What is meant by 'set point' in biological terms?

• A. The ideal external environment
• B. The normal range for a physiological variable
• C. The response rate of feedback loops
• D. The maximum capacity of physiological systems

Answer: (B)

In biological terms, the 'set point' refers to the specific value or range at which a physiological variable is maintained under homeostatic conditions. This concept is crucial for understanding how various systems within the body regulate and stabilize functions such as temperature, pH, and glucose levels. When the body deviates from this set point, feedback mechanisms come into play to restore balance, prompting responses that bring the variable back to its normal range.

For example, consider body temperature: the set point for human body temperature is around 37 degrees Celsius. If the temperature falls below or rises above this range, the body initiates physiological processes such as shivering or sweating to bring it back to the set point. This process highlights the significance of the normal range for a physiological variable, as it is fundamental for maintaining homeostasis and overall health.

Understanding the concept of a set point is essential in physiology, as it illustrates how the body efficiently regulates functions to adapt to internal and external changes.