Glucose is the most simple form of sugar. Carbohydrates are made of complexes of sugars, also called polysaccharides. When you eat a carbohydrate, several processes occur to breakdown polysaccharides into simple glucose. The body relies on glucose to provide energy for working cells. Most importantly, your brain and nervous system rely on glucose to function.
Glucose and Cellular Function
Your working muscle tissue, including cardiac, skeletal and smooth muscle cells all need glucose to provide the energy for their work. Your muscle cells can obtain glucose either from the blood or from their own storage, known as glycogen.
Glucose and Neurological Functioning
Unlike muscle tissue, your nervous system and brain cells do not store glucose for later use. Instead, they rely on a constant supply of glucose from your blood stream. In addition, they do not have the means to run on anything except glucose, so your dietary intake of carbohydrates is important for brain function. According to the Franklin Institute, nearly 10 percent of the energy needed by your body is to maintain nervous and brain system functioning.
Glucose Metabolism
Small structures inside your cells, known as mitochondria, take in and use glucose for fuel. When glucose is inside of your cell, the cell uses special enzymes to break the glucose down into pyruvic acid which then becomes energy for the cell. Energy is made through a complex process inside the mitochondria, known as the Kreb's cycle. The outcome of this cycle is ATP, potential energy for your cells to function.
Types of Metabolism
Glucose can be used in two different types of metabolic processes in your cells. Aerobic metabolism allows you to sustain energy for an extended period of time. It is the metabolic pathway that uses oxygen to liberate stored energy from glucose. Aerobic metabolism occurs during rest or during sustainable activity. Anaerobic metabolism occurs when there is no available oxygen to help with glucose metabolism. Your body usually turns to the anaerobic pathway when the intensity of your work increases the need for oxygen. When your body needs to catch up for the increased need or if your body cannot keep up with the demand, anaerobic metabolism allows your body to produce the energy that you need. However, anaerobic metabolism is not reliable, as it can only provide enough energy for about two minutes of an activity.
References
- "The Human Brain - Carbohydrates"; The Franklin Institute; 2004
- "Exercise Physiology"; George A. Brooks, Thomas D. Fahey, Kenneth M. Baldwin; 2005
