A young boy learns about his heart through the step-by-step construction of a simple circulatory system. He learns how his heart pumps, what blood and blood vessels do, how they do it, and some of the ways to help his heart stay healthy.
1930
2002
1908
1970
1980
1933
1936
1965
1966
2001
1994
2017
1948
1956
2005
2012
1989
2013