Central Nervous System Physiology

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Central Nervous System Physiology

  1. 1. Carlos Darcy Alves Bersot TSA.SBA MD RESPONSÁVEL PELO CET H.F.LAGOAMédico Anestesiologista do Hospital Federal da Lagoa-SUSMédico Anestesiologista do Hospital Pedro Ernesto-UERJ
  2. 2. Nervous System Nervous System stimulus and reaction stimulus and reaction animal organism Nervous systemstimulus reaction sensory Inter- Motor receptor effector neuron neuron neuron
  3. 3. Nervous System Nervous System• Central Nervous System brain, spinal cord: nervous tissue meninges, choroid plexus: connective tissue• Peripheral Nervous System nerve, ganglion, nerve plexus:
  4. 4. Nervous Tissue Nervous TissueCellular Elements Ÿ Neuron (Nerve Cell) Ÿ Neuroglial Cells central neurglia astrocyte, oligodendrocyte, microglia and ependymal cell peripheral neuroglia Schwann cell in nerve and ganglion satellite (capsular) cell in ganglion
  5. 5. Neuron Neuron Neuronal Morphology Neuronal Cell Body (Soma) Ÿ Nucleus Neuronal Processes Ÿ Axon Ÿ DendritesDiversity of Neuronal Size and Morphology
  6. 6. Diversity ofNeuronalMorphology
  7. 7. Neuron Neuron Neuronal FunctionCommunication Receptor - Neuron - Effector- Excitability (Irritability)- Conductivity through membrane in intraneuronal conduction via synapse in interneuronal conduction neurotransmitters
  8. 8. SYNAPSE SYNAPSEŸ Presynaptic Portion: Synaptic Button - synaptic vesicle - mitochondria - presynaptic membrane: tubulinŸ Synaptic Cleft - 20-30 nmŸ Postsynaptic Portion - postsynaptic membrane: actin, fodrin, spectrin - mitochondria
  9. 9. SYNAPSESYNAPSE
  10. 10. Myelin Myelin Myelin Sheath - MYELIN Schwann sheath• formed by wrapped plasma membrane of Oligodendrocyte in CNS Schwann Cell in PNS• Node of Ranvier - Saltatory Conduction - conduction velocity
  11. 11. MyelinStructure of fast nerve conduction
  12. 12. Multiple Slerosis – disease of the myelinoligodendrocyte Jacqueline Du Pre
  13. 13. ORGANIZAÇÃO DO SNORGANIZAÇÃO DO SNCentral Nervous System Gray Matter Nucleus and Cortex White Matter TractsPeripheral Nervous System Nerve (Peripheral Nerve) Ganglion
  14. 14. SISTEMA NERVOSO PERIFÉRICOSISTEMA NERVOSO PERIFÉRICO  Nerve Fiber Myelinated Nerve Fiber Axon, Myelin sheath, Schwann cell Unmyelinated Nerve Fiber Axon, Schwann cell  Connective Tissue Sheath Endoneurium Perineurium – blood vessels Epineurium
  15. 15. ReceptorEndings
  16. 16. TERMINAÇÕES EFERENTES Somatic Efferent Endings Neuromuscular Junction (Myoneural Junction, Motor End Plate) Autonomic Efferent Endings Endings on smooth muscle and blood vessels
  17. 17. Neuromuscular Junction(Myoneural Junction, Motor End Plate) MNMJ N
  18. 18. Myasthenia Gravis Defects in NM Transmission • muscle weakness • autoimmune disease with autoantibodies against Ach receptor • treated with AchT inhibitors, thymectomy, and corticosteroidsbefore treatment after treatment
  19. 19. Autonomic Efferent Endings
  20. 20. Brain Regions1. Cerebrum2. Diencephalon3. Brainstem4. Cerebellum Cerebellum
  21. 21. Cerebrum• O cérebro humano contém cerca de 100 bilhões de neurônios, ligados por mais de 10,000 conexões sinápticas .• Corpo caloso• Massa Cinzenta e Branca.• Giros e Sulcos
  22. 22. • Deeper grooves called fissures separate large regions of the brain. – The median longitudinal fissure separates the cerebral hemispheres. – The transverse fissure separates the cerebral hemispheres from the cerebellum below.• Deep sulci divide each hemisphere into 5 lobes: – Frontal, Parietal, Temporal, Occipital, and Insula
  23. 23. • The central sulcus separates the frontal lobe from the parietal lobe. – Bordering the central sulcus are 2 important gyri, the precentral gyrus and the postcentral gyrus.• The occipital lobe is separated from the parietal lobe by the parieto-occipital sulcus.• The lateral sulcus outlines the temporal lobe. – The insula is buried deep within the lateral sulcus.
