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Britain & the wider world: 1745 -1901
1l the quest for political stability: germany, 1871-1991
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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
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2n revolution and dictatorship: russia, 1917-1953
2s the making of modern britain, 1951-2007
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Biology
12 Dec 2025
38
2 pages
Kiana Coheh @kianacoheh_fdcp
Your blood is like a super-efficient delivery service that never stops working! It's made up of four key... Show more
Think of blood as your body's ultimate multitasking team - each component has a crucial role that keeps you alive and healthy.
Red blood cells (RBCs) are the oxygen delivery specialists. They're packed with haemoglobin, a red pigment that grabs oxygen in your lungs and carries it everywhere it's needed. These cells have no nucleus (making more room for oxygen) and a bi-concave shape that increases their surface area for maximum efficiency.
White blood cells are your personal bodyguards. They're bigger than red blood cells and have large nuclei to control their protective functions. Through phagocytosis, they surround and digest harmful microbes, plus they produce antibodies and antitoxins to fight infections.
The other two components are platelets (tiny cell fragments that help blood clot when you're injured) and plasma (the yellow liquid that transports everything around your body, including carbon dioxide and minerals). The amazing thing about haemoglobin is its reversible reaction haemoglobin + oxygen ↔ oxyhaemoglobin, which makes it possible for oxygen to be picked up in the lungs and released at tissues.
Quick Tip Remember that red blood cells have NO nucleus - this extra space lets them carry more oxygen!
Your blood vessels are like a sophisticated motorway system with three different types of roads, each perfectly designed for their specific job.
Arteries are the high-pressure motorways carrying oxygenated blood away from your heart. They have thick, muscular walls to withstand the powerful pressure from each heartbeat. With no valves and a small lumen (space inside), they're built for speed and efficiency in delivering oxygen and glucose to your body.
Veins work like the return journey - they carry deoxygenated blood back to your heart under much lower pressure. Their large lumen allows them to transport lots of blood, whilst valves prevent any backflow. Think of these valves like one-way gates ensuring blood only flows toward the heart.
Capillaries are where the real action happens - they're the tiny vessels (just one cell thick) that get up close and personal with your body cells. Their thin, permeable walls allow gases and nutrients to exchange easily. With low pressure and slow blood flow, they give plenty of time for this vital exchange to occur.
Remember Arteries = Away from heart, Veins = Toward heart, Capillaries = Close contact with cells!
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.
1
Smart Tools NEW
Transform this note into: ✓ 50+ Practice Questions ✓ Interactive Flashcards ✓ Full Mock Exam ✓ Essay Outlines
Explore the intricate functions of the heart and lungs, including the process of gas exchange in alveoli and the circulation of oxygenated and deoxygenated blood. This summary covers key structures such as the bronchi, alveoli, and heart valves, and discusses the role of the natural pacemaker and artificial pacemakers in maintaining heart rhythm. Ideal for students studying human anatomy and physiology.
BiologyExplore the functions and adaptations of blood vessels in the circulatory system. This summary covers blood flow direction, pressure differences, and the structure of arteries, veins, and capillaries, along with a diagram illustrating the heart's role in blood circulation. Ideal for understanding blood transport in humans.
BiologyExplore key concepts in National 5 Biology Unit 2, covering the nervous and endocrine systems, cell specialization, genetic inheritance, and biological processes. This summary includes essential topics such as mitosis, meiosis, fertilization, and the structure and function of the heart. Ideal for exam preparation and understanding biological systems. Type: Summary.
BiologyExplore the specialisation of animal and plant cells, focusing on their structures and functions. This summary covers key concepts such as muscle, nerve, red blood, root hair, xylem, and phloem cells, detailing how their adaptations enable specific roles within tissues and organs. Ideal for GCSE students preparing for exams.
BiologyExplore the structure and function of the heart and blood vessels in the circulatory system. This summary covers the roles of arteries, veins, and capillaries, detailing how blood is transported throughout the body. Ideal for AQA GCSE Biology students preparing for exams.
BiologyExplore the structure and function of blood vessels, including arteries, veins, and capillaries. Understand how each type is adapted for its role in the circulatory system, focusing on their walls, lumen, and the importance of valves in veins. This summary provides essential insights for students studying human anatomy and physiology.
