Unit 3.5.5 - Feedback Systems Flashcards
What is negative feedback?
A mechanism that restores a system to their original level.
What do receptors detect?
When a level is too high or low?
What two things make up the communication system?
Nervous or hormonal system
What does negative feedback work to?
Keep things around the normal level
Why does negative feedback only work within certain limits?
If the change is to big the effectors might not be able to counteract it.
How many negative feedback mechanisms does homeostasis involve and why?
Multiple for each thing being controlled because having more than one mechanism gives you more control over changes to your internal environment.
What would happen if you only had one negative feedback mechanism for homeostasis?
You would only be to actively change a level in one direction.
What does only having one negative feedback mechanism mean in terms of response and control?
Slow response and less control.
What is a positive feedback mechanism?
One that amplifies the change in your internal environment.
How do the effectors respond in a positive feedback mechanism?
To further increase the level away from the normal level.
When is positive feedback useful?
To rapidly activate processes in the body.
When does positive feedback when the homeostatic system breaks down?
As the body temperature falls during hypothermia the brain doesn’t work properly and shivering stops. Positive feedback takes the temperature away from the normal level.
What hormones control the mammalian oestrous cycle?
FSH, LH, progesterone and oestrogen.
Where is FSH produced?
In the pituitary gland
When is FSH first produced and what type of feedback does this show?
When progesterone levels drop - negative feedback.
