References:

Title page image
Haggstrom, M. (2008, November 23). Heart (vessels only). Retrieved October 20, 2012 from http://commons.wikimedia.org/wiki/File:Heart_(vessels_only).gif

Original blank heart image
Cull, P. (Ed.). (1989). The Sourcebook of Medical Illustration. Park Ridge, NJ: Parthenon. Retrieved October 16, 2012 from http://acccn.net/Bio/book/Bio50/LecNotes/lecnot16a.html

Pulmonary exchange image
Blurpeace. (2009, May 7). Heart-and-lungs. Retrieved November 3, 2012 from http://en.wikipedia.org/wiki/File:Heart-and-lungs.jpg

Heart pumping image
Human Heart Healthy Pumping Pump. Retrieved October 20, 2012 from
http://pixabay.com/en/human-heart-healthy-pumping-pump-41546/

CGI heart video
Gulianelli. (2008, October 1). A Beating Human Heart (3D). Retrieved October 23, 2012 from http://www.youtube.com/watch?v=71olG7fyOCI

Real human heart video
Britannica. (2009, March 11). Heart Beating. Retrieved October 23, 2012 from http://www.youtube.com/watch?v=NYB-rJZQt4w