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The Brain in the Intestine and Pets in Our Body
Mar 1, 2019

We eat, sleep, and go to the bathroom. Yet, we never think about how all these physical needs are processed in the systems of our body when they are functioning normally.

Yes, our bodies are created with perfect systems by which our all kinds of needs are met. The digestive system is one of them. Our intestines are key elements of this system, so much so that asking someone “How are your intestines?” would be as comprehensive as asking “How are you?”

Digestive system

Food is critical to life. A human being can bear hunger for one month at most and can only endure a few days of drought. Thus, eating and drinking is crucial.

Foods as we eat them are not convenient for use by the cells. Food must be broken down into smaller pieces. This process begins in the mouth and ends at the anus, and it is called digestion.

The main task of our stomach and intestines is digestion. The teeth, salivary glands, the tongue, and the gullet – as well as swallowing – are essential secondary elements. Additionally, if the pancreas or liver fall ill, it can paralyze the whole system. While also working with the circulatory system, kidneys have the task of reabsorbing useful substances like glucose, amino acids, and water.

Our digestive system works together with the urinary system and the digestive organs like a factory. How these parts work together is still not fully understood, but more detailed research has been performed and revealed more secrets of the digestive system. By means of every discovery, it is realized that this perfect creation has a more intricate structure than is known.

The brain in the intestine

There are more neurons in our intestines than in our spinal cord and the intestines are created in a way that can move independently from the central nervous system. They have their own nervous system, known as enteric nervous system (ENS), which is also called the “second brain. “Within those yards of tubing lies a complex web of microcircuitry driven by more neurotransmitters and neuromodulators than can be found anywhere else in the peripheral nervous system. These allow the ENS to perform many of its tasks in the absence of central nervous system (CNS) control…” [1]. Thus, “… isolated segments of intestine can independently coordinate propulsive movements and propel content without any neural connections to the brain or spinal cord [2].

The intestines take action when food comes into the stomach. This movement is known as colonic migrating motor complexes (CMMC), and it moves the substances that cannot be digested, like bone and fiber. According to neurophysiologist Nick Spencer et al, “The gut wall contains a complete network of intrinsic nerves capable of propelling contents along the bowel, without any requirement of nerves originating in the brain or spinal cord” [3].

Eat different types of food

70% of our immune system cells are in our intestines. A big part of the approximately 38 trillion bacteria in our body are in our intestines, and they are useful; they have a big role in digesting food. Different groups of bacteria feed on different types of food; so for intestinal flora it is very important to have a variety of food on our table. For the ideal day on a plate Dr. Megan Rossi recommends people should “aim for at least 30 different plant species per week.” “The reason for this is that each plant contains different types of fibres and phytochemicals (the super healthy components of plants) that feed different good bacteria. The more plant variety, the more variety of gut bacteria - which is associated with health and happiness” [4].

Pets in our body

For Dr. Megan Rossi, “microbes are like our pets, so you have to take care of them and feed them” [5].

Of course, germ flora in our body is not just limited to the ones in the intestines. Bacteria, viruses, and fungi in our body are nearly scattered throughout the whole body. These living things produce pellicle on our head skin, irritate the gaps between our toes, live on our skin, are on duty among our teeth, and have ecosystems and assigned positions convenient to them. According to the situation, they keep their living spaces healthy or unhealthy. Although they number 50 trillion, they are approximately 200 grams of our body weight.  

Useful microbes

An average size human adult houses about 1012 bacteria on the skin, 1010 in the mouth, and 1014 in the gastrointestinal tract [6].

These microorganisms are useful microbes with duties in our body. The harmless flora of microbes is generally present on the skin, mouth, teeth, nose, throat, and bowel and genital areas. There isn’t normal flora in internal organs except the large bowel. Internal organs have no microbes. If we look closely, flora is inserted in every part of our body which is dirty and has contact with the outer environment. If it was not for the useful flora, microorganisms causing illness would settle instead. Only intestinal bacteria are permanent microbes which are useful. For example, vitamin K plays a part in a crucial event like blood clotting and is produced in the intestine.

Control your stress

Research has revealed that mental and psychological stress affects the health of the intestines. Serotonin is produced automatically in case of need, and 85% of it is produced in the digestive tract. Stress suppresses the level of serotonin produced. Psychological illnesses are associated with low levels of serotonin.

Studies have shown that relaxing practices like meditation for 15-20 minutes can be good for health and reduce stress. At this point, daily prayers are a kind of therapy. Other ways to stay healthy include: avoiding things like alcohol and caffeine, and sleeping well.

Our body has ways of telling us when it’s not healthy. For instance, we can learn the digestive tract isn’t healthy if we have to use the toilet more than three times a day and fewer than three times a week.


  1. Gershon, Michael D. “The Enteric Nervous System: A Second Brain.”
  2. Spencer et al. 2018. “Identification of a Rhythmic Firing Pattern in the Enteric Nervous System That Generates Rhythmic Electrical Activity in Smooth Muscle.”