How your brain and nervous system work

SMARTER UK – RESOURCES FOR SCHOOLS Please feel free to use this PowerPoint presentation in the classroom. It is intended to support the KS3 & KS4 curriculum and the Scottish S3-S4 curriculum.

KEY LEARNING: The structure of the brain and how the central nervous system works, including information about what happens at a synapse and information about how our brains adapt and change. Specific curriculum areas include: KS4 GCSE Biology Syllabuses OCR 3.3 Fundamental Scientific Processes. Module B1d – The nervous system Foundation tier only: low demand • Name and locate the main parts of the nervous system, to include: o the central nervous system (CNS) (brain and spinal cord) o the peripheral nervous system Both tiers: standard demand • Name and locate the parts of a motor neurone: cell body, axon and sheath. • Recall that the nerve impulse passes along the axon of a neurone. Higher tier only: high demand • Recall that the gap between neurones is called a synapse. • Describe how an impulse triggers the release of a transmitter substance in a synapse and how it diffuses across to bind with receptor molecules in the membrane of the next neurone causing the impulse to continue. OCR 21st Century Science MODULE B6: BRAIN AND MIND – OVERVIEW B6.2 How is information passed through the nervous system? Structure of motor neurons; transmission of electrical impulses, including synapses.

AQA 11.1 How do human bodies respond to changes inside them and their environment? • The nervous system enables humans to react to their surroundings • and coordinate their behaviour. • Information from receptors passes along cells (neurones) in nerves to the brain. The brain coordinates the response. • The role of receptors, sensory neurones, motor neurones, relay neurones, synapses and effectors in simple reflex actions. Edexcel Topic 2: Responses to a changing environment • 2.19) Recall that the central nervous system consists of the brain and spinal cord and is linked to sense organs by nerves • 2.20) Explain the structure and function of dendrons and axons in the nervous system • 2.21) Describe how stimulation of receptors in the sense organs sends electrical impulses along neurones • 2.23) Describe the structure and function of sensory, relay and motor neurones and synapses

Scottish S3-S4 science Biological Systems - Body systems and Cells • SCN 2-12a I have explored the structure and function of organs and organ systems and can relate this to the basic biological processes to sustain life. Scottish Certificate in Education, Standard Grade Biology. Topic 5: The body in action. Subtopic c: Coordination 18) Examine the gross structure of the nervous system of a mammal. 19) Obtain and present information on the flow of information in the nervous system. • State that the nerves carry information from the senses to the central nervous system and from the central nervous system to the muscles. • 20) Obtain and present information on the three main parts of the brain. Identify the cerebrum, cerebellum and the medulla and state their functions in simple terms.

Your brain and nervous system How does it work?

your

nervous system is divided into the central

nervous system (CNS)

Credit Medical Art Service, Munich /, Wellcome Images

spinal cord

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and the

peripheral nervous system (PNS) which connects everything

to the brain and spinal cord

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Medical Art Service, Munich /, Wellcome Images

which is the brain and

your

brain

interprets the information it gets though your senses in order to monitor and regulate your body as well as being responsible for

Credit: Heidi Cartwright, Wellcome Images

thinking, learning, memory and emotion

Different parts of your brain have different functions…

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different regions have different

Cerebral cortex

functions

Functions include: planning; reasoning; language; recognising sounds and images; memory.

Corpus callosum connects the brain’s right and left hemispheres

Brain stem

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Credit: Mark Lythgoe & Chloe Hutton, Wellcome Images

regulates heart rate, breathing, sleep cycles and emotions

Cerebellum important for coordination, precision and timing of movement

the cells of the nervous system are called

neurones

nerve endings

dendrites

myelin sheath

cell body nucleus

axon Smarter UK

structure of a neurone

there are different

types of neurone

dendrites

cell body

direction of electrical signal

myelin sheath axon

nerve endings

motor neurone sends signals to your muscles to tell them to move

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sensory neurone sends signals from your sense organs

relay neurone connects neurones to other neurones

communicate with each other using a mixture of electrical & chemical signals neurones

dendrites

nerve endings

myelin sheath But what happens when the signal reaches the end of the axon? cell body

an electrical signal is transmitted along the axon

nucleus

axon

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signals cross between neurones at the

synapse

synapse dendrites

nerve endings vesicle myelin sheath

synaptic cleft nucleus

cell body receptor

neurotransmitter the signal

is transmitted to another neurone across a junction called a synapse by axon chemicals called

neurotransmitters. Smarter UK

1

electrical impulse triggers vesicles to move to the synapse membrane

vesicles fuse with the membrane and 2 release neurotransmitter into the synaptic cleft 3

neurotransmitter diffuses across the cleft and binds to receptors on the other side synaptic cleft nucleus

signals cross between neurones at the

synapse

synapse dendrites

nerve endings vesicle myelin sheath

cell body receptor

4 Once enough receptors have neurotransmitters bound to them, the signal is transmitted…

neurotransmitter the signal

is transmitted to another neurone across a junction called a synapse by axon chemicals called

neurotransmitters. Smarter UK

The point where your muscles and nervous system meet is called the

neuromuscular junction (NMJ)

Signals sent from your central nervous system to the NMJ tell muscles to move

The synapses at the NMJ use a neurotransmitter called

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acetylcholine

Your brain changes and adapts What happens as our brains mature?

your

brain changes and adapts all the time and all through your life

Credit Marina Caruso, Wellcome Images

your brain learns and forms memories by strengthening synapses that are used a lot and weakening those that are used less often

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What happens as you

grow? Between birth and age 3 your brain makes lots of new synapses A toddler has 2-3 times more synapses than an adult

As your brain matures, it prunes synapses to make it more efficient During adolescence your brain has a major tidy-up and gets rid of lots of connections it isn’t using This is a critical and delicate process. It is thought that conditions such as schizophrenia could be the result of it going wrong Some evidence suggests that using drugs can disrupt this process