CNS

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  • http://biomed.brown.edu/Courses/BI108/BI108_1999_Groups/Vision_Team/Definition.htm
  • CNS

    1. 1. Central NervousSystemSpinal Cord and Brain AnatomyIntegrative FunctionChapter 48 page 1042-1051
    2. 2. Central Nervous System (CNS)Organs Bone Fluid-filled cavityBrain Skull VentriclesSpinal Cord Spinal column,spine, vertebraeCentral canal
    3. 3. Spinal Cord
    4. 4. Spinal cordAscending tract Descending tract
    5. 5. Paired Spinal Nerves Paired spinal nervesoriginate in thespinal cord andinnervate the entirebody.From http://www.infovisual.info/03/039_en.html
    6. 6. Paired Cranial Nerves Paired cranialnerves originatein the brain andinnervate thehead and face.From http://www.chiro.org/chimages/diagrams/cranialn.jpg
    7. 7. Cavities – frontal view
    8. 8. Cavities – lateral view
    9. 9. Cerebrospinal fluid (CSF) a fluid that fills the cavities in the CNS formed by filtration of blood contains nutrients, hormones, white bloodcells act as shock absorber (cushion)
    10. 10. Cerebrospinal fluid (CSF)http://antranik.org/wp-content/uploads/2011/11/circulation-of-csf-interventricular-foramen-aperture-cerebral-aqueduct.jpg
    11. 11. Meninges three layers of toughelastic connectivetissue Dura Mater Arachnoid Mater Pia Mater within the skull andspinal column surrounds the brainspinal cord
    12. 12. Meninges in Brain
    13. 13. Meninges in Spinal Cordhttp://biologydiaries.files.wordpress.com/2011/05/12-30b_spinalcord_1.jpg
    14. 14. Meninges Function Encase and protect your brain Blood-brain barrier: blood vessels located inthe subarachnoid space (between thearachnoid and pia mater)http://apbrwww5.apsu.edu/thompsonj/Anatomy%20&%20Physiology/2010/2010%20Exam%20Reviews/Exam%204%20Review/meninges.frontal.fig.12.20a.jpg
    15. 15. Meninges & the Blood-BrainBarrier Recall: blood-brain barrier prevents substances in theblood vessels from being absorbed into the brain. Selectively allows some substances to pass (e.g.oxygen, glucose) Nutrients to the brain is transported by thecerebrospinal fluid located in: middle of the spinal cord inner layers of meninges
    16. 16. Meningitis inflammation of themeninges viruses bacteria antibodies do not reachthe brain requires promptmedical treatment
    17. 17. Bundling of axon White matter: bundles of myelinated axons Gray matter: unmyelinated axons, nuclei, anddendrites.
    18. 18. Gray & White Matter
    19. 19. Spinal Cord: cross sectionhttp://lifesci.rutgers.edu/~babiarz/histo/nerve/sc1L.jp
    20. 20. White and gray matterin the brainFrom http://cas.bellarmine.edu/tietjen/HumanBioogy/Brain01.gifGraymatterWhitematter
    21. 21. Anatomy of the Brain
    22. 22. Three Sections of the Brain1. Forebrain2. Midbrain3. Hind brain
    23. 23. Anatomy of the BrainForebrainHindbrainMidbrain
    24. 24. BrainstemFig. 48.20
    25. 25. Brainstem: “lower brain”Hindbrain
    26. 26. Brainstem Function Data conduction Relay information from higher brain regions Large-scale coordination body movement (e.g. walking)
    27. 27. Hind Brain Medulla oblongata: at base of brain stem controls involuntarymuscles (e.g. heartrate, dilation of bloodvessels, swallowing) Pons: bridgesinformation betweencerebellum andmedulla oblongata“littlecerebrum”Cerebellum:Unconcious coordination:posture, body/limb movement,balanceVoluntary motor skills (e.g.writing, riding a bike)
    28. 28. Medulla Oblongata Descending axons (brain to spinal cord)carrying instructions about movement willcrisscross from right to left (and vice versa) Thus right side of brain controls movement of leftside of body etc. Crossing of axons occur at the medulla
    29. 29. Midbrain Processes information from eyes, ears, nose Integration of sensory information Superior colliculi: visual Inferior colliculi: auditory system
    30. 30. Forebrain Regions Regions: Thalamus Epithalamus Hypothalamus Pituitary gland Cerebrum“Lower”Pineal gland inepithalamus
    31. 31. Forebrain in the “lower brain”Fig. 48.20
    32. 32. Forebrain“Lower” Functions Thalamus: “great relay station” Receives sensory input and sorts and sends tocerebrum Receives motor output information from cerebrum Epithalamus: Has a tiny projection called the pineal gland thatsecretes a hormone to regulate functions related tolight and seasonal changes Hypothalamus & Pituitary gland: homeostaticregulation (hormone production)
    33. 33. Forebrain “higher” brainFig. 48.20
    34. 34. Cerebrum Largest and most highlyevolved structure ofmammalian brain Divided into 2 hemispheresand 4 lobes Corpus callosum: Connects left and right side Communication betweenhemispheres White matterFig. 48.24a
    35. 35. Cerebral Cortex Outer covering for mammals Gray matter 6 sheets of neurons on brain surface 5 mm thick, but 80%of total brain mass Convolutions increase surface area Greater cognitive abilities, more sophisticatedbehaviour
