Positive feedback loop

Definition

A positive feedback loop is a physiological process where the output of a system amplifies the original stimulus. This can lead to an exponential increase or runaway effect in biological systems until an external factor intervenes.

5 Must Know Facts For Your Next Test

1. Positive feedback loops are less common than negative feedback loops in maintaining homeostasis.
2. One classic example is the release of oxytocin during childbirth, which intensifies contractions.
3. Positive feedback loops often push a system to its extreme state, leading to a necessary change or end point.
4. Blood clotting is another example where platelets release chemicals that attract more platelets, rapidly forming a clot.
5. While effective for certain rapid processes, positive feedback loops can be dangerous if unchecked, potentially leading to pathological conditions.

Review Questions

• What is the primary difference between positive and negative feedback loops?
• Can you explain how oxytocin functions in a positive feedback loop during childbirth?
• Why are positive feedback loops generally less common in maintaining homeostasis compared to negative feedback loops?

Related terms

Negative Feedback Loop: A process where the output of a system suppresses or diminishes the original stimulus to maintain balance and stability.

Homeostasis: The body's ability to maintain stable internal conditions despite changes in external environments.

Oxytocin: A hormone involved in various physiological processes, including childbirth and lactation, and acts as part of a positive feedback loop during labor.