Digestion and enzymes


Enzymes are large protein molecules which act as catalysts to accelerate the chemical reactions of digestion.

If not for the enzymes, not only digestive, chemical reactions in the body would not be fast enough for the body to perform its functions.

After years of research, it is known that almost all body complex chemical processes are initiated and controlled by the activity of the enzymes.

The digestion in the mouth and amylase

The first enzyme in the digestive process that comes into play is salivary amylase. When food enters the mouth, the salivary glands occurs in small amount of this enzyme.

It acts on a part of the starch present in the food and breaks down starch into smaller molecules. Amylase is an enzyme that fails to operate in an environment such as stomach acid, but its effects last until juices acids penetrate inside the food pellet that had formed in the mouth.

The protein digestion in the stomach and pepsin

When the food reaches the stomach is pepsin. This enzyme is responsible for the partial decomposition of the long molecules of the protein more assimilable amino acids. Pepsin to implement the action of decomposition need a highly acidic environment, and this is right in the stomach. In the stomach is another enzyme, renin, clotting casein, milk basic protein.

The protein digestion in the duodenum and pancreatic enzymes

When the bolus reaches the duodenum, is attacked by a battery of enzymes produced in the pancreas and duodenum and the walls of the intestine. All these enzymes need a slightly alkaline to do its work. Thus, the mixture of stomach acid is converted by alkaline juice poured the pancreas into the duodenum through the ampulla of Vater.

The pancreas also produces two other enzymes: trypsin and chymotrypsin. These enzymes are decomposing proteins into shorter sections loose amino acids that can be absorbed by the small intestine. But the process is so complex that in reaching its conclusion needed two enzymes: peptidase and dipeptidase produced by the intestinal wall.

However, in this process the digestion of proteins is a curiosity. The pancreas as most proteins consists organs. If pancreatic enzymes within the pancreas were excreted in active form, could digest the pancreas itself or the tube that connects the pancreas to the intestine. To prevent this from happening the pancreas produces enzymes in an inactive form, and when the pancreatic juice reaches the intestine are activated to fulfill its mission to break down proteins. In the pancreas which is made is the trypsinogen and chymotrypsinogen, inactive compounds, that on reaching the duodenum are activated by another enzyme called enterokinase, developed in the duodenal wall.

The fat digestion and lipase

We know that oil and water do not mix. The fat tends to settle in the intestine in the form of globules, and the enzyme has to decompose these compounds fat globules into smaller absorbable many lipase enzyme is also produced by the pancreas. For lipase may actually break down the fat must be emulsified before. This assistance is performed by the stored bile in the gallbladder and the liver generated. The basic function is to divide the bile fat globules into droplets small enough so that the lipase acted on.

The digestion of carbohydrates

We have said that the carbohydrate digestion begins in the mouth by the action of amylase. To complete the digestion of carbohydrates pancreas also produces another enzyme similar to previous pancreatic amylase. Thanks to the action of these enzymes, food starches break down to simple sugars such as monosaccharides and disaccharides, especially labeled maltose. To that end disaccharides into monosaccharides are completely decomposed in the small intestine wall there is another series of specific enzymes to accomplish this end mission. These enzymes are maltase, sucrase and lactase.

The absorption in the small intestine

The small intestine is a tube having a dimension of about 7.5 meters long and 2.5 cm inside diameter. It has three parts: the duodenum about 30 cm long, the jejunum about 3 meters, and the final section, about 4.5 meters, consisting of the ileum.

But the design of the small intestine is something that should not go unnoticed. A tube as long as it has so many folds, could twist and cause a blockage. Not so! The small intestine is attached to the back of the abdomen by a structure called mesentery. The mesentery is a membranous tissue that not only keeps the small intestine in place, but also thanks to its numerous blood vessels, carries nutrients and oxygen to the gut.

But beyond that, the small intestine has an inner surface designed to perform maximum absorption. Its consists mucosa epithelial folds turn, viewed microscopically, are constituted by so-called intestinal villi. These villi protruding from the lumen, or central section of the intestinal tract. But if deeper into the design of the intestinal villi Villus discovered that each turn is formed by microvilli calls. This allows the intestinal absorption of nutrients is multiplied by 200 times the entire surface of the skin.

If the small intestine was a simple tube without more, would have an area of ​​just over 3 square meters. However, thanks to the folds, villi and microvilli, the absorption surface reaches about 250 m2, larger than a tennis court. In addition to facilitating the absorption of nutrients makes possible proper digestion, since a lot of enzymes fulfill their function within the microvilli.

Once there was the breakdown of food into its basic components, one is that the capillaries in the villi absorb them. These nutrients are absorbed in the small blood transported through the portal vein to the liver where it will produce a new chemical reorganization to meet the body's needs.

The intestinal malabsorption

The small intestine is the organ that rarely causes problems, in fact hardly hear of bowel cancer, although it produces.

Most often, the primary small bowel disease is related to the way the intestine breaks down and absorbs food. This disorder is known by the name: malabsorption, and within this disorder is primarily the poor absorption of fats.

Some symptoms of malabsorption of fats is voluminous and malodorous stools that float in the toilet. This is due to the high content of fat in the stool.

Other symptoms of intestinal malabsorption are:

  • Weight loss due to lack of nutrients
  • Anemia malabsorption of iron and folic acid
  • Disorders in calcium levels by malabsorption of vitamin D (liposoluble)

Besides these problems, the most important is undoubtedly celiac disease or gluten enteropathy.

To learn more about this disease visit the following article: gluten intolerance. Celiac. Symptoms and Diagnosis.

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