The Digestive, Respiratory, and Urinary Systems
After glucose is absorbed by the small intestine, it is transported to the liver, where many “decisions” are made regarding its fate. These decisions are hormonally effected, and include release of some glucose into the blood, storage of some as glycogen, and conversion of some to fat.
The hormones insulin and glucagon are produced by the pancreas; insulin is produced in response to high blood sugar, as after a meal, and tells body cells to take up glucose from the blood, while notifying the liver to store or convert any excess. Glucagon targets the liver when blood sugar is low, telling it to break down some glycogen and release it into the blood as glucose. The interaction of these hormones acts like a thermostat to maintain a relatively constant blood glucose concentration.
In individuals with diabetes mellitus type I, insulin is no longer produced by the pancreas, and must be supplemented by intravenous injection, or the afflicted individual will eventually die.
Sometimes if the administration of glucose is not timed properly, insulin is injected but an individual does not eat for a prolonged period of time. This can lead to insulin shock, during which a person loses consciousness and can die. The probable cause of insulin shock is:
|A||The injected insulin causes the blood sugar to become so low that glucose is not available to fuel the body’s needs.|
|B||The injected insulin causes so much glucose to be released into the blood that the surge of energy can cause heart rhythm irregularities.|
|C||The injected insulin suppresses hunger, so that the person does not realize they should eat.|
|D||Injected insulin causes the inhibition of glucagon synthesis, so no glycogen can be broken down to glucose by the liver.|
Since the job of insulin is to reduce the blood sugar, excess insulin will do just that, by any means it can. Choice B describes the opposite effect, and therefore must be discarded. Both choices C and D are unreasonable and unsupported by the passage.