Homeostasis Flashcards
Define enzymes:
(Proteins) work under certain (optimum) conditions, and cells only work with it.
What is homeostasis?
The process in which organisms maintain a relatively constant or stable environment for body cells (within narrow limits).
Define stimulus :
Some change in the internal or external environment.
Negative feedback?
Response is opposite (counteracts) to the stimulus
Positive feedback?
The same direction or encouraged (amplifies) the stimulus.
Three homeostasis examples :
- Body temperature
- Level of CO2
- Blood pressure
The reflex arc ?
Bypasses the brain and is controlled by the CNS. (Where you give no thought for the reaction) eg. Go outside into the cold is a reflex arc, where answering a question isn’t.
Do cells respond to a particular hormone?
No, if they respond, it to a particular receptor and not hormone.
The effector is?
What has changed to either enhance or counteract the stimulus.
The effector causes the response
Eg. Sweat glands - effector. Sweat - response
What detects the stimulus?
The receptor
In homeostasis what best describes glands in muscles
Effectors
What is the function of the myelin sheath?
Insulation to allow a faster signal throughout the axon
Define hormone
A chemical signalling molecule
Name two effectors
Sweat glands
Blood vessels
What is a statement that is true for ALL viruses ?
Viruses can only reproduce ina living cell.
