The Traveling Man - Glucose

Glucose - A Molecule in Motion with a Purpose

Lets begin with its breakdown. It starts with a polysaccharide to a disaccharide to a monosaccharide (glucose). All of this begins in the mouth. Glucose is so important to you it gives excessive time to digest all the basic sugar components of nutrition you provide. 

Keep in mind, the pancreas is both an endocrine organ ( insulin and glucagon) and an exocrine organ (digestive enzymes for disaccharides, dipeptides and fats). Hormones are secreted directly into the circulatory system and are global( Reaches all cells supplied by blood capillaries). Enzymes work locally and enter  their workplace through a tube into the small intestine.

One very important principal is the concept of surface area. There is a direct correlation between an increase in the rate and quantity of absorption of digestion products and the increase in the surface area exposed to the end product glucose.

Surface area is one of the factors that scientists use to differentiate lower animals from higher animals like us. The increased surface area in our intestines (especially the small intestine) allows us to meet our energy demands efficiently and quickly. This is a big improvement over lesser creatures.

Once in its final stage of breakdown (the monosaccharide glucose) it is absorbed in the small worm-like villae that cover the inside of the small intestine. They really increase the surface area used for absorption.

Remember, it passes through the mosaic membrane of the cells (intracellular fluid compartment) that are in direct contact with the glucose in the small intestine. It now exits that membrane cell on the other side of the cell membrane into a fluid matrix called the interstitial fluid compartment of the extracellular fluid compartment. It travels through that compartment where it enters the intracellular fluid compartment of a cell layer that makes up blood capillary.

It leaves the cell that lines the blood capillary. In review, it goes from an intracellular compartment into the blood capillary fluid that makes up the other compartment of the extracellular fluid.

The blood, with the dissolved glucose in it is transported to all the cells that use glucose for energy.

Excess glucose that isn't used enters the kidneys where it is excreted into the urine. It is similar to water flowing over a dam. This occurs when something is amiss. Maybe insulin is not produced adequately and this excess is in addition to the glucose transported to the liver for storage as glycogen. It may be called back as glucose in emergencies.

The glucose that is still present in the blood, in very high amounts, even after flowing over the dam in the kidneys, is Diabetes. (The result of not facilitating the uptake of glucose that we described above)

This trip we just took is a one way trip. There is some glucose that is converted to a more complex molecule and stored in the liver. This more complex stored molecule breaks down in the liver, when called upon, to provide glucose when your blood sugar is low due to a number of factors.

I don't know about you but my feet are a little sore from walking with the glucose molecule on its trip. You should begin to realize now how complex your body has developed to accomplish all this without you really knowing that it is happening.