Homeostasis and negative feedback
- Created by: Katieh211
- Created on: 12-03-14 14:25
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- Homeostasis and negative feedback
- Homeostasis
- The maintenance of the internal environment in a constant state despite external changes
- Many organisms have to keep a great deal of conditions constant inside the body. Such as:
- Body temperature
- Blood glucose concentration
- Blood salt concentration
- Water potential of the blood
- Blood pressure
- Carbon dioxide concentraion
- Negative feedback
- In order to maintain a constant internal environment a number of processes must occur.
- Any change to the internal environment must be detected
- The change must be signalled to other cells.
- There must be a response that reverses the change
- The change must be signalled to other cells.
- Any change to the internal environment must be detected
- The reversal of a change in the internal environment to return to a steady state or optimum position
- For negative feedback to work effectively there must be a complex arrangement of structures that are all coordinated through cell signalling.
- Stimulus-Receptor- communication pathway (cell signalling)-effector-response
- There are a number of structures required for this pathway to work
- Sensory receptors
- Temperature receptors or glucose concentration receptors.
- They are internal and monitor conditions inside the body
- A communication system
- The nervous system or the hormonal system
- Signals between cells
- Transmits a message from the receptor cells to the effector cells
- Effector cells
- Liver cells or muscle cells
- These bring about a response that reverses the change detected by the receptor cells.
- Sensory receptors
- There are a number of structures required for this pathway to work
- Stimulus-Receptor- communication pathway (cell signalling)-effector-response
- In order to maintain a constant internal environment a number of processes must occur.
- Positive feedback
- Less common than negative feedback
- A process that increases any change detected by the receptors. It tends to be harmful and does not lead to homeostasis
- Homeostasis
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