What is the structure of autonomic nervous system?
The autonomic nervous system (ANS) is a part of the peripheral nervous system that controls the body's involuntary functions, such as heart rate, digestion, and respiration. The ANS is divided into two branches:
* Sympathetic nervous system (SNS): This branch of the ANS is responsible for preparing the body for physical activity and responding to stress.
* Parasympathetic nervous system (PNS): This branch of the ANS is responsible for slowing down the body and conserving energy.
The ANS is made up of a network of nerves and ganglia (clusters of nerve cells) that are located throughout the body. The sympathetic nervous system originates in the spinal cord and travels to the body through a chain of ganglia called the sympathetic chain. The parasympathetic nervous system originates in the brainstem and travels to the body through several cranial nerves and through a network of ganglia located in the walls of organs.
The ANS works by releasing neurotransmitters, which are chemical messengers that transmit signals from one nerve cell to another. The main neurotransmitters of the sympathetic nervous system are norepinephrine and epinephrine (adrenaline). The main neurotransmitters of the parasympathetic nervous system are acetylcholine and nitric oxide.
The ANS is important for maintaining homeostasis, or the body's internal balance. By regulating involuntary functions, the ANS helps to keep the body functioning properly.