Autonomic System: Understanding Sympathetic & Parasympathetic Impulses

[rashida564]

what does mean "Both the sympathetic and parasympathetic systems relay impulses to thesame organs, but the overall response depends on the intensities of the opposing"

 

[BillTre]

The sympathetic NS, generally speaking, signals various tissues and organs to change their functioning and metabolism to a state more appropriate for more active behavior. Its might be involved in flight or fright responses (in the extreme).
The parasympathetic signals direct tissues to chill out, relax, and do digestion.
These are kind of behavioral opposites so the two inputs are, in some way, weighted at the target organ(s), resulting in some level of arousal, at or between the two extremes.

 

[Fervent Freyja]

The body strives for a balance with opposing signals in the two systems. They are sent through different pathways: The cranial nerves are the pathways for the PSNS signals and the spinal nerves are the pathways for the SNS signals. They normally balance each other out; however, a difference in 'intensity' of signalling will trigger a feedback response cycle and one system will dominate over the other. Think about long it takes to calm down when upset, or how long it takes to gather some energy upon waking.