The nervous system

1. The nervous system

2. Main Function: This communication system controls and coordinates functions throughout the body and responds to internal and external stimuli. Recap: The nervous system Our nervous system allows us to feel pain.

3. Recap: Nervous system • It consists of 2 parts: • The central nervous system consists of the brain, spinal cord (CNS), • The peripheral nervous system contain the other nerves and receptors of our body.

4. Notes: Sympathetic nervous system • Speeds up functions of the body • Prepares body for emergencies • Makes body alert and ready to act • Diverts blood away from digestive tract • Stops peristalsis • Opens bronchioles – more oxygen • Increases heart rate • Dilates pupil – more light • Increase blood flow to heart

5. Notes: Para-sympathetic nervous system • Slows everything down • In control when you are resting • Increases blood flow to digestive tract • Stimulates salivary galnds • Reduces bronciole diameter- less oxygen • Controls heart beat • Reduces diameter of pupil

6. Notes: How is information transmitted? • Information passes from receptors along nerve cells called neurones. • Nerve cells are long and thin to carry messages called impulses. Cell body Dendrites Myelin sheath nucleus Axon

8. 1 2 3 Task: Draw a neuron • Cell body: contains nucleus & most of the cytoplasm • Dendrites: projections that bring impulses into the neuron to the cell body. • Axon: long projection that carries impulses away from cell body

9. Notes: There are 3 types of neurone: • Sensory neurone – carry impulse from receptor to CNS • Relay – connects sensory to motor • Motor – connects CNS to effector which makes a response. (muscle, gland)

10. Reflex Arc A reflex is an involuntary response that is processed in the spinal cord not the brain. Reflexes protect the body before the brain knows what is going on.

11. Reflex response – Draw flow of signal Stimulus >> receptor>> sensory >> co –ordinator (spinal cord) >> motor >> Effector >Response

12. Neurotransmitters Neurotransmitters are chemicals that transmit signals from a neuron to a target cell across a synapse (gap)

13. Because neurons never touch, chemical signalers called neurotransmitters must travel through thespace called synapse between two neurons. Define – Neuro-transmitter Neurotransmitters (pink spheres) The message is transferred whenRECEPTORSreceive neurotrans-mitters. Synapse (gap)

14. Neurotransmitters

15. Ruler drop test • Aim • Variables • Hypothesis • Materials • Procedure • Safety • Data table

16. Ruler drop test • Graph – comparison of response in your group • Analyse numbers etc • Conclusion of findings • Evaluation

17. Analysis questions to consider • 1. What happened to ………….. reaction time as he had more tries? • 2. What happened to ……………. reaction time as she had more tries? • 3. Who improved the most from the first to the fifth try? • 4. Who had the fastest reaction time? • 5. What do you think might happen if ……….. has more tries? • 6. What have you found out about reaction time so far? • 7. What else would you like to find out about reaction time?

18. What might we be able to find out from our investigation? • Who has the fastest reaction time in the class? • Do boys have better or worse reaction times than girls? • Do sporty people have the fastest reaction times? • Do people who play video games have the fastest reaction times? • Does the oldest person in the class have the fastest reaction time? • Do children have faster reaction times than grown ups? • If you try the reaction test every day for a week will your reaction time improve?