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GCSE Biology AQA 9-1 Notes: The Brain and Homeostasis

Your brain is essentially your body's command centre, controlling everything from your thoughts and memories to your heartbeat... Show more

THE BRAIN (4.5.2.2)
HYPOTHALAMUS
-thermoregulatory
centre
PITUITARY GLAND
-master gland
MEDULLA
-unconscious ac
activity
-breathing
- heart

The Brain Structure and Function

Ever wondered why a head injury can affect someone's speech but not their ability to walk? That's because your brain has specialised regions, each with specific jobs that keep you functioning.

The cerebral cortex is the wrinkly outer layer that makes you uniquely human. This highly folded area handles your consciousness, memory, intelligence, and language - basically everything that makes you "you". When you're solving maths problems or chatting with mates, this is the part working overtime.

Your cerebellum might be smaller, but it's crucial for muscle coordination, movement, and balance. Without it, you'd struggle to walk in a straight line or catch a ball. Meanwhile, the medulla works behind the scenes, controlling unconscious activities like your heart rate and breathing - vital functions you never have to think about.

The hypothalamus acts as your body's thermoregulatory centre, keeping your temperature just right. The pituitary gland is often called the "master gland" because it controls other hormone-producing glands throughout your body.

Quick Tip Remember that your spinal cord is part of the central nervous system too, connecting your brain to the rest of your body for complex behaviours.

Investigating the Brain

Studying the brain presents unique challenges that make it one of the most difficult organs to research. It's protected by the skull, making direct access nearly impossible in living patients.

Scientists have developed clever methods to work around these difficulties. They study patients with brain damage to understand which areas control specific functions. Electrical stimulation of brain regions during surgery can reveal what different areas do. Modern MRI scanning allows researchers to see brain activity in real-time without any invasive procedures.

The brain's extreme complexity and delicate nature mean that even tiny changes can have massive effects on behaviour and thinking. This is why brain research progresses slowly but provides fascinating insights into how we function.

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Paul T

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Biology

468

30 Nov 2025

1 page

GCSE Biology AQA 9-1 Notes: The Brain and Homeostasis

Your brain is essentially your body's command centre, controlling everything from your thoughts and memories to your heartbeat and balance. Understanding how different parts work together helps explain why brain injuries can have such varied effects on people.

THE BRAIN (4.5.2.2)
HYPOTHALAMUS
-thermoregulatory
centre
PITUITARY GLAND
-master gland
MEDULLA
-unconscious ac
activity
-breathing
- heart

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The Brain Structure and Function

Ever wondered why a head injury can affect someone's speech but not their ability to walk? That's because your brain has specialised regions, each with specific jobs that keep you functioning.

The cerebral cortex is the wrinkly outer layer that makes you uniquely human. This highly folded area handles your consciousness, memory, intelligence, and language - basically everything that makes you "you". When you're solving maths problems or chatting with mates, this is the part working overtime.

Your cerebellum might be smaller, but it's crucial for muscle coordination, movement, and balance. Without it, you'd struggle to walk in a straight line or catch a ball. Meanwhile, the medulla works behind the scenes, controlling unconscious activities like your heart rate and breathing - vital functions you never have to think about.

The hypothalamus acts as your body's thermoregulatory centre, keeping your temperature just right. The pituitary gland is often called the "master gland" because it controls other hormone-producing glands throughout your body.

Quick Tip: Remember that your spinal cord is part of the central nervous system too, connecting your brain to the rest of your body for complex behaviours.

Investigating the Brain

Studying the brain presents unique challenges that make it one of the most difficult organs to research. It's protected by the skull, making direct access nearly impossible in living patients.

Scientists have developed clever methods to work around these difficulties. They study patients with brain damage to understand which areas control specific functions. Electrical stimulation of brain regions during surgery can reveal what different areas do. Modern MRI scanning allows researchers to see brain activity in real-time without any invasive procedures.

The brain's extreme complexity and delicate nature mean that even tiny changes can have massive effects on behaviour and thinking. This is why brain research progresses slowly but provides fascinating insights into how we function.

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?

That's right! Enjoy free access to study content, connect with fellow students, and get instant help – all at your fingertips.

6

Smart Tools NEW

Transform this note into: ✓ 50+ Practice Questions ✓ Interactive Flashcards ✓ Full Mock Exam ✓ Essay Outlines

Mock Exam
Quiz
Flashcards
Essay

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Brain Anatomy Overview

Explore the essential components of the brain, including the cerebrum, cerebellum, medulla, hypothalamus, and pituitary gland. This summary highlights their functions in the central nervous system, such as coordination, unconscious activities, and hormonal regulation. Ideal for students studying the human nervous system.

BiologyBiology
11

Animal Cell Components

Explore the essential structures of animal cells, including mitochondria, ribosomes, and the nucleus. This summary covers their functions in cellular processes such as aerobic respiration and protein synthesis, along with a detailed diagram for visual reference.

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Comprehensive Brain Anatomy

Explore the intricate structures of the brain, including ventricles, lobes, and key functions of the limbic system. This detailed summary covers the roles of the hypothalamus, thalamus, and the significance of hemispheric lateralization in language and memory. Ideal for students studying neuroanatomy and the human nervous system.

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12

Brain and Eye Anatomy

Explore the intricate anatomy of the brain and eye, focusing on their functions, risks of surgery, and how they interact. This summary covers key concepts such as the roles of the cerebrum, cerebellum, and the structure of the human eye, including the retina and lens. Ideal for GCSE Biology students seeking to understand neuroscience and eye physiology.

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Understanding Eye Anatomy

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BiologyBiology
10

Human Nervous System Overview

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Students love us — and so will you.

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Stefan S

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Thomas R

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David K

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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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Xander S

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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.

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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 😍😁😲🤑💗✨🎀😮

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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

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