Lecture Notes: Homeostasis and Feedback Mechanisms

Introduction to Homeostasis

• Homeostasis is a state of balance in the body.
• Involves maintaining certain ranges for:
  • Blood pH
  • Blood glucose
  • Internal body temperature
• Major body systems work together to achieve homeostasis.

Feedback Mechanisms

• Types: Positive feedback and Negative feedback.
• Relate to how body systems collaborate to maintain homeostasis.

Negative Feedback

• Definition: A process where a variable triggers a counteracting response to return to a set point.
• Example 1: Body temperature regulation
  • When hot (Texas Summer):
    • Sensors (nerves) signal the brain.
    • Brain triggers sweat glands to reduce temperature.
    • Blood vessels dilate to release heat.
  • When cold (AC exposure):
    • Sweating stops and shivering begins.
    • Blood vessels constrict to conserve heat.
• Example 2: Blood glucose regulation
  • High glucose: Insulin is released to help cells intake glucose.
  • Low glucose: Glucagon is released to stimulate liver to release glucose.

Positive Feedback

• Definition: Intensifies a variable rather than counteracting it.
• Example: Childbirth
  • Pressure on cervix leads to hormone release and contractions.
  • More hormones mean more contractions, creating a cycle until the baby is born.

Importance of Feedback Mechanisms

• Essential for maintaining homeostasis.
• Understanding feedback helps identify disorders in feedback systems.
  • Example: Type 1 Diabetes
    • Pancreas fails to produce insulin.
    • Glucose remains outside cells, impacting cellular respiration.
    • Patients need to manage with insulin and blood sugar monitoring.

Conclusion

• Importance of feedback in health and disease management.
• Encouragement to "stay curious" about biological processes.