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
11 Dec 2025
518
1 page
Ever wonder how your body keeps itself running smoothly without you having to think about it? Homeostasisis... Show more
Your body is constantly working behind the scenes to keep everything balanced through homeostasis. Think of it like a really smart thermostat that controls your blood glucose, body temperature, and water levels automatically.
Every control system in your body works like a well-oiled machine with three main parts. Receptors act like sensors that spot changes (imagine tiny security cameras throughout your body). Coordination centres like your brain and pancreas process this information and decide what to do. Finally, effectors such as muscles and glands actually carry out the response.
Your nervous system works like the body's electrical wiring system. When receptor cells detect something, they convert it into an electrical signal that zooms along sensory neurones to your central nervous system. After processing, motor neurones carry the response back to your muscles or glands to take action.
Quick Tip Remember the pathway - receptors detect, coordination centres decide, effectors respond!
Reflex actions are your body's emergency response team - they're automatic, lightning-fast, and happen without you even thinking. When you touch something hot, the signal travels from sensory neurones to relay neurones (via neurotransmitters across synapses), then to motor neurones, and finally to your muscles to pull your hand away.
Your brain has different areas with specific jobs. The cerebral cortex handles your personality, memory, and language - basically everything that makes you "you". The cerebellum keeps your movements smooth and coordinated, whilst the medulla quietly manages vital functions like breathing and heartbeat. Scientists find studying the brain challenging because it's incredibly complex and easily damaged.
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.
3
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Transform this note into: ✓ 50+ Practice Questions ✓ Interactive Flashcards ✓ Full Mock Exam ✓ Essay Outlines
Explore the intricate relationship between the nervous system and eye anatomy in this comprehensive study resource. Covering key concepts such as synaptic transmission, visual processes, and the structure of photoreceptors, this material is tailored for Edexcel IGCSE Biology students. Understand how the eye accommodates for vision and the role of sensory receptors in perception.
BiologyExplore the anatomy and function of the human eye in this GCSE AQA Biology summary. Key topics include the cornea, retina, fovea, cones and rods, and the mechanisms of accommodation. Understand conditions like myopia and hyperopia, and how the eye adapts to different light conditions through circular and radial muscles.
BiologyExplore the structure of the eye, including key components like the cornea, lens, and retina. Learn about short-sightedness (myopia) and long-sightedness (hyperopia), their causes, and correction methods such as concave and convex lenses. This summary provides essential insights into the visual process and eye health.
BiologyExplore the detailed structure and functions of the human eye, including the roles of the sclera, cornea, iris, and lens. Understand vision defects like myopia and hyperopia, and learn about corrective treatments such as contact lenses and laser surgery. This summary is essential for GCSE biology students focusing on eye anatomy and visual processes.
BiologyExplore the intricate structures of the eye and brain, including common defects like myopia and hyperopia, and their corrective treatments. This summary covers key concepts such as eye anatomy, brain structure, and neuroimaging techniques, providing a comprehensive overview for students studying human biology.
BiologyExplore the structure and function of the human nervous system, including neurons, reflex arcs, and the adaptation of the eye. This summary covers key concepts such as neural transmission, synapses, and the anatomy of the eye, providing essential insights for AQA GCSE students.
BiologyQuotes from every main character
English LiteratureApp 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
Ever wonder how your body keeps itself running smoothly without you having to think about it? Homeostasisis your body's amazing ability to maintain perfect internal conditions, like keeping your temperature steady and your blood sugar levels just right, even... Show more
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Your body is constantly working behind the scenes to keep everything balanced through homeostasis. Think of it like a really smart thermostat that controls your blood glucose, body temperature, and water levels automatically.
Every control system in your body works like a well-oiled machine with three main parts. Receptors act like sensors that spot changes (imagine tiny security cameras throughout your body). Coordination centres like your brain and pancreas process this information and decide what to do. Finally, effectors such as muscles and glands actually carry out the response.
Your nervous system works like the body's electrical wiring system. When receptor cells detect something, they convert it into an electrical signal that zooms along sensory neurones to your central nervous system. After processing, motor neurones carry the response back to your muscles or glands to take action.
Quick Tip: Remember the pathway - receptors detect, coordination centres decide, effectors respond!
Reflex actions are your body's emergency response team - they're automatic, lightning-fast, and happen without you even thinking. When you touch something hot, the signal travels from sensory neurones to relay neurones (via neurotransmitters across synapses), then to motor neurones, and finally to your muscles to pull your hand away.
Your brain has different areas with specific jobs. The cerebral cortex handles your personality, memory, and language - basically everything that makes you "you". The cerebellum keeps your movements smooth and coordinated, whilst the medulla quietly manages vital functions like breathing and heartbeat. Scientists find studying the brain challenging because it's incredibly complex and easily damaged.
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.
3
Smart Tools NEW
Transform this note into: ✓ 50+ Practice Questions ✓ Interactive Flashcards ✓ Full Mock Exam ✓ Essay Outlines
Explore the intricate relationship between the nervous system and eye anatomy in this comprehensive study resource. Covering key concepts such as synaptic transmission, visual processes, and the structure of photoreceptors, this material is tailored for Edexcel IGCSE Biology students. Understand how the eye accommodates for vision and the role of sensory receptors in perception.
BiologyExplore the anatomy and function of the human eye in this GCSE AQA Biology summary. Key topics include the cornea, retina, fovea, cones and rods, and the mechanisms of accommodation. Understand conditions like myopia and hyperopia, and how the eye adapts to different light conditions through circular and radial muscles.
BiologyExplore the structure of the eye, including key components like the cornea, lens, and retina. Learn about short-sightedness (myopia) and long-sightedness (hyperopia), their causes, and correction methods such as concave and convex lenses. This summary provides essential insights into the visual process and eye health.
BiologyExplore the detailed structure and functions of the human eye, including the roles of the sclera, cornea, iris, and lens. Understand vision defects like myopia and hyperopia, and learn about corrective treatments such as contact lenses and laser surgery. This summary is essential for GCSE biology students focusing on eye anatomy and visual processes.
BiologyExplore the intricate structures of the eye and brain, including common defects like myopia and hyperopia, and their corrective treatments. This summary covers key concepts such as eye anatomy, brain structure, and neuroimaging techniques, providing a comprehensive overview for students studying human biology.
BiologyExplore the structure and function of the human nervous system, including neurons, reflex arcs, and the adaptation of the eye. This summary covers key concepts such as neural transmission, synapses, and the anatomy of the eye, providing essential insights for AQA GCSE students.
BiologyQuotes from every main character
English LiteratureApp 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