The body, in a nutshell, is everything physical, tangible and measurable about us. This includes our total anatomy and physiology. Our anatomy is the parts that make up what we are. I do not believe that we have any spare parts or useless parts. Just because we don't know what it does, doesn't mean it does nothing.

Our physiology is how all those parts function. This is where we get very complicated. Each and every part has its own function, but it also has a greater, cohesive and complementary function within its system. Each of these systems also has its own function and a complementary function with all the other systems. The nervous system sends impulses to other systems and guides them like complex traffic control. Some of these systems have control functions like the nervous system and others have more blue-collar jobs like the digestive or immune systems. 

Each of them gives and receives feedback to and from the other systems to communicate the wishes of the mind of the one they belong to. These signals can be electrical, chemical, mechanical, electromagnetic or something else entirely or a combination of all of them. The beauty of all of these parts and signals and functions is that they are mirrored at every level from the cell all the way to the body and even into society. Yes, our world is just another level of the function of the body. Some say that community is the definition of holism, but it is simply a logical and tangible extension of the body. It is an interconnected system of bodies that are trying to communicate with each other through all the same means and is definitely a component in our health.