问题 问答题 简答题

试述胎儿循环系统的解剖学特点。

答案

参考答案:

胎儿循环系统的解剖学特点有:

①一条脐静脉,来自胎盘的血液经脐静脉进入胎肝及下腔静脉,生后脐静脉闭锁成肝圆韧带。

②两条脐动脉,来自胎儿的血液经脐动脉注入胎盘与母血进行物质交换,生后脐动脉闭锁成腹下韧带。

③动脉导管位于肺动脉与主动脉弓之间,生后肺循环建立后,动脉导管闭锁成动脉韧带。

④卵圆孔位于左、右心房之间,生后数分钟卵圆孔开始关闭,多在生后6~8周完全关闭。

多项选择题
单项选择题

When Dave was eighteen, he bought a secondhand car for 200 so that he could travel to and from work more (1) than by bus. It worked quite well for a few years, but then it got so old, and it was costing him (2) much in repairs that he decided that he had better (3) it.

He asked among his friends to see if anyone was particularly (4) to buy a cheap car, but they all knew that it was falling to pieces, so (5) of them had any desire to buy it. Dave’s friend Sam saw that he was (6) when they met one evening, and said, "What’s (7) , Dave"

Dave told him, and Sam answered, "Well, what about advertising it in the paper You may (8) more for it that way than the cost of the advertisement!" Thinking that Sam’s (9) was sensible, he put an advertisement in an evening paper, which read "For sale: small car, (10) very little petrol, only two owners. Bargain at 50. " For two days after the advertisement first appeared, there was no (11) . But then on Saturday evening he had an enquiry. A man rang up and said he would like to (12) him about the car. "All right, " Dave said, feeling happy. He asked the man whether ten o’clock the next morning would be (13) or not. "Fine, " the man said, "and I’ll (14) my wife. We intend to go for a ride in it to (15) it. "

The next morning, at a quarter to ten, Dave parked the car in the square outside his front door, (16) to wait there for the people who had (17) his advertisement. Even Dave had to (18) that the car really looked like a wreck. Then, soon after he had got the car as clean (19) it could be, a police car stopped just behind him and a policeman got out. He looked at Dave’s car and then said, "Have you reported this (20) to us yet, sir\

10().

A.uses 

B.loses 

C.has 

D.spends