Maths
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Responding to change (a2 only)
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Organisms respond to changes in their internal and external environments (a-level only)
Biological molecules
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Substance exchange
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Britain & the wider world: 1745 -1901
1l the quest for political stability: germany, 1871-1991
The cold war
Inter-war germany
Medieval period: 1066 -1509
2d religious conflict and the church in england, c1529-c1570
2o democracy and nazism: germany, 1918-1945
1f industrialisation and the people: britain, c1783-1885
1c the tudors: england, 1485-1603
2m wars and welfare: britain in transition, 1906-1957
World war two & the holocaust
2n revolution and dictatorship: russia, 1917-1953
2s the making of modern britain, 1951-2007
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Biology
3 Dec 2025
273
1 page
Leia ๐ซง @aleyahafsa
Your circulatory system is like a massive motorway network, but instead of cars, it carries blood around your... Show more
Think of blood vessels as three different types of roads in your body's transport system. Arteries are like motorways carrying blood away from your heart at high speed. Capillaries act as tiny local streets where all the actual deliveries happen. Veins are the return routes bringing blood back to your heart.
Each vessel type has a completely different job, which explains why they're built so differently. Arteries need to handle the powerful pumping force from your heart, whilst veins just need to guide blood gently back home.
Arteries are the tough guys of the blood vessel world. Since your heart pumps blood through them at high pressure, they've got thick, muscular walls packed with elastic fibres. The walls are actually thicker than the space (called the lumen) where blood flows through - imagine a garden hose with really thick rubber walls.
Quick Tip Remember "A for Away" - Arteries carry blood Away from the heart!
Capillaries are where the magic happens. These microscopic vessels are only one cell thick, making them super permeable so oxygen, food, and waste can easily pass through. Blood flows much slower here, giving time for your cells to grab what they need and dump their rubbish like carbon dioxide.
Veins have the easiest job but face one big challenge - fighting gravity. Since blood pressure is much lower by the time it reaches veins, they have thin walls and large lumens to help blood flow smoothly. They also have special valves that act like one-way gates, stopping blood from flowing backwards when you're standing up.
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.
You can download the app from Google Play Store and Apple App Store.
That's right! Enjoy free access to study content, connect with fellow students, and get instant help โ all at your fingertips.
6
Smart Tools NEW
Transform this note into: โ 50+ Practice Questions โ Interactive Flashcards โ Full Mock Exam โ Essay Outlines
Explore the intricacies of the mammalian circulatory system, including the structure and function of the heart, the cardiac cycle, and the roles of various blood components. This summary covers key concepts such as blood circulation, heart anatomy, and the types of blood cells, providing essential insights for A Level Biology students.
BiologyExplore the essential components of blood, including plasma, erythrocytes, leukocytes, and platelets. Understand the blood clotting process step-by-step and its significance in the circulatory system. This summary also includes key questions to test your knowledge on blood functions and disorders like hemophilia.
BiologyExplore the key functions and components of the circulatory system, including blood circulation, blood vessels, and heart functions. This summary covers the roles of red and white blood cells, plasma, and the mechanics of arteries, veins, and capillaries. Ideal for GCSE biology students preparing for exams.
BiologyExplore the critical role of haemoglobin in oxygen transport within red blood cells. This summary covers the quaternary structure of haemoglobin, the oxyhaemoglobin dissociation curve, the Bohr effect, and adaptations in different organisms. Ideal for AQA AS and A-level Biology students preparing for exams.
BiologyComprehensive overview of plant reproduction processes, including gamete formation, pollination mechanisms, fertilization, and germination. This resource covers key concepts such as mitosis and meiosis, plant anatomy, and the roles of plant hormones, tailored for EDUQAS A Level Biology students.
BiologyExplore the essential roles of the circulatory system, including the heart, blood vessels, and their functions in transporting oxygen, nutrients, and waste. This summary covers key concepts such as pulmonary and systemic circulation, emphasizing the importance of maintaining healthy organs and tissues. Ideal for students studying animal transport systems.
