homeostasis Flashcards
1
Q
what is homeostasis?
A
maintaining internal environment
2
Q
what are the three stages of automatic control systems?
A
- receptors
- processing centres
- effectors
3
Q
how does negative feedback work ?
A
- receptor detects change in environment - high/low levels
- processing centre receives information and co-ordinates response
- effector produces response to counteract change
4
Q
how is temperature regulated?
A
- temperature receptors - hot/cold
- thermoregulatory centre (hypothalamus) processes info to trigger immediate response
- effectors counteract change
5
Q
how do effectors counteract change when it is too cold?
A
vasoconstriction
- hairs stand up - trap air and provides insulation
- contraction of muscles to shiver requires respiration which releases energy to warm body
6
Q
how do effectors counteract change when it is too hot?
A
vasodilation - blood closer to surface makes it easier for heat to be transferred to environment
- sweat glands produce sweat - evaporates from skin removing heat
7
Q
what is insulin?
A
a hormone produced by pancreas
8
Q
what is a hormone?
A
a chemical messenger which travels in blood to a target organ
