Question

Which of the following is an example of negative feedback? a. Uterine contractions increase as labor progresses. b. Insulin decreases blood sugar levels after eating a meal. c. Sweating increases as body temperature drops. d. Platelets continue to plug an opening in a blood vessel until blood flow stops.

Short answer

The correct example of negative feedback is: b. Insulin decreases blood sugar levels after eating a meal.

Step-by-step solution

Understand Negative Feedback

Negative feedback is a self-regulating mechanism that helps to maintain homeostasis in biological systems. This feedback process aims to counteract and reduce the effects of changes in a variable, returning it back to its normal state.

Analyze the Options

Carefully examine each example to determine whether it illustrates a negative feedback mechanism or not. a. Uterine contractions increase as labor progresses: This is a positive feedback mechanism because the response (contractions) intensifies as labor progresses. b. Insulin decreases blood sugar levels after eating a meal: When blood sugar levels are high, insulin is produced to help cells take up this sugar, reducing the concentration of sugar in the blood. This can be considered a negative feedback process because insulin counteracts the initial change (high blood sugar). c. Sweating increases as body temperature drops: This is not an example of negative feedback since an increase in sweating would not be expected when body temperature drops. d. Platelets continue to plug an opening in a blood vessel until blood flow stops: This is another example of a positive feedback mechanism because the response (platelet plugging) intensifies until blood flow is stopped.

Identify the Correct Option

Based on the analysis of the examples, we can confidently conclude that: The correct example of negative feedback is: b. Insulin decreases blood sugar levels after eating a meal.

Key concepts

Understanding Homeostasis

Homeostasis is an essential concept in biology. It refers to the ability of an organism or environment to maintain a stable internal state despite changes occurring externally. Balancing various bodily functions is crucial to ensuring survival and optimal functionality.

Think of homeostasis as a thermostat that keeps the temperature in your house constant. When it gets too hot, the thermostat triggers the air conditioning until it cools down to the desired temperature. Conversely, if it gets too cold, the thermostat starts the heater to warm it up again. Similarly, biological systems have mechanisms to regulate body temperature, pH levels, glucose concentration, and other factors.

• Maintains stability
• Balances internal conditions
• Responds to external changes

Homeostasis is primarily maintained through negative feedback systems, which help bring variables back to their normal state.

The Role of Negative Feedback in Blood Sugar Regulation

Blood sugar regulation is a perfect example of negative feedback in action. It is crucial for maintaining the energy balance in our bodies. When you consume a meal, especially one rich in carbohydrates, your blood glucose levels rise. Insulin, a hormone produced by the pancreas, plays a significant role here.

Once the pancreas detects high levels of glucose in your bloodstream, it releases insulin. Insulin helps your cells absorb glucose, using it for energy, or storing it as glycogen in the liver and muscles for later use. This process decreases the blood sugar level back to its normal state. If glucose levels drop too low, another hormone, glucagon, is released, which increases blood sugar by breaking down glycogen.

• Insulin decreases blood sugar after eating
• Glucagon increases blood sugar when it gets too low
• Maintains energy balance

This regulation mechanism exemplifies the negative feedback process, constantly working to keep our blood sugar levels in check.

Interconnected Biological Systems and Feedback Mechanisms

Biological systems are complex networks where various processes and feedback loops work in harmony. They ensure that organisms operate efficiently and adapt to changes in their environment.

For example, your nervous and endocrine systems collaborate to regulate bodily functions through signals and hormones. The negative feedback mechanism is a recurring theme across these systems, guiding them back to equilibrium when disturbances occur.

Take thermoregulation; when your body overheats, sweat glands secrete sweat, which evaporates and cools the body down. Suppose your internal environment is too cool; muscles may shiver, generating heat. Both scenarios illustrate how your body acts to restore balance.

• Negative feedback mechanisms in action
• Collaboration between different systems
• Restoring equilibrium after disturbances

These interactions highlight how our biological systems are structured to preserve stability and adapt effectively to various challenges.