Question

What is a negative feedback? What is a positive feedback? Give an example of each kind of feedback.

Short answer

Negative feedback is a self-regulating process that helps to maintain stability by counteracting the output of a system, while positive feedback amplifies the initial input, causing rapid changes and possibly unstable behavior. An example of negative feedback is the human body's regulation of blood sugar levels through insulin secretion. In contrast, an example of positive feedback is the blood clotting process, where platelets aggregate and release chemicals to attract more platelets, reinforcing the clot formation.

Step-by-step solution

Define Negative Feedback

Negative feedback is a self-regulating process in which the output of a system or an action is reduced or counteracted by the system. It is a stabilizing force that helps to maintain a steady state or achieve equilibrium. Negative feedback loops are most commonly used in control systems, where they help to maintain stability and prevent runaway behavior.

Define Positive Feedback

Positive feedback is a process where the output or effect of a system or an activity amplifies or enhances the initial input, causing a chain-reaction or self-reinforcing cycle. This can result in rapid changes and a deviation from the original state or equilibrium. Positive feedback is often unstable and can lead to extreme behavior or amplification. It is crucial in some biological and behavioral processes but can sometimes cause problems if left unchecked.

Example of Negative Feedback

An example of negative feedback can be found in the human body's regulation of blood sugar levels. When blood sugar levels rise after a meal, the pancreas releases insulin, which helps cells absorb sugar from the bloodstream and store it as glycogen. As sugar levels in the blood decrease, insulin secretion is reduced. Consequently, it creates a feedback loop that helps to maintain stable blood sugar levels within a healthy range.

Example of Positive Feedback

An example of positive feedback can be observed in the process of blood clotting. When a blood vessel is damaged, platelets begin to aggregate at the site of injury, and a clotting cascade is initiated. As more platelets gather, they release chemicals that attract even more platelets to the site, reinforcing the clotting process. This positive feedback loop ensures that clots form quickly and effectively, sealing the wound and preventing further blood loss.