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8 Cards in this Set
- Front
- Back
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1b afferent fiber reflex |
-attaches to golgi tendon organ to transfer sensation of muscle tension -excites interneuron to excite antagonist muscle (to counteract the force causing the muscle stress) -excites inhibitory interneuron to agonist muscles (on same side) so they relax and alleviate stress |
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gamma motor neurons in response to muscle stretch |
they are activated in response to muscle shortening -they cause intrafusil muscle fibers (that sense muscle stretch) to contract along with the muscle -control the sensitivity of the muscle spindle fiber when they shorten |
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1a afferent fiber |
sensory fiber that transfers sensations from the muscle spindle -shortens in response to external forces pulling on muscle (ie when the hammer taps it pulls on the tendon, stretching the muscle) -excites agonist muscles to contract, excites inhibitory interneuron to antagonist muscles (so they contract) |
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golgi tendon reflex |
-involves the golgi tendon organs -reverse of the stretch reflex -agonist muscles relax and antagonist muscles contract -why you might drop a load if it gets too heavy -when tendons sense they are under tension, muscles act to alleviate that tension |
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stretch reflex -what is it? examples |
-examples: flexing biceps to maintain glass being held at a certain level when beer is added to the glass, having reflexes tested at the doctor's office -when a muscle senses it it stretched, muscles react to keep maintaining that muscle length |
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what is the effect of lower motor neuron damage on the stretch reflex? |
-hyporeflexia, less response to stretch -happens in response to damage to the Ia afferent fiber |
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what is the effect of upper motor neuron damage to the stretch reflex? |
-hyperreflexia |
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how does upper motor neuron damage cause the effect they do on the stretch reflex? |
-a lot of upper motor neuron control is inhibitory -with less inhibitions, the gamma motor neuron is more active, and therefore the spindle fibers are more sensitive -alpha motor neurons in spinal cord receive less inhibitory inputs, and are more sensitive to being triggered to contract |
