Unit 3 - Area of Study 1: How does the nervous system enable psychological functioning?

1. Unit 3 - Area of Study 1: How does the nervous system enable psychological functioning? Nervous system functioning Study design Key Knowledge: The roles of different divisions of the nervous system (central and peripheral nervous systems and their associated sub-divisions) in responding to and integrating and coordinating with, sensory stimuli received by the body. The distinction between conscious and unconscious responses by the nervous system to sensory stimuli, including the role of the spinal reflex. The role of the neuron (dendrites, axon, myelin and axon terminals) as the primary cell involved in the reception and transmission of information across the synapse (excluding details related to signal transduction). The role of neurotransmitters in the transmission of neural information between neurone (lock-and-key process) to produce excitatory effects (as with glutamate) or inhibitory effects (as with GABA) The effects of chronic changes to the functioning of the nervous system due to interference to neurotransmitter function, illustrated by the role of GABA in Parkinson’s disease

2. Chapter 2 - Nervous System Functioning To start - complete your diagram of the division of the nervous system. You should know this from unit 1!

3. Main functions of the nervous system • The nervous system is a communication system between the body’s internal cells and organs and the external world. • Its three main functions are to: • Receive information • Process information • Coordinate a response to information

4. Divisions of the nervous system

5. The central nervous system is made up of the brain and the spinal cord. The main function of the CNS is to process information received from the body’s internal and external environments and to activate appropriate responses. Central Nervous System

6. The brain • The brain is a complex network of cells that plays a vital role in processing information received through neural pathways from the body and in directing actions within the body. • The brain is responsible for virtually everything we think, feel and do. • Can you remember the functions of the different areas of the brain?

7. The brain • Despite some specialised functions, most parts of the brain have integrating and overlapping functions. • https://www.youtube.com/watch?v=o6JVMmkBF-I • Many brain functions involve the activation of neural pathways that link different brain areas and structures. • These pathways consist of one or more circuits of interconnected neurons that form communication networks.

8. The spinal cord • The spinal cord is a long, thin uncle of nerve tissue that extends from the base of the brain to the lower back. • It links the brain to other parts of the body. • The two major functions of the spinal cord are to: • Receive sensory information from the body and send these messages to the brain for processing. e.g…. • receive motor information from the brain and send it to relevant parts of the body to control muscles, glands and internal organs so that appropriate action can be taken. e.g….

9. The spinal cord • Transmission of information along the spinal cord, to and from the brain, occurs through interconnected neurons that form nerve pathways. • What do you think might happen if the spinal cord is injured? • The spinal cord can also trigger simple motor reactions independent of the brain called spinal reflexes.

10. What do you think would happen if your PNS shut down for 30 seconds? The Peripheral Nervous System • The peripheral nervous system Peripheral Nervous System includes all of the nerves throughout the body, outside of the brain and spinal cord • Is responsible for sending messages to the CNS, and carrying out instructions sent from the CNS. • It is made up of theSomaticand Autonomic Nervous Systems

11. Remember SAME - Sensory Afferent, Motor Efferent Somatic Nervous System • The SNS is sometimes called the skeletal nervous system as it controls the muscles attached to the skeleton – involved in voluntary movement • Has two major functions: • Transmits sensory information from receptors in the skin to the central nervous system. • Sensory (Afferent) Neuron • To control voluntary skeletal muscle movement via messages sent from the central nervous system. • Motor (Efferent) Neurons

12. The Autonomic Nervous System relays messages between the CNS and the involuntary muscles(internal organs and glands) The autonomic branch often operates without our conscious awareness, it keeps us alive automatically. Consists of sympathetic and parasympathetic nervous systems Peripheral Nervous System

13. Divisions of the ANS: Sympathetic Nervous System • Responsible for increases the activity of most visceral (internal) muscles and glands in times of vigorous activity, stress or threat. • Activated at times of high arousal (a stressful situation) • The release of adrenalin and noradrenalin causes some bodily functions to ‘speed up’. • This has become known as the ‘Fight or Flight Response’ where our body reacts to combat the stressor. • Our body reacts with physiological changes that assist survival

14. Divisions of the ANS: Parasympathetic Nervous System • The parasympathetic nervous system is responsible for decreasing the activity of most visceral muscles, organs and glands and restoring body functioning to its normal state. • Two major functions: • To keep the body in a relative state of balance – homeostasis – during normal day to day activities. • To bring the body back to a balanced/stable level after any arousal due to sympathetic nervous system activity.

