Subjects
Maths
Chemistry
Biology
English Language
History
Responding to change (a2 only)
Infection and response
Homeostasis and response
Energy transfers (a2 only)
Cell biology
Organisms respond to changes in their internal and external environments (a-level only)
Biological molecules
Organisation
Substance exchange
Bioenergetics
Genetic information & variation
Inheritance, variation and evolution
Genetics & ecosystems (a2 only)
Ecology
Cells
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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
World war one
Britain: 1509 -1745
Show all topics
Biology
3 Dec 2025
536
2 pages
George @george_aakl
Your heart is basically a powerful pump that never stops working, pushing blood around your body 24/7. Understanding... Show more
Ever wonder how your heart manages to pump blood to every single cell in your body? The process is surprisingly straightforward! Blood flows into the two upper chambers (atria) from major veins, then gets squeezed down into the lower chambers (ventricles), which pump it back out to your organs.
Arteries are like motorways for blood - they carry it away from your heart at high pressure. That's why they need thick, muscular walls with elastic fibres that can stretch and bounce back. Think of them as high-pressure hoses that need to be strong enough not to burst.
When arteries reach your tissues, they branch into tiny capillaries - these are where the real action happens. They're incredibly thin (just one cell thick) and have permeable walls, making it super easy for oxygen and nutrients to slip out to your cells whilst carbon dioxide and waste slip back in.
Veins bring blood back to your heart, but by now the pressure's much lower. They've got bigger internal spaces and special valves to keep blood flowing in the right direction - a bit like one-way gates preventing backflow.
Quick Tip Remember that arteries carry blood away from the heart - both words start with 'A'!
Blood isn't just red liquid - it's actually a complex tissue made up of different components floating in a straw-coloured liquid called plasma. Each part has a specific job that keeps you alive and healthy.
Red blood cells are your body's delivery service for oxygen. They're shaped like doughnuts without holes (biconcave), which gives them loads of surface area to pick up oxygen. They're packed with haemoglobin - the red stuff that actually carries the oxygen - and don't have a nucleus so there's more room for this vital protein.
White blood cells are your personal bodyguards, fighting off nasty microorganisms in three main ways. They can literally eat invaders (phagocytosis), produce antibodies to target specific threats, and make antitoxins to neutralise any poisonous substances. Unlike red blood cells, these do have a nucleus.
Platelets are tiny cell fragments that act like natural plasters. When you get cut, they clump together to form clots, stopping bleeding and keeping germs out. Plasma carries everything around - from nutrients and hormones to waste products heading for disposal.
Remember You can calculate blood flow rate by dividing the volume of blood by the number of minutes - useful for exam calculations!
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 – all at your fingertips.
5
Smart Tools NEW
Transform this note into: ✓ 50+ Practice Questions ✓ Interactive Flashcards ✓ Full Mock Exam ✓ Essay Outlines
A comprehensive summary of key concepts in Biology Paper 1, covering topics such as blood flow, the immune system, cellular processes, and disease classification. This resource is ideal for students preparing for exams, providing insights into cardiovascular health, cellular respiration, and the role of enzymes. Enhance your understanding of biological systems and processes with this concise guide.
BiologyComprehensive summary of key concepts in GCSE Biology, covering cell structures, respiration, transport systems, digestion, and the immune response. Ideal for AQA GCSE students preparing for Paper 1. Enhance your understanding of enzymes, photosynthesis, and the circulatory system with this concise guide.
BiologyExplore the key functions and components of the circulatory system, including blood flow, heart structure, and the role of blood vessels. This summary covers the effects of exercise on pulse rate, the importance of red and white blood cells, and the process of blood circulation in the body. Ideal for GCSE Biology students preparing for exams.
BiologyExplore key concepts in human and plant organization with this interactive study resource. Covering blood components, circulatory and digestive systems, plant structures, and the role of enzymes, this resource is designed for GCSE Biology students. Engage with active recall questions to reinforce your understanding of topics such as heart disease, cancer, and nutrient transport. Perfect for exam preparation and enhancing your knowledge of biological systems.
BiologyExplore the intricacies of the cardiovascular system, including the cardiac cycle, blood circulation, and the structure and function of the heart and blood vessels. This summary provides essential insights into how the heart pumps blood, the roles of arteries and veins, and the significance of the circulatory system in transporting nutrients and oxygen throughout the body.
BiologyExplore the key concepts of human body organization, focusing on the circulatory and digestive systems. This summary covers the structure and function of major organs, including the heart, lungs, and digestive tract, essential for AQA Combined Science revision.
