Brain and Mind

1. Brain and Mind

2. Detecting changes in our environment Smell Touch Pressure and temperature Hearing Sound and Balance Sight Light Tongue Taste

3. Our Nervous System • Brain and • Spinal cord form the central nervous system (CNS) • Nerves Peripheral nervous system (PNS)

4. Nerves Nerves carry electrical impulses • fast • short-lived responses

5. Simple Reflexes

6. Simple Reflexes What is a reflex? Pupil reflex Knee jerk reflex • Rapid and involuntary • Help our survival – to avoid injury.

7. Simple reflexes in newborns http://www.youtube.com/watch?v=Sv5SsLH70mYhttp://www.youtube.com/watch?v=Yr3jOXRU0IA Grasping Stepping Startle Dive Why are these reflexes important? Why do you think these reflexes disappear after 6 months? Sucking Rooting

8. Dropping a hot object……. Does he think about his reaction? Does the message reach his brain?

9. Receptors • detect stimuli, e.g. light receptor cells in eye

10. A car swerves on to the pavement and nearly hits you. Describe your response…

11. Effectors • Effectors produce the response, e.g. muscle cells contract to make you move e.g. a gland secretes a hormone (give an example?)

12. Reflexes for survival https://www.youtube.com/watch?v=OdOOIxcUjAs processing centre 1……… 2……… jumps quickly out of the way car on pavement CNS receptor cells in ……

13. How do animals respond to changes in their environment? • Stimulus • Receptor • Processing centre (CNS) • Effector • Response

14. Flow diagram stimulus  receptor CNS effectorresponse e.g. you pick up a hot plate e.g. someone suddenly shouts at you e.g. dust blows into your eye Heat Temperature receptor in skin CNS  Muscle Movement away from heat

15. 2 types of messages • nerves carry electrical impulses • fast, short-lived responses • hormones are chemicals that are produced in glands and travel in the blood • slower, longer-lasting responses, • e.g. insulin and oestrogen

16. Messengers: Nerves vs Hormones

17. Neurons are nerve cells B6 The Brain and Mind

18. Label a neuron diagram • Cell membrane • Nucleus • Fatty sheath • Axon • Cytoplasm • Show direction of the electrical impulse

19. Answers 6. Direction of impulse Check and add to your answers: Connections to cell body will have incoming synapses. 3. Myelin/Fatty Sheath 4. Axon 5. Cytoplasm 7. Neuron endings 2. Nucleus 1. Cell membrane Neuron endings: All neuron endings will have synapses to connect to other neurons and send messages

20. What is the fatty sheath for? • it insulates the neuron from neighbouring cells and • increases the speed of transmission of a nerve impulse

21. Which is faster and why?

22. How do reflexes work? • Reflexes are involuntary • Don’t ‘think’ about them. • Controlled by the spinal cord. • So very fast. http://www.bbc.co.uk/schools/gcsebitesize/science/add_ocr_pre_2011/brain_mind/reflexactionsrev1.shtml

23. Spinal Reflex Arc • Does not go to the brain • Therefore automatic and so very rapid, since no processing of information is required

24. Relay neuron • Sensory neuron 3 types of neurons • Sensory neuron • carries impulse from receptor cells • Relay neuron (CNS) • links sensory and motor neurons • Motor neuron • carries signals to effector cells: muscles, glands etc. • http://www.bbc.co.uk/schools/gcsebitesize/science/aqa/human/thenervoussystemact.shtml - • Motor neuron

25. Spinal Reflex Arc A fixed pathway pathway which includes • receptor • sensory neuron • relay neuron • spinal cord • motor neuron effector

26. Spinal Reflex Arc receptor sensory neuron stimulus effector relay neuron motor neuron spinal cord

27. Spinal Reflex Arc: Diagram • Colour the sensory neuron green, relay red and motor blue. • Add arrows to show direction of impulse.

