1. The autonomic nervous system
Stellek Bálint Sándor
The autonomic nervous system (ANS) is a division of the peripheral nervous system (other division is somatic nervous system)
It influences the function of internal organs
It acts largely unconsciously
It regulates bodily functions such as heart rate, digestion, urination, respiratory rate etc.
Within the brain, the ANS regulated by the hypothalamus
The peripheral nervous system (PNS) is the part of the nervous system that consists of the nerves and ganglia outside of the brain and spinal cord. The main function of the PNS is to connect the central nervous system (CNS) to the limbs and organs, essentially serving as a communication relay going back and forth between the brain and spinal cord with the rest of the body. Unlike the CNS, the PNS is not protected by the bone of spine and skull, or by the blood–brain barrier, which leaves it exposed to toxins and mechanical injuries.

2. The autonomic nervous system is divided into two part:
Sympathetic nervous system
Emerges from the spinal cord in the thoracic and lumbar areas ("thoracolumbar outflow”)
Parasympathetic nervous system
It has “craniosacral outflow”, meaning that the neurons begin at the cranial nerves and sacral spinal cord.

3. Sympathetic nervous system
It’s primary process is to stimulate the body's fight-or-flight response
And it constantly active at a basic level to maintain homeostasis.

4. Parasympathetic nervous system
The parasympathetic nervous system (PSNS) is the other divisions of the autonomic nervous system
The parasympathetic system is responsible for stimulation of "rest-and-digest" or "feed and breed” activities.
These occur when the body is at rest, especially after eating, including sexual arousal, salivation, lacrimation (tears), urination, digestion and defecation.
It has 3 main division (nerves): Cranial nerves, vagus nerve and pelvic splanchnic nerves

5. Two kinds of neurons involved in the transmission of any signal through the sympathetic and parasympathetic system: pre-ganglionic and post-ganglionic
Ganglion is a nerve cell cluster or a group of nerve cell bodies located in the autonomic nervous system. Ganglia house the cell bodies of afferent nerves.
In the sympathetic and parasympathetic nervous system, efferent nerve signals are carried from the central nervous system to their targets by a system of two neurons.
The axons of preganglionic parasympathetic neurons are usually long, extending from the CNS into a ganglion that is either very close to or embedded in their target organ (sympathetic is the opposite).