For convenience of understanding, we have names for each bit of us and its function.
But we have to remember that the distinction is imaginary.
Your mind is essentially brain activity. And brain is a bit of your body.
Walking is a leg activity. And leg is a bit of your body.
What you eat, when and how much have a direct effect on how you think.
When you exercise, how much you exercise, when you rest, how much you rest all this effects your mental capacity.
Similarly your thoughts affect your health. A good mind helps one stay alive longer.
Your body and mind are One.
Thinking they are separate is useful in many ways – but it is Not-a-Fact.
Synaptic transmission
Picture from Wikipedia (http://en.wikipedia.org/wiki/Chemical_synapse)