  24. 24. Where’s the insula?
  25. 25. Cerebral Cortex• 3 types of functional areas: 1. Motor  Control voluntary motor functions 2. Sensory  Allow for conscious recognition of stimuli 3. Association  Integration
  26. 26. Cortical Motor Areas1. Primary Motor Cortex2. Premotor Cortex3. Broca’s Area
  27. 27. Primary motor Premotor cortex cortexFrontal Eye Field Broca’s Area
  28. 28. Primary (Somatic) Motor Cortex• Located in the precentral gyrus of each cerebral hemisphere.• Contains large neurons (pyramidal cells) which project to SC neurons which eventually synapse on skeletal muscles – Allowing for voluntary motor control. – These pathways are known as the corticospinal tracts or pyramidal tracts.
  29. 29. Panfiled?
  30. 30. • Located just anterior Premotor Cortex to the primary motor cortex.• Involved in learned or patterned skills.• Involved in planning movements.• How would damage to the primary motor cortex differ from damage to the premotor cortex?
  31. 31. Broca’s Area• Typically found in only one hemisphere (often the left), anterior to the inferior portion of the premotor cortex.• Directs muscles of tongue, and throat that are used in speech production.• Involved in planning speech production and possibly planning other activities.
  32. 32. Sensory Areas• Found in the parietal, occipital, and temporal lobes. 1. Primary somatosensory cortex 2. Somatosensory association cortex 3. Visual areas 4. Auditory areas 5. Olfactory cortex 6. Gustatory cortex 7. Vestibular cortex
  33. 33. Primary Somatosensory Cortex• Found in the postcentral gyrus.• Neurons in this cortical area receive info from sensory neurons in the skin and from proprioceptors which monitor joint position.• Contralateral input.
  34. 34. Somatosensory Association Cortex• Found posterior to the primary somatosensory cortex• Synthesizes multiple sensory inputs to create a complete comprehension of the object being felt. – How would damage to this area differ from damage to the primary somatosensory cortex?
  35. 35. Primary Visual Cortex• Found in the posterior and medial occipital lobe.• Largest of the sensory cortices. – What does this suggest?• Contralateral input.
  36. 36. Association Areas• Allows for analysis of sensory input.• Multiple inputs and outputs. Why?1. Prefrontal cortex2. Language areas3. General interpretation area4. Visceral association area
  37. 37. Prefrontal Cortex• Anterior frontal lobes• Involved in analysis, cognition, thinking, personality, conscience, & much more.• What would a frontal lobotomy result in?• Look at its evolution
  38. 38. Phineas Gage’s lesion reconstructed (H. Damasio and R. Frank, 1992)
  39. 39. • Large area for Language Areas language understanding and production surrounding the lateral sulcus in the left (language- dominant) hemisphere• Includes: NEGLIGENCIA – Wernicke’s area  understanding oral/written words – Broca’s area  speech production
  40. 40. Basal Nuclei• Set of nuclei deep within the white matter.• Includes the: – Caudate Nucleus – Lentiform Nucleus • Globus pallidus • Putamen • Components of the extrapyramidal system which provides subconscious control of skeletal muscle tone and coordinates learned movement patterns and other somatic motor activities. • Doesn’t initiate movements but once movement is underway, they assist in the pattern and rhythm (especially for trunk and proximal limb muscles
  41. 41. Basal GangliaBasal Ganglia Components Components ff
  42. 42. Parkinson’s PD DiseaseDisease of mesostriatal dopaminergic systemMuhammad Ali in Alanta Olympic normal
  43. 43. SYDENHAM’S CHOREA SYDENHAM’S CHOREA Clinical Feature - Complication of Rheumatic Fever - Fine, disorganized , and random movements of extremities, face and tongue - Accompanied by Muscular Hypotonia -Principal Pathologic Lesion: Corpus Striatum
  44. 44. HUNTINGTON’S CHOREA Clinical Feature - Predominantly autosomal dominantly inherited chronic fatal disease (Gene: chromosome 4)Principal Pathologic Lesion: Corpus Striatum (esp. caudate nucleus) and Cerebral Cortex
  45. 45. Diencephalon• Forms the central core of the forebrain• 3 paired structures: 1. Thalamus 2. Hypothalamu s 3. Epithalamus
  46. 46. Thalamus• 80% of the diencephalon• Sensory retransmission station where sensory signals can be edited, sorted, and routed.• Also has profound input on motor (via the basal ganglia and cerebellum) and cognitive function.
