So far no one has an answer as to what causes irritable bowel syndrome (IBS). Until recently many “authorities” on the subject of irritable bowel felt that IBS was psychosomatic. This belief came about because IRS is a functional disease. That is there appears to be nothing wrong with the digestive system organs that affects colon health.
The symptoms however are very real if you are the one afflicted with irritable bowel syndrome. The symptoms vary from person to person One person may experience diarrhea while another may have constipation. Gas, bloated feeling, mucous discharge may be present in stools. Sufferers can also experience moderate to severe abdominal pain. Pain in the lower left abdomen can be so severe as to be debilitating. Then at times the symptoms can disappear altogether. The problem is that there is nothing visibly wrong that the doctors can see but the lower digestive tract just doesn’t work properly.
To understand irritable bowel syndrome and how it affects colon health it is necessary to get a basic understanding of how your digestive system works. The digestive system is essentially a long tube with mouth on the input end and anus at the output end. When food is taken into the mouth the digestive process begins. Food is chewed, mixes with saliva, and the first step in digestion occurs. Starches are broken down into simple sugars by the saliva in the mouth.
The chewed food is swallowed and enters the throat. An involuntary muscle contraction is triggered. The contraction, called peristalsis, occurs in all the smooth muscle organs of the body. The esophagus, stomach, small intestines, large intestines, and the female uterus are all smooth muscle organs and all perform the muscle contractions called peristalsis. This is important to note and will come into play again. Peristalsis moves food down the esophagus and into the stomach. Entry into the stomach is through a valve called the lower esophageal sphincter. The esophageal sphincter keeps gastric juices in the stomach and relaxes only to let food pass. The food is mixed by muscle contractions in the stomach and enzymes and stomach acid are added. After about 30 minutes the mixture, called chime, is ready to pass into the first part of the small intestine.
The small intestine is where most of the nutrients are absorbed from the digested food. The inside walls of the small intestine are convoluted and wrinkled. The wrinkles are called villi and on the villi are even more and finer wrinkles called microvilli. The villi and microvilli increase the surface area inside the small intestine through which the chime passes. The inside surface area is about the size of a tennis court. The villi are specialized as to what nutrients they absorb so there are many different variations of villi.
Remember the muscular contraction called peristalsis? Well it is that same involuntary contraction of the muscle walls that moves the food mixture through the small intestine. It takes a matter of hours for the food to move through the small intestine to the beginning of the large intestine.
Food passes from the small intestine and is pushed by peristalsis into the large intestine known as the colon. By the time the mixture reaches the colon it contains organic left over’s, indigestible fiber, bacteria, and about 25% water. The colon absorbs water from the left over’s. The waste moves into the last section of the large intestine called the rectum. This is the holding area for waste. Final phase is elimination through the anus sphincter muscle.
This is a quick overview of how the digestive system works. We are now getting to the irritable bowel syndrome and how it affects colon health. Remember peristalsis, the muscle contraction that moves the food down the entire length of the digestive system. Peristalsis is an involuntary muscle contraction. The muscles are controlled by the brain. The brain receives input information from the organs in the digestive tract. Nerves called receptors monitor the enzymes, chemicals, pressure, in the digestive system. The brain uses this feedback information to decide what to make the organs in the digestive system do. The brain sends signals to the smooth muscle organs to cause peristalsis to happen to move food down the digestive tract.
Now here is where the problem is. The smooth muscles are not doing what they need to be doing. The movement of food through the digestive system is either too fast or too slow. If the food moves too fast then diarrhea can occur because there will be too much water left in the waste. Also fast movement won’t allow enough time for the nutrients to be absorbed in the small intestine.
On the other hand, slow movement means that the mixture spends more time in the colon. The colon absorbs more water from the waste and it becomes hard and solid causing constipation.
Here is the difficult part. Does the digestive system function abnormally because the receptor nerves aren’t working properly? If the receptors send incorrect information to the brain then the brain uses that incorrect information to tell the digestive system what to do. So the brain tells the smooth muscle organs to function improperly because it received incorrect feedback.
Or is there something in the brain not right. If the brain receives correct signals from the receptor neurons and then provides incorrect function signals to the digestive system then the digestive results are again incorrect causing the IBS
Or is the problem with the nerves themselves? No body knows.
And here is something else to ponder. Neurobiologist Dr. Michael Gershon of Columbia University has discovered that the stomach and digestive system has as many neurons as the brain and he suggests that the stomach not the brain controls digestion. Perhaps even the stomach may be causing the irritable bowel syndrome problem.
The fact is that we just don’t know what causes the incorrect function of the smooth muscles in the digestive system to occur. We just don’t know what causes irritable bowel syndrome.