Homeostasis and Feedback Loop Notes
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____________ - refers to the ability of an organism or environment to maintain ____________
in spite of changes. The human body is full of examples of homeostasis
Homeostasis happens in _____ Kingdoms: Archaebacteria, Eubacteria, Protista, Fungi,
Plantae, and Animalia
The Human Body
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The components of the human body, from _______, to tissues to _________ to organ systems,
__________ to maintain homeostasis
What is Homeostasis?
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The maintenance of a _____________ environment in the body
Achieved by many different internal controlled mechanisms that _______ deviations and make
_____________ actions
Your body has mechanisms to keep the cells in a constant environment OR _________________
Homeostatic Loop
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Body cells work best if they have the correct: ______________________, __________________,
Glucose concentration, Calcium Concentration, and _______________________
Feedback Mechanisms
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In order to maintain homeostasis, the body uses feedback loops
There are two types:
1. _________________________
2. _________________________
Negative Feedback Loop (decreases effects) - Stimulus produces a response which ___________ the
original stimulus. (used for homeostasis)
Examples
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_____________ (reduces being hot)
Shivering (_______________ being cold)
_____________ (reduces blood sugar)
Stomata's and guard cells in __________ (reduce water loss in ________________)
Positive Feedback Loop (increases effects) -Stimulus produces a response which ________________ the
stimulus
Examples
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Drug addicts (needs _________ drugs)
Apple ripening (ethylene is ______________)
____________ produced to speed up contractions in childbirth (___________ faster childbirth)
Negative Feedback Mechanism
________________ Regulation
Stimulus 
1. Initial hormone is released
2. Stimulates 2nd hormone to release
3. Inhibits further release of initial hormone
Positive Feedback Mechanism
The release of oxytocin to _____________ the contractions
that take place during ________________
Stimulus 
1. Initial hormone is released
2. Stimulates 2nd hormone to release
3. Inhibits further release of initial hormone
Difference Between Negative and Positive Feedback Loops
Negative feedback: the response is moved to the target set point
Example: Thermostat turns on the A/C when the house get too hot
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2.
3.
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6.
__________ (Blood sugar regulation)
__________ in plants and guard cells in plants; regulates transpiration
Blood Pressure
Hunger
Temperature Regulation
______ Balance
Positive feedback: the response is moved away from the target set point
Example: Speakers, sound going into microphone is processed to produce a magnified response sound
coming out of the speakers
1.
2.
3.
4.
___________ (Labor)
Breastfeeding
________ _____________
Fruit Ripening