Feedback Mechanisms Flashcards

Study Notes

Negative Feedback

Regulates systems by counteracting changes to maintain a steady state or homeostasis.
Most common feedback mechanism in the body.
Original stimulus is reduced or shut off to restore balance.
Everyday example: Thermostat controlling home temperature.
Physiological examples include:
- Regulation of body temperature through shivering and sweating.
- Insulin secretion lowering high blood sugar levels.
- Increased heart and respiratory rates in response to high blood CO2 and low O2 levels.
- Thirst mechanism activated by dehydration.

More Examples of Negative Feedback

Home thermostat acts as a receptor (thermometer) and control center.
If temperature drops below set point (70°F), the heater (effector) activates.
Heater turns off once the desired temperature is reached, maintaining stability.
Control of blood sugar involves the pancreas responding to elevated glucose by secreting insulin.
Insulin reduces blood sugar levels, and once homeostasis is achieved, its release stops.

Positive Feedback

Enhances the original stimulus until a specific endpoint is reached.
Less common; typically governs infrequent events that do not need ongoing adjustment.
Everyday examples include mass panic and addiction.
Physiological examples involve:
- Increased labor contractions during childbirth enhanced by the hormone oxytocin.
- Platelet aggregation for blood clotting in response to vessel injury.

More Examples of Positive Feedback

Positive feedback systems amplify the original stimulus, unlike negative feedback which inhibits it.
Childbirth example: Oxytocin release intensifies contractions, leading to more oxytocin release until delivery occurs.
Blood clotting process operates similarly; damaged vessels attract platelets that release chemicals, prompting further platelet accumulation until a clot is formed.
Key distinction: Positive feedback mechanisms effectively push processes to completion, while negative feedback seeks to maintain stability.

Description

Explore the concept of feedback mechanisms with these flashcards focusing on negative feedback. Learn how this regulatory process maintains homeostasis in the body through various physiological examples, like temperature regulation and insulin response. Perfect for biology students studying anatomy or physiology.