Homeostatic Mechanisms

Homeostatic Mechanisms

Defining Homeostasis

  • Homeostasis is the process that maintains a stable internal environment within an organism, despite changes in the external environment.
  • This balance is crucial for an organism’s survival and functioning.

Components of Homeostatic Systems

  • Homeostatic systems use a combination of components; namely, receptors, control centre, and effectors.
  • The receptor senses changes in the environment (internal or external), the control centre assesses this information and formulates a response, and the effector carries out the necessary action to restore balance.

Negative Feedback Loops

  • Negative feedback loops are a key component of homeostasis. They work to reduce or oppose the change detected, bringing the system back towards the desired set point.
  • Examples of negative feedback include the body’s regulation of temperature and blood glucose levels.

Positive Feedback Loops

  • Positive feedback loops amplify or increase changes; this propels the system further from the set point.
  • Positive feedback loops are less common but play important roles during specific events such as blood clotting and childbirth.


  • Thermoregulation is the process of maintaining the body’s core internal temperature within a narrow range.
  • When the body temperature rises, sweat glands produce sweat, and blood vessels expand (vasodilation) to help reduce body heat.
  • When the body temperature drops, shivering and vasoconstriction (narrowing of blood vessels) occur to conserve and generate heat.


  • Osmoregulation is the control of water levels and mineral salts in the blood.
  • The kidneys play a crucial role in this process; controlling the excretion and reabsorption of water and salts.

Blood Glucose Regulation

  • Blood glucose regulation is critical in maintaining homeostasis, and it uses both insulin and glucagon to control the levels of glucose within the body.
  • After eating, blood glucose levels rise, signalling the pancreas to release insulin; this hormone helps body cells absorb glucose, thus lowering the blood glucose levels.
  • Fasting or lower blood sugar levels trigger the release of glucagon, which instructs the liver to release stored glucose back into the bloodstream.

Remember, though the body faces constant internal and external changes, homeostatic systems work tirelessly to keep our internal environment as stable as possible. It is this balance that allows our bodies to function optimally. Understanding these systems empowers us to be mindful of our actions, knowing they can influence these delicate balances.