innervated fascial sheaths such as the diaphragms . Let us explore the anatomy and physiology of the ENS and its close relationship with the ANS and CNS at greater depth . The better informed we are as bodyworkers about the anatomical and physiological features we are working with , the deeper our touch can reach and the more precise and effective it can be .
Bodywork is potentially a very important tool which can return balance and better functioning to an imbalanced ENS , thus directly influencing the communication pathways of the ANS to improve its self-regulation ability and its inherent resilience .( 2 ) This in turn can influence the level of wellbeing that the client is experiencing mentally , emotionally and physically .
An understanding of any part of the human body is greatly enriched by an investigation of its earliest embryological origins . As highlighted by Blechschmidt ,( 3 ) developmental history expresses functionally in each organ and skeletal structure from conception to death . This applies particularly to the digestive tract and its ENS dynamic , as this realm is functional but not yet fully developed at birth , and is therefore very susceptible to early post-birth experiences that imprint on its future functional expression .
Anatomy and physiology of the ENS
Gershon ( 1 ) states that even though the ENS is partly formed by the inherent components present in the early embryological gut tube , a significant part of it is formed from the embryonic neural crest , which arises in the third week of embryonic development . Cells migrate from three very specific regions of the neural crest to form and shape the digestive tract :
( i ) At the level of the crest just below the developing ears of the embryo , next to the developing hindbrain , we find the vagal region of the crest . The neural crest cells migrate from the vagal area to the bowel along a pathway that is later followed by the actual vagus nerve . These vagal crest cells colonise the entire oral-to-anal extent of the gut .
( ii ) A second set of neural crest cells travels from just above the tail of the embryo , the sacral region of the crest , and colonises the hindgut below the umbilicus .
( iii ) The oesophagus receives the third infusion of crest cells , which migrate from the level inferior to the vagal crest .
In addition to the above three regions , the microenvironment of the gut itself contributes to the development of the ENS . Healthy embryological dynamics are an essential foundation for a robust digestive tract . Electron microscopy shows that the ganglia within the ENS are brain-like , rather than exhibiting the structure of peripheral nerves .( 4 ) These structures have evolved sufficiently by full-term birth to be functional . Viable life completely depends on having a sufficiently functioning ENS ; however , it is still developing and evolving in post-natal infants . Early experiences of a young digestive system will therefore have an impact on the second brain that develops within it . This is a substantial reason for encouraging gentle bodywork treatments for early infants .
Functional bowel diseases , including irritable colon , may well have developmental origins directly influenced by the immune system . The nervous system works so closely with the immune system in defending the gut that the developmental interaction between the two are likely to be a significant formative influence on the ENS and the entire digestive tract .
There are many good reasons why the enteric realm has evolved to be as independent an operator from the CNS as it is . The assimilation and absorption of vital nutrients gained from the food that we consume is a biochemically highly complex process which requires a system of sensors that can constantly evaluate conditions . ‘ So much nervous horsepower is involved in getting the gut to operate properly that it makes good sense for evolution to have put the requisite brain right in the organ itself .’( 1 , p19 )
Neurotransmitters that were thought only to be brain-based are present in the gut to a significant degree : serotonin , dopamine , GABA , acetylcholine to name but a few .( 1 ) The same applies to neuropeptides such as substance P ( biochemical units which carry our emotional experience ), interneurons and glia — all creating a nerve plexus of a complexity that is second only to the brain .( 1 )
In addition to the key role it plays in food absorption , the entire digestive tract is also a very important part of our immune system . The digestive tract is essentially an open tube from the mouth to the anus that permits the external world to flow right through us . The vital nutrients required for survival are absorbed by specialised cells within the walls of our digestive tract , only then to enter our body . Pathogenic bacteria and viruses , which might be contaminating the items we swallow , are in turn prevented entry to the GIT by the prominent presence of immune cells which are regulated by the autonomous decision-making processes of the ENS .( 1 )
It is interesting to note that our CNS is directly involved with the acts of swallowing and defecation ; however , all other digestive function occurring from the oesophageal sphincter to the junction point between rectum and anus ( with the exception of the pyloric sphincter , which is governed by the CNS via the vagus nerve ), is entirely regulated by the ENS and can continue operating even if the owner of that GIT were to be brain-dead .( 1 )
The ENS is the master conductor of all digestive processes , which are not merely a simple deposit of digestible material into a pipe filled with digestive
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