Positive feedback has occurred when
A) an increase in blood sugar increases the secretion of a hormone that stimulates the movement of sugar out of the blood.
B) a decrease in blood sugar increases the secretion of a hormone that increases the conversion of glycogen to glucose.
C) uterine contractions needed for the birthing process are expedited by the pressure of a moving baby in its mother's uterus.
D) an increase in calcium concentration increases the secretion of a hormone that promotes the storage of calcium in bone.
E) a decrease in blood calcium increases the amount of the hormone that causes the release of calcium from bone.

Question

Quizplus · Accepted Answer

Positive feedback occurs when a stimulus causes an increase in a process which in turn causes an increase in the stimulus, resulting in a self-amplifying cycle. In this case, the pressure of a moving baby in the uterus stimulates the release of oxytocin, which in turn stimulates uterine contractions, leading to the eventual birth of the baby. This is an example of positive feedback because the initial stimulus (pressure of the baby) causes an increase in a process (uterine contractions via oxytocin release), which in turn further increases the initial stimulus (pressure of the baby), resulting in a self-amplifying cycle.

Positive Feedback Has Occurred When