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Zara
24/06/2023
Biology
Topic 8- action potential notes (edexcel biology a level)
214
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24 Jun 2023
•
Understanding Nerve Impulse Conduction and Action Potential for Edexcel Biology A Level
Zara
@zara_ccce
Synaptic Transmission
This page delves into the crucial process of synaptic transmission, which is essential for understanding how signals are passed between neurons in the nervous system.
Synaptic Transmission Process
Synaptic transmission involves several steps that allow a signal to pass from one neuron to another :
- Action Potential Arrival: When an action potential reaches the end of the presynaptic axon, it depolarizes the membrane.
- Calcium Influx: This depolarization opens voltage-gated calcium channels, allowing calcium ions to enter the synaptic knob.
- Vesicle Fusion: Calcium ions cause synaptic vesicles to move towards and fuse with the presynaptic membrane.
- Neurotransmitter Release: The fusion of vesicles releases neurotransmitters into the synaptic cleft through exocytosis.
- Diffusion and Binding: Neurotransmitters diffuse across the synaptic cleft and bind to receptor molecules on the postsynaptic membrane.
- Channel Opening: This binding causes sodium ion channels to open, allowing sodium to diffuse into the postsynaptic cell.
- Postsynaptic Potential: If enough neurotransmitter molecules bind, an action potential is generated in the postsynaptic neuron.
Highlight: The importance of synaptic transmission in A level Biology cannot be overstated, as it forms the basis for all neural communication.
Neurotransmitter Breakdown
To prevent continuous stimulation of the postsynaptic neuron, neurotransmitters are quickly broken down or removed from the synaptic cleft.
Example: In a cholinergic synapse, the enzyme acetylcholinesterase breaks down acetylcholine into acetate and choline. The choline is then recycled to produce more acetylcholine.
Vocabulary: Exocytosis is the process by which vesicles fuse with the cell membrane to release their contents outside the cell.
The detailed understanding of synaptic transmission is crucial for comprehending various neurological processes and disorders, making it a key topic in AQA A level Biology synaptic transmission exam questions.
Action Potential and Resting Potential
The process of nerve impulse conduction involves complex changes in the neuron's membrane potential. This page explains the resting state of neurons and the generation of action potentials.
Resting Potential
Neurons maintain a resting potential when not actively transmitting signals. This state is characterized by an imbalance of ions across the cell membrane.
Definition: The resting potential is the difference in electrical charge between the inside and outside of a neuron when it's not transmitting a signal, typically around -70mV.
Key features of the resting state include:
- Sodium-potassium pumps actively remove sodium ions from the cell cytoplasm.
- Potassium ions diffuse out of the cell through ion channels, following their concentration gradient.
- The balance of forces on potassium ions results in no net movement at the resting potential.
Highlight: The resting membrane potential is maintained by the balance between active ion pumping and passive ion diffusion.
Action Potential
When a neuron is stimulated, it can generate an action potential, which is the basis of nerve impulse conduction.
The stages of an action potential are:
- Depolarization: Stimulation causes sodium channels to open, allowing sodium ions to enter the neuron. This makes the inside of the cell less negative.
- Threshold: When the membrane potential reaches about -55mV, more sodium channels open, rapidly depolarizing the cell to about +30mV.
- Repolarization: Sodium channels close and potassium channels open. Potassium ions leave the cell, restoring the negative charge inside.
- Hyperpolarization: A brief period where the cell becomes more negative than its resting state due to the delayed closing of potassium channels.
- Return to Resting State: The sodium-potassium pump helps restore the original ion concentrations.
Vocabulary: The refractory period is a short time after an action potential when the neuron cannot be excited again, ensuring that signals travel in one direction only.
Example: An action potential travels along an axon like a wave. As one area depolarizes, it triggers depolarization in the adjacent region, propagating the signal.
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Wow, I am really amazed. I just tried the app because I've seen it advertised many times and was absolutely stunned. This app is THE HELP you want for school and above all, it offers so many things, such as workouts and fact sheets, which have been VERY helpful to me personally.
Anna
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Best app on earth! no words because it’s too good
Thomas R
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Just amazing. Let's me revise 10x better, this app is a quick 10/10. I highly recommend it to anyone. I can watch and search for notes. I can save them in the subject folder. I can revise it any time when I come back. If you haven't tried this app, you're really missing out.
Basil
Android user
This app has made me feel so much more confident in my exam prep, not only through boosting my own self confidence through the features that allow you to connect with others and feel less alone, but also through the way the app itself is centred around making you feel better. It is easy to navigate, fun to use, and helpful to anyone struggling in absolutely any way.
David K
iOS user
The app's just great! All I have to do is enter the topic in the search bar and I get the response real fast. I don't have to watch 10 YouTube videos to understand something, so I'm saving my time. Highly recommended!
