All of the following are prime examples of negative feedback loops, except for:
A Testosterone
B Human growth hormone
C Calcitonin
D Oxytocin
E All of these options are prime examples
The correct answer and explanation is:
The correct answer is D) Oxytocin.
Explanation:
Negative feedback loops are processes that work to counteract changes in the body, helping maintain homeostasis by bringing the system back to its baseline or set point. These loops are common in the regulation of hormones and other physiological processes.
- Testosterone: Testosterone production is regulated by a negative feedback loop. When testosterone levels rise, they signal the hypothalamus and pituitary gland to reduce the secretion of gonadotropin-releasing hormone (GnRH) and luteinizing hormone (LH), which in turn lowers testosterone production by the testes. This helps keep testosterone levels within a balanced range.
- Human Growth Hormone (HGH): The secretion of HGH is also regulated by negative feedback. When growth hormone levels rise, they stimulate the liver to produce insulin-like growth factor 1 (IGF-1), which inhibits the release of growth hormone from the pituitary gland. This negative feedback mechanism ensures that growth hormone levels do not become too high.
- Calcitonin: Calcitonin is a hormone produced by the thyroid gland that helps regulate calcium levels in the blood. When blood calcium levels rise, calcitonin is released to lower calcium by inhibiting osteoclast activity in bones and increasing calcium excretion in the kidneys. This process is also an example of a negative feedback loop.
- Oxytocin: Oxytocin is an example of a positive feedback loop rather than a negative one. It plays a crucial role during labor and childbirth. When labor begins, oxytocin stimulates uterine contractions, and these contractions trigger more oxytocin release, intensifying the contractions. This cycle continues until childbirth is completed, making oxytocin a classic case of positive feedback.
In summary, oxytocin differs from the other hormones listed in the question because it amplifies a physiological response rather than opposing it.