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25 Dec 2025
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Understanding the Human Body for GCSE PE AQA
Amelia
@_de4aqhxcxfsyib3ryl6
1 / 3
The Human Body: Functions and Joints
Your body performs six major functions: blood cell production, movement, protection, support, shape, and mineral storage. Each of these keeps you alive and functioning properly every day.
Joints are points where two bones meet, allowing movement. Synovial joints include hinge joints (knees, elbows, ankles) and ball and socket joints (hips, shoulders). When you move these joints, specific terms describe the actions: flexion decreases the angle at a joint, while extension increases it.
Your ankle has special movements called plantar flexion (pointing toes down, like standing on tiptoes) and dorsiflexion (pointing toes toward your shin). Other important movement terms include abduction (moving limbs away from the body), adduction (moving limbs toward the body), and rotation (twisting a body part).
Remember this: Every movement you make has a specific name that describes exactly what's happening at the joint. Understanding these terms helps you talk about physical activity with precision!
Muscles and Movement
Your body contains three types of muscles. Cardiac muscle is found only in your heart, while smooth muscle works involuntarily in organ walls like your stomach. Skeletal muscles attach to your bones and help you move voluntarily.
Muscles contain different fibre types: fast twitch fibres produce quick, powerful movements (perfect for sprinting), while slow twitch fibres support endurance activities like long-distance running.
Muscles always work in pairs on opposite sides of joints. The agonist muscle contracts while the antagonist relaxes—together forming an antagonistic pair. This teamwork allows smooth, controlled movements in different directions.
Muscle contractions come in different forms. Isometric contractions occur without joint movement (like holding a plank), while isotonic contractions maintain tension as muscle length changes. Isotonic contractions include concentric (muscle shortens) and eccentric (muscle lengthens) types.
Try this: Bend your arm at the elbow and feel your bicep. It's contracting (agonist) while your tricep relaxes (antagonist). Now straighten your arm and feel how the roles reverse!
Gaseous Exchange
Gaseous exchange is vital for survival! This process happens in your lungs where oxygen from the air in the alveoli moves into the blood in the capillaries. At the same time, carbon dioxide travels from your blood into the alveoli to be exhaled.
This exchange works through diffusion, a natural process where molecules move from areas of high concentration to areas of low concentration. In your lungs, oxygen concentration is higher in the alveoli than in your blood, so oxygen moves into your bloodstream. The opposite is true for carbon dioxide.
Did you know? Your lungs contain approximately 600 million alveoli, creating an enormous surface area (about the size of a tennis court) for this gas exchange to take place efficiently!
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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.
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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.
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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.
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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!
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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
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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
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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
Understanding the Human Body for GCSE PE AQA
Amelia
@_de4aqhxcxfsyib3ryl6
The human body is an incredible machine with complex systems working together. Understanding how our bodies move, function, and exchange gases is essential knowledge in biology and physical education. These notes cover key body functions, joints, muscles, and gas exchange.
The Human Body: Functions and Joints
Your body performs six major functions: blood cell production, movement, protection, support, shape, and mineral storage. Each of these keeps you alive and functioning properly every day.
Joints are points where two bones meet, allowing movement. Synovial joints include hinge joints (knees, elbows, ankles) and ball and socket joints (hips, shoulders). When you move these joints, specific terms describe the actions: flexion decreases the angle at a joint, while extension increases it.
Your ankle has special movements called plantar flexion (pointing toes down, like standing on tiptoes) and dorsiflexion (pointing toes toward your shin). Other important movement terms include abduction (moving limbs away from the body), adduction (moving limbs toward the body), and rotation (twisting a body part).
Remember this: Every movement you make has a specific name that describes exactly what's happening at the joint. Understanding these terms helps you talk about physical activity with precision!
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Muscles and Movement
Your body contains three types of muscles. Cardiac muscle is found only in your heart, while smooth muscle works involuntarily in organ walls like your stomach. Skeletal muscles attach to your bones and help you move voluntarily.
Muscles contain different fibre types: fast twitch fibres produce quick, powerful movements (perfect for sprinting), while slow twitch fibres support endurance activities like long-distance running.
Muscles always work in pairs on opposite sides of joints. The agonist muscle contracts while the antagonist relaxes—together forming an antagonistic pair. This teamwork allows smooth, controlled movements in different directions.
Muscle contractions come in different forms. Isometric contractions occur without joint movement (like holding a plank), while isotonic contractions maintain tension as muscle length changes. Isotonic contractions include concentric (muscle shortens) and eccentric (muscle lengthens) types.
Try this: Bend your arm at the elbow and feel your bicep. It's contracting (agonist) while your tricep relaxes (antagonist). Now straighten your arm and feel how the roles reverse!
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Gaseous Exchange
Gaseous exchange is vital for survival! This process happens in your lungs where oxygen from the air in the alveoli moves into the blood in the capillaries. At the same time, carbon dioxide travels from your blood into the alveoli to be exhaled.
This exchange works through diffusion, a natural process where molecules move from areas of high concentration to areas of low concentration. In your lungs, oxygen concentration is higher in the alveoli than in your blood, so oxygen moves into your bloodstream. The opposite is true for carbon dioxide.
Did you know? Your lungs contain approximately 600 million alveoli, creating an enormous surface area (about the size of a tennis court) for this gas exchange to take place efficiently!
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.
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Is Knowunity really free of charge?
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Most popular content: Musculoskeletal System
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Can't find what you're looking for? Explore other subjects.
Students love us — and so will you.
4.9/5
App Store
4.8/5
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