A sensor, also referred to a receptor, is a component of a feedback system that monitors a physiological value. Negative FeedbackĪ negative feedback system has three basic components ( Figure 1.10 a). The maintenance of homeostasis by negative feedback goes on throughout the body at all times, and an understanding of negative feedback is thus fundamental to an understanding of human physiology. Therefore, negative feedback maintains body parameters within their normal range. Negative feedback is a mechanism that reverses a deviation from the set point. Control centers in the brain and other parts of the body monitor and react to deviations from homeostasis using negative feedback. For example, the set point for normal human body temperature is approximately 37☌ (98.6☏) Physiological parameters, such as body temperature and blood pressure, tend to fluctuate within a normal range a few degrees above and below that point. A normal range is the restricted set of values that is optimally healthful and stable.
A set point is the physiological value around which the normal range fluctuates. From body temperature to blood pressure to levels of certain nutrients, each physiological condition has a particular set point. Maintaining homeostasis requires that the body continuously monitor its internal conditions. Contrast negative and positive feedback, giving one physiologic example of each mechanism.Discuss the role of homeostasis in healthy functioning.By the end of this section, you will be able to:
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