The Medulla OblongataAllows brain and spinal cord to communicatedCoordinates complex autonomic reflexesControls visceral functionsNuclei in the MedullaAutonomic nuclei control visceral activities (cardiovascular, respiratory, reflexes)Sensory and motor nuclei of cranial nervesRelay stations along sensory and motor pathwaysThe PonsSensory and motor nuclei of cranial nerves (V, VI, VII, VIII)Nuclei involved with respirationApneustic center and pneumotaxic centerModify respiratory rhythmicity center activityNuclei that process and relay information to and from cerebellumAscending, descending and transverse tractsTransverse fibers (axons)Link nuclei of pons with opposite cerebellar hemisphereThe CerebellumFunctions includeAdjustment of postural musclesFine-tunes conscious and subconscious movementsStructuresArbor Vitae (tree of life)- high branched, internal white matter of cerebellum.Cerebellar nuclei embedded in arbor vitae relay information to Purkinje CellsPurkinje Cells- large, branched cells found in cerebellar cortex. Receive input from up to 200,000 synapsesDisordersAtaxia- damage from trauma or stroke. Disturbs muscle coordinationIntoxication- temporary impairmentThe MidbrainStructuresTectum- processes visual and auditory sensationsTegmentum- affects limb position and muscle toneReticular activating system- component of the reticular formation in the midbrain. Important for alertness and attentivenessThe DiencephalonIntegrates sensory information and motor commandsConsists ofThalamus- filters ascending sensory info for primary sensory cortexInfo on touch, pressure pain, temp, proproceptionLeft & Right Thalamus separated by the Third VentricleEpithalamus- roof of diencephalonPineal Gland- found in posterior epithalamusSecretes melatonin which is important in the regulation of day-night cycle and reproductive functionHypothalamusEight FunctionsProvide subconscious control of skeletal muscleControls autonomic functionCoordinates activity of nervous and endocrine systemsSecrete hormonesAntidiuretic Hormone (ADH) by supraoptic nucleusOxytocin (OT;OXT) by paraventricular nucleusProduce emotions and behavioral driveThe feeding and thirst centersCoordinates voluntary and autonomic functionsRegulate body temp, preoptic areaControl circadian rhythms (day-night cycles)Suprachiasmatic nucleusInfundibulum- narrow stalk that connects hypothalamus to pituitary glandMamillary bodies- process olfactory and other sensory info, control reflex eating movementsTuberal Area- located between the infundibulum and mamillary bodies. Help control pituitary gland functionThe Limbic SystemFunctional Group thatEstablishes emotional states such as rage, fear, pain, sexual arousal, pleasureLinks conscious functions of cerebral cortex with autonomic functions of brain stemFacilitates memory storage and retrievalConsists of regions of the cerebrum and diencephalonThe Cerebrum- the largest part of the brainControls all conscious thought and intellectual functionsProcesses somatic sensory and motor informationGray matter- in cerebral cortex and basal nucleiWhite matter- deep to basal cortexAssociation Fibers- connections within one hemisphereCommissural Fibers- bands of fibers connecting two hemispheresProjection Fibers- connect cerebrum with lower areasPass through diencephalon. Link Cerebral cortex with:Dienscephalon, brain stem, cerebellum, and spinal cordInternal capsule- all ascending and descending projection fibersStructures-Gyri of neural cortex- increase surface area, increase number of cortical neuronsLongitudinal Fissure- separates cerebral hemispheresLobes- divisions of hemispheres, divided by sulcusCentral sulcus- divides the anterior frontal lobe from the posterior parietal lobeLateral Sulcus- divides frontal lobe from temporal lobeParieto-occipital Sulcus- divides parietal lobe from occipital lobeThree Functional PrinciplesEach cerebral hemisphere receives sensory info from, and sends motor commands to, the opposite side of the bodyLeft hemisphere to right side of the body & visa versaHemispheres have different functions, despite like structuresCorrespondence between a specific function and a specific region of cerebral cortex is not preciseMotor and Sensory Areas of the cortexCentral sulcus separates motor and sensory areasMotor AreasPrecentral gyrus of frontal lobe (primary motor cortex)- directs voluntary movementsPostcentral gyrus of parietal lobe (primary sensory cortex)- receives somatic sensory infoTouch, pressure, pain, vibration, taste, tempSpecial Sensory CortexesVisual cortex- information from sight receptorsAuditory cortex- information from sound receptorsOlfactory cortex- information from odor receptorsGustatory cortex- information from taste receptorsAssociation AreasSensory association areas- monitor and interpret arriving information at sensory areas of cortexVisual Association Area- interprets visual cortex activityAuditory Association Area- monitors auditory cortexSomatic Motor Association Area (Premotor cortex)- coordinates motor responses (learned movements)Somatic sensory association area- interprets input to primary sensory cortex (eg. Recognizes and responds to touch)General Interpretive Area (AKA Wernicke’s Area)Present in only one hemisphere, usually the left oneReceives information from all sensory association areasCoordinates access to complex visual and auditory memoriesOther Integrative AreasSpeech Center (broca’s area)- associated with general interpretive area. Coordinates all vocalization functionsPrefrontal cortex of frontal lobe- integrates information from sensory association areas. Performs abstract intellectual activities (e.g. predicting consequences of actions)Hemispheric LateralizationFunctional differences between left and right hemispheres.Each cerebral hemisphere performs certain functions that are not ordinarily performed by the opposite hemisphereLeft Hemisphere- usually dominant, controls:Reading, writing, mathDecision makingSpeech and languageRight Hemisphere- relates to:Senses- touch, smell, sight, taste, feelRecognition- faces, voice inflectionsMonitoring Brain Activity- brain activity assessed by electroencephalogram (EEG)Electrodes are placed on skulls, patterns of electrical activity (brain waves) are printed outFour Categories of Brain WavesAlpha Waves- found in healthy, awake adults at rest with eyes closedBeta Waves- high frequency, hound in adults concentrating or mentally stressedTheta Waves- found in children and intensely
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