Motor units Flashcards
1
Q
Lower motor neurons
A
Alpha neurons
- Large cell body
- extensive dendritic tree
- large axon- up to 1+ m in length
- myelinated with schwann cells
- rapid conduction velocity
2
Q
motor unit made up of
A
Cell body
its axon
all the muscle fibers that axon innervates- motor neuron pool
3
Q
S-Slow motor unit
A
Small peak force
slow to fatigue
4
Q
FR- fast fatigue resistant
A
Fast rate of force increase during twitch
-moderate peak force
will stop producing force after many seconds
5
Q
FF- fast, fatiguable
A
Large peak force
stops producing force within seconds
6
Q
Recruitment
A
previous silent motor unit
- stronger inputs lead to recruitment of more powerful motor units
- Size principle
7
Q
Rate-coding
A
already firing motor unit
- increase firing rate
- partially fused force output
- Fully fused at highest firing rate
