脊椎动物血液循环系统内容在中学生物课中既是重点,又是难点,学生在学习过程中,普遍感到难学、难记、易记错。这里,笔者谈谈自己多年来在教学过程中的一点体会。 脊椎动物亚门有五个纲;鱼纲、两栖纲、爬行纲、鸟纲、哺乳纲。这五个纲的血液循环系统以鱼纲结构最简单,哺乳纲结构最复杂。其共同点是:都包括心脏和血管,心脏都由心房和心室构成。不同点是:心房及心室数目、心室构造、血液循环路线不完全相同。 鱼类的血液循环系统虽然是五个纲中最简单的,但我却把它当作重点的重点去讲述,这不仅是因为它在进化地位上很重要,而且它在学 The contents of the vertebrate blood circulatory system are both important and difficult in the biology class of middle school students. Students generally find it difficult to learn, hard to remember and easy to remember. Here, the author talks about his own experience in the teaching process over the years. There are five classes of vertebrate subphylums; fish classes, amphibia, reptilia, birds, and mammals. The five types of blood circulation system are the simplest fish skeleton and the most complex mammalian structure. What they have in common is that they both include the heart and blood vessels, and the heart consists of the atria and the ventricle. The differences are: the number of atria and ventricles, ventricular structure, and blood circulation are not exactly the same. Although the fish’s blood circulation system is the simplest of the five categories, I have described it as the focal point of emphasis, not only because it is important in evolutionary status, but also because it is