    36. 36. 4 Lobes of the CerebrumFig. 48.24b
    37. 37. Frontal Lobe controls voluntary muscle movement responsible for reasoning modulates emotions based on sociallyacceptable norms Integrates sensory information from theother lobes
    38. 38. Phineas Gage Story On September 13, 1848 twenty-five-year-old Gage was foreman of a work gang blastingrock while preparing the roadbed for the Rutland & Burlington Railroad outside the town ofCavendish, Vermont. Setting a blast involved boring a hole deep into a body of rock; adding blasting powder, afuse, and sand; then compacting this charge into the hole using a tamping iron—a largeiron rod. Gage was doing this around 4:30 PM when the iron struck a spark against the rock(possibly because the sand was omitted) and the powder exploded, carrying an instrumentthrough his head an inch and a fourth in diameter, and three feet and seven inches inlength, which he was using at the time. The iron entered on the side of his face passingback of the left eye, and out at the top of the head The equilibrium or balance, so to speak, between his intellectual faculties and animalpropensities, seems to have been destroyed. He is fitful, irreverent, indulging at times inthe grossest profanity (which was not previously his custom), manifesting but littledeference for his fellows, impatient of restraint or advice when it conflicts with his desires,at times pertinaciously obstinate, yet capricious and vacillating, devising many plans offuture operations, which are no sooner arranged than they are abandoned in turn forothers appearing more feasible. A child in his intellectual capacity and manifestations,he has the animal passions of a strong man. Previous to his injury, although untrained in the schools, he possessed a well-balancedmind, and was looked upon by those who knew him as a shrewd, smart businessman, veryenergetic and persistent in executing all his plans of operation. In this regard his mind wasradically changed, so decidedly that his friends and acquaintances said he was "no longerGage"
    39. 39. Temporal Lobe Processes hearing Hippocampus: long-term memory Amygdala: processes memory and emotions
    40. 40. Occipital Lobe responsible for primary visual informationprocessing coordinates information gathered from theretina
    41. 41. Parietal Lobe Processes touch & temperature(somatosensory cortex), and taste Visuospatial analysis examines numbers and processes ratios Visuospatial Tests: http://www.alliqtests.com/tests/6/11/
    42. 42. Regions of the Cerebrumhttp://lh4.ggpht.com/_lRGislJejZ0/SRp7sb6QjHI/AAAAAAAAB8c/xeGXGZP0LUY/image20_thumb4.png?imgmax=800
    43. 43. Integrative Function Specialized function in the brain thatintegrate various areas of the cerebrum Forms of integrationA. Processing of sensory inputB. LateralizationC. Language and SpeechD. EmotionsE. Memory and Learning
    44. 44. A. Processing of Sensory Input1. Sensory input2. Primary sensory areas in lobes Parietal, Occipital, temporal, frontal3. Adjacent association areas in lobes Information is integrated and assessed forsignificance4. Frontal association area in frontal lobe Compose a motor response5. Primary Motor cortex Direct movement of skeletal muscles6. Motor Output
    45. 45. A. Processing of Sensory Input:Primary sensory areasFig. 48.24b
    46. 46. Sensory Input Processingin Lobes of CerebrumSensory input Primary sensoryareas in lobesAdjacentassociation areaVisualHearingSmellTasteTouch: pain, pressureTemperatureLimb position
    47. 47. Sensory Input Processingin Lobes of CerebrumSensory input Primary sensoryareas in lobesAdjacentassociation areaVisual OccipitalHearing TemporalSmell FrontalTaste Parietal: tasteTouch: pain, pressureTemperatureLimb positionParietal: primarysomatosensorycortex
    48. 48. A. Processing of Sensory Input1. Sensory input2. Primary sensory areas in lobes3. Adjacent association areas in lobes Information is integrated and assessed forsignificance4. Frontal association area in frontal lobe Composed a motor response5. Primary motor cortex Direct movement of skeletal muscles6. Motor output
    49. 49. A. Processing of Sensory Input:Adjacent association areasFig. 48.24b
    50. 50. Sensory Input Processingin Lobes of CerebrumSensory input Primary sensoryareas in lobesAdjacentassociation areaVisual Occipital VisualHearing Temporal AuditorySmell Frontal FrontalTaste Parietal: taste SomatosensoryTouch: pain, pressureTemperatureLimb positionParietal: primarysomatosensorycortexSomatosensory
    51. 51. A. Processing of Sensory Input1. Sensory input2. Primary sensory areas in lobes3. Adjacent association areas in lobes Information is integrated and assessed forsignificance4. Frontal association area in frontal lobe Composed a motor response5. Primary motor cortex Direct movement of skeletal muscles6. Motor output
    52. 52. A. Processing of Sensory Input:Frontal association areaFig. 48.24bSmell
