There are movies of the heart at this site.

http://www.medtropolis.com/vbody/heart.html

This site from Columbia Healthcare has information about high blood pressure, cholesterol, and other circulatory issues.

http://www-rics.bwh.harvard.edu/sickle/scd_background.html

Good explanations and clear illustrations of sickle cell disease can be found here.

http://oncolink.upenn.edu/classroom/bmtmm/

This site provides information about bone marrow transplants for patients with multiple myeloma.