Homeostasis: Definition | Biology for GCSE/IGCSE - Year 11 PDF Download

Homeostasis: Definition

• Homeostasis is defined as the maintenance of a constant internal environment

Role of Insulin in Homeostasis

• Homeostasis refers to maintaining internal body conditions like temperature, blood pressure, water, and glucose levels within specific limits. This balance is crucial for cell functions and overall organism survival.
• If any of these conditions deviate significantly from the norm and are not corrected, the body's ability to function properly is compromised, ultimately leading to death without medical intervention.

The Role of Insulin

• Insulin is released into the bloodstream when blood sugar levels are elevated.
• This typically occurs shortly after a meal.
• The kidneys have a limited capacity to manage blood glucose levels; excess glucose is expelled through urine, akin to fuel wastage from a leaky petrol tank in a car.
  • Excess glucose is excreted in the urine, resembling fuel loss in a car with a leaky tank.
• To prevent this wastage, insulin converts surplus glucose into glycogen temporarily, storing it in the liver and muscles, thereby reducing blood glucose levels.
  • Insulin plays a crucial role in decreasing blood glucose concentration.
• Excess glycogen is reconverted into glucose hours later when blood sugar levels drop due to cellular respiration throughout the body.