    53. 53. A. Processing of Sensory Input1. Sensory input2. Primary sensory areas in lobes3. Adjacent association areas in lobes Information is integrated and assessed forsignificance4. Frontal association area in frontal lobe Composed a motor response5. Primary motor cortex Direct movement of skeletal muscles6. Motor output
    54. 54. A. Processing of Sensory InputFig. 48.24b
    55. 55. Primary CortexFig. 48.25Motor Output(Voluntary control ofskeletal muscles)Sensory Input:Somatic sense of touch(Not specialized senses:sight, sound, smell, taste)
    56. 56. Primary Cortex Primary somatosensory cortex receives and integrates sensory information Input from: skin, muscle, joints Senses: touch, temperature, limb position Primary motor cortex sends signals to skeletal muscles
    57. 57. B. Lateralization allocation of brain function to right or lefthemisphere occurs during brain development (child)
    58. 58. Lateralization of BrainFunctionLeft hemisphere Language math, logic operations processing of serialsequences ofinformation Processing of finevisual & auditory details Specialized in detailedactivities required formotor controlRight hemisphere pattern recognition,spatial relationships face recognition &emotional processing music Multi-tasking Specialized ininterpreting wholecontext
    59. 59. C. Language and Speech areashttp://www.pennmedicine.org/health_info/body_guide/reftext/images/anatomy_brain.jpg
    60. 60. C. Language and Speech areasAreas Broca WernickeLocation Frontal lobe Temporal lobeFunction Speech production(motor)Speechcomprehension(sensory)Damage Can understandspeech, can’t speakCan say words, butdoesn’t make anysense
    61. 61. C. Language and Speech areashttp://lh4.ggpht.com/_lRGislJejZ0/SRp7sb6QjHI/AAAAAAAAB8c/xeGXGZP0LUY/image20_thumb4.png?imgmax=800Broca’s area(motor speech)Wernicke’s area(sensory speech)
    62. 62. C. Language and Speech Other speech areas also involved Examples: Reading printed words out loud: visual cortex andBroca (seeing, speaking, without understanding) Determining meaning to generate words: frontallobe & Wernicke
    63. 63. Mapping Languagehttp://www.ncbi.nlm.nih.gov/bookshelf/br.fcgi?book=neurosci&part=A1914No talking TalkingNocomprehensionPassively viewing words: Visual Speaking words: BrocaComprehensionListening to words: Wernicke,auditoryGenerating words: Wernicke,Broca
    64. 64. D. Limbic System: Function Generates emotions Mediates primary emotions: laugh, cry, fearanger e.g. Instinct to nuture infants, emotional bonding Attaching emotions to basic survivalprograms e.g. feeding, aggression, sexuality
    65. 65. D. Limbic System: Anatomyhttp://www.colorado.edu/intphys/Class/IPHY3730/image/figure5-8.jpgHypothalamus
    66. 66. D. Limbic System: Anatomy Hippocampus Olfactory cortex Amygdala thalamus and hypothalamus
    67. 67. Amygdala In temporal lobe Receives input from the hippocampus Recognizes emotional content of facialexpressions Identifies how other people are feeling Keeps a history of emotional memories e.g. Infants learn to distinguish between “right”and “wrong” when the caregiver “smiles” or“frowns” respectively
    68. 68. E. Memory and Learning Nerve cells can make new connections asyou learn/refine skills Skill memories, once learned, are difficult tounlearn (bad habits are hard to break)
    69. 69. Long-term memory Activated by hippocampus enhanced by repetition influenced by emotional states mediated bythe amygdala influenced by association with previouslystored information
    70. 70. Short-term memory Stored in frontal lobe has a limited capacity, about 7 items has a limited duration, about 30 seconds is the bottleneck in the memory systembecause it limits how much information wecan transfer to long-term memory.
    71. 71. Functional Changes insynapses Long-term potentiation (LTP) Long-term depression (LTD)
    72. 72. Long-term potentiation (LTP) occurs when a postsynaptic neuron displaysincreased responsiveness to stimuli Induced by brief, repeated action potentialsthat strongly depolarize the postsynapticmembrane. May be associated with memory storage andlearning.
    73. 73. Long-term depression (LTD) occurs when a postsynaptic neuron displaysdecreased responsiveness to actionpotentials Induced by repeated, weak stimulation E.g. inability to smell a stench after a periodof continuous exposure
    74. 74. Neuronal plasticity Plasticity: the ability of mature nerves andneurons to adapt to environmental influencessuch as learning or compensation afterdisease or injury.
    75. 75. Neuronal plasticity Short-term plasticity: may involve theenhancement of existing synapticconnections. Long-term plasticity: may involve physicalchanges such as the formation of newsynapses.
    76. 76. Examples of neuronalplasticity Rehabilitation after:- strokes- epilepsy- car crashes- loss of limbs- being in outer space

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