Enteric Nervous System (ENS)

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The Enteric Nervous System (ENS) is Often overlooked.  It is a mini-brain (0.5% as many neurons as the brain, but five times as many neurons as in the spinal cord) capable of independent reflexes.  It is autonomous and connected to the brain via the parasympathetic and sympathetic nerve channels.

Your gut does indeed think (albeit in a primitive way), but it can’t communicate back to us like the higher brain cortex circuits.  It registers unhappiness and distress back to the unconscious brain, and similarly an unhappy unconscious brain can shut down the gut from its digestive duties.  The feeling of “butterflies in the stomach” comes from a stressed and nervous brain signalling its discomfort to the gut.  Many eating disorders (over-eating, under-eating, allergies – see anorexia and bulimia) are the result of stress which results from the brain communicating with the gut through the parasympathetic nerve channels.  There is significant communication from the ENS back to the brain via the vagus nerve – some estimates are that 80% of the signals across the vagus nerve is sensory information from the ENS being sent to the brain (what is it doing with all this information?).

Most of the body’s serotonin is created and stored in the gut, and hence disorders of the gut have a majority impact on our mood (see neurotransmitters).

The ENS (diagram below) has a very different structure from the brain.


As mentioned above in the section on the immune system, bacteria in the gut also plays a vital role in protecting the body from infection.  A strong population of “good” bacteria in the gut protects the body from infection by “bad” bacteria.  This is important as many germs enter the body through the mouth by way of food or drink, and the warm moist intestines is a great environment for them to reproduce and enter the blood.

The importance of these millions of good bacteria in maintaining body health is often overlooked, and the benefits of this symbiotic relationship in attaining enlightenment is taught by some spiritual organisations (eg Rosicrucians, BOTA).  The hallucinogenic drug DMT can also be produced by some types of gut bacteria, and this may be the experience they are referring to (in which case, it isn’t really enlightenment at all).