Subjects
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
2 Dec 2025
71
5 pages
Ummi @ummi_.com
The nervous system is a complex network of specialised cells that coordinates and controls all your bodily functions.... Show more
Your nervous system works like your body's communication network, constantly sending and receiving messages to keep everything running smoothly. It's responsible for all your sensations, movements, thoughts and automatic functions like breathing.
The nervous system has two main divisions. The central nervous system (CNS) includes your brain and spinal cord, serving as the command centre. The peripheral nervous system (PNS) connects the CNS to the rest of your body.
Your brain is truly remarkable – it's the control centre that handles everything from complex thoughts and memories to emotions and voluntary movements. Think of it as your body's most sophisticated computer!
Fascinating fact Your nervous system processes information faster than the world's most advanced computers, with signals travelling up to 120 metres per second through certain nerves!
The spinal cord is a long bundle of nerve tissue that connects your brain to the rest of your body. It acts like a motorway for signals travelling between your brain and peripheral nervous system.
Your peripheral nervous system has two main components. The somatic nervous system controls your voluntary movements, like picking up a pencil or kicking a football. The autonomic nervous system manages all the unconscious functions you don't need to think about.
Within your autonomic system are two opposing forces working together. The sympathetic nervous system triggers your "fight or flight" response when you're stressed or in danger. Meanwhile, the parasympathetic nervous system promotes "rest and digest" functions, helping your body relax and recover.
Remember this Your sympathetic system prepares you for action (think "S" for "Stress"), while your parasympathetic system helps you calm down and recover (think "P" for "Peace").
Neurons are the specialised cells that form the foundation of your nervous system. These remarkable cells transmit electrical signals throughout your body. Each neuron has dendrites that receive signals from other neurons and an axon that sends signals onward.
The gap between neurons where signals jump across is called a synapse. Supporting your neurons are glial cells, which protect and nourish these vital message-carriers.
Signals travel through your nervous system as action potentials – brief electrical impulses that zip down the axon of a neuron. When an action potential reaches the end of the axon, it triggers synaptic transmission, where the signal jumps across the synapse to continue its journey.
Quick tip Think of neurons like a relay team passing a baton – dendrites receive the baton, the cell body processes it, and the axon passes it to the next runner!
Neurotransmitters are chemical messengers that carry signals across synapses. These include chemicals like acetylcholine, dopamine, serotonin, and norepinephrine, each with specific roles in your body and brain functions.
Your nervous system connects to the outside world through your five sensory systems. Your vision system detects light, allowing you to see the world around you. Hearing picks up sound waves, while touch receptors in your skin detect pressure, temperature and pain.
Your chemical senses include taste, which detects chemicals in food, and smell, which identifies airborne chemicals. Together, these sensory systems provide a complete picture of your environment.
Did you know? Your brain processes sensory information before you're even consciously aware of it – that's why you can pull your hand away from something hot before you feel pain!
Your somatic motor system controls all your voluntary movements through skeletal muscles. Whether you're writing notes or playing sports, this system translates your intentions into precise actions. Meanwhile, your autonomic motor system manages involuntary functions in smooth muscles, cardiac muscle, and glands.
Unfortunately, the nervous system can develop various disorders. Stroke occurs when brain tissue is damaged due to a blocked or ruptured blood vessel. Alzheimer's disease progressively damages the brain, causing memory loss and cognitive decline.
Parkinson's disease affects movement and coordination due to the breakdown of certain neurons. Multiple sclerosis is an autoimmune condition where the body attacks the protective myelin sheath around nerve fibres, disrupting normal nerve function.
Important note Many nervous system disorders share similar symptoms initially, which is why early diagnosis by medical professionals is crucial for effective treatment.
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
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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
Ummi
@ummi_.com
The nervous system is a complex network of specialised cells that coordinates and controls all your bodily functions. It receives sensory information, processes it, and generates appropriate responses, enabling everything from conscious thought to automatic bodily functions. Understanding how this... Show more
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Improve your grades
Join milions of students
By signing up you accept Terms of Service and Privacy Policy
Your nervous system works like your body's communication network, constantly sending and receiving messages to keep everything running smoothly. It's responsible for all your sensations, movements, thoughts and automatic functions like breathing.