28. Pass the impulse! Stimulus – bright light in eyes Stimulus  Receptor  Sensory Neuron  Relay Neuron Motor Neuron  Effector  Response Response – raise hand to shield eyes

29. Bingo Brain Survive Sensory Neuron Reflex Receptor Stimulus Gland Fast Peripheral Nervous System (PNS) Reflex arc Spinal Cord Involuntary Relay neuron Effector Motor neuron Central Nervous System (CNS) Adapt Response

30. How does the impulse cross the gaps? relay neuron

31. Synapses • Neurons do not touch each other. • The gap is called a synaptic cleft. • Synapses allow controlled responses to stimuli.

32. Presynaptic neuron Postsynaptic neuron What is a synapse?

33. Neurotransmitter neurotransmitter release The release of neurotransmitters When an impulse arrives at the end of one neuron it triggers the release of neurotransmitters.

34. synapse nerve impulse receptor Continuing the impulse http://www.bbc.co.uk/schools/gcsebitesize/science/aqa/human/thenervoussystemrev2.shtml https://www.youtube.com/watch?v=H_81gwAnjDU Neurotransmitter crosses the synapse and binds to receptors on the next neuron, causing another impulse.

35. Sort the cards to explain what’s happening 1 4 5 3 2 This triggers the ends of the 1st neuron to release chemical messengers called neurotransmitters. These chemicals diffuse across the synapse (gap) and bind to specific receptors on the 2nd neuron. 2 3 Receptors are only found on the 2nd neuron. The 2nd neuron is stimulated and transmits an electrical impulse down its axon. 4 An electrical impulse travels along an axon and to the ends of a neuron. 5 1

36. Draw the diagram: Sort the cards to explain what’s happening How does this make sure the impulse only travels in one direction? What has to happen to the neurotransmitter molecules after the impulse been stimulated in the 2nd neuron?

37. Drugs and the brain • Some toxins and drugs e.g. Ecstasy, betablockers and Prozac affect the transmission of impulses across synapses.

38. Serotonin • The pleasure neurotransmitter • Low levels linked to depression.

39. Which brain is the smartest? Mammals have big brains…. But why are big brains smarter?

40. Cerebral cortex • Consciousness • Memory • Intelligence • Language

41. The Cerebral Cortex sensory cortex motor cortex speech taste reading speech hearing vision smell Credit Heidi Cartwright, Wellcome Images How do we know which parts of the brain control what?

42. Study people withbrain damage! https://www.youtube.com/watch?v=MvpIRN9D4D4 1848: Phineas Gage fired large iron rod through his brain. He survived, but his personality was changed. Autopsy showed frontal part of his cerebralcortex was gone. The frontal cerebral cortex controls personality. sensory cortex motor cortex speech taste reading speech hearing vision smell Credit Heidi Cartwright, Wellcome Images B0003275

43. Study living brains! The motor cortex was mapped by stimulating exposed brain during brain surgery. B6 The Brain and Mind

44. Imaging the Brain MRI: Magnetic Resonance Imaging • Measures blood-flow changes in the brain. • Active areas ‘light up’ MRI showing areas used for recognising faces MRI showing the visual cortex

45. Quick Brain Check • What is the brain made of? • What 4 functions is the cerebral cortex responsible for? • How did we learn what each part of the brain does? • Is it ethical to study patients with brain damage or during surgery? EXT: Why is a complex brain important for survival? Neurons and synapses! Language, memory, intelligence, consciousness Studies of patients with brain damage or living patients. Own opinion with justification. So that you can learn by experience and from other people (social learning).

46. Intelligence It’s all in the brain…. And who you know • What do elephants, humans and dolphins have in common? • Social animals have big brains. • Learn most things from others. • Reflexes can be modified through experience.

47. Normal spinal reflex arc

48. Using your brainHow to modify a reflex! THINK A signal from the brain can modify the reflex The Gag Reflex If the hot plate is actually very, very expensive….. Can you stop yourself sneezing, blinking? Can you control your pupil reflex ?

49. Brainstorm!!! What is learning? How do you learn? How did you learn to tie your shoelaces? How will you learn to drive? How do you learn things for an exam?

50. Human brains and learning • Billions of neurons • New neuron pathways (connections-synapses) develop as we grow. • New experiences make new pathways. • Unused pathways are ‘pruned’. • Millions of potential pathways in big brains make us ‘adaptable’.