Nervous system...

[soonny]

What is the main difference between the sympathetic and parasympathetic nervous system? They exert different effects, some excitatory and some inhiitory on various organs but I still don't understand how did the effects came about? What exactly is the sympathetic nervous system?

[Philtaz]

Both are part of the autonomic nervous system. Sympathetic produces generalised physiological responses and responds to stress, strong emotion, any threat e.g. fright or flight. It produces adrenaline and causes restriction of blood vessels. Parasympathetic are found at cranial and sacral levels of the nervous system. The responses to PS innovation are localised and specific for various parts of the body. It is concerned with the restoration and conservation of body energy and elimination of body wastes. It slows the heart rate and conserves cardiac energy.