[ 265 ] Life Science GED ® TEST SCIENCE FLASH REVIEW • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • Blood glucose levels are tightly regulated in the human body by the hormones insulin and glucagon. When glucose levels become too high or low, the pancreas produces the appropriate hormone to return the body to homeostasis. The diagram shows the feedback mechanism for regulating blood glucose levels. Body cells take up more glucose. Insulin Beta cells of pancreas release insulin into the blood. Liver takes up glucose and stores it as glycogen. STIMULUS: Blood glucose level rises. Blood glucose level declines. Homeostasis: Blood glucose level (about 90 mg/100 mL STIMULUS: level rises. Blood glucose Blood glucose level falls. Alpha cells of pancreas Liver breaks release glucagon. down glycogen and releases glucose. Glucagon Diabetes mellitus is a disease in which the pancreas is unable to produce the insulin needed to regulate blood glucose levels. What result would occur from providing an insulin injection to a diabetic person with high blood sugar? A. The insulin travels to the liver where it binds to and destroys excess glucose in the bloodstream. B. The insulin signals the pancreas to produce glucagon, which increases the level of glucose in the bloodstream. C. The insulin causes the liver to convert glucose to glycogen, removing excess glucose from the bloodstream. D. The insulin breaks down glycogen into glucose, releasing stored glucose into the bloodstream.