Flashcards in Homeostasis Deck (23):
What is homeostasis?
The process in which organisms maintain a relatively constant or stable environment for body cells (within narrow limits).
(Proteins) work under certain (optimum) conditions, and cells only work with it.
Define stimulus :
Some change in the internal or external environment.
Response is opposite (counteracts) to the stimulus
The same direction or encouraged (amplifies) the stimulus.
Three homeostasis examples :
1. Body temperature
2. Level of CO2
3. 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?
In homeostasis what best describes glands in muscles
What is the function of the myelin sheath?
Insulation to allow a faster signal throughout the axon
A chemical signalling molecule
Name two effectors
What is a statement that is true for ALL viruses ?
Viruses can only reproduce ina living cell.
Example of fungi
Mould and yeast
Chemicals that cross the synapse to cast messages.
Chemically and electrically excitable cell.
Transmits the electrical impulse
The gaps between neutrons
What is changed
What is measured