The internal surface area of the gastro-intestinal tract has long been considered to be between 180 and 300 square meters. Scientists at the Sahlgrenska Academy have used refined microscopic techniques that indicate a much smaller area.
“Actually, the inner surface of the gastro-intestinal tract is only as large as a normal studio apartment,” says scientist Lars Fändriks.
The digestive tract, which passes from the mouth through the esophagus and onwards through the intestines, has a length of about 5 meters in a normal adult, and is built up with many folds and protrusions.
Previous calculations, which are reproduced in reference works and textbooks, state that the area of the inner surface of the digestive tract is between 180 and 300 square meters – as large as, or even larger than, a tennis court.
A new study from the Sahlgrenska Academy, published in the Scandinavian Journal of Gastroentorology, shows that these figures are wrong.
Scientists Lars Fändriks and Herbert Helander have used quantitative microscopic techniques to determine that the surface area of the gastro-intestinal tract in healthy adults is “only” between 30 and 40 square meters.
By far the greatest part of this is the small intestine. The area of the large intestine is approximately 2 square meters, while the mouth, esophagus and stomach amount to less than 1 square meter.
Half of a badminton court
Lars Fändriks finds it surprising that the area of the gastro-intestinal tract is not that of a tennis court, rather half of a badminton court.
“It may appear to be simply a curious fact, but the dimensions of the inner surface of the gastro-intestinal tract are important for the uptake of nutrients and drugs, and the new information will help us understand how the mucous membrane protects the body from harmful factors in the intestinal contents,” he says.
The Gothenburg scientists explain how the previously erroneous results were arrived at:
“The gastro-intestinal tract is a dynamic system that is difficult to access in the abdominal cavity, and this makes it difficult to measure. Since the past measurements were carried out either during post mortems or during abdominal surgery, when the tissue is relaxed, it is easy to obtain misleading measurements,” says Herbert Helander.
The two scientists from Gothenburg have used data from radiological investigations, supplemented with studies of the microscopical structure of the gastro-intestinal tract, where they have used endoscopes to obtain samples of the mucous membrane of the intestines.
The scientists emphasize that the new dimensions are valid for a healthy “average” adult: the length and surface area of the digestive tract differs from person to person. In addition, the measurement for an individual is probably affected by diet and lifestyle.
“From an anatomical point of view, 30-40 square meters is more than enough for the uptake of nutrients. Furthermore, the smaller area is actually quite logical, since it means that the risk of effects from the intestinal contents is lower,” says Herbert Helander.
The article Surface area of the digestive tract – revisited was published in the Scandinavian Journal of Gastroenterology on 2 April.
Link to the article: http://informahealthcare.com/doi/abs/10.3109/00365521.2014.898326
FACTS ABOUT THE DIGESTIVE TRACT
The principle function of the digestive tract is the digestion of food and the absorption of nutrients. The tract is also an important “detection point” for the body’s immune system. Both of these functions require a large surface area. On the other hand, the intestinal contents contain toxins that have accompanied the food, as well as bacteria, which may cause disease. The mucous membrane of the intestines then functions as a barrier to these harmful factors – and in this case it is an advantage to have a small surface area.
Herbert Helander, Professor emeritus at the Sahlgrenska Academy, University of Gothenburg
Tel.: +46 300 74421
Mobile: +46 705 505139
Lars Fändriks, Professor at the Sahlgrenska Academy, University of Gothenburg
Tel.: +46 31 342 4123
Mobile: +46 70 592 2603
Krister Svahn | idw - Informationsdienst Wissenschaft
Punctuating messages encoded in human genome with transposable elements
04.08.2015 | Aelan Cell Technologies
Real-time imaging of lung lesions during surgery helps localize tumors and improve precision
30.07.2015 | American Association for Thoracic Surgery
Continuing current carbon dioxide (CO2) emission trends throughout this century and beyond would leave a legacy of heat and acidity in the deep ocean. These...
Glacier decline in the first decade of the 21st century has reached a historical record, since the onset of direct observations. Glacier melt is a global phenomenon and will continue even without further climate change. This is shown in the latest study by the World Glacier Monitoring Service under the lead of the University of Zurich, Switzerland.
The World Glacier Monitoring Service, domiciled at the University of Zurich, has compiled worldwide data on glacier changes for more than 120 years. Together...
Using ultracold atoms trapped in light crystals, scientists from the MPQ, LMU, and the Weizmann Institute observe a novel state of matter that never thermalizes.
What happens if one mixes cold and hot water? After some initial dynamics, one is left with lukewarm water—the system has thermalized to a new thermal...
Physicists from Regensburg and Marburg, Germany have succeeded in taking a slow-motion movie of speeding electrons in a solid driven by a strong light wave. In the process, they have unraveled a novel quantum phenomenon, which will be reported in the forthcoming edition of Nature.
The advent of ever faster electronics featuring clock rates up to the multiple-gigahertz range has revolutionized our day-to-day life. Researchers and...
Researchers have developed an ultrafast light-emitting device that can flip on and off 90 billion times a second and could form the basis of optical computing.
04.08.2015 | Event News
23.07.2015 | Event News
10.07.2015 | Event News
04.08.2015 | Information Technology
04.08.2015 | Power and Electrical Engineering
04.08.2015 | Materials Sciences