Under normal conditions, blood sugar levels are controlled within a narrow range by negative feedback. Two hormones are involved in maintaining blood sugar levels at the set point (about 90 mg of glucose/100 mL of blood). When blood sugar levels rise above the set point, the hormone insulin signals the liver to absorb the excess sugar. When blood sugar levels drop below the set point, the hormone glucagon signals the liver to release its stored glucose to the bloodstream.
-For negative feedback control of blood glucose homeostasis to function properly,
A) the set point changes in response to changes in blood glucose levels.
B) there must be sensors that monitor blood glucose levels.
C) glucagon acts as a stimulus to trigger the control center to activate a response.
D) an increase in blood glucose is continuously amplified by the liver.

Question

Quizplus · Accepted Answer

For negative feedback control to function properly, there must be sensors that monitor blood glucose levels. This is because the feedback loop relies on detecting changes in the variable being controlled (in this case, blood glucose levels) and responding accordingly. The other choices are incorrect. The set point remains constant under normal conditions, glucagon acts as a response to low blood glucose levels rather than a stimulus, and an increase in blood glucose is not continuously amplified by the liver.

Under Normal Conditions, Blood Sugar Levels Are Controlled Within a Narrow