We often perceive digestion as a straightforward process of food going in and waste coming out. However, the gastrointestinal tract - or alimentary canal -, also facilitates a vital process: providing the body with the nutrients and energy contained in the food we consume. The gastrointestinal tract covers a significant area of the body; it stretches approximately 7 meters in length from the mouth to the anus, extending through the oesophagus, the stomach and the small and large intestines on the way. It is also connected to the liver and the pancreas and, together, they ensure that food is converted into nutrients and that these nutrients are absorbed. Food takes an average of 24 hours to make its way through, aided on its journey by peristalsis, a combination of contraction and relaxation of the muscles along the wall of the gastrointestinal tract.
Did you know that, since the two ends of the gastrointestinal tract are open to the environment, the food inside it is actually considered as being outside the body?