Glucose is the sugar from our foods that our body needs for energy. When we eat the energy is taken out of the food and turned into liquid glucose and absorbed by the blood. The blood then transports this to the organs and muscles to convert to the energy required for them to function. Our muscles store energy as well in the form of glycogen. When this is needed it then turns it back to glucose to utilise withn the blood stream as energy again. All our organs and muscles need this to be able to function.
Essentially its a simple sugar. Its structure is important as our body can break it down very quickly to get energy, compared to fats for example. Pretty much all organs rely heavily on glucose as a fuel and skeletal muscle is one of these major consumers. Insulin release is linked to glucose in the circulation as it stimulate muscle to take up glucose from the blood into the muscle. Type 2 diabetes is associated with high daily levels of glucose in the blood as the muscle is not able to take in the normal amount in response to insulin.