Homeostasis and Feedback Loops

Homeostasis

• Definition: A stable internal environment maintained by all body systems working together.
• Components necessary for homeostasis:
  • Receptor: Monitors physiological conditions and detects changes.
  • Control Centre: Processes information from receptors and directs appropriate responses.
  • Effector: Executes commands from the control centre to restore balance.

Feedback Loops

• Negative Feedback Loop:

  • Response reduces or stops the initial stimulus.
  • Restores normal range and brings the body back to homeostasis.
  • Example: Air-conditioning system adjusts temperature based on sensor feedback.

• Positive Feedback Loop:

  • Response amplifies the initial stimulus, moving the body away from homeostasis.
  • Generally used in situations requiring a quick and decisive change.
  • Examples:
    • Labor during childbirth; accelerates contractions until delivery.
    • Blood clotting; accelerates until a clot is formed.

Regulation of Homeostasis

• Thermoregulation:

  • Monitors and regulates body temperature.
  • Receptors detect heat, control centre (hypothalamus) integrates the information, and effectors (blood vessels, sweat glands) enact physical changes.

• Blood Glucose Regulation:

  • High glucose levels trigger insulin release from the pancreas, lowering blood sugar.
  • Low glucose levels trigger glucagon release, which raises blood sugar by breaking down glycogen in the liver.

Types of Regulation

• Intrinsic (Autoregulation):

  • Automatic responses within cells, tissues, or organs to local environmental changes.

• Extrinsic Regulation:

  • Responses guided by the nervous and endocrine systems to broader systemic changes.

Importance of Homeostasis

• Essential for survival; when homeostasis is disrupted, illness may occur.
• Maintains optimal levels of chemicals, temperature, and pressure essential for cell survival.