The nervous system has two main divisions. The central nervous system (CNS) includes your brain and spinal cord, serving as the command centre. The peripheral nervous system (PNS) connects the CNS to the rest of your body.
Your brain is truly remarkable – it's the control centre that handles everything from complex thoughts and memories to emotions and voluntary movements. Think of it as your body's most sophisticated computer!
Fascinating fact: Your nervous system processes information faster than the world's most advanced computers, with signals travelling up to 120 metres per second through certain nerves!
Access to all documents
Improve your grades
Join milions of students
By signing up you accept Terms of Service and Privacy Policy
The spinal cord is a long bundle of nerve tissue that connects your brain to the rest of your body. It acts like a motorway for signals travelling between your brain and peripheral nervous system.
Your peripheral nervous system has two main components. The somatic nervous system controls your voluntary movements, like picking up a pencil or kicking a football. The autonomic nervous system manages all the unconscious functions you don't need to think about.
Within your autonomic system are two opposing forces working together. The sympathetic nervous system triggers your "fight or flight" response when you're stressed or in danger. Meanwhile, the parasympathetic nervous system promotes "rest and digest" functions, helping your body relax and recover.
Remember this: Your sympathetic system prepares you for action (think "S" for "Stress"), while your parasympathetic system helps you calm down and recover (think "P" for "Peace").
Access to all documents
Improve your grades
Join milions of students
By signing up you accept Terms of Service and Privacy Policy
Neurons are the specialised cells that form the foundation of your nervous system. These remarkable cells transmit electrical signals throughout your body. Each neuron has dendrites that receive signals from other neurons and an axon that sends signals onward.
The gap between neurons where signals jump across is called a synapse. Supporting your neurons are glial cells, which protect and nourish these vital message-carriers.
Signals travel through your nervous system as action potentials – brief electrical impulses that zip down the axon of a neuron. When an action potential reaches the end of the axon, it triggers synaptic transmission, where the signal jumps across the synapse to continue its journey.
Quick tip: Think of neurons like a relay team passing a baton – dendrites receive the baton, the cell body processes it, and the axon passes it to the next runner!
Access to all documents
Improve your grades
Join milions of students
By signing up you accept Terms of Service and Privacy Policy
Neurotransmitters are chemical messengers that carry signals across synapses. These include chemicals like acetylcholine, dopamine, serotonin, and norepinephrine, each with specific roles in your body and brain functions.
Your nervous system connects to the outside world through your five sensory systems. Your vision system detects light, allowing you to see the world around you. Hearing picks up sound waves, while touch receptors in your skin detect pressure, temperature and pain.
Your chemical senses include taste, which detects chemicals in food, and smell, which identifies airborne chemicals. Together, these sensory systems provide a complete picture of your environment.
Did you know? Your brain processes sensory information before you're even consciously aware of it – that's why you can pull your hand away from something hot before you feel pain!
Access to all documents
Improve your grades
Join milions of students
By signing up you accept Terms of Service and Privacy Policy
Your somatic motor system controls all your voluntary movements through skeletal muscles. Whether you're writing notes or playing sports, this system translates your intentions into precise actions. Meanwhile, your autonomic motor system manages involuntary functions in smooth muscles, cardiac muscle, and glands.
Unfortunately, the nervous system can develop various disorders. Stroke occurs when brain tissue is damaged due to a blocked or ruptured blood vessel. Alzheimer's disease progressively damages the brain, causing memory loss and cognitive decline.
Parkinson's disease affects movement and coordination due to the breakdown of certain neurons. Multiple sclerosis is an autoimmune condition where the body attacks the protective myelin sheath around nerve fibres, disrupting normal nerve function.
Important note: Many nervous system disorders share similar symptoms initially, which is why early diagnosis by medical professionals is crucial for effective treatment.
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
App 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