Understanding the Digestive System: The Gastrointestinal Tract
You need to understand the functions of your gastrointestinal tract if you want to comprehend how surgery for weight loss works. The absorption of nutrients happens because a variety of enzymes and digestive juices are introduced into the gastrointestinal tract at very specific stages as the food you eat passes through it. Anything that is not absorbed needs preparation in order to be eliminated. Below, you will see a simple gastrointestinal tract description. You should obtain a description with more detail from your doctor to gain a better understanding of how the surgery for weight loss works.
- Food moves to the stomach from the mouth through a long muscular tube known as the esophagus.
- All of the organs of digestion are contained in the stomach.
- At the top of the abdomen, the stomach sits. After a single meal, this organ normally holds just 1500 ml of food. To assist with digestion, an acid in the stomach is produced and mixed with the food. Other digestive juices, in addition to the acid, work to break down the carbohydrates, fats, and complex proteins into units that are smaller and more absorb-able.
- The food is allowed into the stomach by a valve located at the stomach entrance. This valve also prevents food mixed with acid from going back into the esophagus which is a sure recipe for pain and damage.
- Located at the entrance of the first section of the small intestine (the duodenum) and at the stomach’s outlet is a small round muscle known as the pylorus. The pylorus closes the outlet from the stomach so that food can be digested into a form that is more easily absorbed and smaller. The contents of the stomach are only allowed to pass into the duodenum after they have been digested properly which stimulates the pylorus to open.
- Most of the nutrient absorption takes place within the 4.5 to 6 meter long small intestine. The ileum, jejunum, and the duodenum are the three sections of the small intestine.
- Juices from the pancreas and bile made in the liver is mixed in with the food that makes its way into the first section of the small intestine, the duodenum. Absorption of most of the calcium and iron happens here.
- The section responsible for digestion is the jejunum which runs between the duodenum and the ileum in the small intestine.
- Finally, the ileum is the last segment of the intestine which is where the nutrients and vitamins such as A, D, E, and K that are fat soluble are absorbed.
- In order to keep the colon contents, laden with bacteria, from backing up into the small intestine, another valve separate the large from the small intestine.
- Firm stool is formed afte excess fluids are absorbed in the large intestines. When necessary, proteins may be absorbed in the colon.