酸中毒时常伴有血清钾浓度降低而导致心律失常，甚至发生心脏传导阻滞或心室颤动。
胎儿时期有________根脐静脉，_________根脐动脉。
下列哪项无肺内多发空洞() ["A．肺结核","B．肺泡细胞癌","C．转移性肺癌","D．肺吸虫病","E．韦格肉芽肿"]
最易出现空洞内液平的病变是() ["A．肺结核","B．急性肺脓肿","C．慢性纤维空洞型肺结核","D．肺癌","E．肺囊肿合并感染"]
促胃液素的生理作用有() ["A．刺激胃黏膜细胞增殖","B．刺激壁细胞分泌盐酸","C．抑制主细胞分泌胃蛋白酶原","D．刺激胰液、胆汁和肠液分泌","E．刺激幽门与回音括约肌收缩 "]
胎儿期供应脑、心、肝及上肢血氧量较下半身为________。
