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Tutorials » Regulation of Biological Systems

Physiological Homeostasis
- Regulation of Biological Systems

Negative Feedback Control

In animals such as ourselves, the internal environment of our bodies must have certain conditions within tolerable limits to continue the healthy functioning of us.

This is done by a process called negative feedback control, where various receptors and effectors bring about a reaction to ensure that such conditions remain favourable. In this tutorial, we investigate the control of blood sugar concentrations, water concentrations and temperature.

The principle of negative feedback control is illustrated by the diagram below

Principle of Negative Feedback Control

This occurrence is known as physiological homeostasis, translating in layman's terms to the physical equilibrium. It is essentially a corrective mechanism, consider the following scenario in a person

  • The level of glucose in the bloodstream drops
  • The person requires glucose in cells to meet the demand for ATP
  • The body detects this with a particular receptor designed for this function
  • These receptors release hormones, chemical messages that initiate the start of the feedback mechanism
  • The hormones travel to their target tissue and initiate a corrective response
  • In this case, the corrective response is the secretion of more glucose into the bloodstream

Requirement of Negative Feedback Control

Because mammals are warm blooded, the enzymes that are part of their make-up as a warm blooded animal require a certain temperature to operate optimally. Also, the water concentration of a cell and its chemical concentration must remain at a certain level to allow normal cellular processes to occur.

In light of this, the feedback mechanism in such warm blooded animals is essential in regards to allowing the body to work in optimal conditions - so any change in from the norm in temperature is corrected by the feedback mechanism.

Advantages of Homeostasis

Homeostasis has survival value because it means an animal can adapt to a changing environment. It can deal with the temperature difference you face when you step our your front door.

The body will attempt to maintain a norm, the desired level of a factor to achieve homeostasis. However, it can only work within tolerable limits, where extreme conditions can disable the negative feedback mechanism

In these instances, death can result, unless medical treatment is executed to bring about the natural occurrence of these feedback mechanisms

The following page looks at regulation of blood sugar concentration and temperature regulation in detail.

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