BiologyApp Store
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 itโs 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 didnโt even know about this app three days until the exam and it has helped A LOT. Please actually trust me and use it as Iโm 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 ๐๐๐ฒ๐ค๐โจ๐๐ฎ
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 itโs 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 didnโt even know about this app three days until the exam and it has helped A LOT. Please actually trust me and use it as Iโm 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 ๐๐๐ฒ๐ค๐โจ๐๐ฎ
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
Leia ๐ซง
@aleyahafsa
Your circulatory system is like a massive motorway network, but instead of cars, it carries blood around your body. Understanding the three types of blood vessels and how they work differently is crucial for grasping how your body delivers oxygen... Show more
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Think of blood vessels as three different types of roads in your body's transport system. Arteries are like motorways carrying blood away from your heart at high speed. Capillaries act as tiny local streets where all the actual deliveries happen. Veins are the return routes bringing blood back to your heart.
Each vessel type has a completely different job, which explains why they're built so differently. Arteries need to handle the powerful pumping force from your heart, whilst veins just need to guide blood gently back home.
Arteries are the tough guys of the blood vessel world. Since your heart pumps blood through them at high pressure, they've got thick, muscular walls packed with elastic fibres. The walls are actually thicker than the space (called the lumen) where blood flows through - imagine a garden hose with really thick rubber walls.
Quick Tip: Remember "A for Away" - Arteries carry blood Away from the heart!
Capillaries are where the magic happens. These microscopic vessels are only one cell thick, making them super permeable so oxygen, food, and waste can easily pass through. Blood flows much slower here, giving time for your cells to grab what they need and dump their rubbish like carbon dioxide.
Veins have the easiest job but face one big challenge - fighting gravity. Since blood pressure is much lower by the time it reaches veins, they have thin walls and large lumens to help blood flow smoothly. They also have special valves that act like one-way gates, stopping blood from flowing backwards when you're standing up.
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.
You can download the app from Google Play Store and Apple App Store.
That's right! Enjoy free access to study content, connect with fellow students, and get instant help โ all at your fingertips.
6
Smart Tools NEW
Transform this note into: โ 50+ Practice Questions โ Interactive Flashcards โ Full Mock Exam โ Essay Outlines
Explore the intricacies of the mammalian circulatory system, including the structure and function of the heart, the cardiac cycle, and the roles of various blood components. This summary covers key concepts such as blood circulation, heart anatomy, and the types of blood cells, providing essential insights for A Level Biology students.
BiologyExplore the essential components of blood, including plasma, erythrocytes, leukocytes, and platelets. Understand the blood clotting process step-by-step and its significance in the circulatory system. This summary also includes key questions to test your knowledge on blood functions and disorders like hemophilia.
BiologyExplore the key functions and components of the circulatory system, including blood circulation, blood vessels, and heart functions. This summary covers the roles of red and white blood cells, plasma, and the mechanics of arteries, veins, and capillaries. Ideal for GCSE biology students preparing for exams.
BiologyExplore the critical role of haemoglobin in oxygen transport within red blood cells. This summary covers the quaternary structure of haemoglobin, the oxyhaemoglobin dissociation curve, the Bohr effect, and adaptations in different organisms. Ideal for AQA AS and A-level Biology students preparing for exams.
BiologyComprehensive overview of plant reproduction processes, including gamete formation, pollination mechanisms, fertilization, and germination. This resource covers key concepts such as mitosis and meiosis, plant anatomy, and the roles of plant hormones, tailored for EDUQAS A Level Biology students.
BiologyExplore the essential roles of the circulatory system, including the heart, blood vessels, and their functions in transporting oxygen, nutrients, and waste. This summary covers key concepts such as pulmonary and systemic circulation, emphasizing the importance of maintaining healthy organs and tissues. Ideal for students studying animal transport systems.
BiologyApp Store
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 itโs 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 didnโt even know about this app three days until the exam and it has helped A LOT. Please actually trust me and use it as Iโm 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 ๐๐๐ฒ๐ค๐โจ๐๐ฎ
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 itโs 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 didnโt even know about this app three days until the exam and it has helped A LOT. Please actually trust me and use it as Iโm 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 ๐๐๐ฒ๐ค๐โจ๐๐ฎ
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
Sociology