voluntary

voluntary Done in accordance with the conscious will of the individual. The opposite of voluntary is involuntary. The terms voluntary and involuntary apply to the human nervous system and its control over muscles. The nervous system is divided into two parts: somatic and autonomic. The somatic nervous system operates the skeletal muscles, which are under voluntary control. The autonomic (automatic, or visceral) nervous system regulates individual organ function and is involuntary. For example, opening the mouth is voluntary, and blushing and the beating of the heart are involuntary. See also autonomic nervous system.