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
Show all topics
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
12 Dec 2025
117
3 pages
Gabby Drewery @gabbydrewery
Your body is like an incredibly smart machine that constantly adjusts itself to keep you alive and healthy. ... Show more
Ever wonder how your body knows exactly what to do when you touch something hot? Homeostasis is your body's built-in autopilot that regulates internal conditions like blood glucose, body temperature, and water levels. Think of it as your personal life-support system that never takes a break.
Your body uses two main communication networks the nervous system (super fast electrical signals) and hormones . Every control system has three key players receptors that detect changes, coordination centres like your brain that process information, and effectors (muscles or glands) that actually do something about it.
Reflex arcs are your body's emergency response team. When you touch something dangerously hot, sensory neurones instantly send signals to your spinal cord, which immediately activates motor neurones to pull your hand away. This happens faster than conscious thought – potentially saving you from serious injury.
The signal travels along neurones (long nerve cells) and jumps across tiny gaps called synapses using chemical messengers. Meanwhile, hormones like adrenaline are produced by glands, travel through your bloodstream, and create longer-lasting effects than nerve signals.
Quick Tip Remember the three-step control system detect (receptors) → process (coordination centres) → respond (effectors)
Your pancreas is like a glucose detective, constantly monitoring your blood sugar levels. When levels get too high after eating, it releases insulin to move glucose into your cells for energy or storage. When levels drop too low, it releases glucagon to convert stored glycogen back into glucose.
This creates a perfect negative feedback loop – high blood sugar triggers insulin release, which lowers blood sugar, which reduces insulin production. It's like a thermostat for your glucose levels, keeping everything balanced automatically.
Type 1 diabetes occurs when your pancreas can't produce enough insulin, requiring insulin injections. Type 2 diabetes happens when your cells stop responding to insulin properly, often linked to obesity and treated through diet and exercise changes.
Your reproductive system runs on key hormones too. Oestrogen and progesterone control the menstrual cycle, whilst FSH and LH manage egg development and ovulation. The menstrual cycle has three main phases follicular (preparation), ovulation (egg release), and luteal (waiting for potential pregnancy).
Exam Focus Learn the insulin-glucagon partnership – they work as opposites to maintain blood glucose balance
Contraception gives people control over fertility using various methods. Hormonal options like oral contraceptives work by stopping FSH production so no eggs mature, whilst barrier methods like condoms physically prevent sperm reaching the egg.
For couples struggling with infertility, fertility treatments can help. IVF treatment involves using FSH and LH to stimulate multiple egg production, collecting and fertilising eggs in a laboratory, then implanting embryos back into the uterus. However, success rates aren't guaranteed and the process can be emotionally challenging.
When you're stressed or scared, your adrenal glands pump out adrenaline – the famous "fight or flight" hormone. This instantly increases your heart rate and delivers extra oxygen and glucose to your brain and muscles, preparing your body for action.
Thyroxine from your thyroid gland controls your basal metabolic rate – essentially how fast your body's engine runs. It's crucial for growth and development, and like most hormones, it's regulated by negative feedback to maintain perfect balance.
Real-World Connection Understanding these systems helps explain everything from why you feel alert during exams (adrenaline) to how athletes manage their energy (glucose control)
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.
0
Smart Tools NEW
Transform this note into: ✓ 50+ Practice Questions ✓ Interactive Flashcards ✓ Full Mock Exam ✓ Essay Outlines
I hope this helps for higher tier biology
BiologyExplore the intricate hormonal control mechanisms in animals, focusing on the menstrual cycle, homeostasis, and the roles of key hormones like FSH, LH, oestrogen, and progesterone. This summary provides essential insights for GCSE Biology students, covering topics such as the menstrual cycle stages, hormone functions, and the impact of hormones on bodily processes. Ideal for exam preparation and understanding animal physiology.
BiologyExplore the intricate relationship between hormones and homeostasis in this comprehensive summary. Key topics include hormonal contraception, diabetes management, blood sugar regulation, and the menstrual cycle. Ideal for students aiming for high grades in biology, this resource provides essential insights into the endocrine system and its role in maintaining balance within the body.
BiologyExplore the stages of the menstrual cycle and the roles of the four key hormones: FSH, estrogen, LH, and progesterone. This summary covers the physiological changes throughout the cycle, including menstruation, ovulation, and hormonal regulation, essential for understanding female reproductive health.
BiologyExplore key concepts in human reproduction with this comprehensive set of revision questions. Covering topics such as gametogenesis, fertilization, the menstrual cycle, and hormonal control, this resource is tailored for A Level Biology students. Enhance your understanding of the male and female reproductive systems, embryology, and the hormonal processes involved in reproduction.
BiologyExplore the male and female reproductive systems, including the anatomy and functions of key structures such as the testes, ovaries, and uterus. Understand the menstrual cycle phases, ovulation, and hormonal changes. This summary provides essential insights for students studying human reproduction.
