The sympathetic and parasympathetic nervous systems are the operations management team
for all the bits of your internal function and guts that you take for granted.
Together they are called the Autonomic Nervous System.
The most well known is the Sympathetic part, as it is the adrenaline response we are all aware of. The fabulous fight and flight response that gets you up and going, living in the fast lane, and getting things ticked off on that to-do list. While your heart and lungs speed up, and your muscles are tenser
and senses heightened, and you sweat more to get rid of all the heat generated by the increased metabolism – your immune, digestive
and reproductive departments are dampened down, all long term projects that are not needed in the immediacy of the sympathetic
But the other part is an extraordinary system, the Parasympathetic. [I wish there was a different word than ‘Parasympathetic’, to act as a magnet of people’s interest towards this amazing system.]
When you activate this it is like plugging your body into a recharger. Your digestive, reproductive and immune systems are heightened and the parts of your brain that do creativity, lateral problem solving and new ideas are more active.
The word Parasympathetic is because ‘para’ means alongside, as while the sympathetic nerves travel from the brain to the body via the thoracic spine the parasympathetic enters the body from the brain either side of that. it comes from above it by a nerve from the brain and below it from nerves in the sacrum.
The 2 mostly work in opposition to each other,
and these 2 pictures show the nerves coming
out and going to the different body parts.
The green one shows the sympathetic nerves
coming from the thoracic area to the organs via
one of the sympathetic chains. These are 2
chains of nerve fibres that look like a string of
pearls tucked up against the ribs, one either
side of the spinal cord.
The blue one shows the vagus nerve coming from
the brain and a few parasympathetic nerves exiting
from the sacral area.
This picture is one of my hot favorites.
Sorry about the fuzzy words, but actually the words are very medical and not that important. I think the impact of this picture is that it shows in yellow, the passage of the vagus nerve from the brain.
It comes down the neck and enters the heart and lungs, and then intricately wraps itself aroung the oesophagus and passes through the diaphragm muscle with it into the abdominal cavity. Once there is goes to all the abdominal organs.The pelvic organs recieve their parasympathetic innervation via nerves that come down the spinal cord and exit at the sacurm.
No wonder the word ‘vagus’ means ‘wanderer’.
And actually the vagus is 90% spy. i.e. 10% of it brings messages from the brain to the body, but the rest tells the brain what is going on throughout the body. Big Brother is always watching.
Here is a chart that shows how the sympathetic and parasympathetic affect the different organs. You can see that the Sympathetic is perfect for increased excitement and activity while the Parasympathetic is for recovery and renewal. Perfect teamwork as long as we activate them both. I think people have forgotten how to do the Parasympathetic – so see my articles on learning to release tension and do easy nose-diaphragm breathing to learn how to enter Calm and activate it !
Here is a Footrot Flats [an iconic Kiwi cartoon] of Wal as always over-reacting and his neighbour Cooch, always chilled out, modelling each side of the Autonomic Nervous Sytem. [image used with permission of Murray Ball]
|Sympathetic Nervous System||Parasympathetic Nervous System|
|Pupil of the Eye|| Constrict to have a central focus
|| Dilatation to improve peripheral
|Nose mucous & Salivary glands||Reduced mucous and saliva||Increased mucous and saliva|
|Lungs||Muscles relax around the airways to bring in more air.||Airways back to normal size.|
|Heart||Beats faster and stronger||Decreased speed and strength|
|Blood Vessels|| Constrict, especially in one’s
| Dilate, so hands and feet feel
|Muscles|| Fight and flight muscles are
tense and have more blood.
| Back to normal tone over the
|Gut|| Less digestive juices, blood
supply and movement.
| Increased gut movement,
blood supply and juices.
|Immune System||Dampened down|| More active to fight intruders
and cancer cells
|Kidney||Less urine produced||Better kidney function|
| Bladder and Bowel
||The muscles relax and the openings tighten so you don’t feel like going to the toilet so often.||Back to normal function|
|Sweat glands|| Adrenaline stimulates more
|Respond to heat as normal.|