A Journey Through Our Large Intestine

Kirstie takes us on an educational tour of our digestive system

When clients see me for the first time, they often are not sure about the workings of the digestive system or where in the body the stomach, small and large intestines are positioned. I remember in my biology lesson at school having to draw an outline of a person and each of the organs in the place where we thought they were. I have to say, this was certainly a steep learning curve for me! I thought the stomach sat like a balloon in the central part of the body, with the other organs kind of just positioned around this- the gut wasn't even included. Well, I came to discover this certainly is not the case, and it is in fact the large and small intestines that occupy a huge proportion of the abdominal area! Knowing the positioning of these really helps to understand where we are feeling discomfort at times in the times we do. The large colon (intestine/ bowel) sits like an upside down horseshoe below the rib cage, with the small intestine all folded up within it and the stomach sitting up towards the left hand side, with the liver on the right. After food passes through our stomach and through the long winding tubes of the small intestine, the remaining material, mostly waste products in liquid form, move in to the colon. The colon is approximately 6 feet/ 1.5m long and aims to absorb water from the waste products through its walls. The muscles on the outer wall of the colon create wave-like contractions (peristalsis) which move the stool along. The colon begins at the lower right hand corner of the abdomen, where it's called the caecum. It is sometimes here that we can feel discomfort as this is also known as the 'bag of worms', and where most of the bacteria lie, and if we are experiencing an imbalance in gut bacteria, this area can feel uncomfortable. This area is also where the appendix is attached, which has been found to form part of the immune system. The colon then travels up the right side of our abdomen, then when it reaches our lower right ribs (just below the liver), it turns at a right angle to travel across the abdomen to just below the lower left ribs- from where it makes another turn and travels down the left side of the abdomen. The colon then makes one last turn toward the middle of the lower abdomen, forming an "S" shaped segment (called the sigmoid colon) which empties waste materials into our rectum, which stores faeces until contractions in the large intestine stimulate a bowel movement. It is also in the sigmoid colon that waste matter can accumulate if not released, and why the left hand side of the lower abdomen can become tender to the touch. Waste is stored in the rectum until a contraction is triggered and it is excreted via the anus. However, if we choose not to release stools when we experience the urge to do so, our reflex contractions may stop, in which case we won't be likely to have a significant bowel movement until the next mass peristalsis occurs. On average, the colon experiences anywhere from three to twelve moderate waves of contractions every minute. After every substantial meal, the colon experiences a much larger contractile wave, called "mass peristalsis" which pushes waste materials from the transverse colon (which lies under the ribs) all the way to the rectum. To have healthy bowel movements, mass peristalsis would occur about three times a day. The colon normally absorbs around 10 percent of water from our food and drink (the rest being done in the small intestine), which amounts to anywhere between a pint and two pints of water, so represents a significant portion of the body's daily intake of water. Some nutrients are also absorbed in the colon, mainly minerals like sodium and chloride. It takes anywhere between three to ten hours for the large intestine to absorb enough water from waste material to turn it into solid or partially solid stools. Our stools consist mainly of water, mucous, fibre, old cells from the intestinal lining, old blood cells and millions of microorganisms. The position of the colon and its individual parts with different functions means that congestion can occur more often in certain areas, which can cause us discomfort. Self massage on your tummy from lower right, up and around to lower left can help to ease discomfort and can be done whilst on the toilet. All the movement that should naturally occur due to the contractions that take place helps to explain the gurgles and noises that are made in our tummy with all of that matter moving around. So it really does like to talk to us to remind us it's there!