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
Kiana Coheh
@kianacoheh_fdcp
Your blood is like a super-efficient delivery service that never stops working! It's made up of four key components that each have specific jobs, and it travels through a network of blood vessels that are perfectly designed for different tasks.
Access to all documents
Improve your grades
Join milions of students
By signing up you accept Terms of Service and Privacy Policy
Think of blood as your body's ultimate multitasking team - each component has a crucial role that keeps you alive and healthy.
Red blood cells (RBCs) are the oxygen delivery specialists. They're packed with haemoglobin, a red pigment that grabs oxygen in your lungs and carries it everywhere it's needed. These cells have no nucleus (making more room for oxygen) and a bi-concave shape that increases their surface area for maximum efficiency.
White blood cells are your personal bodyguards. They're bigger than red blood cells and have large nuclei to control their protective functions. Through phagocytosis, they surround and digest harmful microbes, plus they produce antibodies and antitoxins to fight infections.
The other two components are platelets (tiny cell fragments that help blood clot when you're injured) and plasma (the yellow liquid that transports everything around your body, including carbon dioxide and minerals). The amazing thing about haemoglobin is its reversible reaction: haemoglobin + oxygen ↔ oxyhaemoglobin, which makes it possible for oxygen to be picked up in the lungs and released at tissues.
Quick Tip: Remember that red blood cells have NO nucleus - this extra space lets them carry more oxygen!
Access to all documents
Improve your grades
Join milions of students
By signing up you accept Terms of Service and Privacy Policy
Your blood vessels are like a sophisticated motorway system with three different types of roads, each perfectly designed for their specific job.
Arteries are the high-pressure motorways carrying oxygenated blood away from your heart. They have thick, muscular walls to withstand the powerful pressure from each heartbeat. With no valves and a small lumen (space inside), they're built for speed and efficiency in delivering oxygen and glucose to your body.
Veins work like the return journey - they carry deoxygenated blood back to your heart under much lower pressure. Their large lumen allows them to transport lots of blood, whilst valves prevent any backflow. Think of these valves like one-way gates ensuring blood only flows toward the heart.
Capillaries are where the real action happens - they're the tiny vessels (just one cell thick) that get up close and personal with your body cells. Their thin, permeable walls allow gases and nutrients to exchange easily. With low pressure and slow blood flow, they give plenty of time for this vital exchange to occur.
Remember: Arteries = Away from heart, Veins = Toward heart, Capillaries = Close contact with cells!
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.
1
Smart Tools NEW
Transform this note into: ✓ 50+ Practice Questions ✓ Interactive Flashcards ✓ Full Mock Exam ✓ Essay Outlines
Explore the intricate functions of the heart and lungs, including the process of gas exchange in alveoli and the circulation of oxygenated and deoxygenated blood. This summary covers key structures such as the bronchi, alveoli, and heart valves, and discusses the role of the natural pacemaker and artificial pacemakers in maintaining heart rhythm. Ideal for students studying human anatomy and physiology.
BiologyExplore the functions and adaptations of blood vessels in the circulatory system. This summary covers blood flow direction, pressure differences, and the structure of arteries, veins, and capillaries, along with a diagram illustrating the heart's role in blood circulation. Ideal for understanding blood transport in humans.
BiologyExplore key concepts in National 5 Biology Unit 2, covering the nervous and endocrine systems, cell specialization, genetic inheritance, and biological processes. This summary includes essential topics such as mitosis, meiosis, fertilization, and the structure and function of the heart. Ideal for exam preparation and understanding biological systems. Type: Summary.
BiologyExplore the specialisation of animal and plant cells, focusing on their structures and functions. This summary covers key concepts such as muscle, nerve, red blood, root hair, xylem, and phloem cells, detailing how their adaptations enable specific roles within tissues and organs. Ideal for GCSE students preparing for exams.
BiologyExplore the structure and function of the heart and blood vessels in the circulatory system. This summary covers the roles of arteries, veins, and capillaries, detailing how blood is transported throughout the body. Ideal for AQA GCSE Biology students preparing for exams.
BiologyExplore the structure and function of blood vessels, including arteries, veins, and capillaries. Understand how each type is adapted for its role in the circulatory system, focusing on their walls, lumen, and the importance of valves in veins. This summary provides essential insights for students studying human anatomy and physiology.
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