Neuro L.5 Main Concepts Flashcards
What do Aβ fibers detect?
Touch, vibration, and pressure (fastest)
Aβ fibers are part of the DCML pathway.
What do Aδ fibers detect?
Sharp pain and temperature (fast)
Aδ fibers are part of the lateral spinothalamic pathway.
What do C fibers detect?
Crude touch and temperature (unmyelinated, slow)
C fibers are part of the anterior spinothalamic pathway.
What do 1a fibers detect?
Muscle stretch (fastest)
1a fibers are associated with muscle spindles.
What do 1b fibers detect?
Tendon stretch (fast)
1b fibers are associated with Golgi tendon organs (GTOs).
What do II fibers detect?
Steady state muscle length.
What are the types of efferent fibers?
γ MN and α MN.
What do γ MN fibers innervate?
Intrafusal muscle fibers of muscle spindles.
What do α MN fibers innervate?
Extrafusal muscle fibers of muscle spindles.
What are the types of intrafusal muscle fibers?
Dynamic nuclear bag, static nuclear bag, and nuclear chain fibers.
What is the main effect of polysynaptic inhibitory reflexes?
Inhibits antagonist muscle.
What is the purpose of reciprocal inhibition?
Allows smooth movement and coordination.
What does autogenic inhibition protect against?
Protects muscle from damage.
What is the main effect of cutaneous withdrawal reflex?
Withdrawal of limb away from painful stimulus.
What is the main effect of the cross extensor reflex?
Flexion of stimulated limb and extension of opposite limb.
What is the stimulus for the phasic stretch reflex?
Quick stretch (tendon tap).
What is a motor neuron pool?
Clusters of motor neurons within the spinal cord that innervate a single muscle.
What is a motor unit?
One α MN and all the muscle fibers it innervates.
What is a myotome?
Group of muscles innervated by a single spinal nerve.
What does poliomyelitis attack?
Lower motor neurons of the ventral horn.
What is postpolio syndrome?
Giant motor units formed during recovery leading to new weakness, fatigue, and pain.
