Muscle Function pt 1 Flashcards
3 types of muscle
skeletal
cardiac
smooth
muscle fiber types
Type IA
Type IIA
Type IIB
can individual muscles have different fiber types?
yes
an individual muscle can contain multiple fiber types
how are variations of muscle fibers believed to be determined?
genetically
Type I muscle fibers visually
dark (d/t containing larger numbers of mitochondria and a high concentration of myoglobin)
how are type I muscle fibers referred to
slow-twitch or slow oxidativve
do type I muscle fibers contract over a long or short period of time
long period of time
type IIB muscle fibers visually
pale (d/t fewer mitochondria and only small amounts of myoglobin)
how are type IIB fibers referred to
fast-twitch or fast glycolytic
which muscle fiber type are largest in diameter
type IIB
what happens as the muscle fiber’s diameter increases
it generates more force
which muscle fiber will twitch quicker
type IIB
which muscle fiber fatigues the quickest
type IIB
type IIA fibers visually
intermediate in characteristics
-middle amounts of mitochondrion and myoglobin
-fiber diameter is smaller than IIA but larger than I
-don’t fatigue as quickly as type IIA, but don’t last as long as I
-speed of contraction is quicker than type I, but slower than IIA
how are type IIA muscle fibers referred
fast oxidative-glycolytic
what are muscles with a high proportion of type I fibers able to do
carry on sustained activity d/t the fibers not fatiguing quickly
what muscles are considered to have high proportions of type I fibers
stability and postural muscles
ex: soleus, adductor pollicis, tibialis anterior
what are muscles with a high proportion of type IIA fibers referred to as
mobility or non postural or phasic muscles
what do muscles with high proportions of type IIA fibers do
-produce larger ROM
-respond quickly to a stimulus
-fatigue more rapidly
ex: biceps brachii
what happens when structure and function match
things work well
what happens when structure and function do not match
there will be breakdown
2 types of material found in skeletal muscle
muscle tissue (contractile)
connective tissue (non-contractile)
elasticity
the ability of soft tissue to return to its resting length after a passive stretch
d/t primarily non-contractile tissue
contractility
refers to the muscle’s ability to develop tension
d/t contractile tissue
irritability
refers to the muscle’s ability to respond to chemical, electrical or mechanical stimuli