neurones
- Created by: vezting
- Created on: 19-10-15 14:07
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- neurones
- sensory
- transmit nerve impulses from receptor to CNS
- short dendrites, one long Dendron, short axon
- sensory receptors convert an impulse into electrical energy (transducers)
- resting potential
- na+ and k+ pumps use active transport. 3 na+ out for ever 2 k+ in
- -70mV
- Na+ cant diffuse back in, creating electrochemical gradient
- potassium ion channels open so k+ can diffuse out as well as being pumped in
- outside of membrane is positively charged, inside is negatively charged
- generator potential
- when stimulus is detected the membrane becomes more permeable allowing ions in and out
- this alters the potential difference.
- action potential
- when the generator potential reaches threshold frequency an action potential will occur
- generator potential
- when stimulus is detected the membrane becomes more permeable allowing ions in and out
- this alters the potential difference.
- generator potential
- a stimulus causes excitement, sodium channels open, diffuse down gradient
- inside becomes less negative
- depolarisation is when potential diff. reaches -55mV voltage gates channels open
- more Na+ enter/ flood in
- Repolarisation is when potential difference is +30mV.
- sodium channels close, potassium ones open
- k+ diffuse out down concentration gradient
- sodium channels close, potassium ones open
- hyper polarisation
- K+ channels are slow to close. too many diffuse out
- neurone goes past -70mV
- when the generator potential reaches threshold frequency an action potential will occur
- sensory
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