FISIOLOGI SUSUNAN SYARAF PUSAT & KELAINAN YANG MUNGKIN TIMBUL

FISIOLOGISUSUNAN SYARAF PUSAT& KELAINAN YANG MUNGKIN TIMBULRahmatina B. HermanBagian FisiologiFK-UNAND

1Overview Central Nervous System (CNS)CNS consists of brain and spinal cordEstimated 100 billion neurons in brain are assembled into complex networks that enable human to:1. subconsciously regulate internal environment2. experience emotions3.voluntarily control movements4. perceive (be consciously aware of) body and surroundings5.engage in other higher cognitive processes such as thought and memory2.Overview Central Nervous System (CNS)No part in brain acts in isolation from other brain regionsNetworks of neurons are anatomically linked by synapsesNeurons throughout brain communicate extensively with each other by electrical and chemical meansEven though the brain is a functional whole, it is organized into different regions 3.Overview Central Nervous System (CNS))Physiologically parts of brain can be grouped into:1.Forebrain: a.Cerebrum:-cerebral cortex-basal nucleib.Diencephalon:-thalamus-hypothalamus2. Cerebellum3.Brain stem4

5Overview Functions of BrainFOREBRAIN: CEREBRUMCerebral cortexSensory perceptionVoluntary control of movementLanguagePersonality traitsSophisticated mental events, such as thinking, memory, decision making, creativity, self consciousnessBasal nucleiInhibition of muscle toneCoordination of slow, sustained movementsSuppression of useless patterns of movements6Overview Functions of BrainFOREBRAIN: DIENCEPHALONThalamusRelay station for all synaptic inputCrude awareness of sensationSome degree of consciousnessRole in motor controlHypo-thalamusRegulations of many homeostatic functions, such as temperature control, thirst, urine output, food intakeImportant link between nervous and endocrine systemsExtensive involvement with emotion and basic behavioral patterns7.Overview Functions of BrainCEREBELLUMMaintenance of balanceEnhancement of muscle toneCoordination and planning of skilled voluntary muscle activity BRAIN STEM (MIDBRAIN, PONS, MEDULLA)Origin of majority peripheral cranial nervesCardiovascular, respiratory, digestive control centersRegulations of muscle reflexes involved with equilibrium and postureReception and integration of all synaptic input from spinal cord: arousal and activation of cerebral cortexRole in sleep-wake cycle8Cerebral Cortex4 pairs of lobes for different activities:1. Occipital lobes: initial processing of visual input 2.Temporal lobes:initial receiving of sound sensation3.Parietal lobes:receiving and processing sensory input4.Frontal lobes:- voluntary motor activity- speaking ability- elaboration of thought9

10Parietal lobes:Somatosensory CortexSomesthetic sensation: sensation from surface of body: touch, pressure, heat, cold, pain, etcProprioception: awareness of body positionSensory homunculus11Parietal lobes:..Somatosensory CortexLocalizes source Perceives level of intensity of stimulusSpatial discrimination: shapes of object, distinguish differences in similar subjectProjects the sensory input to adjacent higher sensory areas for further elaboration, analysis, and integration Receive sensory input from the opposite side of body Damage: sensory deficit/losses of the opposite side12Frontal lobes:Primary Motor CortexVoluntary control over movement produced by skeletal muscleMotor homunculusExtent of representation in motor cortex is proportional to the precision and complexity of motor skillsControls muscle on the opposite side of bodyDamage: paralysis on the opposite side13Other Region for Motor ControlSupplementary motor area:-Programming complex sequences of movementPremotor cortex-Orienting body and arms toward targetPosterior parietal cortex-integration of somatosensory and visual input, important for complex movementLesions: interfere with performance of integrated movements (not paralysis)14

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17Aspects of CommunicationTwo aspects of communicationThe sensory aspect (language input) that involving: -ears, and -eyesThe motor aspect (language output) that involving: -vocalization, and -its control18

Wernickes areaBrocas area19Brocas and Wernickes Area:Complex Form of CommunicationBrocas area: speaking abilityWernickes area:-critical role in understanding both spoken and written massage-formulating coherent patterns of speech-controls articulation of speechFormation in mind of thoughts to be expressed and choice of words to be usedMotor control of vocalization and actual act of vocalization itself20

21Language DisordersDestruction of portions of auditory association areas of cortex -auditory receptive aphasia (word deafness): in inability to understand the spoken word Destruction of portions of auditory association areas of cortex -visual receptive aphasia (word blindness = dyslexia): in inability to understand the written word22.Language DisordersDestruction of Brocas area:- motor aphasia: capable of deciding what he wants to say and vocalizing but cannot make vocal system emit words instead of noisesDestruction of Wernickes area:-Wernickes aphasia: capable of understanding either the spoken word or the written word but are unable to interpret the thought to be expressed and choice of words to be used23Basal Nuclei (Ganglia Basalis)Play an important inhibitory role in motor controlLesions in globus pallidus frequently lead to spontaneous and often continuous writhing movements of a hand, an arm, the neck, or the face which is called athetosis24.Basal Nuclei (Ganglia Basalis)Lesion in subthalamus often leads to flailing movements of entire which is called hemiballismus Lesions in putamen leads to flicking movements in hands, face and other parts of body, which is called choreaLesions of substantia nigra leads to common and extremely severe disease of rigidity, akinesia, and tremors known as Parkinsons disease25Limbic SystemIs not a separate structureA ring of forebrain structures that surround brain stem and interconnected by intricate neurons pathwayComplex interacting networks which is associated with emotions, basic survival and sociosexual behavioral patterns, motivation and learning26

27MemoryPhysiologically, memories caused by changes in capability of synaptic transmission from one neuron to the next as a result of previous neural activityThe changes in turn cause new pathways or facilitated pathways to develop for transmission of signals through the neural circuits of the brainThe new or facilitated pathways are called memory traces28Consolidation of MemoryShort-term memory to be converted into long-term memory, it must become consolidatedThat is, chemical, physical and anatomical changes in synapses which are responsible for long-term type of memoryThis process requires 5-10 minutes for minimal consolidation and 1 hour for strong consolidationHippocampus: specific parts of brain in memory process29Hippocampusis one of the most important output pathways from reward and punishment areas at limbic systemThese provide background mood and motivations Motivations is the drive in brain to remember experiences and thoughts that are either pleasant or unpleasantcan promote storage of memoriesis not important in reflexive learning30Amnesia AnterogradeAfter removal of hippocampi:-memory for information stored in brain before hippocampal removal is not seriously affected-but after removal that person has no capability for storing verbal and symbolic types of memories in long-term memory, or even in intermediate long-term memory> So this person is unable to establish new long-term memory which is basis of intelligence or learning. >This is called anterograde amnesia31Amnesia RetrogradeInability to recall memories from the pastDegree of amnesia for recent events is likely to be much greater than for events the distant past, because memories for events distant past have been rehearsed so many timesCaused by damage in some area of thalamus, because thalamus might play a role in helping search memory store house and thus read out the memories32

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