Unit 12 Human Body Review—AAC BIO
Answers for all of the Human Body review sheet questions are in your
Human Body notes that were posted after we finished presentations.
Homeostasis and Feedback Notes
1. What is homeostasis?
Homeostasis is the regulation and maintenance of the internal environment.
2. What is feedback inhibition?
The end product of a process is able to inhibit, or stop, the process at the beginning so no more
product is made. Allows pathways to be turned on and off as needed to regulate amount of
product made.
3. What is the difference between a negative feedback loop and a positive feedback loop? Be able
to recognize examples and graphs. For more examples and for graphs, see your homework.
The parts of a control system work together in what is known as a feedback loop.
Feedback is information from sensors that allows a control center to compare current
conditions to a set of ideal values. Negative feedback loops counteract any change that moves
conditions above or below a set point, so they maintain homeostasis and keep conditions
constant. For instance, if your fluid balance falls below a set point, your brain sends signals that
cause you to drink more. Positive feedback loops increase change away from set points, taking
you farther away from homeostasis until a goal is reached, and then finally once it’s over, you’re
able to return to homeostasis. In an emergency, for example, adrenaline pours into your system
to give you more strength until the emergency is over.