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 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
George
@george_aakl
Your heart is basically a powerful pump that never stops working, pushing blood around your body 24/7. Understanding how your circulatory system works is crucial for GCSE Biology - and it's actually pretty fascinating once you see how perfectly designed... Show more
Access to all documents
Improve your grades
Join milions of students
By signing up you accept Terms of Service and Privacy Policy
Ever wonder how your heart manages to pump blood to every single cell in your body? The process is surprisingly straightforward! Blood flows into the two upper chambers (atria) from major veins, then gets squeezed down into the lower chambers (ventricles), which pump it back out to your organs.
Arteries are like motorways for blood - they carry it away from your heart at high pressure. That's why they need thick, muscular walls with elastic fibres that can stretch and bounce back. Think of them as high-pressure hoses that need to be strong enough not to burst.
When arteries reach your tissues, they branch into tiny capillaries - these are where the real action happens. They're incredibly thin (just one cell thick) and have permeable walls, making it super easy for oxygen and nutrients to slip out to your cells whilst carbon dioxide and waste slip back in.
Veins bring blood back to your heart, but by now the pressure's much lower. They've got bigger internal spaces and special valves to keep blood flowing in the right direction - a bit like one-way gates preventing backflow.
Quick Tip: Remember that arteries carry blood away from the heart - both words start with 'A'!
Access to all documents
Improve your grades
Join milions of students
By signing up you accept Terms of Service and Privacy Policy
Blood isn't just red liquid - it's actually a complex tissue made up of different components floating in a straw-coloured liquid called plasma. Each part has a specific job that keeps you alive and healthy.
Red blood cells are your body's delivery service for oxygen. They're shaped like doughnuts without holes (biconcave), which gives them loads of surface area to pick up oxygen. They're packed with haemoglobin - the red stuff that actually carries the oxygen - and don't have a nucleus so there's more room for this vital protein.
White blood cells are your personal bodyguards, fighting off nasty microorganisms in three main ways. They can literally eat invaders (phagocytosis), produce antibodies to target specific threats, and make antitoxins to neutralise any poisonous substances. Unlike red blood cells, these do have a nucleus.
Platelets are tiny cell fragments that act like natural plasters. When you get cut, they clump together to form clots, stopping bleeding and keeping germs out. Plasma carries everything around - from nutrients and hormones to waste products heading for disposal.
Remember: You can calculate blood flow rate by dividing the volume of blood by the number of minutes - useful for exam calculations!
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 – all at your fingertips.
5
Smart Tools NEW
Transform this note into: ✓ 50+ Practice Questions ✓ Interactive Flashcards ✓ Full Mock Exam ✓ Essay Outlines
A comprehensive summary of key concepts in Biology Paper 1, covering topics such as blood flow, the immune system, cellular processes, and disease classification. This resource is ideal for students preparing for exams, providing insights into cardiovascular health, cellular respiration, and the role of enzymes. Enhance your understanding of biological systems and processes with this concise guide.
BiologyComprehensive summary of key concepts in GCSE Biology, covering cell structures, respiration, transport systems, digestion, and the immune response. Ideal for AQA GCSE students preparing for Paper 1. Enhance your understanding of enzymes, photosynthesis, and the circulatory system with this concise guide.
BiologyExplore the key functions and components of the circulatory system, including blood flow, heart structure, and the role of blood vessels. This summary covers the effects of exercise on pulse rate, the importance of red and white blood cells, and the process of blood circulation in the body. Ideal for GCSE Biology students preparing for exams.
BiologyExplore key concepts in human and plant organization with this interactive study resource. Covering blood components, circulatory and digestive systems, plant structures, and the role of enzymes, this resource is designed for GCSE Biology students. Engage with active recall questions to reinforce your understanding of topics such as heart disease, cancer, and nutrient transport. Perfect for exam preparation and enhancing your knowledge of biological systems.
BiologyExplore the intricacies of the cardiovascular system, including the cardiac cycle, blood circulation, and the structure and function of the heart and blood vessels. This summary provides essential insights into how the heart pumps blood, the roles of arteries and veins, and the significance of the circulatory system in transporting nutrients and oxygen throughout the body.
BiologyExplore the key concepts of human body organization, focusing on the circulatory and digestive systems. This summary covers the structure and function of major organs, including the heart, lungs, and digestive tract, essential for AQA Combined Science revision.
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 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
Sociology