Unit 4 The circulatory and excretory systems

There is an excellent blog made in a science bilingual project, we are going to use it as a source of good learning material, for example this one related to circulatory system.
How can we measure blood pressure?
How a normal heart pumps blood?
And please donét forget the lymphatic system,  another video.
The best 2012 scientific video is catalan and about the heart,    let´s look at it


And now, lets´look at our kidneys: How kidneys work,  The kidneys ,  kidney: structure and function ;  and nephron