6．心室等容收縮期時(shí)的瓣膜情況是(      )

A．房室瓣開(kāi)、動(dòng)脈瓣開(kāi)                                B．房室瓣開(kāi)、動(dòng)脈瓣關(guān)

C．房室瓣關(guān)、動(dòng)脈瓣關(guān)                                D．房室瓣關(guān)、動(dòng)脈瓣開(kāi)

7．竇房結(jié)P細(xì)胞0期去極化是由下列哪種離子跨膜移動(dòng)所引起?(      )

A．Na⁺內(nèi)流                                                   B．K⁺外流

C．C1^-內(nèi)流                                                    D．Ca²⁺內(nèi)流

8．心肌細(xì)胞不產(chǎn)生完全強(qiáng)直收縮的原因是由于(      )

A．肌漿網(wǎng)Ca²⁺貯存少                                   B．有效不應(yīng)期特別長(zhǎng)

C．受自動(dòng)節(jié)律性控制                                   D．“全或無(wú)”式收縮

9．平靜呼吸時(shí)，肺內(nèi)壓在下列哪一個(gè)時(shí)相中低于大氣壓?(      )

A．吸氣中                                                     B．呼氣末

C．呼氣中                                                     D．吸氣末

10．氣體交換的動(dòng)力是(      )

A．呼吸肌的運(yùn)動(dòng)                                          B．胸膜腔內(nèi)負(fù)壓

C．氣體分壓差                                              D．肺的回縮力