ppt introduction of nervous system by qazi

1. INTRODUCTION OF NERVOUS SYSTEM BY QAZI IMTIAZ RASOOL H.O.D GMC

2. What are we doing with ourbrains at this moment? Don’t get nervous about NERVOUS SYSTEM 4/10/2011 2

3. The student’s brain; Feeling your chair Squirming (moving) , Watching ,Listening, Remembering ,Paying Attention, Sleeping Feeling anxious Feeling hungry What happens when you ask a question? 4/10/2011 3

4. MAINTENANCE AND PROTECTION OF THE CNS Glial Cells: physical and metabolic support Skull and Spinal Column Cerebrospinal fluid Blood-brain barrier Blood supply 4/10/2011 4

5. Skull and Spinal Column PROVIDE MECHANICAL SUPPORT PROTECTS THE NEURAL AND SUPPORTING TISSUE 4/10/2011 5

6. CEREBROSPINAL FLUID SHOCK ABSORBER DENSITY IS THE SAME AS BRAIN 4/10/2011 6

7. Blood-brain barrier LIMITS ACCESS OF BLOOD MATERIALS TO BRAIN TISSUE PROTECTS BRAIN FROM FLUCTUATIONS IN BLOOD LEVELS 4/10/2011 7

8. INTRODUCTION TO NERVOUS SYSTEM 4/10/2011 8

9. 4/10/2011 9 Primary Tissues4 Different Primary Tissues:Muscle Nervous Epithelial Connective

10. 11 Systems 4/10/2011 10

11. Homeostasis Maintaining constancy of internal environment. Body temp ; urine vol ; gas vol ; Circulation, movement 2.Dynamic consistency. Sensory device, sight, hearing, taste, pain Maintained by feedback loops. 4/10/2011 11

12. Basic physiological Functions of the Nervous System Sensation Monitors changes/events occurring in and outside the body. Such changes are known as stimuli and the cells that monitor them are receptors. Integration The parallel processing and interpretation of sensory information to determine the appropriate response Reaction Motor output. The activation of muscles or glands (typically via the release of neurotransmitters (NTs)) 4/10/2011 12

13. . 1. Electrical properties of the neuron 2. Signal transmission 3. Action potential 4. Events at the synapse 5. Electrical synapses 6. Ionic environments of the neurons 7. Chemical messengers of the neurons a. Neurotransmitters b. Neuromodulators c. Neuropeptides d. Neurohormones 4/10/2011 13 Basic Principles of NS Function at molecular level

14. NUMBER 4/10/2011 14

15. History of Neurobiology 4/10/2011 15

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17. 4/10/2011 17 Luigi Galvani . (1737-1798 AD)

18. Cell theory Schlieden +Schwann-1839 4/10/2011 18

19. 4/10/2011 19 Camillo Golgi

20. Reymonds-1896 4/10/2011 20

21. Waldeyer 4/10/2011 21

22. Evolution 4/10/2011 22

23. ARBORAZATION 4/10/2011 23

24. Is Handedness Inherited? human bias for right-handedness has been around a long time and is pervasive studies of prehistoric cave drawings, tools, and arm/hand bones (Corballis, 1989; Steele, 2000) right-handedness prevalent in all human cultures before effects of culture: more than 9 of 10 fetuses suck the right hand’s thumb in the womb (Hepper et al., 1990, 2004) chimpanzees and gorillas (closely related to humans) = 65% right-handed (Hopkins et al., 2005) other, more distant primates are more evenly split

25. SPECIAL FEATURES OF NERVOUS SYSTEM 4/10/2011 25

26. BASIC FUNCTIONAL UNIT 4/10/2011 26

27. Nervous Tissue Highly cellular 2 cell types Neurons Functional, signal conducting cells Neuroglia Supporting cells 4/10/2011 27 1. 2.

28. 1.COMPARISION WITH COMPUTORS 4/10/2011 28

29. COMPARISION WITH COMPUTORS INPUT OUTPUT CENTRE INTEGRATION SPEED NEW IDEAS ENERGY PROPER CONNECTIONS INSULATION DAY DREAMING OUTPUT FLEXIBILITY ORGINALITY 4/10/2011 29

30. Computers vs. Brains Processing elements: There are,108 transistors R 10 synapses Processing speed: 109 Hz Intelligence and consciousness: the computer shows lack of intelligence. Evolution: computers have been evolving for decades Brain 100 Hz 2. The brain is highly intelligent andconscious. 3.The brains have been evolving for tens of millions of years, 4/10/2011 30 14

31. Fault tolerant: The brain is fault tolerant Adaptive: The brain learns fast. The brain computes in parallel and distributedmode, Fault tolerant: whereas the computer is not. Adaptive: whereas the computer doesn’t evencompare with an infant’s learning capabilities. 3. Style of computation: whereas the computer mostly serially and centralized 4/10/2011 31

