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.
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.
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 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
From the Top to the Bottom
This ordered list sums digestive organs and their enzymes:
Small Intestine-lactase, disaccharides, peptidases
- Sugar and Enzymes
- Digestive Organs
- Digestive Enzymes
- Glucose and Insulin
- Cellular Processes