Sudenaz Ocak
Android user
In school I was really bad at maths but thanks to the app, I am doing better now. I am so grateful that you made the app.
Greenlight Bonnie
Android user
very reliable app to help and grow your ideas of Maths, English and other related topics in your works. please use this app if your struggling in areas, this app is key for that. wish I'd of done a review before. and it's also free so don't worry about that.
Rohan U
Android user
I know a lot of apps use fake accounts to boost their reviews but this app deserves it all. Originally I was getting 4 in my English exams and this time I got a grade 7. I didn’t even know about this app three days until the exam and it has helped A LOT. Please actually trust me and use it as I’m sure you too will see developments.
Xander S
iOS user
THE QUIZES AND FLASHCARDS ARE SO USEFUL AND I LOVE THE SCHOOLGPT. IT ALSO IS LITREALLY LIKE CHATGPT BUT SMARTER!! HELPED ME WITH MY MASCARA PROBLEMS TOO!! AS WELL AS MY REAL SUBJECTS ! DUHHH 😍😁😲🤑💗✨🎀😮
Elisha
iOS user
This apps acc the goat. I find revision so boring but this app makes it so easy to organize it all and then you can ask the freeeee ai to test yourself so good and you can easily upload your own stuff. highly recommend as someone taking mocks now
Paul T
iOS user
The app is very easy to use and well designed. I have found everything I was looking for so far and have been able to learn a lot from the presentations! I will definitely use the app for a class assignment! And of course it also helps a lot as an inspiration.
Stefan S
iOS user
This app is really great. There are so many study notes and help [...]. My problem subject is French, for example, and the app has so many options for help. Thanks to this app, I have improved my French. I would recommend it to anyone.
Samantha Klich
Android user
Wow, I am really amazed. I just tried the app because I've seen it advertised many times and was absolutely stunned. This app is THE HELP you want for school and above all, it offers so many things, such as workouts and fact sheets, which have been VERY helpful to me personally.
Anna
iOS user
Best app on earth! no words because it’s too good
Thomas R
iOS user
Just amazing. Let's me revise 10x better, this app is a quick 10/10. I highly recommend it to anyone. I can watch and search for notes. I can save them in the subject folder. I can revise it any time when I come back. If you haven't tried this app, you're really missing out.
Basil
Android user
This app has made me feel so much more confident in my exam prep, not only through boosting my own self confidence through the features that allow you to connect with others and feel less alone, but also through the way the app itself is centred around making you feel better. It is easy to navigate, fun to use, and helpful to anyone struggling in absolutely any way.
David K
iOS user
The app's just great! All I have to do is enter the topic in the search bar and I get the response real fast. I don't have to watch 10 YouTube videos to understand something, so I'm saving my time. Highly recommended!
Sudenaz Ocak
Android user
In school I was really bad at maths but thanks to the app, I am doing better now. I am so grateful that you made the app.
Greenlight Bonnie
Android user
very reliable app to help and grow your ideas of Maths, English and other related topics in your works. please use this app if your struggling in areas, this app is key for that. wish I'd of done a review before. and it's also free so don't worry about that.
Rohan U
Android user
I know a lot of apps use fake accounts to boost their reviews but this app deserves it all. Originally I was getting 4 in my English exams and this time I got a grade 7. I didn’t even know about this app three days until the exam and it has helped A LOT. Please actually trust me and use it as I’m sure you too will see developments.
Xander S
iOS user
THE QUIZES AND FLASHCARDS ARE SO USEFUL AND I LOVE THE SCHOOLGPT. IT ALSO IS LITREALLY LIKE CHATGPT BUT SMARTER!! HELPED ME WITH MY MASCARA PROBLEMS TOO!! AS WELL AS MY REAL SUBJECTS ! DUHHH 😍😁😲🤑💗✨🎀😮
Elisha
iOS user
This apps acc the goat. I find revision so boring but this app makes it so easy to organize it all and then you can ask the freeeee ai to test yourself so good and you can easily upload your own stuff. highly recommend as someone taking mocks now
Paul T
iOS user
Understanding Nerve Impulse Conduction and Action Potential for Edexcel Biology A Level
Zara
@zara_ccce
Understanding nerve impulse conduction is crucial in Edexcel A Level Biology. This summary covers the process of action potential generation and synaptic transmission, key components of Topic 8 Biology Edexcel A level.
- Action potentials are the basis of... Show more
Synaptic Transmission
This page delves into the crucial process of synaptic transmission, which is essential for understanding how signals are passed between neurons in the nervous system.
