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在高三的生物复习时,我们利用青蛙连续进行“用显微镜观察蛙蹼内血液流动的现象”、“观察蛙心脏的节律性搏动”和“脊蛙反射”三个实验,取得较好的效果。有关实验目的、要求与实验步骤详见课本,这里只介绍连续完成这三个实验的有关问题。 1.实验准备一定要充分。包括指导学生预习实验内容及实验所需仪器药品的准备。特别要注意选择具有良好生命力的蛙或蟾蜍。由于蛙的脊休克时间较蟾蜍长(多达数十秒),因此,我们用蟾蜍作材料,且不能用铁叉扦或其它有伤蛙体的捕捉方法。捕来的蛙或蟾蜍要保养在有浅水而阴湿的池中,最大限度地使
In the third year of biological review, we use the frog to continuously conduct “microscope observation of the phenomenon of blood flow in the frog webbed”, “observe the rhythmic beat of the frog heart” and “frog reflection” three experiments and achieved good results. For the purpose of the experiment, requirements and experimental procedures see textbook, here only describes the success of these three experiments to complete the relevant issues. 1. Experimental preparation must be full. Including guidance for students to preview the contents of the experiment and the preparation of equipment required for the experiment. In particular, pay attention to choose the frog or toad with good vitality. Since frogs have a longer time to shock than toads (up to tens of seconds), we use toads as materials and can not use iron forks or other methods to catch the frog. Caught frogs or toads should be kept in shallow, damp pools to maximize their use