We have already studied the Circulatory System as well as the Respiratory System.
Let´s star watching some videos related to Circulatory System of human beings.
This is a very long video,
but it is worth watching it!!
Nice and calm explanation about how our HEAR works. Click on this video, please.
This video is more realistic. Have a look!! (Stop at minute 1:50)
And if you would like to listen to a song, let´s click on next video!
Respiratory System