The Enteric Nervous System: An Expanded View of the Spleen and Stomach

The Enteric Nervous System (ENS) is the most extensive and intricate part of the Autonomic Nervous System (ANS), consisting of approximately 400-600 million neurons. Present in two primary networks—the myenteric and submucosal plexuses—the human ENS begins its development during the gestational period and experiences its most active growth state peri-natally through the first year of life. (Waxenbaum JA, [Updated 2023 Jul 24])The ENS receives both sympathetic and parasympathetic innervation and manages the entire pathway for digestion of food and drink, referred to in Traditional Chinese Medicine (TCM) as the production of post-natal Qi. This process starts with a series of ganglionic plexuses following the digestive tract from the trachea to the anus.

Parasympathetic innervation is crucial for maintaining the ENS, with the Sympathetic-Adrenal-Medullary (SAM) axis and stress hormones downregulating its function in response to external challenges. "Rest and digest," repair, and other parasympathetic functions become inhibited under fight-flight-freeze patterns.

As a component of the ANS, the ENS functions autonomously and independently of the central nervous system (CNS), earning it the title "gut-brain." (Waxenbaum JA, [Updated 2023 Jul 24])
The ANS communicates with the individual organs by way of ganglionic plexuses in each of the Zang (Yin) Organs.  These plexus become the basis for the Zang organ function,  while the somatic nervous system supports the meridian relationships described in the classics. 
Examples of the primary plexuses are below, but this is only a sample.  A nerve plexus is a cluster of nerve centers with both sympathetic and parasympathetic nerve endings. The plexuses are myriad, and include plexuses in all of the Zang organs, but also larger plexuses which are representative of the three jiaos. They are essential for maintaining homeostasis and facilitating numerous bodily functions.
Here are some instances of plexuses along with their alignment with Traditional Chinese Medicine (TCM) meridians, although this compilation is not complete.

Plexus	Governs	TCM Correspondence
Cardiac Plexus	Controls the heart	Heart meridian
Celiac Plexus (Solar Plexus)	Governs the spleen and stomach	Spleen/Pancreas/Stomach meridians
Superior Mesenteric Plexus	Regulates the small intestine	Small Intestine meridian
Inferior Mesenteric Plexus	Manages the large intestine	Large Intestine meridian
Pulmonary Plexus	Manages the lungs	Lung meridian
Esophageal Plexus	Manages the esophagus	Qiaos
Hepatic Plexus	Controls the liver	Liver meridian
Gastric Plexus (Ventral Vagal Trunk)	Governs the stomach	CHONG

Expanding Traditional Chinese Medicine (TCM) theory to include modern neuroscience provides an opportunity to unveil the interconnectivity of the body's systems.

 Attrition: Henry Vandyke Carter, Public domain, via Wikimedia Commons

In "Chinese Acupuncture," George Soulié de Morant (GSM) characterizes the gallbladder, encompassing both the organ and channel, as embodying the entire biliary digestive process. This includes the bile duct, secondary hepatic recirculation, and Oddi's sphincter (Soulié de Morant, 1994). Building on this idea, we can broaden our understanding of the Spleen's function of transformation and transportation to incorporate not only its role in the pancreas secreting insulin but also parasympathetic activity and digestion within the middle jiao. GSM describes the spleen-pancreas relationship as intrinsic and interconnected, similar to the biliary system.

The spleen's roles in transformation and transportation (T&T) are interconnected with insulin function. Insulin-induced cell activation (transformation) facilitates glucose uptake and utilization in muscle and adipose tissues, while innervation of smooth muscle tissue supports peristalsis (transportation). The transformation is making it a living substance that our bodies can take in for nourishment. Furthermore, insulin impacts protein synthesis and fat storage from the liver, underscoring its importance in maintaining glucose homeostasis and overall metabolic function.

In our analysis, we can compare the spleen and stomach in Traditional Chinese Medicine (TCM) to the Enteric Nervous System (ENS). Notably, many sympathetic ganglia in the trunk align closely with parts of the Stomach channel, emphasizing the interconnected nature of these systems.

Indeed, the lower command points on the leg yang Ming channel (ST 37, 38, 39-40) mirror the entire digestive process and waste elimination, reflecting the sympathetic aspects of digestion from the trachea to the anus. The Stomach channel and organ embody the complete sympathetic role in digestion. Furthermore, the tibial aponeurosis is indicative of vagal tone quality through the stomach, with many clients exhibiting not only complete spasticity but also adhered tissue to the tibialis anterior muscle.