The brain controls and coordinates all body function. You live your life through your nervous system. Think of it this way, if you severe the brain/body connection at the base of the skull, death is instantaneous. The brain is literally responsible for life. Now if you were to go farther down the spine and severe a nerve where it exits the spine, wherever that nerve goes, dies.
When there are twists and kinks in the spine (subluxations), they choke off and damage the nerves. Now whatever part of the body controlled by those nerves no longer functions properly. Chiropractors restore health through the process of adjusting the spine to reduce the damage to the nerves. This then allows your body's nervous (master control) system to restore normal physiological function.