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21 Dec 2025
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Understanding the Conduction System in A Level PE (AQA)
Flo Wood
@flowood
Heart's Electrical System and Blood Flow
Think of your heart as having its own built-in electrical circuit that keeps everything running smoothly. The cardiac conduction system is like the heart's personal electrician - it sends electrical signals that make your heart contract in exactly the right order.
Your heart is myogenic, which means it generates its own electrical impulses without needing signals from your brain. Pretty cool, right? It all starts with the SA node (sinoatrial node), which is basically your heart's natural pacemaker located in the right atrium.
Here's how the electrical wave travels: The SA node fires an electrical impulse that spreads through the atria walls, making them contract and push blood into the ventricles. Then the signal hits the AV node (atrioventricular node), which acts like a traffic light - it delays the signal for about 0.1 seconds to make sure the atria finish contracting before the ventricles start.
Quick Tip: Think of it like a Mexican wave - the electrical impulse spreads through your heart muscle in a coordinated wave pattern!
The signal then travels down the bundle of His and splits into bundle branches before spreading through Purkinje fibres in the ventricle walls. This makes the ventricles contract and pump blood out of your heart. Meanwhile, your blood vessels have specific jobs: the aorta carries oxygenated blood from your heart to your body, whilst the vena cava brings deoxygenated blood back to your heart.
How Your Heart Responds to What You Need
Your heart isn't just beating randomly - it's constantly adjusting based on what your body needs. The cardiac control centre uses special sensors called chemoreceptors and baroreceptors to monitor your body and adjust your heart rate accordingly.
Chemoreceptors are like chemical detectives located in your carotid arteries (in your neck) and aortic arch (near your heart). They're constantly checking your blood for changes in carbon dioxide levels and pH. When CO₂ levels rise (like during exercise), these receptors send signals to speed up your heart rate through the sympathetic nervous system.
Baroreceptors work differently - they're pressure sensors in your arterial walls that detect changes in blood pressure. When your blood pressure changes, these receptors feel the stretching of the arterial wall and send signals to adjust your heart rate accordingly.
Real-world Connection: This is why your heart rate increases when you exercise - your chemoreceptors detect rising CO₂ levels and your body responds by pumping faster to deliver more oxygen!
This whole system works together to make sure your heart rate matches what your body actually needs at any given moment. It's like having an automatic transmission in a car - everything adjusts smoothly without you having to think about it.
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Anna
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Best app on earth! no words because it’s too good
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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
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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
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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
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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
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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
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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 the Conduction System in A Level PE (AQA)
Flo Wood
@flowood
Your heart is basically an electrical powerhouse that runs on its own internal wiring system. Understanding how blood flows through your heart and how it controls its own rhythm is crucial for A-level Biology - and it's actually pretty fascinating... Show more
Heart's Electrical System and Blood Flow
Think of your heart as having its own built-in electrical circuit that keeps everything running smoothly. The cardiac conduction system is like the heart's personal electrician - it sends electrical signals that make your heart contract in exactly the right order.
Your heart is myogenic, which means it generates its own electrical impulses without needing signals from your brain. Pretty cool, right? It all starts with the SA node (sinoatrial node), which is basically your heart's natural pacemaker located in the right atrium.
Here's how the electrical wave travels: The SA node fires an electrical impulse that spreads through the atria walls, making them contract and push blood into the ventricles. Then the signal hits the AV node (atrioventricular node), which acts like a traffic light - it delays the signal for about 0.1 seconds to make sure the atria finish contracting before the ventricles start.
Quick Tip: Think of it like a Mexican wave - the electrical impulse spreads through your heart muscle in a coordinated wave pattern!
The signal then travels down the bundle of His and splits into bundle branches before spreading through Purkinje fibres in the ventricle walls. This makes the ventricles contract and pump blood out of your heart. Meanwhile, your blood vessels have specific jobs: the aorta carries oxygenated blood from your heart to your body, whilst the vena cava brings deoxygenated blood back to your heart.
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How Your Heart Responds to What You Need
Your heart isn't just beating randomly - it's constantly adjusting based on what your body needs. The cardiac control centre uses special sensors called chemoreceptors and baroreceptors to monitor your body and adjust your heart rate accordingly.
Chemoreceptors are like chemical detectives located in your carotid arteries (in your neck) and aortic arch (near your heart). They're constantly checking your blood for changes in carbon dioxide levels and pH. When CO₂ levels rise (like during exercise), these receptors send signals to speed up your heart rate through the sympathetic nervous system.
Baroreceptors work differently - they're pressure sensors in your arterial walls that detect changes in blood pressure. When your blood pressure changes, these receptors feel the stretching of the arterial wall and send signals to adjust your heart rate accordingly.
Real-world Connection: This is why your heart rate increases when you exercise - your chemoreceptors detect rising CO₂ levels and your body responds by pumping faster to deliver more oxygen!
This whole system works together to make sure your heart rate matches what your body actually needs at any given moment. It's like having an automatic transmission in a car - everything adjusts smoothly without you having to think about it.
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?
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Is Knowunity really free of charge?
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Most popular content: Circulatory System
Most popular content in Physical Education
Most popular content
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