Nerves. God-carriers.

神経。Shinkei - is the word for a nerve.
The first kanji 'shin'　神 also can be read as 'kami' and is the kami in 神様 or God, and the jin in jinja 神社 or shrine/temple.　So, 神 is God.
The 'kei' in shinkei - 経　means among other things - 'to transport'.
The 72,000 naaDis in the human body, as seen by the ancient seers in China must have made their way into the formation of this compound.

In the seven dhaatus that make up our body (rasa, rakta, maansa, meda, asthi, majjaa, shukra), as documented in ayurveda, majjaa is associated with the kapha in the bone marrow and the nerves. This is the dhaatu closest to shukra or seminal fluid in terms of refinement and proximity to our essence. What our senses 'eat' gets converted into these dhaatus in steps of progressive refinement from rasa (plasma) [all English translations of the dhaatus are rather loose, because Ayurveda is a different model altogether - it becomes a bit like trying to write device driver code in Visual Basic], rakta (the cells in the plasma), maansa(flesh), meda(fat), asthi(bones), majjaa( the kapha oiliness that forms the marrow and nerves) and further the most refined part of what we consume is converted eventually into shukra or the purest essence of our reproductive fluids. The essence of this is further converted into ojas, among whose outward indicators are a strong immune system and a glow on the face and skin. (How am I aware of all this - I experienced this first hand - as I lost all my dhaatus and ojas, and NO modern medicinal model could explain why. They couldn't even correlate all the symptoms I was experiencing. My gut feel is that modern medical science, specifially, their methods of diagnosis and the models of the human body they use, hack problems at the level of 'if, then, while' loops even if a problem lies at the use case, requirement, design or architecture level. )

Our ahamkaara as we know it is like the tip of an iceberg, and it is not all 'bad' as it is made out to be. For it is responsible for maintaining the very existence of our mind-body complex. It is like a faithful servant making sure that all the internal processes that make up 'living' function properly, a guardian - it fights anything - 'idea', 'food particle', microbe, virus ... that attempts to violate the internal boundary of the digestive canal and the outer boundary of the skin, and all other such boundaries that make up our mind-body complex. The most subtle, refined, essence of this Ahamkaara, resides in the body in the lowermost chakra - and is also called the Kundalini. (link goes to a home page in the eecs dept. in Berkeley U.)

Now, I had heard about this Kundalini thing in 1994 when I was in my senior high school (XIth standard in India), when my first contact with praaNaayaama and yoga was through Shri. Anil Koparkar Guruji of the Rishi Samskriti Vidyaa Kendra and the Siddha Samaadhi Yoga program. At the time, I had scoffed at the whole thing, and said "I don't know what this energy thing means, praaNaayaam is 'breathing exercises' and all that is okay, but this energy-wenergy stuff, don't know man...". However in the last few years, among other things, I realized that not only can one experience this energy - but a lot of profound ancient knowledge has been relegated to esoterica, much to our detriment.

So, this energy eventually frees itself from the 'knots' or 'granthis' that make up our koshas  or our bodies. And it rises up through the central naaDi or the sushumnaa (whose visible manifestation is perhaps what you'd see running through the vertebral column).

These naaDis are sookshma. Not visible. Yet their sthoola roop, or visible interface of some of them is through the nervous system. (As far as visible goes, you may notice, neither are electrons or quarks. You know they exist because of the effects of employing the model on which their existence is hypothesised. When one confuses models with reality, and tries to masquerade it as real, it is perhaps Not a Good Thing(tm). Ancient Indian traditions had seen and synthesised models that were comprehensive, sustainable, complex and abstract.)

Anyways, the point here is that, these naaDis are the carriers of that which is the most refined in our body, our essence, our spirit. So refined that it was associated with the 'God' meme. NaaDis are the carriers of the spirit or God. And -this- is reflected in the everyday word that modern japanese doctors use to refer to the nerves or the nervous system. 神経。God-carriers.

Another instance of Indian and Chinese knowledge systems and culture being preserved by the everyday language.