揚州大学Chapter 10. Nervous SystemAll figures are from internet, textbooks and papers, all rights reserved to the originalauthors
Chapter 10. Nervous System All figures are from internet, textbooks and papers, all rights reserved to the original authors
ParietalCeritralobosulcusOutlineOccipitalloboiewoftheNervousSystemfopaoeStructureandFunctionofNeuronsSynapsesSection C.Control of Body MovementSonactsrootsDorsaAutonomicNervousSystemMuscleverwHigherFunctionofNervousSystVerl
Outline • Overview of the Nervous System • Structure and Function of Neurons • Synapses • Section C. Control of Body Movement • Autonomic Nervous System • Higher Function of Nervous System
How do they achieve these movements?tupian.baike.comforum.eedu.org.cn
How do they achieve these movements? tupian.baike.com forum.eedu.org.cn
OutlineMotor control hierarchy Local control of motor neurons. The Brain Motor Centers and the DescendingPathways They Control
Outline • Motor control hierarchy • Local control of motor neurons • The Brain Motor Centers and the Descending Pathways They Control
Control of Body MovementsAlphaMotor unitmotorneuronOne motor neuron together with all theMotorskeletalmuscle fibers thatthis neuronunitinnervatesMusclefibers1motorneuron~nmusclefibers1axon~1musclefiber(a) Motor neuron poolMotorneuronpoolAll the motor neurons that supply a givenmuscle-Muscle1muscle~nmotorneurons(b)
Control of Body Movements • Motor unit One motor neuron together with all the skeletal muscle fibers that this neuron innervates 1 motor neuron ~ n muscle fibers 1 axon ~ 1 muscle fiber • Motor neuron pool All the motor neurons that supply a given muscle 1 muscle ~ n motor neurons
Control of Body MovementsFinal common pathwaySkeletalmuscleAll neural influences on skeletal muscleNeuromuscularout of CNS converge on the motorjunctionsneuronsand canonlyaffectskeletalMusclefibersmusclethoroughthemIsometriccontractionsSchwannactive during contractions generatecellstrength),nochangeoflengthMyelinsheathMyofibrilsMotorneuronen.wikipedia.org
Control of Body Movements • Final common pathway All neural influences on skeletal muscle out of CNS converge on the motor neurons and can only affect skeletal muscle thorough them • Isometric contractions active during contractions (generate strength), no change of length en.wikipedia.org
Motor Control HierarchyNeuralsystemsCopyrightThe McGraw-Hill Companies, Inc.Permission required for reproduction or display.controlling bodyThecommandneuronsHighercentersmovementSensorimotorcortexBasal nuclei.DescendingpathwaysariseAmotorprogramThalamusMiddlelevelCerebellumBrainstem-Motorneurons,BrainstemandinterneuronsspinalcordMotorcontrolWhich,WhenhierarchyAfferentMotorneurons(finalcommonHighest levelneuronspathway)MiddlelevelLocal levelReceptorsMusclefibers
Motor Control Hierarchy The command neurons A motor program •Motor neurons, interneurons •Which, When •Descending pathways arise
Motor Control Hierarchy·MotorProgramNeuralsystemscontrolling bodyThe pattern of neuron activityHighercentersmovementrequired to properly performSensorimotor.cortexthe desired movement.Basal nuclelMiddle levelThalamusMiddlelevelBrainstemCerebellumIntegrationof afferentinformation with the signalsBrainstemandspinal.cordMotorcontrolformthecommandneuronshierarchyAfferentMotorneuronsneurons(final commorHighestlevepathway)Middie levelReceptorsLocal levelMuscle fibersProprioception→a constantstream of updatedafferentinformationaboutthemovementstakingplace
Motor Control Hierarchy • Motor Program The pattern of neuron activity required to properly perform the desired movement. Middle level Integration of afferent information with the signals form the command neurons Proprioception → a constant stream of updated afferent information about the movements taking place
Summarizes of the Motor Control HierarchyLevelFunctionStructureAreasinvolvedinmemoryandFormscomplexplansindividualsintention;emotions,supplementarymotorHigherCentersCommunicateswiththemiddlearea,associationcortex→receivelevel→commandneuronsandcorrelateinputsConverts plansfromthehighestlevelto smallermotorprogramsSensorimotor cortex, cerebellum,The Middle subprograms determiningtheparts of basal nuclei,someLevelmovementofindividualjointsbrainstemnucleidescendingpathwayThe LowestSpecifiesmusclestensionandLevelLevelsofbrainstemorspinalcordjointangleatspecifictimestofromwhichmotorneuronsexit(The Localcarry outthe programsandsubprogramsLevel)
Summarizes of the Motor Control Hierarchy Level Function Structure Higher Centers Forms complex plans → individuals intention; Communicates with the middle level → command neurons Areas involved in memory and emotions,supplementary motor area , association cortex → receive and correlate inputs The Middle Level Converts plans from the highest level to smaller motor programs → subprograms determining the movement of individual joints → descending pathway Sensorimotor cortex, cerebellum, parts of basal nuclei, some brainstem nuclei The Lowest Level (The Local Level) Specifies muscles tension and joint angle at specific times to carry out the programs and subprograms Levels of brainstem or spinal cord from which motor neurons exit
Voluntary and Involuntary ActionsVoluntarymovements(1) conscious awareness → what/why doing(2)attention > the action/its purposeInvoluntarymovementsUnconscious,automatic,reflexMost motor behavior include both,might shift along this continuum
Voluntary and Involuntary Actions • Voluntary movements (1) conscious awareness → what/why doing (2) attention → the action/its purpose • Involuntary movements Unconscious, automatic, reflex Most motor behavior include both, might shift along this continuum