Synaptic Transmission Process
Synaptic transmission involves several steps that allow a signal to pass from one neuron to another :
- Action Potential Arrival: When an action potential reaches the end of the presynaptic axon, it depolarizes the membrane.
- Calcium Influx: This depolarization opens voltage-gated calcium channels, allowing calcium ions to enter the synaptic knob.
- Vesicle Fusion: Calcium ions cause synaptic vesicles to move towards and fuse with the presynaptic membrane.
- Neurotransmitter Release: The fusion of vesicles releases neurotransmitters into the synaptic cleft through exocytosis.
- Diffusion and Binding: Neurotransmitters diffuse across the synaptic cleft and bind to receptor molecules on the postsynaptic membrane.
- Channel Opening: This binding causes sodium ion channels to open, allowing sodium to diffuse into the postsynaptic cell.
- Postsynaptic Potential: If enough neurotransmitter molecules bind, an action potential is generated in the postsynaptic neuron.
Highlight: The importance of synaptic transmission in A level Biology cannot be overstated, as it forms the basis for all neural communication.
Neurotransmitter Breakdown
To prevent continuous stimulation of the postsynaptic neuron, neurotransmitters are quickly broken down or removed from the synaptic cleft.
Example: In a cholinergic synapse, the enzyme acetylcholinesterase breaks down acetylcholine into acetate and choline. The choline is then recycled to produce more acetylcholine.
Vocabulary: Exocytosis is the process by which vesicles fuse with the cell membrane to release their contents outside the cell.
The detailed understanding of synaptic transmission is crucial for comprehending various neurological processes and disorders, making it a key topic in AQA A level Biology synaptic transmission exam questions.
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Action Potential and Resting Potential
The process of nerve impulse conduction involves complex changes in the neuron's membrane potential. This page explains the resting state of neurons and the generation of action potentials.
Resting Potential
Neurons maintain a resting potential when not actively transmitting signals. This state is characterized by an imbalance of ions across the cell membrane.
Definition: The resting potential is the difference in electrical charge between the inside and outside of a neuron when it's not transmitting a signal, typically around -70mV.
Key features of the resting state include:
- Sodium-potassium pumps actively remove sodium ions from the cell cytoplasm.
- Potassium ions diffuse out of the cell through ion channels, following their concentration gradient.
- The balance of forces on potassium ions results in no net movement at the resting potential.
Highlight: The resting membrane potential is maintained by the balance between active ion pumping and passive ion diffusion.
Action Potential
When a neuron is stimulated, it can generate an action potential, which is the basis of nerve impulse conduction.
The stages of an action potential are:
- Depolarization: Stimulation causes sodium channels to open, allowing sodium ions to enter the neuron. This makes the inside of the cell less negative.
- Threshold: When the membrane potential reaches about -55mV, more sodium channels open, rapidly depolarizing the cell to about +30mV.
- Repolarization: Sodium channels close and potassium channels open. Potassium ions leave the cell, restoring the negative charge inside.
- Hyperpolarization: A brief period where the cell becomes more negative than its resting state due to the delayed closing of potassium channels.
- Return to Resting State: The sodium-potassium pump helps restore the original ion concentrations.
Vocabulary: The refractory period is a short time after an action potential when the neuron cannot be excited again, ensuring that signals travel in one direction only.
Example: An action potential travels along an axon like a wave. As one area depolarizes, it triggers depolarization in the adjacent region, propagating the signal.
We thought you’d never ask...
What is the Knowunity AI companion?
Our AI Companion is a student-focused AI tool that offers more than just answers. Built on millions of Knowunity resources, it provides relevant information, personalised study plans, quizzes, and content directly in the chat, adapting to your individual learning journey.
Where can I download the Knowunity app?
You can download the app from Google Play Store and Apple App Store.
Is Knowunity really free of charge?
That's right! Enjoy free access to study content, connect with fellow students, and get instant help – all at your fingertips.
Can't find what you're looking for? Explore other subjects.
Students love us — and so will you.
4.9/5
App Store
4.8/5
Google Play
The app is very easy to use and well designed. I have found everything I was looking for so far and have been able to learn a lot from the presentations! I will definitely use the app for a class assignment! And of course it also helps a lot as an inspiration.
Stefan S
iOS user
This app is really great. There are so many study notes and help [...]. My problem subject is French, for example, and the app has so many options for help. Thanks to this app, I have improved my French. I would recommend it to anyone.
Samantha Klich
Android user
Wow, I am really amazed. I just tried the app because I've seen it advertised many times and was absolutely stunned. This app is THE HELP you want for school and above all, it offers so many things, such as workouts and fact sheets, which have been VERY helpful to me personally.
