The gastrointestinal system, mobile at the same time

Synchronization cycle

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to live in a spirit of fraternity is to freely express one’s personality, without imposing one’s opinions and beliefs on others. It is giving value to Life. Fraternal gestures are spontaneous and not calculated, coming from the heart they bring well-being to the one who gives them and the one who receives them.

Darkness cannot drive out darkness; only light can do that.
Hate cannot drive out hate; only love can do that.
Martin Luther King

The peculiarity of the gastrointestinal system is to be able, to digest, to absorb, to regulate unknown foods, in a short period of time and to provide energy to the body:

The delimitation to fulfill functions

The gastrointestinal system consists of a conduit -the digestive tract of about 10 meters starting from the oral cavity and extending to the anal canal, and associated glands.

The digestive tract includes:

  • The oral cavity: the tongue, teeth and salivary glands;
  • The pharynx: the throat subdivided into naso-pharynx, oropharynx and laryngo-pharynx;
  • The esophagus;
  • The stomach ;
  • The small intestine: the duodenum, jejunum and ileum;
  • The large intestine: the cecum, the ascending colon, the transverse colon, the descending colon, the sigmoid colon, the rectum and the anal canal.

The associated glands are:

  • The salivary glands: three major glands and thousands of tiny and microscopic minor salivary glands dispersed in the oral mucosa;
  • The liver: the largest gland in the body;
  • The gallbladder: stores and concentrates the bile necessary for the digestion of fats;
  • The pancreas: an exocrine gland (producer of digestive enzymes) and endocrine.

The digestive tract imposes the direction, order and speed of digestion of nutrients from the mouth to the anal canal, the glands intervene independently of the food bowl.

Active / passive duality

Certain stages of the digestion process involve an action on our part and are under the control of the central nervous system (CNS), while others are under the control of the autonomic nervous system (ANS) and we will be passive in carrying them out.

  • Brushing teeth eliminates food flows to prevent cavities. When the lower esophageal sphincter -a smooth muscle controlled by the ANS- loses its tone, it lets stomach acid go up, which can damage the health of the teeth.
  • We can decide not to swallow the food we have in our mouths. As soon as swallowing begins, the smooth muscles of the esophagus -under control of the ANS- will contract automatically to bring the food bowl down to the stomach. The stomach -itself made up of smooth muscles- will contract and the digested food will reach the duodenum, and continue on its way to be absorbed.
  • The bile, necessary for the digestion of fats, is produced by the hepatocyte cells of the liver. It is discharged into the bile duct, either it directly reaches the duodenum, or it goes into the gallbladder where it will be stored and concentrated. The liver produces about 900 ml of bile and the gallbladder has a storage capacity of 30 to 50 ml. The bile will leave the gallbladder under a stimulating effect resulting from the ANS and the hormonal system.
  • The anal canal is closed thanks to the tonic contraction of the internal anal sphincter -a smooth muscle under the control of the ANS, and the external anal sphincter -a skeletal muscle under the control of the CNS. When the rectum is distended by the feces, the internal sphincter relaxes, but defecation can only occur with voluntary relaxation of the external sphincter and contraction of the smooth muscles of the distal colon and rectum.

Even if the course of the digestive tract and the digestive functions are the same for everyone, the passive intervention of the autonomic and hormonal nervous systems means that the absorption resulting from the ingestion of the same food by two people, will not be not necessarily identical in the two organisms.

Mobility develops interactions

When the digestive tract of the embryo, suspended by the mesentery, begins to grow in length and in width, it undergoes a rotation on itself so that the intestinal length necessary for a complete digestion can be positioned in the constrained space of the abdomen.

As intestinal rotation and growth takes place, part of the intestine and associated digestive glands is pushed back to the posterior abdominal wall, adjoins it and merges with the posterior peritoneum, losing its meso and thus becoming retroperitoneal.

Other parts of the intestine keep their mesentery and thus continue to be intraperitoneal.

Here are the different parts of the gastrointestinal tract, in the order of intervention in the digestive system, and their relationship to the peritoneum:

of the gastrointestinal tract
Relation avec le péritoine
Jejunum and ileumIntraperitoneal
Ascending colonRetroperitoneal
Transverse colonIntraperitoneal
Descending colonRetroperitoneal
Sigmoid colonIntraperitoneal

All parts of the digestive system come from the embryonic digestive tract. Its transformation during embryogenesis – by rotations, plicatures, delimitations – means that one in two parts has retained its mesentery, or on the contrary has lost it.

Let’s use the inter-dependence of synchronized delimitation to live in the present moment:

If we consider Humanity as a human body,
where each of Us sets life in motion;

We can work together for common happiness;

Humanize the World,
we will get peace on Earth, like the harmony of a body.

Bibliographic reference:
– The information on the gastrointestinal is taken from the book « The Netter’s Anatomy Coloring Book », John T. HANSE, Elsevier Masson SAS, 2017 (the french version).

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