The human body is a machine consisting of many different, interconnected machines. Each machine (heart, lungs, intestines, etc.) runs at its own individual speed, but all function in a specific, predetermined relationship to each other. In this sense, the body is analogous to the most complicated man-made machines, such as automobiles, tape recorders, or space capsules, which consist of many separately functioning components that are mechanically linked together, each of which, in itself, is a complete machine. In fact, the body is the most complex of all such compound machines. But unlike man-made machines, the various machines that make up the body are not in a rigid, inflexible, unchanging interrelation to each other.
Urinary or Excretory System