The nerve impulse
- Created by: Shreeya Bhan
- Created on: 07-04-13 09:03
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- Inactive neuron
- Positive ions int he fluid outside
- negative ions inside (-70mv) - this inactive charge is called resting potential
- When charge reaches -50mv, neuron reaches its threshold and nerve impulse is triggered
- nerve impulse is an all or nothing event
- During this nerve impulse or action potential, the axon membrane is pierced by tiny holes called ion channels
- The molecules blocking these tiny openings pop open and allow Na+ to rush into the axon (the channels open near soma first and then down the length of the axon)
- After the action potential passes, there is a negative after potential state as K+ flow out of the axon to quickly restore its negative charge
- When charge reaches -50mv, neuron reaches its threshold and nerve impulse is triggered
- Ultra-small electrodes places inside and outside an axon measure its activity
- Saltatory conduction can occur instead of normal nerve impulse
- Axons of some neurons are coated with a fatty layer called myelin; small gaps in myeling help nerve impulses move faster by leaping from gap to gap
- If the myelin is damanged: numbness, weakness or paralysis eg - multiple sclerosis
- Axons of some neurons are coated with a fatty layer called myelin; small gaps in myeling help nerve impulses move faster by leaping from gap to gap
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