1. PowerLecture: Chapter 34 Integration and Control: Nervous System

2. Fig. 34-1, p.572

3. p.573a

4. Nerve Net  interconnected nerve cells that can send impulses 2 directions Figure 34.3 Page 574

5. Bilateral Nervous Systems FlatwormEarthworm CrayfishGrasshopper Fig. 34.14a Page 589

6. Fig. 34-4, p.575

7. Communication Lines Stimulus (input) Receptors (sensory neurons) Integrators (interneurons) motor neurons Effectors (muscles, glands) Response (output) Figure 34.5 Page 575

8. Fig. 34-6d2, p.576 Neurons

9. Neurons  3 classes Sensory neurons Interneurons Motor neurons

10. Fig. 34-6d1, p.576 dendrites cell body trigger zone input zone conducting zone output zone axon endings axon Structure of a Neuron

11. cell body axon dendrites Fig. 34-6a, p.576

12. axon dendrites cell body Fig. 34-6b,c, p.576 dendrites

13. Resting Potential  -70millivolts Charge difference across membrane of neuron  inside cell negative

14. Ion Concentrations at Resting Potential  Potassium (K + ) Higher inside than outside Higher inside than outside  Sodium (Na + ) Higher outside than inside Higher outside than inside

15. outside plasma membrane inside K+K+ K+K+ Na + p.577

16. How Ions Move across Membrane Passive transporters with open channels Passive transporters with voltage-sensitive gated channels Active transporters Lipid bilayer of neuron membrane Interstitial fluid CytoplasmNa + /K + pump Figure 34.7 Page 577

17. Pumping and Leaking Interstitial fluid Plasma membrane Cytoplasm Na + leaks in Na + pumped in Na + pumped out Na + leaks out K + leaks out Figure 34.7 Page 577

18. Action Potential  Temporary reversal in membrane potential  Voltage change causes voltage-gated channels to open  Inside neuron becomes more positive than outside

19. Action Potential Na + K+K+ K+K+ K+K+ K+K+ K+K+ K+K+ K+K+ 12 34 Figure 34.8a-d Page 578-79

20. Positive Feedback neuron becomes more positive inside more gated channels for Na + open more Na + ions flow into the neuron

21. All or Nothing  All action potentials are same size  Stimulation below threshold level, no action potential  Above threshold level, always same size

22. Repolarization  Movement of Na + out repolarizes cell  back to resting potential

23. one of a pair of stellar nerves with giant axons inside Fig. 34-9a, p.579

24. electrode outside electrode inside unstimulated axon Fig. 34-9b, p.579

25. Fig. 34-9c,d, p.579

26. stimulated axon Fig. 34-9e1, p.579

27. action potential threshold resting membrane potential Time (milliseconds) Membrane potential (millivolts) -70 0 0 1 23 4 5 Figure 34.9f Page 579

28. Propagation of Action Potentials  Action potential in one part of axon triggers neighboring region  Action potential travels as a wave of depolarization along cell

29. Chemical Synapse  Gap between the terminal ending of an axon and the input zone of another cell synaptic vesicle plasma membrane of axon ending of presynaptic cell plasma membrane of postsynaptic cell synaptic cleft membrane receptor Figure 34.10a Page 580

30. Synaptic Transmission  Action potential in axon ending of presynaptic cell causes voltage-gated calcium channels to open  calcium Flow into presynaptic cell releases neurotransmitter into synaptic cleft

31. Synaptic Transmission  Neurotransmitter diffuses across cleft and binds to receptors on membrane of postsynaptic cell  Binding of neurotransmitter to receptors opens ion channels in postsynaptic cell

32. Ion Gates Open ions neurotransmitter receptor for neurotransmitter gated channel protein Figure 34.10c Page 580

33. neuromuscular junction part of a skeletal muscle motor neuron axons from spinal cord to skeletal muscle cells transverse slice of spinal cord Fig. 34-11a, p.581

34. muscle fiber axon ending Fig. 34-11b, p.581

35. Neurotransmitters  ACh  Norepinephrine  Epinephrine  Dopamine  Serotonin  GABA  Derived from amino acids

36. Fig. 34-13b,c, p.582

37. Neuropeptides  Neuromodulators – magnify or reduce the effects of neurotransmitters substance P substance P enkephalins enkephalins endorphins endorphins

38. Neuroglia  more than half the volume of vertebrate nervous system  metabolically assist, structurally support, and protect the neurons

39. Fig. 34-14, p.583

40. Nerve  Bundle of axons within connective tissue sheath Figure 34.15 Page 584 axon myelin sheath nerve fascicle

41. Myelin Sheath  A series of Schwann cells that block ion movements  Action potential must “jump” from node to node Figure 34.15b Page 584

42. Multiple Sclerosis  Nerve fibers lose their myelin  Slows conduction  Symptoms include visual problems, numbness, muscle weakness, and fatigue

43. Reflexes  Automatic movements in response to stimuli  Most reflexes involve an interneuron  Reflex arcs - sensory neurons synapse directly on motor neurons

44. Stretch Reflex STIMULUS Biceps stretches. Response Biceps contracts. Figure 34.16 Page 585 motor neuron sensory neuron

45. Central and Peripheral Nervous Systems  Central nervous system (CNS) Brain Brain Spinal cord Spinal cord  Peripheral nervous system Nerves that thread through the body Nerves that thread through the body

46. Peripheral Nervous System  Somatic nerves Motor functions Motor functions (Shown in green) (Shown in green)  Autonomic nerves Visceral functions Visceral functions (Shown in red) (Shown in red)

