The Digestive Juices and the Transportation of Nutrients
Our bodies are amazing machines that have been designed to perform a function in perfect harmony. Organs, nerves, glands and blood cells all do their individual tasks, which harmonize perfectly with the overall function of the digestive system in order to nourish our body so that it can function properly.
The first glands that are called into action are those that are located in the mouth. These glands are called, “salivary glands”. These glands produce, saliva. The saliva contains an enzyme that is used to digest certain starches from food we put into our mouth and to form smaller molecules of these starches.
The stomach contains the next set of glands in the digestive system. The stomach lining contains glands that produce stomach acid, which contains an enzyme capable of breaking down protein in the foods that we eat. The mucosa present in our stomach acts to protect our stomach lining from the stomach acids that are produced by these stomach glands.
Next, in the process of digestion the pancreas and the small intestine secret other juices that carry a wide array of enzymes that further break down carbohydrate, fat, and protein of the food remaining in our small intestine.
Our liver produces another digestive juice, called bile. Our gallbladder stores this bile that is produced by the liver, until we need it. The gallbladder has a system of ducts (pipes) that reach the small intestine and provides the bile that is used to mix with the fat that we consume in our food. The bile dissolves this fat and makes it into a watery substance, much like detergents in our sink can dissolve the grease from our pots and pans into disgusting looking water. The small intestine looks much the same as it holds the now dissolved watery fats. The pancreas and the small intestine secrets the enzymes that further dissolve the fats in the small intestine.
Once the digestive process breaks down the food and liquids we consume into useable molecules they are absorbed through the intestine walls and into the bloodstream by crossing over the mucosa lining of the small intestine. The bloodstream carries the molecules to other body parts where they are further digested by chemical changes or stored until the body needs them.
Carbohydrates:
Foods that commonly contain carbohydrates are breads, potatoes, legumes, rice, pasta, fruits, and vegetables. Many of these contain both fiber and starches.
The carbohydrates that are digestible are broken into molecules by enzymes in the saliva, from the pancreatic juices, and also the juices of the small intestine.
The table sugar that we take in our beverages or spoon on cereal or grapefruits are digested by enzymes in the lining of the small intestine and turned into glucose and fructose so that they can be absorbed from the intestinal cavity and into our bloodstream.
Milk and milk products contain the sugar – lactose that is changed into an absorbable molecule by an enzyme called lactase that is found in the lining of the small intestine. Individuals who are lactose intolerant have an insufficient amount of the enzyme lactase and so they cannot properly digest the lactose found in milk and milk products. When lactose is unable to be absorbed it sits in the small intestine undigested.
Foods that contain protein such as meats, eggs, and beans are needed to build and repair body tissues. The enzyme in the juices of the stomach break down protein and then the pancreatic and intestinal enzymes further break down the protein into small molecules called, “amino acids”. These amino acids are then absorbed by the small intestinal wall and carried by the blood cells to all parts of the body where they are needed to build parts of cells.
Fat molecules from the foods we eat are first dissolved into a watery content in the intestinal cavity and then the bile from our liver dissolves the fat and the enzymes break the large fat molecules into smaller more useable molecules. The bile acids actually combine with these smaller fat molecules and move them into the cells of the mucosa where they then form back into large molecules, and pass into vessels near the intestine. These small vessels to the veins of the chest then carry the fat, and fat is also carried by the blood to storage deposits in different parts of the body. The more fat we consume, the more of it gets carried to these storage depots.
Vitamins are absorbed by the small intestine. There are two types of vitamin absorption going on in the intestine – water-soluble vitamins (B vitamins and vitamin C) and fat-soluble vitamins (vitamin A, D, and K).
The water we drink and the salt we take in are absorbed from the cavity of the small intestine.
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