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Biology B5 Revision Notes and Mindmaps
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Homeostasis and Control Systems
Ever wondered why your body temperature stays around 37°C whether you're in a hot classroom or outside in winter? That's homeostasis in action - your body's brilliant way of keeping internal conditions stable no matter what's happening around you.
Every automatic control system in your body follows the same pattern: receptors detect changes, coordination centres (like your brain) interpret what's happening, and effectors (muscles or glands) carry out the response. Think of it like a thermostat that automatically adjusts your heating.
Your body uses this system to control three crucial things: body temperature, blood glucose levels, and water content. These systems can work through your nervous system (super fast electrical signals) or through hormones (slower chemical messages).
Quick Tip: Remember the sequence - stimulus → receptor → coordination centre → effector → response. This pattern appears in every control system you'll study!
The Nervous System
Your nervous system is like your body's electrical wiring, sending lightning-fast messages to keep you safe and functioning. It's split into two main parts: the Central Nervous System (CNS) - your brain and spinal cord - and all the nerves that branch out from there.
When something happens (like touching something hot), receptors detect it and fire electrical impulses down sensory neurones to your CNS. Your brain or spinal cord then sends signals down motor neurones to effectors (muscles or glands) that create a response.
Reflex arcs are your body's emergency shortcuts that bypass your brain entirely. When you touch something painful, signals zip through your spinal cord and back to your muscles in milliseconds, pulling your hand away before you even realise what's happened. This rapid response system literally saves you from serious injury.
Remember: Reflexes are automatic, rapid, and don't involve the conscious brain - that's why they're so brilliantly protective!
Synapses and the Endocrine System
Synapses are the tiny gaps between nerve cells where the magic happens. Since electrical signals can't jump across gaps, your neurones release chemicals that diffuse across and trigger the next nerve cell. It's like passing a message by throwing a note across a small stream.
Your endocrine system works completely differently from your nervous system. Instead of electrical signals, it uses hormones - chemical messengers that travel through your bloodstream to specific target organs. Think of hormones as letters posted to particular addresses in your body.
Key hormone-producing glands include your pancreas (makes insulin to control blood sugar), ovaries and testes (produce sex hormones for puberty and reproduction), thyroid (controls growth and metabolism), and adrenal glands (release adrenaline during stress or fear).
The pituitary gland in your brain is the 'master gland' because it controls other glands, telling them when to release their hormones. While the nervous system is fast but short-lasting, the endocrine system works more slowly but has longer-lasting effects.
Key Difference: Nervous system = fast electrical signals; Endocrine system = slower chemical signals with lasting effects.
Blood Glucose Control
Your cells need glucose for energy, so keeping blood sugar levels stable is absolutely crucial for survival. This is where your pancreas becomes the hero of glucose control, constantly monitoring your blood sugar levels like a vigilant security guard.
After you eat a carb-heavy meal (think pasta or pizza), your blood glucose shoots up. Your pancreas responds by releasing insulin, a hormone that acts like a key, unlocking your cells so they can absorb glucose from your bloodstream.
Insulin also tells your liver and muscle cells to store excess glucose as glycogen - basically your body's glucose savings account. As glucose gets absorbed and stored, your blood sugar drops back to normal levels, keeping your cells happy and energised.
This whole process is a perfect example of homeostasis in action. Without this control system, your blood sugar would swing wildly up and down, which could be dangerous or even life-threatening.
Memory Trick: Think 'Insulin lets glucose IN' to help remember that insulin helps cells absorb glucose from the blood.
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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
Biology B5 Revision Notes and Mindmaps
P
Princy
@princy_15
Your body is constantly working behind the scenes to keep everything running smoothly, even when you're not thinking about it. This is called homeostasis - your body's automatic control system that keeps vital things like blood sugar, temperature, and water... Show more
Homeostasis and Control Systems
Ever wondered why your body temperature stays around 37°C whether you're in a hot classroom or outside in winter? That's homeostasis in action - your body's brilliant way of keeping internal conditions stable no matter what's happening around you.
Every automatic control system in your body follows the same pattern: receptors detect changes, coordination centres (like your brain) interpret what's happening, and effectors (muscles or glands) carry out the response. Think of it like a thermostat that automatically adjusts your heating.
Your body uses this system to control three crucial things: body temperature, blood glucose levels, and water content. These systems can work through your nervous system (super fast electrical signals) or through hormones (slower chemical messages).
Quick Tip: Remember the sequence - stimulus → receptor → coordination centre → effector → response. This pattern appears in every control system you'll study!
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The Nervous System
Your nervous system is like your body's electrical wiring, sending lightning-fast messages to keep you safe and functioning. It's split into two main parts: the Central Nervous System (CNS) - your brain and spinal cord - and all the nerves that branch out from there.
When something happens (like touching something hot), receptors detect it and fire electrical impulses down sensory neurones to your CNS. Your brain or spinal cord then sends signals down motor neurones to effectors (muscles or glands) that create a response.
Reflex arcs are your body's emergency shortcuts that bypass your brain entirely. When you touch something painful, signals zip through your spinal cord and back to your muscles in milliseconds, pulling your hand away before you even realise what's happened. This rapid response system literally saves you from serious injury.
Remember: Reflexes are automatic, rapid, and don't involve the conscious brain - that's why they're so brilliantly protective!
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Synapses and the Endocrine System
Synapses are the tiny gaps between nerve cells where the magic happens. Since electrical signals can't jump across gaps, your neurones release chemicals that diffuse across and trigger the next nerve cell. It's like passing a message by throwing a note across a small stream.
Your endocrine system works completely differently from your nervous system. Instead of electrical signals, it uses hormones - chemical messengers that travel through your bloodstream to specific target organs. Think of hormones as letters posted to particular addresses in your body.
Key hormone-producing glands include your pancreas (makes insulin to control blood sugar), ovaries and testes (produce sex hormones for puberty and reproduction), thyroid (controls growth and metabolism), and adrenal glands (release adrenaline during stress or fear).
The pituitary gland in your brain is the 'master gland' because it controls other glands, telling them when to release their hormones. While the nervous system is fast but short-lasting, the endocrine system works more slowly but has longer-lasting effects.
Key Difference: Nervous system = fast electrical signals; Endocrine system = slower chemical signals with lasting effects.
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Blood Glucose Control
Your cells need glucose for energy, so keeping blood sugar levels stable is absolutely crucial for survival. This is where your pancreas becomes the hero of glucose control, constantly monitoring your blood sugar levels like a vigilant security guard.
After you eat a carb-heavy meal (think pasta or pizza), your blood glucose shoots up. Your pancreas responds by releasing insulin, a hormone that acts like a key, unlocking your cells so they can absorb glucose from your bloodstream.
Insulin also tells your liver and muscle cells to store excess glucose as glycogen - basically your body's glucose savings account. As glucose gets absorbed and stored, your blood sugar drops back to normal levels, keeping your cells happy and energised.
This whole process is a perfect example of homeostasis in action. Without this control system, your blood sugar would swing wildly up and down, which could be dangerous or even life-threatening.
Memory Trick: Think 'Insulin lets glucose IN' to help remember that insulin helps cells absorb glucose from the blood.
We thought you’d never ask...
What is the Knowunity AI companion?
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.
Where can I download the Knowunity app?
You can download the app from Google Play Store and Apple App Store.
Is Knowunity really free of charge?
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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