问题 问答题

骨移植的种类有哪些?各有何优缺点?

答案

参考答案:骨移植的分类及优缺点如下:(1) 自体骨移植:目前认为自体骨移植是加强骨折修复的最佳方法和材料。自体松质骨的效果最佳,因为松质骨具备了骨再生所需的3个基本要素:骨传导、骨诱导及骨生成细胞。其缺点主要有:供体部位的缺损、来源有限以及偶尔的移植骨生物力学强度较低。(2) 异体骨移植:异体骨移植最为人们担心的是其潜在的疾病传播的可能性,异体骨的结合过程要比自体骨慢。其与宿主骨结合的能力也肯定不及自体骨,因为异体骨的骨生成性和骨诱导性均有相当程度的减弱。异体移植可产生较大的免疫反应。(3) 人工合成骨移植替代物:运用人工合成或工程化骨移植材料可增强骨折愈合,而不用担心传染疾病。这些人工合成材料一般只具有骨传导性,不过可在其中加入骨诱导蛋白质和(或)骨母细胞,改善其骨诱导性和骨生成性。

完形填空
阅读下面短文,从短文后所给各题的四个选项(A、B、C和D)中,选出可以填入空白处的最佳选项,并在答题卡上将该项涂黑。
One sunny afternoon, a seven-year-old girl went for a walk. She crossed a large area of grassland into the woods   she realized that she was lost.
Sitting on a rock and   what to do, she began crying. After a while,She   to walk along a wide path lined with tall trees and thick bushes.     it was getting dark, she saw a small, dark wooden house. She opened the door and   stepped in. Suddenly, she heard a strange noise, and she ran out the door and back to the   . Cold and tired, she fell asleep near a   .
The girl’s parents were out and her dog, Laddy, was at home. Laddy   that his mistress(女主人) was in danger. He jumped   a window, breaking the glass. He looked in the fields. But he couldn’t find his mistress anywhere. However, from the ground came a   scent(气味) as he lowered his head. He   the scent and walked across the grassland. Barking   into the air, the dog   through the woods until he found the   . But the girl was not there, so he headed back to the woods. Much to his   , he saw his mistress’ blue shirt in the distance. He   over some bushes and saw the little stream, where the girl was   .
When she opened her eyes and   her dog standing beside her, the girl said, “you   me, Laddy.” and she kissed him several times. Seeing their daughter and dog coming back, the parents burst into tears of   . That night Laddy had a hero’s supper, a huge meal of steak.
小题1:
A.beforeB.since C.whileD.as
小题2:
A.wonderingB.forgetting C.remembering D.regretting
小题3:
A.preferredB.expectedC.failedD.decided
小题4:
A.WhenB.UntilC.If D.Because
小题5:
A.carelesslyB.cautiously C.hopelesslyD.unwillingly
小题6:
A.treesB.bushesC.woods D.grasses
小题7:
A.streamB.rockC.treeD.house
小题8:
A.foundB.sensedC.heardD.smelt
小题9:
A.atB.throughC.inD.onto
小题10:
A.terrible B.StrangeC.pleasantD.familiar
小题11:
A.missedB.discovered C.followedD.ignored
小题12:
A.calmlyB.loudlyC.merrily D.gently
小题13:
A.searchedB.wandered C.lookedD.travelled
小题14:
A.window B.girlC.houseD.hero
小题15:
A.satisfactionB.disappointment C.embarrassmentD.delight
小题16:
A.jumped B.climbedC.walkedD.flew
小题17:
A.awakeB.abandoned C.availableD.asleep
小题18:
A.spotted B.watchedC.observedD.saw
小题19:
A.disturbedB.comforted C.rescued D.scared
小题20:
A.painB.shockC.sorrowD.relief
单项选择题 A1型题