15. Sympathetic and Parasympathetic Nervous Systems • Put simply… • The sympathetic branch controls arousal, fight or flight response - it fires us up. Adrenaline is released, heart rate and breathing increase. • The parasympathetic branch calms us back down, keeps levels stable

18. Exam question deconstruction

20. Exam question deconstruction

21. Exam question deconstruction

22. Conscious and unconscious responses to sensory stimuli • What do the words ‘conscious’ and ‘unconscious’ mean? • What would you do in the following situations? • You feel a headache • You touch a very hot pan on the stove • You get a blood nose in class • You accidentally step on sharp drawing pin • Which of these responses is conscious/unconscious

23. Conscious and unconscious responses to sensory stimuli • A conscious response to a sensory stimulus is a reaction that involves awareness. You will have paid attention to the stimulus and your response will usually be voluntary • An unconscious response to a sensory stimulus is a reaction that does not involve awareness. It is involuntary, unintentional and automatic and we cannot control it from occurring.

24. Place the spinal reflex sequence in the correct order Spinal reflex • A spinal reflex is an unconscious, involuntary and automatically occurring response to certain stimuli without any involvement of the brain. • The immediate response at the spinal cord allows a faster reaction time and so a spinal reflex with a withdrawal response (e.g. jerking your hand away from a hot pan) is thought to be a survival response - it saves time that could potentially minimise harm or save the life of the organism

25. Place the spinal reflex sequence in the correct order Spinal reflex • Because reflexes are so predictable, they can be useful in providing information about the functioning of the nervous system. • Damage or disease anywhere along the reflex arc can cause a reflex to be absent or abnormal. • 3 different types of neurons are responsible for converting a sensory stimulus into an action in a reflex: • Interneurons • sensory neurons • motor neurons

26. Practice question • Serena was sitting in the garden and playing when she felt something crawl onto her leg. She saw that it was a bee and brushed it away. Shortly after, she involuntarily kicked out her leg and then felt a stinging sensation that made her scream loudly in pain. She realised that she had been stung by a bee. • Identify the division of the nervous system and the type of response involved when Serena brushed the bee of her leg (2 marks)

27. Practice question • Serena was sitting in the garden and playing when she felt something crawl onto her leg. She saw that it was a bee and brushed it away. Shortly after, she involuntarily kicked out her leg and then felt a stinging sensation that made her scream loudly in pain. She realised that she had been stung by a bee. • Identify the division of the nervous system and the type of response involved when Serena brushed the bee of her leg (2 marks)

28. Serena was sitting in the garden and playing when she felt something crawl onto her leg. She saw that it was a bee and brushed it away. Shortly after, she involuntarily kicked out her leg and then felt a stinging sensation that made her scream loudly in pain. She realised that she had been stung by a bee. Identify the division of the nervous system and the type of response involved when Serena brushed the bee of her leg (2 marks) Practice question This question comprised four parts and drew on knowledge from Unit 3, Area of Study 1, in relation to the role of the nervous system in conscious and unconscious responses to stimuli.

29. Given that Serena brushing away the bee was a voluntary action, the correct response identified the somatic nervous system as the division of the nervous system and a voluntary/conscious/controlled response. Students needed to read the scenario carefully to ensure they did not confuse the event in question with Serena’s later action of kicking out her leg. Practice question Serena was sitting in the garden and playing when she felt something crawl onto her leg. She saw that it was a bee and brushed it away. Shortly after, she involuntarily kicked out her leg and then felt a stinging sensation that made her scream loudly in pain. She realised that she had been stung by a bee. Identify the division of the nervous system and the type of response involved when Serena brushed the bee of her leg (2 marks)

30. Write down everything that you can remember about neurons. Label your diagram as best you can The role of the neuron

31. Dendrites Nucleus Soma Myelin sheath Axon Axon terminals The role of the neuron

32. Match the definitions with the features of the neuron. The role of the neuron • A neuron is an individual nerve cell that is specialised to receive, process and/or transmit information. • The entire nervous system is comprised of neurons organised into networks through which information is continually transmitted. • Neurons have specialised functions and vary in size and shape depending on where they are and what their function is.

