Neurophys III part two Flashcards
What fiber type innervates the GTO?
What activates the GTO and what does it measure?
Group Ib fiber
Activated by tension measuring muscle force/tension.
Where does the GTO report to?
Reports to the spinal cord fo the reflex.
Reports to the cerebellum for unconscious proprioception.
Reports to the cerebral cortex.
How does the Group Ib reflex arc work?
Increased tension on muscles increases the firing of the Ib fiber
The Ib fiber will then synapse onto the inhibitory interneuron that inhibits motor neuron on the homonymous muscle.
Decreased tension will inhibit the Ib fiber.
Describe the myotactic reflex that occurs in the muscle spindle.
Stretch agonist and relaxes the antagonist.
What controls the inverse myotatic reflex?
The GTO.
What is the reciprocal inhibition?
Ex: Patellar tendon reflex.
Muscles on one side of the joint relaxes to accomadate contraction on the other side of the joint.
What is the recurrent inhibition?
Activity in a population of neurons excites a second population that in turn inhibits the activity of the first.
What is disinhibition?
The inhibition of an inhibitor.
What are the functions of Renshaw cells?
Prevent muscular damage from tetanus.
Which motor neurons are Renshaw cells associated with?
Associated with alpha neurons by recieving a collateral supply from them to calculate how vigorously that neuron is being fired.
From there they can act to inhibit multiple muscle groups.
Which group of nerves can inhibit Renshaw cells?
Descending pathways.
Spastic patients can have abnormal renshaw function.
What occurs in muscle spindle signalling when a muscle is passively stretched?
Afferent activity is increased
What occurs in muscle spindle signalling when a muscle is actively contracted?
Decreased afferent activity.
What occur in the GTO when a muscle is passively stretched?
Decreased frequency of afferent activity.
What occurs in the GTO when a muscle is actively stretched?
Increased frequency of afferent activity.