32. Neuroscience in the news 1.relatively recent 2.interdispilanary 3.uses many levels of analysis Organisms (behavior) Systems Circuits Neurons Molecules 4. Neuro -genesis Growth of new neurons Once thought impossible 4/10/2011 32

33. . 1.Stem cells research , Immature cells that renew themselves and have the potential. to develop into mature cells 2.Embryonic stem cells are most useful Controversial 3.In 2001, President U.S.A signed executive order preventing creation of new cell lines. 4.Some scientists want the ban lifted 4/10/2011 33

34. 2.LACK OF LYMPHACITIC SYSTEM 4/10/2011 34

35. 3.DEVELOPMENT 4/10/2011 35

36. 4.Neural Induction Induction signals From embryonic tissue Modulate gene expression Retinoic acid Steroid hormone Peptide hormones Fibroblast growth factor (FGF) Transforming growth factor (TGF) 4/10/2011 36

37. Neuronal structure develops in 4 major stages: Proliferation,Neurogenesis Migration Differentiation Synaptogenesis 4/10/2011 37

38. 5. .Development of the neuronal structure physiologically occurs in 8 stages Mitosis/Proliferation Migration(rate=6-10µm/min) Differentiation Aggregation Synaptogenesis Neuron Death Synapse Rearrangement Myelination

39. 4/10/2011 39 Stages of Development neurogenesis synaptogenesis migration morphological differentiation axonal extension target identification

40. 6.Critical Periods in Human Development Embryonic development (9 week) Fetal development (until birth) Postnatal development e.g. Critical period for language acquisition 4/10/2011 40

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43. 7. MATURATION 4/10/2011 43

44. 8.NEUROPLASICITY Development Activity Learning Habituation Response to injury Rehabilitation 4/10/2011 44

45. 9 stimulating environment increases dendritic branching and number of dendritic spines 4/10/2011 45 Standard environment Enriched environment

46. 4/10/2011 46

47. 4/10/2011 47 10 .DESTRUCTION 1..one-year old human has about 100 billion (1011) neurons. 2. No new neurons will be formed after that age,??? 3.neurons will be lost at a rate of roughly 200,000 per day (a net loss of 2 to 5% by age 50). 4.Maximum brain weight is achieved at about age 21 5.Hypothalamus is the last to deverlopecompeletly

48. 10. RMP= -65mV 48

49. 4/10/2011 49 11.NUMBER OF THE CELLS Guess what? There are more nerve cells in the human brain than there are stars in the Milky Way.

50. 4/10/2011 50 The Human Brain 100 billion 1 billion In The Spinal Cord

51. A single neuron on the surface of a microprocessor A cm3 of the brain will contain >50 million neurons 4/10/2011 51

52. Number of neurons cerebellum= 70 billons 12.Number of neurons &connections in the cortex alone12-15 billons+60 trillion 4/10/2011 52

53. 4/10/2011 53 11.DIFFERENT TYPES 50 MILLION DIFFERENT CELLS

54. 13. PRODUCTION1/3 million per min in 9 months of gestation 4/10/2011 54

55. 14.LOSS OF DIVIDING PROPERTIES 4/10/2011 55

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57. 15.Binary code Principle -encode information at the cellular level. Neurons encode information by the Frequency modulation On and Off mechanism of electrical impulses, controlled by chemical signal(NT) from other cells. 4/10/2011 57

58. 1. 2. 3. FREQUENCY CODE Weak stimulus Moderate stimulus Strong stimulus

59. 16. BUOYANCY 4/10/2011 59

60. CSF is a watery “ broth”found in and around the brain and spinal cord It forms a liquid cushion that gives buoyancy to the CNS organs With the brain floating, CSF reduces brain weight by 97% and thus prevents the brain from crushing under its own weight 4/10/2011 60

61. 17. ASYMMETRICAL FUNCTIONING IN THE BRAIN 4/10/2011 61

62. 18.SEX DIFFERENCE IN LATERALISATION OF LANGUAGE 1. MALES ------LEFT HEMISPHERE ACTIVATION ONLY 2. FEMALES SHOW LEFT & RIGHT 4/10/2011 62

63. 19.Sexual Dimorphism In Grey Matter Thickness(MRI) Note women have more grey matter on the right(0.45 mm thicker) inferior parietal and posterior temporal areas 4/10/2011 63

64. 20 .LENGTH OF NERVOUS SYSTEM 4/10/2011 64

65. LENGTH OF THE CELL IN THIS SYSTEM (NEURON) 4/10/2011 65 AXON SOMA 0.1 - 1,000 mm length thin, uniform width DENDRITES

66. 21.Longest cell blue whale neuron 10-30 meters giraffe axon 5 meters human neuron 1-2 meters 4/10/2011 66

