AQA GCSE FOUNDATION Biology: Homeostasis Basics

AQA GCSE Foundation Biology: Homeostasis Basics

What is Homeostasis?

Homeostasis is the process by which living organisms maintain a stable internal environment, despite changes in their external environment. It's like a thermostat in your house, keeping the temperature comfortable even when it's freezing outside.

Why is Homeostasis Important?

• Survival: Our cells need specific conditions to function properly. Homeostasis ensures these conditions are met.
• Optimum Function: Enzymes, which control chemical reactions in our bodies, work best at specific temperatures and pH levels. Homeostasis keeps these conditions stable.

Key Factors Controlled by Homeostasis:

• Temperature: Our body temperature needs to stay around 37°C for optimal functioning.
• Blood Sugar Level: The amount of glucose in our blood needs to be balanced for energy production.
• Water Content: The amount of water in our body needs to be regulated to prevent dehydration or overhydration.
• pH Levels: The acidity or alkalinity of our blood and other bodily fluids needs to be maintained within a narrow range.

How does Homeostasis work?

1. Receptors: These detect changes in the internal environment. For example, temperature receptors in our skin detect changes in external temperature.
2. Control Centre: This receives information from receptors and compares it to the set point (the ideal value). For example, the hypothalamus in our brain acts as the control center for body temperature.
3. Effectors: These carry out the necessary response to restore balance. For example, muscles and sweat glands help regulate body temperature.

Examples of Homeostasis:

• Temperature Regulation:
  • When we get too hot, we sweat to cool down.
  • When we get too cold, we shiver to generate heat.
• Blood Sugar Regulation:
  • When blood sugar is high, insulin is released to lower it.
  • When blood sugar is low, glucagon is released to raise it.

Key Terms:

• Homeostasis: Maintaining a stable internal environment.
• Receptor: Detects changes in the environment.
• Control Centre: Processes information and sends signals to effectors.
• Effector: Carries out the response to restore balance.
• Set Point: The ideal value for a controlled factor.

Understanding Homeostasis is crucial for understanding how our bodies function and the importance of maintaining a healthy lifestyle.