Chapter 37 Main Points

🔑 Key Definitions

          Homeostasis: Maintenance of stable internal environment through physiological regulatory mechanisms

          Feedback System: Regulatory mechanism that detects deviation from set point and triggers corrective response

          Feed-Forward System: Anticipatory regulation that prepares body for expected changes before they occur

          Set Point: Target value for a regulated variable (e.g., 37°C body temperature)

🧠 Homeostatic Mechanisms

Feedback Systems: Detect deviation → trigger response → return to set point (e.g., thermostat)
Negative Feedback: Response opposes the deviation (most common homeostatic mechanism)
Feed-Forward: Anticipate change and respond before deviation occurs (e.g., salivation before eating)
Set Point: Optimal value system tries to maintain

📊 Temperature Regulation

Ectotherms: "Cold-blooded" animals; regulate temperature behaviorally (reptiles, fish)
Endotherms: "Warm-blooded" animals; regulate temperature physiologically (mammals, birds)
Neutral Zone: Temperature range where minimal regulatory effort needed
Hypothalamus: Contains temperature sensors and control centers; maintains set point around 37°C

📊 Regulatory Responses

Heat Production: Shivering, increased metabolism, brown fat thermogenesis
Heat Conservation: Vasoconstriction, piloerection, behavioral (seeking warmth)
Heat Loss: Vasodilation, sweating, panting, behavioral (seeking cool)

💡 Exam Tips

Homeostasis = maintaining stability through active regulation
Feedback (reactive) vs feed-forward (anticipatory) - both important
Ectotherms use BEHAVIOR, endotherms use PHYSIOLOGY for temperature control
Hypothalamus is KEY control center for temperature and other homeostatic functions
Set point = target value (can be adjusted, e.g., fever raises set point)
Neutral zone = comfortable range with minimal energy expenditure