Definition of positive feedback
a feedback loop in which the output of a system is amplified with a net positive gain and added to the input signal before the main amplifier
Examples of positive feedback in the following topics:
- In contrast, positive feedback loops push the organism further out of homeostasis, but may be necessary for life to occur.
- Positive Feedback LoopA positive feedback loop maintains the direction of the stimulus and possibly accelerates it.
- There are few examples of positive feedback loops that exist in animal bodies, but one is found in the cascade of chemical reactions that result in blood clotting, or coagulation.
- The direction is maintained, not changed, so this is positive feedback.
- Another example of positive feedback is uterine contractions during childbirth.
- Homeostasis is typically achieved via negative feedback loops, but can be affected by positive feedback loops, set point alterations, and acclimatization.
- A positive feedback relay occurs between the uterus, hypothalamus, and the posterior pituitary to assure an adequate supply of oxytocin.
- An increase in gonad hormone levels inhibits GnRH production through a negative feedback loop .Regulation of the Male Reproductive SystemAt the pituitary, GnRH stimulates the synthesis and secretion of the gonadotropins, FSH and LH.
- These processes are controlled by the size and frequency of GnRH pulses, as well as by feedback from androgens and estrogens.
- Contractions increase in intensity as blood levels of oxytocin rise via a positive feedback mechanism until the birth is complete.
- This is an example of the positive feedback loop that is leading to the rapid rate of increase of global temperatures.