Glucose will always move through the channel dance concentration gradient, which means these transporters are bidirectional. Once insulin binds to that, it does it's intracellular processes, which pushes these receptors or transporters up to the surface. So without insulin, most glucose is trapped in the bloodstream. You need the insulin to get pulled out into the muscle and adipose tissue. If you just look at muscle and fat cells as a percentage of your whole body cells, they're not very no volume wise though, volume and how hungry they are for glucose.