2l.機體調(diào)節(jié)重吸收水量的部位是(      )

A.近端小管                                                 B.髓袢降支細段

C.髓袢升支                                                 D.遠曲小管和集合管

22.終尿中的K⁺主要是由(      )

A.腎小球濾過                                              B.近曲小管分泌

C.髓袢升支分泌                                          D.遠曲小管和集合管分泌

23.當(dāng)被視物體由遠處移向近處時，人眼最主要的調(diào)節(jié)是(      )

A.晶狀體變凸                                              B.瞳孔近反射

C.瞳孔對光反射                                          D.雙眼會聚

24.產(chǎn)生色盲的原因是視網(wǎng)膜中缺乏某種(      )

A.色素細胞                                                 B.視桿細胞

C.視錐細胞                                                 D.雙極細胞

25.聽覺感受器是(      )

A.前庭階                                                     B.鼓階

C.蝸管                                                        D.螺旋器