6.產(chǎn)生老視眼的原因是(      )

Ａ.角膜表面經(jīng)緯線曲率半徑不一致                 B.晶狀體彈性下降

C.眼球前后徑過長                                           D.眼球前后徑過短

7.成對的腦顱骨是(      )

A.頂骨                                                            B.枕骨   

C.額骨                                                            D.篩骨

8.食管的第二狹窄距中切牙(      )

A.10cm                                                           B.15cm  

C.25cm                                                           D.40cm

9.心的正常起搏點是(      )

A.房室結(jié)                                                         B.房室束      

C.竇房結(jié)                                                         D.左、右束支

10.位于脊髓后索內(nèi)的纖維束是(      )

A.皮質(zhì)脊髓束                                                  B.三叉丘系   

C.薄束                                                            D.脊髓丘腦束