The Richter scale doesn't measure quake damage (see: Mercalli Scale) which is dependent on a variety of factors including population at the epicentre, terrain, depth, etc.
The circulatory system works with the muscular system, the nervous system, and the digestive system. The heart is a muscle so it is part of the muscular system. Also the heart and lungs have nerves so it is also part of the nervous system.
Body systems, including the digestive, skeletal, respiratory, circulatory, and nervous systems work together. For instance, your stomach, part of the digestive system, sends messages to your brain, part of the nervous system, when your body is hungry.