Theautonomic nervous system (ANS) controls involuntary functions and is comprisedof the sympathetic nervous system (SANS) which stimulates organs for fight orflight actions and the parasympathetic autonomic nervous system (PANS) whichslows down bodily processes for rest and digesting.
The basiccomponent of the SANS and PANS are the same but differ in their physicalstructure. Signals released by either one have to cross two synapses in orderto reach their desired effector. The neurons travel from root in the spinalcord down axons to the synapse within the ganglia where it is then redirectedto the effector organ where it synapses again to create the signalled response.The difference between the two systems is that they originate at different sightsthe SANS can be found in the thoracolumbar area where a network of nervesradiates from the spine whereas the PANS is located at the craniosacral.Theganglia of the SANS trigger action potentials to other neurons in turnsignalling messages to multiple effectors, the preganglionic cell fibres arealso shorter than their post ganglionic enabling the signals to reach further.
The ganglia of the PANS however is located nearer to the organs that it isserving and extend from cranium andsacrum, their preganglionic cell fibres are therefore longer than their postganglionic enabling them to specific strategic signals at time of rest whenenergy is available. SANSis a vital system needed when faced with fight or flight scenarios but the samephysiological responses can be released in situations of non-immediate stress. Whenyour body exhibits stress two chemicals could be released and the substanceeffect is variable on the location where it is received. The chemicals arereleased via neurotransmitters as part of the nervous system and are createdthen released from the neurons themselves to communicate with the effectororgan across a synapse, or through hormones as part of the endocrine system andare secreted though glands and flow through the bloodstream.