3.6.4.1 Principles of homeostasis and negative feedback Flashcards
1
Q
What is homeostasis?
A
Maintenance of a constant internal environment
2
Q
How can heat be gained?
A
- produced by respiration
- gained from environment
3
Q
How can heat be lost?
A
- evaporation (sweating)
- lost to environment
4
Q
What is the difference between endotherms and ectotherms?
A
- endotherms obtain most of their heat from metabolic activities inside their bodies (eg birds and mammals)
- ectotherms obtain most of their heat from environment (eg reptiles and amphibians)
5
Q
How do ectotherms regulate their temperature?
A
- exposing themselves to sun
- taking shelter
- generating warmth from ground
- generating metabolic heat
- colour variations
6
Q
What methods to endotherms use to increase their temperature?
A
- shivering
- vasoconstriction of superficial arterioles
- hair erector muscles contract (raise hair)
- increased metabolic rate
7
Q
What methods ro endotherms use to decrease their temperature?
A
- sweating
- vasodilation of superficial arterioles
- hair erector muscles relax (lower hair)
- decreased metabolic rate
8
Q
What is negative feedback?
A
- where a change triggers a response which reduces the effect of a change
- to return the system to normal
9
Q
What is positive feedback?
A
- where a change triggers a response which amplifies the effect of a change
- Large deviation from the norm
