The heart is a vital organ that basically serves as a pump. Learn about heart chambers and valves, blood flow, the heart's electrical system and blood supply. Read more about how this amazing organ works.
how-the-heart-works - IJN
How Your Heart Works, Helping Your Heart
Heart - Transplant Living
Heart healthdirect
Circulatory system
How Your Heart Works - Tests & Procedures - Children's Heart Center - Golisano Children's Hospital - University of Rochester Medical Center
The Human Heart
How Do Your Heart and Lungs Work Together
How Does the Heart Work? Review Heart Structure and Function