Out in the open atmosphere, there is enough motion in the air to keep the oxygen and carbon dioxide mixed up. This motion of the air mostly comes from convection currents (i.e. wind) caused by temperature differences.
For homeostasis, insulin is the main hormone involved. Blood sugar regulation is the process by which the levels of blood sugar, primarily glucose, are maintained by the body.here are also several other causes for an increase in blood sugar levels. Among them are the 'stress' hormones such as epinephrine (also known as adrenaline), several of the steroids, infections, trauma, and of course, the ingestion of food.
When the glucose level is high, the beta cells secrete insulin into the blood; when glucose levels are low, secretion of insulin is inhibited. Their neighboring alpha cells, by taking their cues from the beta cells, secrete glucagon into the blood in the opposite manner: increased secretion when blood glucose is low, and decreased secretion when glucose concentrations are high.