34. Three types of neurons • Neurons can be classified in terms of their specific function and the direction they send information: • Sensory neurons - receive and carry sensory information from both the external and internal environments and transmits this to the CNS. • Motor neurons - carry messages from the CNS to the cells in muscles, glands and organs to stimulate activity. • Interneurons - send messages between sensory and motor neurons within the CNS

35. Name the three main components of a neuron and state their interaction in information transmission within the neuron (2 marks) Practice question

36. Name the three main components of a neuron and state their interaction in information transmission within the neuron (2 marks) Practice question 1 mark - stating all 4 components of the neuron 1 mark - stating the interaction

37. Name the three main components of a neuron and state their interaction in information transmission within the neuron (2 marks) The components are - dendrites, axon, myelin and axon terminals Interaction should refer to oneway transmission from dendrites then to the axon and axon terminals - made more efficient by the presence of myelin. Practice question

38. Role of Neurotransmitters • Neurotransmitter - a chemical substance produced by a neuron that carries a message to other neurons or cells in muscles, organs or other tissues. • Synapse - the site where communication occurs between neurons next to each other. • Synaptic gap - the tiny space between the terminal buttons of one neuron and the dendrites of another which receive the neurotransmitter

39. Complete the neurotransmission diagram in your workbook as we watch. Remember to use the term SYNAPTIC GAP, rather than Synaptic Cleft. https://www.youtube.com/watch?v=WhowH0kb7n0 Role of Neurotransmitters

40. Neurotransmitters • There are different types of neurotransmitters that perform different roles, but generally, a specific type of neurotransmitter will have either one of two effects: • Excitatory - the neurotransmitter will stimulate or activate postsynaptic neurons to perform their functions • Inhibitory - the neurotransmitter will block or prevent postsynaptic neurons from firing.

41. Neurotransmitters • Glutamate (Glu) and Gamma-amino butyric acid (GABA) are the two most common neurotransmitters in the CNS. • Neurons in virtually every brain area use these two chemical messengers to communicate with each other.

42. Glutamate (Glu) • Glutamate is the main excitatory neurotransmitter in the CNS - it enhances information transmission by making postsynaptic neurons more likely to fire. • It is involved in most aspects of normal brain function, including perception, learning, memory, thinking and movement. • Too much or too little glutamate can actually be harmful to neurons and brain functioning as a whole. • Find out how

43. Gamma-amino butyric acid (GABA) • GABA is the main inhibitory neurotransmitter in the CNS. • One of its roles is to maintain neurotransmission at the best possible level. Without GABA, activation of postsynaptic neurons might get out of control. • Uncontrolled postsynaptic neuron activation can lead to seizures and other problems. • Low levels of GABA has been linked to anxiety symptoms.

44. Lock-and-key process • Each type of neurotransmitter has a chemically distinct shape and can only bind to receptor sites on the dendrites of postsynaptic neurons that have the correct shape. • Just like a key can only open a particular type of lock, a neurotransmitter can only bind to a certain type of receptor. • The binding then ‘unlocks’ the postsynaptic neuron’s response therefore having either an excitatory or inhibitory effect.

45. Lock-and-key process • A postsynaptic neuron can have many different shaped receptor sites and so it may be able to receive different types of neurotransmitters. • The same neurotransmitter can be either excitatory or inhibitory depending on the properties of the receptor. • Some neurons can only make one type of neurotransmitter, whereas others can make more. • It is important to note that neurotransmission is not the only way that neurons can communicate. Communication can also be electrical.

46. Exam question deconstruction

47. Don, an American university student, has recently come to Australia to study for a year. As soon as he arrived he leased a car, but initially had great difficulty interpreting his speedometer – which measured driving speed in kilometres per hour (kph) – as he had been driving in American cars for the previous five years, which measure speed in miles per hour (mph). Don regularly rehearsed a few conversions; for instance, 40 mph = 64 kph. Explain the role of glutamate in terms of the lock-and-key process that enabled Don to learn the conversions (3 marks) Practice question 1 mark - outline the role of locks 1 mark - outline the role of keys 1 mark - link this to the role of glutamate

48. Practice question Glutamate is an excitatory neurotransmitter which is highly concentrated in the hippocampus and plays a crucial role in learning and memory. When the memory trace for the conversions are activated, the uniquely shaped glutamate neurotransmitters, which represent the ‘keys’, are released from the presynaptic neuronsand bind with the corresponding matching-shaped glutamate receptors on the postsynaptic neurons – the ‘locks’. The excitatory effects of the glutamate make the postsynaptic neuron more likely to fire, which plays a key role in the LTP process.

49. The role of the neuron • Complete questions 1-4 in your workbook *** • Why does the nervous system need neurotransmitters? • What might happen if there are problems with neurotransmitters?

50. How interference to neurotransmitter function can affect nervous system functioning • Our ability to do almost anything is dependent on neurotransmitters in our nervous system functioning as they should, and having the correct amount of different neurotransmitters. • Abnormal amounts of specific neurotransmitters have been linked to various problems with mental processes and behaviours such as depression, schizophrenia and Parkinson’s disease.