Motor Units Flashcards
1
Q
motor unit
A
neurons and fibers they innervate
2
Q
what happens when a motor unit is stimulated?
A
all muscles fibers within it contract
3
Q
slow oxidative (SO) fibers, type 1
A
- slow twitch
- marathon runner, high resistance to fatigue
- smallest diameter with many mitochondria
4
Q
fast oxidative (FO) fibers, type 2A
A
- fast twitch
- sprinter, low resistance
- many mitochondria
5
Q
fast glycolytic (FG) fibers, type 2B
A
- fast twitch
- low resistance
- largest diameter and few mitochondria
6
Q
posture muscles
A
contain type 1 fibers
7
Q
skeletal muscle usually..
A
contains all three fiber types
8
Q
a single motor unit…
A
contains only muscle fibers of the same type
9
Q
postural muscles
A
- slow fibers dominate
- contract almost continually
10
Q
no slow muscle fibers…
A
in muscles that require swift but brief contractions (eyes and hand)
