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Nerves

Nerves. objectives. Nerves. copy this. nerves help us react to our surroundings and control our behaviour. key parts of the nervous system include senses, neurones, brain, spinal cord, and effectors . understand what is meant by a reflex

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Nerves

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  1. Nerves

  2. objectives Nerves copy this • nerves help us react to our surroundings and control our behaviour. • key parts of the nervous system include senses, neurones, brain, spinal cord, and effectors. • understand what is meant by a reflex • describe the pathway of information from stimulus to response.

  3. starter www.xtcidearecords.co.uk

  4. How fast are nerve signals? do NOT copy this The brain can respond to touch, smell or taste stimuli in just 0.1 seconds, but sound and vision take longer. Nerve impulses travel at up to 320mph and take just0.02 seconds to reach the brain.

  5. can you catch a fiver? • if not, why not? stimulus light from note receptor eye nerve coordinator brain nerve effector muscles in fingers response movement of fingers copy this page ! learn keywords all this takes time !

  6. Interpreting signals How can you find your reaction time? 1. Extend your arm over the edge of a table and have a partner hold a ruler between your fingers at the 0cm mark. 2.The partner drops the ruler – catch it between your fingers and thumb as quickly as possible. 3. Repeat the test 10times, recording the results and calculate the mean (average) distance. Then convert the distance into a reaction time.

  7. Common reflexes What types of reflexes do you know?

  8. What are reflexes? a stimulus could be pain or heat or a loud sound a response could be blinking or moving away the CNS is the brain and spinal cord Reflexes are fast, automaticprotective control systems that link a stimulus to a response. Reflex reactions happen without you thinking– they are involuntary. This is because the central nervous system (CNS) sends electrical signals to the muscles FROM THE SPINAL CORD before the brain can pick up the message. copy this page ! learn keywords

  9. What are neurones? Neurones are specialized cells that conduct electrical impulses through the body. A nerve is a bundle of many nerve fibres enclosed within a protective sheath. Nerve fibres are the long axons of neurones together with any associated tissues. nerve nerve fibre

  10. What do neurones look like? Neurones are elongated cells consisting of a cell body and long, thin axon. dendrites myelin sheath cell body axon Thin projections called dendrites extend from the cell body and connect with other neurones, allowing electrical impulses to pass from one to the other. The axons of most neurones are wrapped in an insulating lipid layer called the myelin sheath. Why is this important?

  11. What are sensory neurones? nerve impulse from sense organ Sensory neuronestransmit messages from sense receptors, such as the eye or nose, to the brain or spinal cord. cell body nerve impulse to CNS

  12. What are motor neurones? Motor neuronestransmit messages from the brain and spinal cord to the muscles and glands. cell body muscle

  13. what are the differences and similarities?(use the pictures to help) do this in groups of 4 ( one picture each) copy and complete motor neurones sensory neurones

  14. end of part one on nerves • I’ll be back !

  15. A reflex arc

  16. copy this page ! learn it carefully

  17. presynaptic cell postsynaptic cell What is a synapse? A synapse is a junction between two neurones across which electrical signals pass. The human body contains up to 500 trillion synapses.

  18. The release of neurotransmitters from a synapse When a nerve impulse arrives at the end of one neurone it triggers the release of neurotransmitter molecules from synaptic vesicles. synaptic vesicle neurotransmitter molecules copy this page ! learn it carefully

  19. Continuing the impulse The neurotransmitters diffuse across the synaptic cleft and bind with receptors on the next neurone, triggering another impulse. synaptic cleft nerve impulse receptor

  20. pass the zap • 17 students have a card with a word or two on. • you must arrange yourself in the correct order, facing the front of the class • some cards are at the same time as others

  21. True or false?

  22. What can go wrong?

  23. Multiple-choice quiz

  24. homework • b1a.1a • b1a.1c

  25. extra questions 1) What do these words mean: - stimulus - response - effector 2) What is the special name given to the nerve that carries the impulse from the receptor to the brain or spinal cord? 3) What is the special name given to the nerve that carries the impulse from the brain or spinal cord to the effector? 4) What is the name given to the brain and spinal cord together? 5) Write the chain of events for the following scenario: ‘a stupid year 11 boy has just thrown a pen towards a year 7 boys face. What does the year 7 boy do? Is it a reflex or does he have to think about doing it?’

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