The heart is a pump, the brain is an electrical computer, the leg and arm bones are levers used for lifting and moving physical objects. Our spirit doesn't just wear the body, it operates it. A car is a mechanical devise. Although the engine may be running, without the operator steering the wheel, moving the gear-shift levers, and pressing on the gas pedal and brakes, the car is lifeless. But, with a knowledgable person operating it, the car seems to take on intelligence as it moves about, going from one point to another.
Cars even communicate with one another by use of lights and horns.
On the other hand, even though the driver may be in perfect health, if there's something wrong with the carborator, alternator, spark plugs, or any other part of the automobile's machinery, the car doesn't behave as it should. The same is true of our human body. Even though the spirit inside may be healthy, if there is something wrong with the heart, lungs, gall bladder, liver or any other part, the body doesn't operate as it should. When we speak, we are actually operating a mechanical devise known as the voice box, or larynx. To make it work, we push air from our lungs out through the mouth.