67. one neuron is about 10 microns long. Remember, this is just an example, because neurons come in all different sizes. So, if we line up 100 billion neurons which are 10 microns long . . . 100,000,000,000 neurons x 10 microns= 1000 km or about 600 miles! This may help with the math:1000 microns= 1milimeter (mm)10 mm= 1centimeter (cm)100 cm= 1 meter (m)1000 m= 1 kilometer (km) 4/10/2011 67

68. 22. 40% PARTCIPATION OF GENEtissue-specific gene expression. 4/10/2011 68

69. 23.AMOUNT OF mRNA PRODUCTION 4/10/2011 69

70. 24.NKP 4/10/2011 70

71. 25.B.M.R1.7.5 TIMES THAN THE NON- NERVOUS TISSUES2.Children have twice the metabolic rate/ unit vol. than the adults 4/10/2011 71

72. 4/10/2011 72 26.1.Weight 2-3% of body2.O2 Consumption20% of total3.Brain Energy (Glucose) Utilization20% of total4.Brain Blood Flow20% of heart output at rest

73. 4/10/2011 73 27. FASTEST RESPONSE Nervous system allows for 1 millisecond response time

74. 28.HOMOESTSIS 4/10/2011 74

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76. Nervous vs. Endocrine System 4/10/2011 76

77. Hypothalamus Autonomic nervous system Neuroendocrine Brain stem and spinal cord Pituitary Maintain body homeostasis 4/10/2011 77

78. METHODS OF NEUROPHYSIOLOGY STUDIES 1. Microscopic a. Light microscopy b. TEM , SEM and freeze fracture C) Sharp metal and glass-filled electrodes plus suction electrodes for patch clamp technique 2. Cathode Ray Oscilloscope 3. Stains (1) Methylene blue (2) Cobalt filling (3) Fluorescent-Lucifer yellow and dextran-rhodamine (4) Immunological stains (fluorescent antibodies) 78

79. 4/10/2011 79 4.Histological Analyses

80. 5.Computed tomography (CAT) 4/10/2011 80

81. 6.Magnetic Resonance Imaging (MRI) 4/10/2011 81 Use electromagnetic fields to image atom (hydrogen) density Scan living brain Protons (H+) respond to magnetic field High resolution Expensive

82. 4/10/2011 82 7.Functional MRI

83. 8.CLINICAL PHYSIOLOGY 4/10/2011 83

84. 9.Positron Emission Tomography (PET) 4/10/2011 84

85. 4/10/2011 85 Optical Imaging & TMS

86. 10.Electroencephalogram (EEG) 4/10/2011 86

87. 11. Behavioral Neuroscience: Animal Experimentation 4/10/2011 87

88. EFFCTS OF AGE(BRAIN) 1.Enlargement of the volume of the ventricles: because cells surrounding the ventricles are lost 2. Widening of sulci (the grooves) on the surface of the brain 3. Reduced brain weight and brain volume: caused by the loss of neurons. 4. Loss of NT 5. Neurological disorders: brain disorders Alzheimer’s disease, Parkinson's disease and stroke 4/10/2011 88

89. EFFCTS OF AGE CORD +NERVES 4/10/2011 89 Myelin sheath increases- 1st sensory in foetal life than motor after birth Axon increases in length Arborization increases Synaptic connections increases

90. Glial tissue increases Neuronal size increases 11.Loss of neurones 40% with age more in males than females 4/10/2011 90

91. 4/10/2011 91 HOMUNCULUS

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93. Definition of death Traditionally Doctor Declare A Person Dead When His Heart & Respiration Stops Recent Times Both The Things Can Be Maintained Artifiically For Longer Times For Organ Transplant And Resumption An EEG Silence R Brain Death Is An Accepted Creteria If The Subject Should Be In Coma And Apnoea For 6 Hours Following Which EEG Silence Is Present Continously For At Least 30 Minutes. No Legal Definition EEG Silence Is Defined As Absence Of Electrical Potential Over 2mv. From Symmetrical Placed Electrodes Pairs Over 10 Cms . Apart With An Inter Electrode Resistance Between 100-1000 Ohms. 4/10/2011 93

95. Any maternal infection can have extremely harmful effects4/10/2011 94

96. SUMMARYInteresting Facts 4/10/2011 95 1 A newborn baby's brain grows almost 3 times during the course of its first year.2. Your brain is made mostly of water. (85%)3. A New born baby loses about half of their nerve cells before they are born.4. As we get older, the brain loses almost one gram / year.5. The total surface area of the human brain is about 25, 000 square cm.6. The base of the spinal cord has a cluster of nerves, which are most sensitive.

97. 7. An average adult male brain weighs about 1375 grams.8. An average adult female brain is about 1275 grams.9. 4% percent of the brain's cells work while the remaining cells are kept in reserve.10.Gray matter 3 time > white matter 11.No O2 reserve – loss of consciousness in 10 seconds – irreversible damage in 3-5 minutes 4/10/2011 96