Sympathetic and parasympathetic nervous system are the parts of autonomic nervous system. Autonomic nervous system is a part of peripheral nervous system that supplies stimulation via motor nerves to the smooth and cardiac muscles (the involuntary muscles) and to the glands of the body. The activity of the ANS is controlled principally by the medulla oblongata and hypothalamus of brain. Sympathetic and parasympathetic nervous system tend to work antagonistically on the same organ.