Muscle/Nerve Cross Talk: Impact on Voluntary Muscle Action

Transcription

1 Muscle/Nerve Cross Talk: Impact on Voluntary Muscle Action OBJECTIVES I. Coordination of signaling for agonist and antagonistic muscle action II. Complexity of layered control over voluntary muscle movement Goals

2 concepts 1) Basic gross and micro anatomical structure of muscle movement 2) CNS signaling for monosynaptic & polysynaptic reflex muscle action 3) Coordinated CNS signaling of excitatory and inhibitory neurons 4) Cortical origin of voluntary muscle action 5) Influence of sensory input and learning on voluntary muscle action Goals

3 How is the Cerebral cortex involved in skeletal muscle movement? C5-T1 : Upper limb L4-S3 : Lower limb Skeletal Muscle related Neurology

4 How are motor units recruited to control fine movement? Skeletal Muscle related Neurology

5 How are Motor axons Arranged in the spinal cord? Extension Flexion Proximal Distal Skeletal Muscle related Neurology

6 How is muscle action Compartmentalized in the upper and lower limbs? Upper Limb Extension: Radial N. Flexion: Musculocutaneous N. Flexion: Femoral N. Extension: Tibial N. Lower Limb Skeletal Muscle related Anatomy

7 How does the primary mover differ from Synergistic muscles In Muscle action? Skeletal Muscle related Anatomy

8 How do agonist and antagonist muscles work coordinately? Skeletal Muscle related Anatomy

9 What skeletal muscle receptors Send signals about Proprioception to the CNS? Skeletal Muscle related histology

10 How do muscle spindle and Golgi tendon organ signals To the alpha motor neuron differ? Skeletal Muscle related histology

11 What is a reflex? [gastric distension>increased intestinal peristalsis] [appendicitis>muscle rigidity] /photo/22464/lightning+strike+over+desert Involuntary Muscle action

12 What action induces the monosynaptic knee jerk reflex? Knee Jerk Reflex Monosynaptic reflex loop through spinal cord Involuntary Skeletal Muscle action

13 What afferent signal is activated In the monosynaptic reflex arc? Involuntary Skeletal Muscle action

14 What neurons signal the muscle spindle intrafusal fibers to contract? Involuntary Skeletal Muscle action

15 What is the difference between a Monosynaptic and a polysynaptic reflex? Involuntary Skeletal Muscle action

16 How do signals from the golgi tendon organ Affect agonist and antagonist muscles? Involuntary Skeletal Muscle action

17 What is the role of The Cerebral cortex In voluntary muscle action? Cerebral Cortex Corticospinal Tract (Pyramidal Tract) ] Fiber Decussation Motor cortex control of voluntary muscle action

18 How are the cell bodies for motor axons in the cerebral cortex characterized? Motor cortex control of voluntary muscle action

19 How do muscle spindles and golgi tendon organs impact voluntary muscle movement? voluntary Skeletal Muscle action

20 What extra-pyramidal influences are exerted over voluntary muscle action? Complex neural influence over Voluntary muscle action

21 Where do Extra-pyramidal pathways And muscle proprioceptors interact? Neural regulation of muscle action

22 Why Do our runners reflexively pull the hot coffee cup From Their lips? Complex neural influence over muscle action

23 Complexity of Muscle/Nerve Cross Talk in Skeletal Muscle Action Summary of basic neurology, anatomy and histology Larger areas of motor cortex are dedicated to muscles that are used for fine movements. Fine movements are associated with small motor units while gross movements are associated with larger motor units. Location, Location, Location! of a lesion will determine what impact it has on muscle movement. Muscle spindles & Golgi tendon organs are receptors for proprioception and regulate muscle length and muscle tension respectively. Control of muscle movement

24 Complexity of Muscle/Nerve Cross Talk in Skeletal Muscle Action Summary of basic muscle movement Reflex movement can involve monosynaptic (without interneurons) or polysynaptic (with interneurons) synapses. Skeletal muscle movement is regulated by coordinated signaling of excitatory and inhibitory neurons. Upper motor neurons in the motor cortex signal lower motor neurons in the spinal cord via the corticospinal tract. Muscle movement is influenced by extra-pyramidal pathways, sensory input & learning. Control of muscle movement

25 Questions? Acknowledgments