Physiology of the Autonomic Nervous System

The autonomic nervous systemAutonomic nervous system (ANS) is one of the most important systems in maintaining homeostasisHomeostasis of the human body. It is one of the two parts of the peripheral nervous systemPeripheral nervous system. The peripheral nervous system consists of the autonomic nervous system (ANS)Autonomic nervous system (ANS) and the somatic nervous system. The ANS controls automatic functions and responses such as heart rate and blood pressure. Understanding ANS physiology enables anesthesiologists to safely useMedications medications while maintaining homeostasis. The ANSAutonomic nervous system (ANS) consists of two major subsets of systems: the sympatheticSympathetic nervous system (SNS) and the parasympatheticParasympathetic nervous system (PSNS). This chapter will provide a comprehensive overview of the SNSSympathetic nervous system (SNS) followed by the PSNS. Each system overview will include a description of anatomyAnatomy, ganglionic transmissionGanglionic transmission, transmitter types, release, synthesis, storage, termination of effects, receptor types, effects, and, finally, reflexes and regulation. There will also be a brief discussion of the enteric nervous systemEnteric nervous system at the end of the chapter.