Negative Feedback

Negative Feedback

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Negative feedback is a vital part of how our body regulates itself. While positive feedback loops exist, they're not as common. These feedback loops are necessary to maintain a stable internal environment, which is what we call homeostasis.

Characteristics of Negative Feedback

Negative feedback is when a system or variable deviates from its usual state. In these situations, the feedback loop works to bring the factor back to its baseline level. If the factor continues to deviate from the baseline, the body activates a system to restore it. As the system moves back towards the normal level, it becomes less active, allowing for stabilisation. The normal level of a system or variable is called the baseline state. For example, the typical amount of glucose in the blood for someone without diabetes is between 72-140 mg/dl.

Negative Feedback Examples

Negative feedback is a crucial component in the regulation of several systems, including: Temperature regulation Blood Pressure Regulation Blood Glucose Regulation Osmolarity Regulation Hormone Release

Positive Feedback Examples

Positive feedback works differently than negative feedback. When a system's output increases, positive feedback amplifies the response to stimulus instead of down-regulating the system. This results in a departure from the baseline, rather than restoring it. There are several systems in our body that use positive feedback loops, such as nerve signals, ovulation, birthing, blood clotting, and genetic regulation.

The Biology Of Negative Feedback

Negative feedback systems consist of four main components, including the stimulus, sensor, controller, and effector. The stimulus is the trigger for the system, and the sensor detects changes and reports them back to the controller. The controller compares this information to a set point and activates the effector to bring the system back to baseline.

One example of a negative feedback loop is blood glucose concentration regulation, which involves the hormones insulin and glucagon. Insulin lowers blood glucose levels, while glucagon raises them. When blood glucose levels increase, the beta cells in the pancreas act as sensors and controllers, releasing insulin as the effector lower blood glucose levels. Similarly, when blood glucose levels decrease, the alpha in pancreas release glucagon as the effector to raise blood glucose levels.

Thermoregulation is another example of a negative feedback loop. When body temperature increases above the baseline, temperature receptors act as sensors and the hypothalamus acts as the controller, activating sweat glands and blood vessels as effectors to lower the body temperature. When body temperature decreases below the baseline, shivering and vasoconstriction are activated to raise the temperature back to baseline.

Blood pressure control also involves a negative feedback loop, with pressure receptors acting as sensors and the nervous system acting as the controller. The heart and blood vessels are the effectors that work to either decrease or increase blood pressure back to baseline.

Negative Feedback - Key takeaways Negative feedback occurs when there is a deviation in a system's baseline and in response, the body acts to reverse these changes. Positive feedback is a different homeostatic mechanism which acts to amplify changes of a system. In the negative feedback loop of blood glucose concentration, the hormones insulin and glucagon are key components of regulation. In thermoregulation, negative feedback enables regulation via mechanisms such as vasodilation, vasoconstriction and shivering. In blood pressure control, negative feedback changes the heart rate and triggers vasodilation/vasoconstriction for regulation.

Negative Feedback

What is negative feedback?

Negative feedback occurs when there is a deviation from a variable or system's basal level in either direction and in response, the feedback loop returns the factor within the body to its baseline state.

What is am example of negative feedback? 

An example of negative feedback is regulation of blood glucose levels by insulin and glucagon. Elevated blood glucose levels trigger the release of insulin into the bloodstream, which then lowers the glucose concentration. Decrease blood glucose levels trigger the secretion of glucagon, which increases the blood glucose concentration back to basal levels.

What are examples of negative feedback in homeostasis? 

Negative feedback is used in many homeostatic systems, including thermoregulation, blood pressure regulation, metabolism, blood sugar regulation and red blood cell production. 

Is sweating negative feedback? 

Sweating is part of the thermoregulation negative feedback loop. An increase in temperature triggers vasodilation and sweating, which is then stopped by a decrease in temperature and a return to baseline levels. 

Is hunger positive or negative feedback? 

Hunger is a negative feedback system as the end result of the system, which is the organism eating, downregulates the production of the hormones which stimulate hunger.

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