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25 Cards in this Set
- Front
- Back
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where are "receptors" found?
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Found in the joint capsule, tendons, muscles and ligaments surrounding the joint
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how are RECEPTORS stimulated?
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Receptors are stimulated by being deformed
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what is the function of RECEPTORS?
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“The information from these joint receptors continually apprises the nervous system of the momentary angulation of the joint and of the rate of movement of the joint”
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Joint Receptors
Ruffini Endings: |
Measures angle of change in the joints
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Joint Receptors
Golgi Endings: |
Measure tension
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Joint Receptors
Encapsulated Pacininform Endings: |
Measure Acceleration
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Joint Receptors
Free Nerve Endings |
Measure abnormal stress or chemical agents.
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GOLGI TENDON ORGANS
where located? |
Located within the muscle tendon near the point of attachment of the muscle fiber to the tendon
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GOLGI TENDON ORGANS
on average, how many muscle fibers are associate with each GTO? |
Average of 10-15 muscle fibers in series with each GTO
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GOLGI TENDON ORGANS
how stimulated? |
stimulated by tension produced withing the small bundles of muscle fibers associated with it
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GOLGI TENDON ORGANS
how are nerve impulsed transmitted from each GTO? |
Nerve impulses from the GTO are transmitted over large, rapidly conducting afferent axons (Ib) to the spinal cord and cerebellum
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GOLGI TENDON ORGANS
what does the stimulus from the GTO excite? |
Stimulus from GTO excites inhibitory interneurons-- inhibit motor neurons of the contracting muscle (limits force production)
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MUSCLE SPINDLES
general idea? |
Complex organ with multiple functions
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MUSCLE SPINDLES
where located? |
Present in nearly all muscles, especially in the arms and legs
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MUSCLE SPINDLES
what kind of innervation do they have? |
Has both afferent and efferent innervation
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MUSCLE SPINDLES
what is their function? |
Functions as a stretch receptor (afferent information to brain and spinal cord, regarding magnitude and rate of stretch
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MUSCLE SPINDLES
how are contractile fibers controlled? |
Also contains contractile fibers controlled by nerve impulses connected via small diameter motor axons (efferent, type A, gamma) from the spinal cord
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“The degree of shortening of the contractile portions of the muscle spindle regulates the sensitivity of the stretch receptor portion of the muscle spindle”
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“The degree of shortening of the contractile portions of the muscle spindle regulates the sensitivity of the stretch receptor portion of the muscle spindle”
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MUSCLE SPINDLES
what does activation of the muscle cause? |
Activation of the muscle causes increased frequency of nerve impulses from the receptor (increased vs. resting output)
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MUSCLE SPINDLES
what makes the synaptic connection with the associated motor neurons? |
Afferent nerves from the primary receptors make synaptic connection with the motor neurons controlling the extrafusal muscle fibers in the same muscle
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MUSCLE SPINDLES
general structure? |
Structure- central nuclear bag (contains specialized stretch receptors) and sets of intrafusal fibers attached to the end of the bag
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MUSCLE SPINDLES
how are intrafusal fibers controlled? |
The intrafusal fibers are controlled by motor nerve fibers
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MUSCLE SPINDLES
ways it can be stretched? |
the muscle spindle is stretched when the whole muscle is stretched
when the contractile portions at each end of the bag are shortened (via gamma motor nerve activity) the bag is stretched |
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MUSCLE SPINDLES
why are they important? |
The muscle spindle is important in the regulation of postural muscle tone
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MUSCLE SPINDLES
what would an abrupt stretch cause? |
an abrupt stretch causes firing of the muscle spindle which causes shortening of the involved muscle (which in turn alleviates the “stretch” on the muscle spindle)
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