Understanding Your Gut

Basic Gut Anatomy

Esophagus

Abdomen

Stomach

Lower Esophageal Sphincter

Pyloric Sphincter

Small Intestine

Duodenum

Jejenum

Ileum

Ileal Caecal Sphincter

Colon

Introduction

Most people don't think much about their gut until it gives them discomfort. Even then subtle symptoms like heartburn, flatulence, loose stools, etc are ignored. They continue to ignore the signals that their body is giving them, sometimes for years, until they start to experience pain. Unfortunately, by the stage that pain is experienced sometimes there is serious underlying pathology that requires immediate attention. Minor symptoms are an indication that there is an underlying problem - don't ignore them.

Basic Gut Anatomy

The Gut as an Organ

The gut is a very complex organ. Despite what is taught at school, the gut does much more than just process the food that you put into your mouth. Indeed researchers are having to rethink the relationship of the gut to the rest of the body. For example the gut communicates with the brain and the immune system.

The gut is basically a production line working in reverse - taking food apart and absorbing what it can to provide the body the essential nutrients to function normally. The residue then passes to the rectum where it is evacuated.

A basic description of the gastrointestinal tract appears below.

1.   Esophagus

The esophagus is a long tube that moves the food prepared in the mouth to the stomach. Damage to the lower part of this tube due to the reflux of acidic contents from the stomach can lead to long term problems such as swallowing, Barrett's esophagitis, or cancer. 

2.   Abdomen

The abdomen contains all of the digestive organs. Symptoms of bloating or pain in the abdomen are not normal and should not be ignored.

3.   Stomach

The food entering the stomach is mixed with acid and enzymes. The acid environment and the mixing helps to breakdown complex proteins, fats and carbohydrates into smaller particles so that essential nutrients for our survival can be extracted further down the gut. The pH of the stomach is approximately 2. As we age or eat a diet high in refined carbohydrates the acidity of the stomach decreases. Consequently, digestion is impaired, minerals, such as iron, cannot be absorbed as well, food sits longer in the stomach and digestion is slower.

Nutrients normally absorbed by the stomach: water, ethyl alcohol, copper, iodine, flouride, molybdenum.

4.   Lower Esophageal Sphincter

This is the valve at the entrance to the stomach from the esophagus. It allows food to enter while keeping the acidic food in the stomach from "refluxing" back into the esophagus, causing damage and pain. This valve can be weakened by a poor diet, hence the problems with reflux often experienced when a person lies down after a meal. 

5.   Pyloric Sphincter

This is a muscular valve between the stomach and the duodenum (the first portion of the small intestine). This sphincter is important as it only allows food to enter the small intestine gradually so that the digestive enzymes and juices can do their work properly. 

6.   Small Intestine 

The small intestine consists of three parts: the duodenum, the jejunum and the ileum. In these three parts the majority of the nutrients that we need takes palce. Specific digestive secretions are mixed with food, and the nutrients are extracted and transported into the blood stream. Each section is quite specific in how it processes the food that we eat.

7.   Duodenum

This is the first section of the small intestine, where the food is mixed with bile from the liver and digestive juices from the pancreas. 

Nutrients normally absorbed by the duodenum: calcium, phosphorous, magnesium, iron copper, selenium, thiamine, riboflavin, niacin, biotin, folate, vitamins A, D, E, K, glycerol, fatty acids, monoglycerides, amino acids, monosaccharides, and disaccharides.

8.   Jejunum
The middle part of the small intestine.

Nutrients normally absorbed by the jejunum: glucose, galactose, amino acids, glycerol and fatty acids, nonoglycerides, diglycerides, dipeptides, iron, copper, zinc, potassium, calcium, magnesium, phosphorus, iodine, chromium, manganese, molybdenum, fat-soluble Vitamins A, D, E, and K, most of the B complex, Vitamin C, and alcohol.

9.   Ileum
The last portion of the small intestine.

Nutrients normally absorbed by the ileum: absorbs disaccharides, sodium, potassium, chloride, calcium, magnesium, phosphorus, iodine, the fat soluble vitamins A, D, E, K, vitamin C, B1, B2, B6, B12, and many additional nutrients depending on the transit time.

10.   Ileal Caecal Sphincter

This is a muscular valve which separates the small and the large intestines. This valve stops the passage of bacteria laden contents of the colon moving back into the small intestine. If there is any inflammation in the gut and involves this valve, then there is the real risk of bacteria from the colon moving up into the small intestine and causing an overgrowth within the small intestines.

11.   Colon (Large Intestine)
The colon, or large intestine can be divided into four regions, the caecum, colon, rectum and anal canal.

Nutrients normally absorbed by the colon: sodium, potassium, chloride, water, acids, gases, some short-chain fatty acids metabolized from plant fibers and undigested starch, and vitamins synthesized by bacteria (biotin and Vitamin K). 

Insufficient fibre in the diet and adhering to a refined carbohydrate diet can lead to constipation, diverticulitis, polyps and possibly colon cancer.

For advice or to book a consultation, call (03) 8802 7687 or email me.