Humans are not only thinking animals; they are also eating animals. On average, we swallow as much as 500 kg of food yearly. We are so dependent on our stomach that the Roman physician Galen believed this organ to be an animate creature living within us. He thought it is capable of feeling the emptiness within us that encourages us to look for food. If we exist because we eat, then we need to know more about our digestive system.
1.Digestive Tract And Small Intestine
Your digestive tract is a kind of 9-meter long tube, which starts in the mouth and ends in your anus. In your small intestine there are so many folds, including the most microscopic ones, that the total area of its surface when strengthen out will be about 250 square meters. You can cover a whole soccer field with it!
2.When Does Digestion Begin?
Digestion begins even before you sat down and started to eat. The mere sight and smell of food triggers the production of saliva and digestive juices. So, when the first morsel of food is placed into your mouth, all the digestive system immediately begins to work actively.
3.Digesting Holiday Dinners
We need about 72 hours to digest such holiday dinners as those cooked on Thanksgiving and Christmas. First from what we have just gulped down we digest carbohydrates, such as cakes and pastries. Then comes the turn of dry overcooked protein contained in baked turkey or chicken. The longest we digest fats such as sauces and whipped cream from a cake or ice cream.
4.Mouth And Saliva
Our mouths perform a kind of neutralizing function. They either cool or heat the food we have in them to a temperature that is acceptable to the rest of the digestive tract. Regardless of whether we are using now our mouths to get food to the right temperature, we are producing saliva. Every day we produce about 1.7 liters of it. Saliva is regulated by autonomic system, which means that the process occurs automatically. This is the reason why we get our mouths full with saliva even if we only think of food or see it served.
5.Muscle Contractions and Stomachs.
Muscles of our digestive organs are contracted in a wave-like way. This kind of muscle contraction is called peristalsis. Because muscles in our digestive system are contracted like waves, food gets into our stomachs whatever position we assume. Even if we eat hanging upside-down, food will get where it needs to. Another interesting fact about our stomachs is this: they have huge capacity. The average adult stomach can contain about 1 liter of food.
Hydrochloric acid is the main digestive juice in our digestive system. It is so strong and caustic that it can dissolve metal items, in case we decide to swallow them. Yet if we munch plastic toys, pencils, and hair, these items will get out the other end of the digestive tract almost unchanged.
The main hormone of happiness, serotonin, is produced not in the head but in the stomach. We really depend on our stomachs for our happiness.