  47. 47. Hypothalamus• Functions: – Autonomic regulatory center • Influences HR, BP, resp. rate, GI motility, pupillary diameter. • Can you hold your breath until you die? – Emotional response • Involved in fear, loathing, pleasure • Drive center: sex, hunger – Regulation of body temperature – Regulation of food intake • Contains a satiety center – Regulation of water balance and thirst – Regulation of sleep/wake cycles – Hormonal control • Releases hormones that influence hormonal secretion from the anterior pituitary gland. • Releases oxytocin and vasopressin
  48. 48. Epithalamus• Above the thalamus• Contains the pineal gland which releases melatonin (involved in sleep/wake cycle and mood).
  49. 49. Cerebellum• Lies inferior to the cerebrum and occupies the posterior cranial fossa.• 2nd largest region of the brain. • 10% of the brain by volume, but it contains 50% of its neurons• Has 2 primary functions: 1. Adjusting the postural muscles of the body • Coordinates rapid, automatic adjustments, that maintain balance and equilibrium 2. Programming and fine-tuning movements controlled at the subconscious and conscious levels • Refines learned movement patterns by regulating activity of both the pyramidal and extrapyarmidal motor pathways of the cerebral cortex
  50. 50. Cerebellum• The cerebellum can be permanently damaged by trauma or stroke or temporarily affected by drugs such as alcohol.• These alterations can produce ataxia – a disturbance in balance.
  51. 51. a b c Cerebellar Ataxia ROMBERGd
  52. 52. Pons• The bulging center part of the brain stem• Mostly composed of fiber tracts• Includes nuclei involved in the control of breathing
  53. 53. Medulla Oblongata• The lowest part of the brain stem• Merges into the spinal cord• Includes important fiber tracts• Contains important control centers • Heart rate control • Blood pressure regulation • Breathing • Vomiting
  54. 54. Spinal segment C8, T12, L5, S5, Cx1Anterior (Ventral) RootPosterior (Dorsal) Root Dorsal Root (Spinal) Ganglion
  55. 55. Spinal CordSpinal Cord Meninges MeningesPeriosteum of VertebraPeriosteum of Vertebra --Epidural Space ----------------- epidural anesthesia Epidural Space ----------------- epidural anesthesiaDura Mater SpinalisDura Mater SpinalisArachnoid MembraneArachnoid Membrane --Subarachnoid Space -------- Lumbar Puncture Subarachnoid Space -------- Lumbar Puncture Spinal Anesthesia Spinal AnesthesiaPia Mater SpinalisPia Mater Spinalis
  56. 56. Spinal Cord Spinal Cord Vascular Supply Vascular SupplyArterial SupplyArterial Supply --Spinal Arteries Spinal Arteries Anterior (1) & Posterior (2) Spinal Artery Anterior (1) & Posterior (2) Spinal Artery from Vertebral artery from Vertebral artery --Radicular Arteries ----- Segmental arteries Radicular Arteries ----- Segmental arteries from Vertebral, Ascending Cervical, Intercostal and from Vertebral, Ascending Cervical, Intercostal and Lumbar Artery Lumbar Artery
  57. 57. 5. Adamkiwicz arteryanterior spinal artery segmental arteries
