電大本科病理生理學(xué)復(fù)習(xí)試題與答案小抄(編輯修改稿)
2025-07-09 05:30 本頁(yè)面
【文章內(nèi)容簡(jiǎn)介】 化學(xué)感受器，反射性增強(qiáng)呼吸運(yùn)動(dòng)，此反應(yīng)要在 PaO2 低于 8KPa(60mmHg)才明顯。 PaO 2升高主要作用于中樞化學(xué)感受器，使呼吸中樞興奮，引起呼吸加深加快，當(dāng) PaO2 超過(guò)(80mmHg)時(shí)，反而抑制呼吸中樞，此時(shí)呼吸運(yùn)動(dòng)主要靠動(dòng)脈血低氧分壓對(duì)血管化學(xué)感受器的刺激得以維持。在這種情況下，若吸入高濃度的氧，則可使缺氧完全糾正，呼吸反而抑制使高碳酸血癥更加嚴(yán)重，病情更加惡化。 3① 堿 中毒時(shí)，可使腸道離子型銨 (NH 4＋ )轉(zhuǎn)變成分子氨 (NH 3)而吸收入血； ② 堿中毒時(shí)，可使腎小管上皮細(xì)胞產(chǎn)生的氨，以銨鹽形式排出減少，以游離氨形式彌散入血增多； ③堿中毒時(shí)，可使血液中離子型銨 (NH 4＋ )轉(zhuǎn)變成分子氨 (NH 3)，后者易于通過(guò)血腦屏障和腦細(xì)胞膜，使腦細(xì)胞內(nèi)氨濃度升高。故堿中毒易誘發(fā)肝性腦病。 4 慢性腎功能衰竭時(shí)，因?yàn)?① 殘存的有功能的腎單位代償性增大，血流量增多，濾過(guò)的原尿量超過(guò)正常量，而大量的原尿在通過(guò)腎小管時(shí)，因其流速相應(yīng)增快，使腎小管來(lái)不及重吸收，以致終尿量多于正常； ② 在濾出的原尿中 ，由于溶質(zhì) (尤其是尿素 )濃度較高，可引起滲透性利尿； ③ 腎髓質(zhì)的病變或是在腎小管重吸收障礙時(shí)，因髓質(zhì)滲透壓梯度受到破壞，尿濃縮能力降低，使尿量增多。故慢性腎衰患者，雖然有廣泛的腎實(shí)質(zhì)破壞，但在很長(zhǎng)一段時(shí)間內(nèi)，仍可出現(xiàn)多尿。 Visafree policy brings Chengdu biz, tourism boost. Making national headlines several times, Chengdu39。s 72hour visafree policy has attracted wide attention from both Chinese and foreign experts and businessmen since it took effect on Sept 1 last year. The program permits citizens from 51 countries and regions including the United States, Australia, Canada and Japan who have valid visas and flight tickets to a third country to spend three days in the city. The capital of Sichuan province is the first city in the western region of China to offer foreign tourists a threeday visa and the fourth nationwide to adopt the policy following Shanghai, Beijing and Guangzhou. Li Zhiyong, deputy dean of the tourism institute at Sichuan University, said the move contributes to a large increase in the number of overseas tourists and raises the city39。s level of internationalization. The policy will also bring direct economic revenue, Li said. Chengdu has many cultural legacies and is also a paradise for panda lovers with the world39。s largest breeding and research center. Three days are long enough for foreign visitors to visit those iconic tourist spots, he noted. The city is home to the remains of the Jin sha civilization that dates back more than 3,000 years as well as the Qing cheng Mountains and t
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