Explain negative feedback and give one example in the human body.
Negative feedback is a regulatory mechanism in which the response to a particular stimulus results in the opposite direction of the stimulus. It is a self-regulating process that helps maintain stability and homeostasis in the body.
One example of negative feedback in the human body is the regulation of body temperature. When body temperature rises above the normal range, thermoreceptors in the skin and brain detect this change and send signals to the hypothalamus. The hypothalamus then initiates a series of responses to reduce the body temperature.
For instance, the hypothalamus signals the sweat glands to produce sweat, which then evaporates and cools the body. At the same time, blood vessels near the skin dilate (vasodilation), allowing more blood flow to the skin's surface and promoting heat loss through radiation. These responses work together to bring the body temperature back to its normal range. Once the temperature is regulated, the negative feedback loop is disrupted, and the responses cease.
Negative feedback is a process in which the output or response of a system is used to regulate or diminish the input or stimulus. It is a mechanism that helps maintain homeostasis, which is the balance and stability in the body's internal environment.
To understand negative feedback, let's use body temperature regulation as an example. When the body is exposed to a cold environment, the temperature drops, which can be detected by temperature-sensitive cells in the skin and brain. These cells send signals to the hypothalamus, a region in the brain responsible for regulating body temperature.
In response to the drop in temperature, the hypothalamus triggers several physiological responses to increase body temperature. It causes the blood vessels in the skin to narrow, reducing heat loss through the skin, and stimulates shivering, which generates heat. Additionally, the hypothalamus signals the release of hormones that increase metabolic rate to produce more heat.
Once these corrective measures are taken, the body temperature begins to rise. As the temperature approaches the normal range, the temperature-sensitive cells in the skin and brain detect the change and send signals to the hypothalamus. In response to these signals, the hypothalamus reduces the stimulation for shivering and vasodilation, enabling the body to regain homeostasis and stabilize body temperature within the normal range.
In this example, the negative feedback loop acts to oppose the initial stimulus (cold environment) and counteracts the change by initiating a response (increase in body temperature). The aim of negative feedback is to restore balance and maintain optimal conditions within the body.