A．有刺激必然产生反应 B．产生反应时，必然接受了刺激 C．阈刺激时，必然产生反应 D．有刺激时，不一定产生反应 E．有时反应随刺激强度加大而增强
单项选择题激活胃蛋白酶原的物质是（）
A.肠激酶B.盐酸C.组织液D.胃泌素E.胰泌素
问答题What are typical and common patterns of motility in different parts of gastrointestinal tracts and each function (10 Points)
问答题What is oxygen dissociation curve and please describe some factors influencing this curver. (10 Points)
问答题What is cardiac output and please describe some factors affecting the cardiac output. (10 Points)
问答题What is the concept and basic steps of blood coagulation (15 Points)
