Preload is the stretch. The amount of volume being returned to the right side of the heart from systemic circulation. Afterload is the squeeze. The amount of resistance the left side of the heart has to overcome in order to eject blood.
The Elephant of Surprise: Art for Non-Artists: Easy Doily Watercolor. This would be sooo cute for a journal page or wrapping paper. And you could probably use the now-painted doilies in something too . <<< DID YOU JUST SAY ELEPHANT