A level Biology please help

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username5922831
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Description of functioning of neurons and synapses
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Zarek
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A decent biology textbook or indeed Wikipedia will provide a wealth of information on this topic
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Rootkit77
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(Original post by 728163917)
Description of functioning of neurons and synapses
I'm sure there are numerous books and articles related to your topic. however, avoid Wikipedia
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av0
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(Original post by username5922831)
Description of functioning of neurons and synapses
This could be long but hope it helps

Neurons communicate with each other at junctions called synapses. At a synapse, one neuron sends a message to another neuron through the transmission of a neurotransmitter. As the action potential arrives at the synapse it triggers the movement of calcium ions in the pre-synoptic membrane to diffuse down its gradient towards the membrane. As a result of this, neurotransmitters in their vesicles travel towards the membrane, fuse to it and are "emptied out" of their vesicles into the synaptic cleft (gap) via exocytosis. The neurotransmitters travel across the cleft to the post-synoptic membrane (so the next neurone) and bind to receptors there. Think of this as "lock and key"/enzyme type stuff - neuro transmitters bind to their specific receptors and drugs work by emulating this shape and 'tricking' the neurones into firing or not firing. As soon as the neurotransmitter is recognised by the receptor, depolarisation occurs, sodium ions increase and an action potential is generated and fired.

In terms of electrical changes in neurones and ion placement, at resting neurones are negative and stay at -70mV. As a wave of depolarisation occurs (as an action potential travels along an axon) sodium ions move into the axon through voltage gated channels, making the charge positive at +30mV. This is the highest peak of the action potential and this is the point at which it fires, From here, repolarisation occurs, sodium channels shut and potassium voltage gates open allowing potassium to move in and a negative charge to occur. As it happens, these potassium gates remain open too long and too much potassium moves into the axon - this is known as hyperpolarisation and in terms of electrical charge is around -90mV. To restore equilibrium/resting potassium channels remain open for some to diffuse out again to restore charge to -70mV. Now comes the refractory period, a pause in the axon where channel gates remain shut for a pause - this is to prevent over stimulation and firing. I found this a hell of a lot easier to learn with the graph in front of me showing the electrical changes, i found the CGP one great.

Note that the impulse travels via saltatory conduction, jumping between each node of ranvier. This is to speed up the process of nervous transmission by shortening the distance required to travel.
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Reality Check
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(Original post by av0)
This could be long but hope it helps

Neurons communicate with each other at junctions called synapses. At a synapse, one neuron sends a message to another neuron through the transmission of a neurotransmitter. As the action potential arrives at the synapse it triggers the movement of calcium ions in the pre-synoptic membrane to diffuse down its gradient towards the membrane. As a result of this, neurotransmitters in their vesicles travel towards the membrane, fuse to it and are "emptied out" of their vesicles into the synaptic cleft (gap) via exocytosis. The neurotransmitters travel across the cleft to the post-synoptic membrane (so the next neurone) and bind to receptors there. Think of this as "lock and key"/enzyme type stuff - neuro transmitters bind to their specific receptors and drugs work by emulating this shape and 'tricking' the neurones into firing or not firing. As soon as the neurotransmitter is recognised by the receptor, depolarisation occurs, sodium ions increase and an action potential is generated and fired.

In terms of electrical changes in neurones and ion placement, at resting neurones are negative and stay at -70mV. As a wave of depolarisation occurs (as an action potential travels along an axon) sodium ions move into the axon through sodium gated channels, making the charge positive at +30mV. This is the highest peak of the action potential and this is the point at which it fires, From here, repolarisation occurs, sodium channels shut and potassium gates open allowing potassium to move in and a negative charge to occur. As it happens, these potassium gates remain open too long and too much potassium moves into the axon - this is known as hyperpolarisation and in terms of electrical charge is around -90mV. To restore equilibrium/resting potassium channels remain open for some to diffuse out again to restore charge to -70mV. Now comes the refractory period, a pause in the axon where channel gates remain shut for a pause - this is to prevent over stimulation and firing. I found this a hell of a lot easier to learn with the graph in front of me showing the electrical changes, i found the CGP one great.

Note that the impulse travels via saltatory conduction, jumping between each node of ranvier. This is to speed up the process of nervous transmission by shortening the distance required to travel.
This is broadly correct, but note that they are not 'sodium-gated channels', but voltage-gated ion channels which open as a result of the change in membrane electrical potential.
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av0
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(Original post by Reality Check)
This is broadly correct, but note that they are not 'sodium-gated channels', but voltage-gated ion channels which open as a result of the change in membrane electrical potential.
ahh yes thank you, I always manage to forget the proper name, thank you for pointing it out
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(Original post by av0)
ahh yes thank you, I always manage to forget the proper name, thank you for pointing it out
No problem - and it was a good, accurate, comprehensive answer
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This could be long but hope it helps Neurons communicate with each other at junctions called synapses. At a synapse, one neuron sends a message to another neuron through the transmission of a neurotransmitter. As the action potential arrives at the synapse it triggers the movement of calcium ions in the pre-synoptic membrane to diffuse down its gradient towards the membrane. As a result of this, neurotransmitters in their vesicles travel towards the membrane, fuse to it and are
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