Motor Systems Flashcards
What are the types of anterior motor neurons?
a-motor neurons
g-motor neurons
Where are renshaw cells located?
anterior horn
What neurotransmitter do renshaw cells use?
glycine
Where are muscle spindles located?
within the muscle belly
What do muscle spindles detect?
detect length and velocity changes in the muscle
What are the sensory endings for the muscle spindle? What sensory fibers are they associated with?
Annulospiral ending - type Ia fiber
Flower-spray ending - type II fiber
What is the fastest sensory fiber in the body?
annulospiral (type Ia) ending in muscle spindle
What is the myotatic (muscle stretch) reflex?
when the muscle is stretched, impusles travel from the spindle’s type Ia fibers to the a-motor neuron; induces contraction
What fibers are associated with Golgi tendon organs?
Type Ib fibers
What is the function of the dorsal spinocerebellar tracts?
transmit signals from the muscle spindles and Golgi’s tendon organs to the reticular formation and cortex and cerebellum
What are Betz cells?
large pyramidal neurons found only in primary motor cortex, mediate corticospinal output
What cortical layer are Betz cells located in?
Layer 5
How long does it take for SMA syndrome to resolve?
usually under 6 weeks
