Peripheral nervous system is the nervous system besides the brain and spinal cord. It consists of sensory neurons running from stimulus receptors that inform the CNS of the stimuli and motor neurons running from the CNS to the muscles and glands - called effectors - that take action. It is subdivided to the sensory somatic nervous system and autonomic nervous system.
Autonomic nervous system- the part of the nervous system responsible for control of the bodily functions not consciously directed, such as breathing, the heartbeat, and digestive processes. Divided into the parasympathetic and sympathetic nervous systems.
Sympathetic nervous system- activates what is often referred to as the fight or flight response.
Parasympathetic nervous system- part of the involuntary nervous system that serves to slow the heart rate, increase intestinal and glandular activity, and relax the sphincter muscles