  58. 58. Spinal CordSpinal Cord Ascending Tracts Ascending Tracts Spinothalamic Tract Spinothalamic Tract Modality: Pain & Temperature Sensation, Light Touch Modality: Pain & Temperature Sensation, Light Touch Receptor: Free Nerve Ending Receptor: Free Nerve Ending Ist Neuron: Dorsal Root Ganglion (Spinal Ganglion) Ist Neuron: Dorsal Root Ganglion (Spinal Ganglion) Posterior Root Posterior Root 2nd Neuron: Dorsal Horn (Lamina I, IV, V) 2nd Neuron: Dorsal Horn (Lamina I, IV, V) Spinothalamic Tract --(Spinal Lemniscus) Spinothalamic Tract (Spinal Lemniscus) 3rd Neuron: Thalamus (VPL) 3rd Neuron: Thalamus (VPL) Internal Capsule ----- Corona Radiata Internal Capsule ----- Corona Radiata Termination: Primary Somesthetic Area (S I) & Termination: Primary Somesthetic Area (S I) & Diffuse Widespread Cortical Region Diffuse Widespread Cortical Region
  59. 59. spinothalamic tract decussation anterior white commissure posterior root Spinothalamic Tract Spinothalamic Tract- contralateral loss of pain and temperature sensation below the level of lesion
  60. 60. Spinal Cord Spinal Cord Ascending Tracts Ascending Tracts Spinocerebellar Tract Spinocerebellar Tract Modality: Unconscious Proprioception Modality: Unconscious Proprioception Receptor: Golgi tendon organ, muscular fuse Receptor: Golgi tendon organ, muscular fuse Ist Neuron: Dorsal Root Ganglion (Spinal Ganglion) Ist Neuron: Dorsal Root Ganglion (Spinal Ganglion) Posterior Root ,, Posterior Root2nd Neuron: 1. Clarke’s column2nd Neuron: 1. Clarke’s column Posterior Spinocerebellar Tract Posterior Spinocerebellar Tract 2. Accessory Cuneate Nucleus 2. Accessory Cuneate Nucleus Cuneocerebellar Tract Cuneocerebellar Tract 3. Posterior Horn 3. Posterior Horn Anterior Spinocerebellar rrTract Anterior Spinocerebellar Tract Termination: Cerebellar Cortex Termination: Cerebellar Cortex FUNCTION? FUNCTION?
  61. 61. Spinal CordSpinal Cord Descending Tracts Descending Tracts Corticospinal Tract Corticospinal TractOrigin: Cerebral CortexOrigin: Cerebral Cortex Brodmann Area 4 (Primary Motor Area, M I) Brodmann Area 4 (Primary Motor Area, M I) Brodmann Area 6 (Premotor Area, PM )) Brodmann Area 6 (Premotor Area, PM Brodmann Area 3,1,2 (Primary Somesthetic Area, S I) Brodmann Area 3,1,2 (Primary Somesthetic Area, S I) Brodmann Area 5 (Anterior Portion of Sup. Parietal Lobule) Brodmann Area 5 (Anterior Portion of Sup. Parietal Lobule) Corona Radiata Corona Radiata lnternal Capsule, Posterior Limb lnternal Capsule, Posterior Limb Longitudinal Pontine Fiber Longitudinal Pontine Fiber Pyramid --pyramidal decussation Pyramid pyramidal decussation Corticospinal Tract --Lateral and Anterior Corticospinal Tract Lateral and AnteriorTermination: Spinal Gray (Rexed IV-IX)Termination: Spinal Gray (Rexed IV-IX)
  62. 62. Corona Radiata lnternal Capsule, Longitudinal Pontine Pyramid CR Pyramidal Decussation Corticospinal Tract IC - Lateral and Anterior LPF Corticospinal Tract Corticospinal Tract Pyr PD LCST- ipsilateral UMN syndrome ACST at the level of lesion
  63. 63. Spinal Cord Spinal Cord Syndrome Syndrome Amyotrophic AmyotrophicLateral SclerosisLateral Sclerosis (ALS) (ALS) Lou Gherig’s Lou Gherig’s Disease Disease Stephen Haking (1946- ) British Physicist, A Brif History of Time

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