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CONTROL OF MUSCLE MOVEMENT

CONTROL OF MUSCLE MOVEMENT. D. C. MIKULECKY DEPARTMENT OF PHYSIOLOGY. SPINAL CORD. DORSAL HORN. DORSAL. GREY MATTER. DORSAL ROOT GANGLION. LATERAL. VENTRAL HORN. WHITE MATTER. SPINAL NERVE. VENTRAL. SEGMENTAL STRUCTURE OF SPINAL NERVES. DERMATOMES.

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CONTROL OF MUSCLE MOVEMENT

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  1. CONTROL OF MUSCLE MOVEMENT D. C. MIKULECKY DEPARTMENT OF PHYSIOLOGY

  2. SPINAL CORD DORSAL HORN DORSAL GREY MATTER DORSAL ROOT GANGLION LATERAL VENTRAL HORN WHITE MATTER SPINAL NERVE VENTRAL

  3. SEGMENTAL STRUCTURE OF SPINAL NERVES DERMATOMES

  4. THE THALAMUS IN SOMATIC SENSATION SENSORY NEOCORTEX MEDIAL LEMNISCUS DORSAL COLUMN NUCLEI MEDULLA DORSAL COLUMN

  5. SOMATOTOPIC ORGANIZATION OF THE SENSORY CORTEX

  6. GENERAL FEATURES OF THE MOTOR SYSTEM • HIERARCHICAL ORGANIZATION • VS • PARALLEL ORGANIZATION

  7. HIERARCHICAL ORGANIZATION MOTOR CORTEX CEREBELLUM AND BASAL GANGLIA BRAIN STEM SPINAL CORD SKELETAL MUSCLE

  8. PARALLEL ORGANIZATION MOTOR CORTEX BRAIN STEM SPINAL CORD SKELETAL MUSCLE

  9. THE MOTOR UNIT • A SINGLE MOTOR NEURON AND ALL THE MUSCLES IT INNERVATES • THE FUNCTIONAL UNIT OF THE MOTOR SYSTEM • CORRESPONDS TO THE SENSORY UNIT/RECEPTIVE FIELD RELATIONSHIP • SIZE OF MOTOR UNIT DETERMINES FINENESS OF MOTOR RESPOSE

  10. SOMATOTOPIC ORGANIZATION OF THE MOTOR CORTEX

  11. CORTICAL AREAS INVOVED IN MOTOR CONTROL

  12. THE MOTOR RESPONSE SYSTEM: SPINAL LEVEL • THE ORGANIZATION OF MOTOR NERVES IN THE SPINAL COLUMN • THE ROLE OF INTERNEURONS • THE ROLE OF LOCOMOTOR GENERATORS

  13. THE ORGANIZATION OF MOTOR NERVES IN THE SPINAL COLUMN • DORSAL AREA OF VENTRAL HORN: FLEXOR MOVEMENTS • VENTRAL AREA OF VENTRAL HORN: EXTENSOR MOVEMENTS • DORSOLATERAL AREA OF VENTRAL HORN: INNERVATE EXTREMITIES • VENTROMEDIAL REGION: AXIAL MUSCLES TO MAINTAIN POSTURE

  14. LOCATION OF CELL BODIES FOR EXTENSORS AND FLEXORS FLEXORS EXTENSORS

  15. THE ROLE OF INTERNEURONS • LOCATED IN THE INTER MEDIATE ZONE OF THE SPINAL CORD • LATERAL SIDE NEURONS SYNAPSE IPSILATERALLY (TO DISTAL LIMB MUSCLES) • MIDLINE NEURONS SYNAPSE BOTH SIDES (MUSCLES FOR POSTURE) ALPHA MOTOR NEURONS:EXCITE SYNERGISTIC AND INHIBIT ANTAGONISTIC

