In What Organs Are Enzymes Found That Break Down Food?

This title was requested and the article was rejected. Boo.

The digestive system is one of seven bodily systems requiring complex pathways and hormonal signaling.

The digestive system is one of the seven bodily systems and is a beautifully orchestrated, complex collaboration of organs producing appropriate enzymes in response to a stimulus, eating! Digestive enzymes are produced throughout the body and have the ultimate purpose of making glucose available for every cellular process in the body.

Catabolism

The process of digestion is catabolic. You are probably familiar with anabolic steroids, which aid in the process of building muscle. Catabolism is the opposite process, a breaking down of complex food structures into smaller, usable molecules, such as glucose. You may remember from high school science class that sugars usually end in the suffix, –ose, e.g. lactose. The enzyme, usually ending in –ase, is associated with catabolizing the nutrient. In the case of lactose, lactase catabolizes lactose into glucose and galactose, making a larger molecule into two, simpler and smaller molecules.

Digestion is initiated in the mouth, which produces amylase.

The semi-permeable mucous membrane in the mouth makes saliva, which contains amylase, the first enzyme required to digest food. The semi-permeability of mucous membranes allows for secretion of amylase and absorption of some substances, glucose included, in the mouth. A science experiment you can try at home: put a saltine cracker in your mouth. Do not chew it; simply begin to let it dissolve. At first, the cracker tastes salty, but soon seems to melt into smaller particles. Because of amylase in your mouth, after a few seconds, the cracker now tastes sweet.

Mechanical Digestion in the Stomach

The stomach produces the enzyme, pepsin, and signals the gall bladder and pancreas for bile and insulin, respectively.

The enzyme produced by the stomach is pepsin, which begins to catabolize proteins, e.g. meat. Signaled by the stomach being filled with food, the gall bladder produces bile, which is secreted into the stomach. Thirdly, the pancreas is signaled by the stomach to produce insulin, a complex molecule composed of several enzymes. Insulin is employed in every cellular process of the body to bring glucose into the cell. Insulin is also absorbed into muscle, liver, and brain tissue for the utilization of glucose. While the stomach is often regarded as where digestion occurs, the primary function of the stomach is to mechanically digest food by using the muscles and digestive acids to begin to ready food to pass into the small intestine.

Where the Real Work is Done

The small intestine is the primary organ of nutrient absorption and contains, lactase, disaccharides, and several peptidase enzymes. Insulin and bile used in the stomach also pass into the small intestine. Most of the nutritional value of food, the carbohydrate, fat, and protein components, as well as vitamins and minerals are absorbed into the bloodstream by the small intestine. The remaining fluid and waste products pass into the large intestine, and needed water is absorbed there. Intestine trivia for you: From the beginning of the small intestine from the pyloric valve at the emptying end the stomach to the end of the large intestine is about 13 feet in an adult. If you would like to know more of the gory details about the cellular processes involved in constructing the enzymes, hormonal regulation, and interactions of feedback and feedforward mechanisms between bodily systems, Dee Silverthorn, Ph.D. is a prominent human physiologist and has written several, excellent and thorough textbooks.

From the Top to the Bottom

This ordered list sums digestive organs and their enzymes:
Mouth-amylase
Stomach-pepsin
Gall Bladder-bile
Pancreas-insulin
Small Intestine-lactase, disaccharides, peptidases

Keywords

• Sugar and Enzymes
• Digestive Organs
• Digestive Enzymes
• Glucose and Insulin
• Cellular Processes

Reference

• NIH: Your Digestive System and How It Works [http://digestive.niddk.nih.gov/ddiseases/pubs/yrdd/]
• American Dietetic Association: How Insulin Works [http://www.eatright.org/Public/content.aspx?id=6818]
• Human Physiology Textbooks [http://www.aw-bc.com/silverthorn/]