Question

positive feedback loop
which is an example of a positive feedback system?
during labor
blood calcium regulation
blood glucose regulation
menstrual cycle

Explanation:

• During labor: In a positive feedback loop, the response reinforces the stimulus. During labor, contractions (response) cause the release of oxytocin (stimulus), which in turn increases contractions. This cycle continues until the baby is born.
• Blood calcium regulation: This is a negative feedback loop. When blood calcium levels are high, the thyroid gland releases calcitonin, which lowers blood calcium. When levels are low, the parathyroid gland releases parathyroid hormone, which raises blood calcium. The goal is to maintain a stable level.
• Blood glucose regulation: Also a negative feedback loop. When blood glucose is high (after eating), the pancreas releases insulin, which lowers blood glucose. When blood glucose is low (during fasting), the pancreas releases glucagon, which raises blood glucose.
• Menstrual cycle: While there are hormonal interactions, it is more complex and not a classic positive feedback loop like labor. It involves a series of hormonal changes (e.g., estrogen, progesterone) that regulate the cycle, but the main driver is not a simple reinforcing loop like labor contractions.

Answer:

During labor