  16. THE ROLE OF LOCOMOTOR GENERATORS • RHYTHMIC ACTION OF ALTERANATING FLEXION AND EXTENSION INVOVED IN WALKING MOVEMENTS (CHICKEN WITH ITS HEAD CUT OFF) • SPINAL TRANSECTED ANIMALS CAN WALK ON TREADMILL • UNDER CONTROL OF LOCOMOTOR COMMAND CENTER IN THE BRAIN STEM

  17. SENSORY FIBERS IN THE MUSCLE • THE MUSCLE SPINDLE AS LENGTH DETECTOR • GOGLI TENDON ORGANS: TENSION RECEPTORS

  18. THE MUSCLE SPINDLE AS LENGTH DETECTOR(SENSORY FIBERS) • TYPE Ia NERVE FIBERS: TRANSMIT INFORMATION ABOUT LENGTH AND VELOCITY TO THE CNS • TYPE II NERVE FIBERS:TRANSMIT INFORMATION ABOUT MUSCLE LENGTH TO CNS

  19. TWO TYPES OF INTRAFUSAL FIBERS TYPE IA SENSORY FIBER TYPE II SENSORY FIBER NUCLEAR CHAIN FIBER NUCLEAR BAG FIBER

  20. TWO TYPES OF MOTOR NEURON • ALPHA MOTOR NEURON: INNERVATES EXTRAFUSAL FIBER • GAMMA MOTOR NEURON: INNERVATES INTRAFUSAL FIBERS

  21. STRETCHING AN INTRAFUSAL FIBER SENDS SIGNALS TO CNS

  22. THE ROLE OF GAMMA MOTOR NEURONS IN REGULATING MUSCLE SPINDLE RESPONSE STIMULATE RECORD RECORD Afferent Activity Muscle Force

  23. STIMULATE THE ROLE OF GAMMA MOTOR NEURONS IN REGULATING MUSCLE SPINDLE RESPONSE RECORD RECORD STIMULATE Afferent Activity Muscle Force

  24. GOGLI TENDON ORGANS: TENSION RECEPTORS • IN SERIES WITH EXTRAFUSAL FIBERS • TRANSMITS INFORMATION ABOUT FORCE OR TENSION TO CNS • FREQUENCCY CODING

  25. SPINAL REFLEXES • THE STRETCH REFLEX • THE INVERSE MYOTACTIC REFLEX • THE FLEXOR WITHDRAWAL REFLEX

  26. THE STRETCH REFLEX (KNEE JERK REFLEX) • TAP PATELLAR TENDON BELOW KNEE • SENSORY SIGNALS FROM MUSCLE SPINDLE INDICATE FLEXION OF LEG • FLEXOR IS INHIBITED • EXTENSOR ACTIVATED • LEG EXTENDS

  27. KNEE JERK REFLEX EXTENSOR ACTIVATED SENSORY NEURON FROM MUSCLE SPINDLE DETECTS STRETCH SPINAL CORD FLEXOR INHIBITED

  28. INVERSE MYOTACTIC REFLEX ARM EXTENDS BICEPS & SYNERGYSTIC MUSCLE RELAXEDEXTENSOR CONTRACTED WEIGHT RELEASED

  29. THE FLEXOR WITHDRAWAL REFLEX • PAINFUL STIMULUS DETECTED • IPSILATERAL EXTENSORS INHIBITED • IPSILATERAL EXTENSORS EXCITED • LIMB IS WITHDRAWN • IF INVOLVING ONE FOOT WHILE STANDING, CONTRALATERAL SIDE EXTENSORS ACTIVATED AND FLEXORS INHIBITED TO SUPPORT GREATER WEIGHT

  30. FLEXOR WITHDRAWAL REFLEX SENSORY SIGNAL TO SPINE STEPON TACK VIA INTERNEURONS IPSILATERAL EXTENSORS INHIBITED IPSILATERAL FLEXORS CONTRACT-LEG LIFTS CONTRALATERAL EXTENSORS CONTRACT CONTRALATERAL FLEXORS INHIBITED- MAINTAIN BALANCE AND SUPPORT WEIGHT

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