I am Joe’s Heart

Lubb-dup, lubb-dup, lubb-dup, lubb-dup, lubb-dup, lubb-dup. I am a pump. 1 am all muscle. I am Joes heart. I am the center of his whole body; from me are all the issues of life. A pump? Yes, I pump blood (about ten pints) through Joes body several times a day. I am the size of his fist, located behind his breast bone, protected from injury by it and his ribs. I contain no fat, no bones, just muscle pure muscle. I have four chambers which fill and empty rhythmically controlled by valves called...