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
Gabby Drewery
@gabbydrewery
Your body is like an incredibly smart machine that constantly adjusts itself to keep you alive and healthy. Homeostasisis your body's amazing ability to maintain perfect internal conditions, whilst your nervous and hormonal systems work together like a high-tech... Show more
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Improve your grades
Join milions of students
By signing up you accept Terms of Service and Privacy Policy
Ever wonder how your body knows exactly what to do when you touch something hot? Homeostasis is your body's built-in autopilot that regulates internal conditions like blood glucose, body temperature, and water levels. Think of it as your personal life-support system that never takes a break.
Your body uses two main communication networks: the nervous system (super fast electrical signals) and hormones . Every control system has three key players: receptors that detect changes, coordination centres like your brain that process information, and effectors (muscles or glands) that actually do something about it.
Reflex arcs are your body's emergency response team. When you touch something dangerously hot, sensory neurones instantly send signals to your spinal cord, which immediately activates motor neurones to pull your hand away. This happens faster than conscious thought – potentially saving you from serious injury.
The signal travels along neurones (long nerve cells) and jumps across tiny gaps called synapses using chemical messengers. Meanwhile, hormones like adrenaline are produced by glands, travel through your bloodstream, and create longer-lasting effects than nerve signals.
Quick Tip: Remember the three-step control system: detect (receptors) → process (coordination centres) → respond (effectors)
Access to all documents
Improve your grades
Join milions of students
By signing up you accept Terms of Service and Privacy Policy
Your pancreas is like a glucose detective, constantly monitoring your blood sugar levels. When levels get too high after eating, it releases insulin to move glucose into your cells for energy or storage. When levels drop too low, it releases glucagon to convert stored glycogen back into glucose.
This creates a perfect negative feedback loop – high blood sugar triggers insulin release, which lowers blood sugar, which reduces insulin production. It's like a thermostat for your glucose levels, keeping everything balanced automatically.
Type 1 diabetes occurs when your pancreas can't produce enough insulin, requiring insulin injections. Type 2 diabetes happens when your cells stop responding to insulin properly, often linked to obesity and treated through diet and exercise changes.
Your reproductive system runs on key hormones too. Oestrogen and progesterone control the menstrual cycle, whilst FSH and LH manage egg development and ovulation. The menstrual cycle has three main phases: follicular (preparation), ovulation (egg release), and luteal (waiting for potential pregnancy).
Exam Focus: Learn the insulin-glucagon partnership – they work as opposites to maintain blood glucose balance
Access to all documents
Improve your grades
Join milions of students
By signing up you accept Terms of Service and Privacy Policy
Contraception gives people control over fertility using various methods. Hormonal options like oral contraceptives work by stopping FSH production so no eggs mature, whilst barrier methods like condoms physically prevent sperm reaching the egg.
For couples struggling with infertility, fertility treatments can help. IVF treatment involves using FSH and LH to stimulate multiple egg production, collecting and fertilising eggs in a laboratory, then implanting embryos back into the uterus. However, success rates aren't guaranteed and the process can be emotionally challenging.
When you're stressed or scared, your adrenal glands pump out adrenaline – the famous "fight or flight" hormone. This instantly increases your heart rate and delivers extra oxygen and glucose to your brain and muscles, preparing your body for action.
Thyroxine from your thyroid gland controls your basal metabolic rate – essentially how fast your body's engine runs. It's crucial for growth and development, and like most hormones, it's regulated by negative feedback to maintain perfect balance.
Real-World Connection: Understanding these systems helps explain everything from why you feel alert during exams (adrenaline) to how athletes manage their energy (glucose control)
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.
0
Smart Tools NEW
Transform this note into: ✓ 50+ Practice Questions ✓ Interactive Flashcards ✓ Full Mock Exam ✓ Essay Outlines
I hope this helps for higher tier biology
BiologyExplore the intricate hormonal control mechanisms in animals, focusing on the menstrual cycle, homeostasis, and the roles of key hormones like FSH, LH, oestrogen, and progesterone. This summary provides essential insights for GCSE Biology students, covering topics such as the menstrual cycle stages, hormone functions, and the impact of hormones on bodily processes. Ideal for exam preparation and understanding animal physiology.
BiologyExplore the intricate relationship between hormones and homeostasis in this comprehensive summary. Key topics include hormonal contraception, diabetes management, blood sugar regulation, and the menstrual cycle. Ideal for students aiming for high grades in biology, this resource provides essential insights into the endocrine system and its role in maintaining balance within the body.
BiologyExplore the stages of the menstrual cycle and the roles of the four key hormones: FSH, estrogen, LH, and progesterone. This summary covers the physiological changes throughout the cycle, including menstruation, ovulation, and hormonal regulation, essential for understanding female reproductive health.
BiologyExplore key concepts in human reproduction with this comprehensive set of revision questions. Covering topics such as gametogenesis, fertilization, the menstrual cycle, and hormonal control, this resource is tailored for A Level Biology students. Enhance your understanding of the male and female reproductive systems, embryology, and the hormonal processes involved in reproduction.
BiologyExplore the male and female reproductive systems, including the anatomy and functions of key structures such as the testes, ovaries, and uterus. Understand the menstrual cycle phases, ovulation, and hormonal changes. This summary provides essential insights for students studying human reproduction.
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