1. Homeostasis – Feedback Loops

2. Feedback Loops: 2 Types Positive (+) Negative (-)
When a change causes a greater increase (gets amplified)
unsustainable
When a change is corrected (gets put back to normal)
sustainable
Q: Which type do you think most feedback loops are in your body?

3. Example

4. Practice
or - ?
The more you like math
The better at math you get + +

5. Practice
or - ?
Smile
Feel Happy + +

6. Practice
or -?

7. Practice
or - or no loop?

8. Practice
or -?

9. Practice
or - ?
Amount of studying
Better Grades + +

10. Practice
or -?

11. Practice
or - ?

12. Practice
or - ?

13. Practice
or - ?

14. Blood Sugar

15. Practice
Blood clotting: Once a vessel is damaged like by a cut or bruise, platelets start to cling to the injured site and release chemicals that attract more platelets. The platelets continue to pile up and release chemicals until a clot is formed.
or - ? +

16. Practice
or - ?

17. Practice
or - ?

18. Based off these examples, can we make a hypothesis about which type of feedback loops (+/-) the body uses most often?

19. A Delicate Balancing Act- a cycle/loop
The body uses negative feedback loops to maintain homeostasis (balance)
And less often uses positive feedback loops in more special circumstances (ex: giving birth, blood clotting after cut)
Fill in your diagram

21. Answer during the video:
1. What is the average human body temperature?
2. How do many antibiotic medicines kill bacteria?

22. Video Recap What is the average human body temperature?
2. How do many antibiotic medicines kill bacteria?