Anna
iOS user
Best app on earth! no words because it’s too good
Thomas R
iOS user
Just amazing. Let's me revise 10x better, this app is a quick 10/10. I highly recommend it to anyone. I can watch and search for notes. I can save them in the subject folder. I can revise it any time when I come back. If you haven't tried this app, you're really missing out.
Basil
Android user
This app has made me feel so much more confident in my exam prep, not only through boosting my own self confidence through the features that allow you to connect with others and feel less alone, but also through the way the app itself is centred around making you feel better. It is easy to navigate, fun to use, and helpful to anyone struggling in absolutely any way.
David K
iOS user
The app's just great! All I have to do is enter the topic in the search bar and I get the response real fast. I don't have to watch 10 YouTube videos to understand something, so I'm saving my time. Highly recommended!
Sudenaz Ocak
Android user
In school I was really bad at maths but thanks to the app, I am doing better now. I am so grateful that you made the app.
Greenlight Bonnie
Android user
very reliable app to help and grow your ideas of Maths, English and other related topics in your works. please use this app if your struggling in areas, this app is key for that. wish I'd of done a review before. and it's also free so don't worry about that.
Rohan U
Android user
I know a lot of apps use fake accounts to boost their reviews but this app deserves it all. Originally I was getting 4 in my English exams and this time I got a grade 7. I didn’t even know about this app three days until the exam and it has helped A LOT. Please actually trust me and use it as I’m sure you too will see developments.
Xander S
iOS user
THE QUIZES AND FLASHCARDS ARE SO USEFUL AND I LOVE THE SCHOOLGPT. IT ALSO IS LITREALLY LIKE CHATGPT BUT SMARTER!! HELPED ME WITH MY MASCARA PROBLEMS TOO!! AS WELL AS MY REAL SUBJECTS ! DUHHH 😍😁😲🤑💗✨🎀😮
Elisha
iOS user
This apps acc the goat. I find revision so boring but this app makes it so easy to organize it all and then you can ask the freeeee ai to test yourself so good and you can easily upload your own stuff. highly recommend as someone taking mocks now
Paul T
iOS user
The app is very easy to use and well designed. I have found everything I was looking for so far and have been able to learn a lot from the presentations! I will definitely use the app for a class assignment! And of course it also helps a lot as an inspiration.
Stefan S
iOS user
This app is really great. There are so many study notes and help [...]. My problem subject is French, for example, and the app has so many options for help. Thanks to this app, I have improved my French. I would recommend it to anyone.
Samantha Klich
Android user
Wow, I am really amazed. I just tried the app because I've seen it advertised many times and was absolutely stunned. This app is THE HELP you want for school and above all, it offers so many things, such as workouts and fact sheets, which have been VERY helpful to me personally.
Anna
iOS user
Best app on earth! no words because it’s too good
Thomas R
iOS user
Just amazing. Let's me revise 10x better, this app is a quick 10/10. I highly recommend it to anyone. I can watch and search for notes. I can save them in the subject folder. I can revise it any time when I come back. If you haven't tried this app, you're really missing out.
Basil
Android user
This app has made me feel so much more confident in my exam prep, not only through boosting my own self confidence through the features that allow you to connect with others and feel less alone, but also through the way the app itself is centred around making you feel better. It is easy to navigate, fun to use, and helpful to anyone struggling in absolutely any way.
David K
iOS user
The app's just great! All I have to do is enter the topic in the search bar and I get the response real fast. I don't have to watch 10 YouTube videos to understand something, so I'm saving my time. Highly recommended!
Sudenaz Ocak
Android user
In school I was really bad at maths but thanks to the app, I am doing better now. I am so grateful that you made the app.
Greenlight Bonnie
Android user
very reliable app to help and grow your ideas of Maths, English and other related topics in your works. please use this app if your struggling in areas, this app is key for that. wish I'd of done a review before. and it's also free so don't worry about that.
Rohan U
Android user
I know a lot of apps use fake accounts to boost their reviews but this app deserves it all. Originally I was getting 4 in my English exams and this time I got a grade 7. I didn’t even know about this app three days until the exam and it has helped A LOT. Please actually trust me and use it as I’m sure you too will see developments.
Xander S
iOS user
THE QUIZES AND FLASHCARDS ARE SO USEFUL AND I LOVE THE SCHOOLGPT. IT ALSO IS LITREALLY LIKE CHATGPT BUT SMARTER!! HELPED ME WITH MY MASCARA PROBLEMS TOO!! AS WELL AS MY REAL SUBJECTS ! DUHHH 😍😁😲🤑💗✨🎀😮
Elisha
iOS user
This apps acc the goat. I find revision so boring but this app makes it so easy to organize it all and then you can ask the freeeee ai to test yourself so good and you can easily upload your own stuff. highly recommend as someone taking mocks now
Paul T
iOS user