Maths
Biology
Chemistry
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
1l the quest for political stability: germany, 1871-1991
Britain & the wider world: 1745 -1901
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
19 Nov 2025
250
2 pages
Nadiya Islam @nadiyaaa
The menstrual cycle is a monthly process that prepares your body for potential pregnancy. Four key hormones work... Show more
Your menstrual cycle runs on roughly a 28-day schedule, though this varies between individuals. Every month, your ovaries release an egg during ovulation, whilst your uterus prepares by thickening its lining to potentially support a fertilised egg.
If the egg isn't fertilised by sperm, both the egg and the thick uterine lining are shed during your period. This entire process is controlled by four crucial hormones working in sequence.
Follicle Stimulating Hormone (FSH) kicks off the cycle by making eggs mature in your ovaries. Luteinising Hormone (LH) then triggers the release of that mature egg. Meanwhile, oestrogen and progesterone work together to maintain the uterus lining, keeping it ready for a potential pregnancy.
Key Point Think of these hormones as a relay team - each one passes the baton to trigger the next stage of your cycle.
The hormone interaction follows a precise pattern that's brilliant in its complexity. FSH from your pituitary gland travels to your ovaries, causing egg maturation and triggering oestrogen production.
Rising oestrogen levels create a feedback loop - they stop FSH production whilst simultaneously triggering LH release. This LH surge around day 14 causes ovulation, after which your ovary switches to producing progesterone.
Progesterone keeps the uterus lining thick and blocks further FSH and LH release, preventing additional eggs from developing. However, if fertilisation doesn't occur, progesterone levels plummet, causing the uterine lining to shed as your period begins.
Exam Tip When reading hormone graphs, look for FSH rising first, then oestrogen, followed by the LH peak at ovulation, and finally progesterone's rise and fall.
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.
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Transform this note into: ✓ 50+ Practice Questions ✓ Interactive Flashcards ✓ Full Mock Exam ✓ Essay Outlines
paper 2 combined biology
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 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 fundamentals of electron microscopy, including Transmission Electron Microscopes (TEM) and Scanning Electron Microscopes (SEM). This summary highlights their advantages, disadvantages, and comparisons with light microscopes, focusing on resolution, magnification, and specimen preparation. Ideal for students studying microscopy techniques.
BiologyExplore the intricacies of the menstrual cycle, including the roles of hormones like LH, FSH, progesterone, and oestrogen. This summary covers the two main phases: the follicular phase and the luteal phase, detailing ovulation, endometrial preparation, and the potential for fertilization. Ideal for students studying human reproduction and the female reproductive system.
BiologyExplore the key phases of the menstrual cycle, detailing hormonal changes and physiological events from Day 1 to Day 28. This summary covers the shedding of the uterine lining, egg maturation, ovulation, and the impact of fertilization on the uterine environment. Ideal for students studying human reproduction and the female reproductive system.
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
Nadiya Islam
@nadiyaaa
The menstrual cycle is a monthly process that prepares your body for potential pregnancy. Four key hormones work together like a perfectly timed dance to control ovulation, prepare the uterus, and trigger periods when pregnancy doesn't occur.
Access to all documents
Improve your grades
Join milions of students
By signing up you accept Terms of Service and Privacy Policy
Your menstrual cycle runs on roughly a 28-day schedule, though this varies between individuals. Every month, your ovaries release an egg during ovulation, whilst your uterus prepares by thickening its lining to potentially support a fertilised egg.
If the egg isn't fertilised by sperm, both the egg and the thick uterine lining are shed during your period. This entire process is controlled by four crucial hormones working in sequence.
Follicle Stimulating Hormone (FSH) kicks off the cycle by making eggs mature in your ovaries. Luteinising Hormone (LH) then triggers the release of that mature egg. Meanwhile, oestrogen and progesterone work together to maintain the uterus lining, keeping it ready for a potential pregnancy.
Key Point: Think of these hormones as a relay team - each one passes the baton to trigger the next stage of your cycle.
Access to all documents
Improve your grades
Join milions of students
By signing up you accept Terms of Service and Privacy Policy
The hormone interaction follows a precise pattern that's brilliant in its complexity. FSH from your pituitary gland travels to your ovaries, causing egg maturation and triggering oestrogen production.
Rising oestrogen levels create a feedback loop - they stop FSH production whilst simultaneously triggering LH release. This LH surge around day 14 causes ovulation, after which your ovary switches to producing progesterone.
Progesterone keeps the uterus lining thick and blocks further FSH and LH release, preventing additional eggs from developing. However, if fertilisation doesn't occur, progesterone levels plummet, causing the uterine lining to shed as your period begins.
Exam Tip: When reading hormone graphs, look for FSH rising first, then oestrogen, followed by the LH peak at ovulation, and finally progesterone's rise and fall.
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.
9
Smart Tools NEW
Transform this note into: ✓ 50+ Practice Questions ✓ Interactive Flashcards ✓ Full Mock Exam ✓ Essay Outlines
paper 2 combined biology
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 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 fundamentals of electron microscopy, including Transmission Electron Microscopes (TEM) and Scanning Electron Microscopes (SEM). This summary highlights their advantages, disadvantages, and comparisons with light microscopes, focusing on resolution, magnification, and specimen preparation. Ideal for students studying microscopy techniques.
BiologyExplore the intricacies of the menstrual cycle, including the roles of hormones like LH, FSH, progesterone, and oestrogen. This summary covers the two main phases: the follicular phase and the luteal phase, detailing ovulation, endometrial preparation, and the potential for fertilization. Ideal for students studying human reproduction and the female reproductive system.
BiologyExplore the key phases of the menstrual cycle, detailing hormonal changes and physiological events from Day 1 to Day 28. This summary covers the shedding of the uterine lining, egg maturation, ovulation, and the impact of fertilization on the uterine environment. Ideal for students studying human reproduction and the female reproductive system.
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