47. Two Types of Autonomic Nerves  Sympathetic  Parasympathetic  Most organs receive input from both  Usually have opposite effects on organ

48. Sympathetic Nerves  Originate in Ganglia near the thoracic and lumbar regions of the spinal cord  Promote fight-or-flight response

49. Parasympathetic Nerves  Originate in the brain and the sacral region of the spinal cord  Promote housekeeping responses such as digestion

50. Dr. Robert Sapolsky (Stanford Neurobiologist) studies long term health effects of stress

51. Function of the Spinal Cord  signals between brain and peripheral nerves  direct reflex connections in the spinal cord  Spinal reflexes do not involve brain

52. Structure of the Spinal Cord spinal cord ganglion nerve vertebra meninges (protective coverings) Figure 34.18 Page 587

53. Development of the Brain  develops from a hollow neural tube  Forebrain, midbrain, and hindbrain form

54. Functional Regions  Expansion and modification of dorsal nerve cord produced functionally distinct regions FOREBRAIN MIDBRAIN HINDBRAIN (start of spinal cord) Figure 34.19a Page 588

55. Brain Regions Hindbrain (Rhombencephalon) Medulla oblongata - controls autonomic Medulla oblongata - controls autonomic functions functions Cerebellum - controls motor skills and Cerebellum - controls motor skills and posture posture Pons - controls signals between cerebellum Pons - controls signals between cerebellum and forebrain and forebrain

56. Brain Regions Midbrain ( Mesencephalon) Tectum - Visual Processing Tectum - Visual Processing

57. Brain Regions Forebrain (Prosencephalon) Cerebrum - Higher thinking skills Cerebrum - Higher thinking skills Thalamus - sorting sensory input Thalamus - sorting sensory input Hypothalamus - Homeostatic control Hypothalamus - Homeostatic control

58. forebrain midbrain hindbrain Brain at 7 weeks Fig. 34-19b, p.588 Brain Development

59. Brain at 9 weeks Fig. 34-19c, p.588 Brain Development

60. Brain at birth Fig. 34-19d, p.588 Brain Development

61. Divisions of Brain DivisionMain Parts Forebrain Midbrain Hindbrain Cerebrum Olfactory lobes Thalamus Hypothalamus Limbic system Pituitary gland Pineal gland Tectum Pons Cerebellum Medulla oblongata anterior end of the spiral cord Figure 34.19a Page 588

62. Vertebrate Brains olfactory lobe (part of forebrain) forebrain midbrain hindbrain fish (shark) reptile (alligator) mammal (horse) forebrain midbrain hindbrain olfactory lobe Figure 34.21 Page 589

63. Cerebrospinal Fluid  Surrounds spinal cord  Fills brain ventricles  Blood-brain barrier controls which solutes enter Figure 34.20 Page 588

64. Reticular Formation  Interneuron Mesh extends from spinal cord, through brain stem, into cerebral cortex

65. Anatomy of the Cerebrum  Largest and most complex part of human brain  cortex highly folded  divided into left and right hemispheres

66. Lobes of the Cerebrum Temporal Frontal Parietal Occipital Primary motor cortex Primary somatosensory cortex Figure 34.23 Page 590

67. Fig. 34-22, p.590

68. Limbic System  Controls emotions - role in memory (olfactory tract)cingulate gyrusthalamus amygdala hippocampus hypothalamus Figure 34.24 Page 591

69. Motor cortex activity when speaking Prefrontal cortex activity when generating words Visual cortex activity when seeing written words Fig. 34-23b, p.590

70. Sperry’s Split Brain Expts.  Corpus collosum severed  No communication between hemispheres cowboy

71. Memory  Stored in stages Temporary Temporary Short-term memory Short-term memory Long-term memory Long-term memory

72. Sensor stimuli, as from the nose, eyes, and ears Temporal storage in cerebral cortex SHORT-TERM MEMORY Recall of stored input LONG-TERM MEMORY Input forgotten Input irretrievable Emotional state, having time to repeat (or rehearse) input, and associating the input with stored categories of memory influence transfer to long-term storage Fig. 34-28, p.593

73. premotor cortex motor cortex for this example, a visual stimulus Fig. 34-29a, p.593 corpus striatum caudate nucleus lentiform nucleus Memory Circuitry

74. Drugs and Addiction  A drug is a substance introduced into the body to provoke a specific physiological response  In addiction, a drug assumes an “essential” biochemical role in the body

75. Addiction

76. Stimulants  Increase alertness and body activity, then cause depression Caffeine Caffeine Nicotine - mimics acetylcholine Nicotine - mimics acetylcholine Cocaine - blocks neurotransmitters reuptake Cocaine - blocks neurotransmitters reuptake Amphetamines & Ecstasy - induce dopamine release Amphetamines & Ecstasy - induce dopamine release

77. Fig. 34-30a, p.595 PET Scan  Cocaine’s long term effect

78. Fig. 34-30b, p.595

79. Depressants  Lower activity of nerves and parts of the brain Barbiturates Barbiturates Alcohol - acts directly on the plasma membrane to alter cell function Alcohol - acts directly on the plasma membrane to alter cell function

80. Hallucinogens and Marijuana  Skew sensory perception by interfering with action of neurotransmitters  LSD affects action of serotonin  Marijuana is a depressant at low dose; it can also cause disorientation, anxiety, delusion, and hallucinations

81. Teen Brain  Prefrontal cortex still developing  Amygdala in growth spurt  Increased need for sleep

82. Synaptic Integration Membrane potential (milliseconds) -65 -70 -75 EPSP IPSP what action potential spiking would look like threshold resting membrane potential integrated potential Figure 34.12 Page 581