1 / 27

Chapter 13

Chapter 13. Integrative Physiology I: Control of Body Movement. About this Chapter. Neural reflexes Autonomic reflexes Skeletal muscle reflexes The integrated control of body movement Control of movement in visceral muscles. Neural Reflexes. Table 13-1. Somatic Motor Reflexes.

jezebel
Télécharger la présentation

Chapter 13

An Image/Link below is provided (as is) to download presentation Download Policy: Content on the Website is provided to you AS IS for your information and personal use and may not be sold / licensed / shared on other websites without getting consent from its author. Content is provided to you AS IS for your information and personal use only. Download presentation by click this link. While downloading, if for some reason you are not able to download a presentation, the publisher may have deleted the file from their server. During download, if you can't get a presentation, the file might be deleted by the publisher.

E N D

Presentation Transcript

  1. Chapter 13 Integrative Physiology I: Control of Body Movement

  2. About this Chapter • Neural reflexes • Autonomic reflexes • Skeletal muscle reflexes • The integrated control of body movement • Control of movement in visceral muscles

  3. Neural Reflexes Table 13-1

  4. Somatic Motor Reflexes • Monosynaptic and polysynaptic somatic motor reflexes (a)A monosynaptic reflex has a single synapse between the afferent and efferent neurons. Sensoryneuron Receptor Stimulus SpinalcordIntegrating center Skeletal muscle Somaticmotor neuron Onesynapse Target celleffector Efferentneuron Response Figure 13-1a

  5. Somatic Motor Reflexes (b) Polysynaptic reflexes have two or more synapses. Synapse 1 SpinalcordIntegrating center Sensoryneuron Receptor Stimulus Interneuron Synapse 2 Efferentneuron Target celleffector Response Figure 13-1b

  6. Autonomic Reflexes Some visceral reflexes are spinal reflexes no brain involvement, or brain modulated “bashful bladder” / toilet training / goose pimples Sensoryneuron Stimulus Receptor CNSintegratingcenter Preganglionicautonomicneuron Response Postganglionicautonomicneuron Targetcell Autonomicganglion Figure 13-2

  7. Skeletal Muscle Reflexes • Proprioceptorsare located in skeletal muscle, joint capsules, and ligaments • Proprioceptors carry input sensory neurons to CNS • CNS integrates input signal • Somatic motor neurons carry output signal • Alpha motor neurons α • Effectors are contractile skeletal muscle fibers extrafusal muscle fibers

  8. Proprioceptors • Muscle spindle • Response to stretch • Within muscle fibers as intrafusalfibrer • Automonic with gamma motor neurons • Golgi tendon organ • Muscle tension especially during isometric • Relaxation reflex - protective • Joint receptors • Are found in capsules and ligaments around joints

  9. Proprioceptors • Muscle spindles and Golgi tendon organs are sensory receptors in muscle Extrafusal muscle fibers Alpha motorneuron Musclespindle Golgi tendon organ Tendon (a) Figure 13-3a

  10. Proprioceptors Gamma motor neurons Spindle fibers: Sense stretch To CNS Tonically active sensoryneurons Central regionlacks myofibrils. Gamma motor neuronsfrom CNS Musclespindle Intrafusal fibers Extrafusal fiber (b) Muscle spindle Figure 13-3b

  11. Proprioceptors Extrafusalmuscle fibers Afferent neuron Capsule Sensory neuron Collagenfiber Tendon (c) Golgi tendon organ Figure 13-3c

  12. Muscle Spindles • Muscle spindles monitor muscle length and prevent overstretching 1 Extrafusal musclefibers at resting length 1 3 Sensory neuronendings 2 2 Sensory neuron is tonically active. Sensoryneuron Intrafusal fibersof muscle spindle 3 Spinal cord integrates function. Alpha motorneuron Alpha motor neurons toextrafusal fibers receive tonicinput from muscle spindles. 4 Spinal cord 4 5 5 Extrafusal fibers maintain a certainlevel of tension even at rest. (a) Spindles are firing even when muscle is relaxed. Figure 13-4a

  13. Muscle Spindles Figure 13-4b

  14. Alpha-Gamma Coactivation (a) Alpha-gamma coactivation 1 Muscle shortens 1 Alpha motor neuron firesand gamma motor neuronfires. 1 2 Musclelength 2 Muscle contracts. 3 Intrafusal fibers do not slacken sofiring rate remains constant. 2 Action potentialsof spindlesensory neuron 3 Stretch on centers ofintrafusal fibers unchanged.Firing rate of afferentneuron remains constant. Muscle shortens 1 Time Figure 13-5a

  15. Without Gamma Motor Neurons (b) 1 1 Alpha motor neuron fires. Muscle shortens Musclelength 3 2 Muscle contracts. 2 4 Less stretch onintrafusal fibers Action potential 3 Less stretch on centerof intrafusal fibers Action potentialsof spindlesensory neuron 4 Muscle shortens Firing rate of spindlesensory neuron decreases. Time Figure 13-5b

  16. Muscle Reflexes Help Prevent Damage Muscle spindle reflex Sensory neuron Spindle Spinalcord Add load Motor neuron Muscle (a) Load added to muscle. Figure 13-6a

  17. Muscle Reflexes Help Prevent Damage Figure 13-6b

  18. GTO’s Figure 13-7

  19. Movement • Types of movement • Reflex • Voluntary • Rhythmic

  20. CNS Integrates Movement • Spinal cord integrates spinal reflexes and contains central pattern generators • Brain stem and cerebellum control postural reflexes and hand and eye movements • Cerebral cortex and basal ganglia • Voluntary movement

  21. CNS Integrates Movement Table 13-3

  22. CNS Control of Voluntary Movement Figure 13-10

  23. CNS Control of Voluntary Movement • Feedforward reflexes and feedback of information during movement Figure 13-13

  24. Parkinson’s Disease • Progressive neural disorder • Characterized by abnormal movements, speech difficulties, and cognitive changes • Loss of basal ganglia that release dopamine

  25. Visceral Movement • Moves products in hollow organs • Controlled by ANS • Some create own action potentials

  26. Summary • Neural reflexes • Somatic reflexes, autonomic reflexes, spinal reflexes, cranial reflexes, monosynaptic reflex, and polysynaptic reflex • Autonomic reflexes • Skeletal muscle reflexes • Extrafusal muscle fibers, alpha motor neurons, muscle spindles, intrafusal fibers, gamma motor neurons, muscle tone, and stretch reflex

  27. Summary • Skeletal muscle reflexes (continued) • Alpha-gamma coactivation, golgi tendon organs, myotatic unit, reciprocal inhibitions, flexion reflexes, crossed extensor reflex, and central pattern generator • Integrated control • Reflex movement, postural reflexes, voluntary movement, rhythmic movements, corticospinal tract, basal ganglia, and feedforward reflexes • Control of movement in visceral muscles

More Related