动脉血；因此从肺流出的血液一定是动脉血．从心脏的左心室流出的是动脉血，而从右心室流出的血液是静脉血．故不符合题意．B、体循环的途径是：左心室→主动脉→组织处毛细血管→上下腔静脉→右心房，肺循环的途径是：右心室→肺动脉→肺部毛细血管→肺静脉→左心房；即肺循环和体循环都是由心室→动脉→毛细血管→静脉→心房．故不符合题意．C、DNA是遗传物质的载体，存在于细胞核中；血液中的血细胞只有白血病具有细胞核．因此在医院做“DNA”亲子鉴定时抽取血液，仅仅只用到血细胞中的白血病．故不符合题意．D、某人腿部受伤，吃药后，药物到达受伤部位的途径是：药物→小肠绒毛内毛细血管→…→下腔静脉→右心房→右心室→肺动脉→肺部毛细血管→肺静脉→左心室→主动脉→腿部动脉→腿部毛细血管→受伤处．即药物到达受伤部位先经过体循环，再通过肺循环，然后经过体循环到达受伤部位，即经过两次体循环、一次肺循环．故符合题意．故选：D

单项选择题

在类风湿性关节炎中，最先受累的关节组织是

A．骨组织

B．软骨组织

C．滑膜组织

D．韧带

E．血管

完形填空

It was 4 o'clock in the morning, when I received the phone call.
“This is the emergency room calling and your son was just 36 in with severe burns on his face, neck and arms. We have called for a(n) 37 and are going to fly him to the burn unit in Seattle.” Seattle was 350 miles from his college, so we knew immediately this was 38  . The doctor described the 39 , which caused the burns. At 6 am, our son and his friends decided to barbecue hamburgers in the courtyard of their apartment. When they   40  the charcoal(木炭),it burst into flames because they had sprayed too much gasoline(petrol).The flames 41 my son’s shirt tail and shot from his waist to well over his head.
  42 , one of the boys was quick-minded, grasped my son, and 43 him on the grass. While it saved his life, it was not in 44   to save him from severe burns and the terrible scars(伤疤).
After he 45 from the treatments, the doctors told him they would not do plastic surgery(整容)for 6 months 46 it takes that long for the skin to stop shrinking and wrinkling. So, he had to return to college with scars typical of severe burns.
When I was a child, my mother told my sister, who had a 10-inch very 47 scar on her arm, “Nancy, if you ignore the scar, other people will ignore it. It does not mean they will not   48 it, but it means it will not matter to them if it doesn’t matter to you.”
I 49 this wisdom on to my son. He took my advice to 50 and returned to school with his head held high--glad he was alive.
By the end of the six-month waiting period, he decided that the scars did not 51 . So he made the 52 to give up any plastic surgery. We all have “scars” that we believe 53 people to keep away from us. And we spend a lot of time thinking that if only we looked differently, or dressed differently, people would like us better.
But you see, people will only judge you by your looks, or your clothes, if you are judging yourself by these same 54 standards. Put your imperfections out of your mind and concentrate on what you value 55 yourself, and your beauty will shine through.

C．burned　　

C．caught 　　

A．Fortunately

B．Surprisingly

D．considerate