B6-056 Muscle Contraction Flashcards
smallest unit of contraction in the muscle
sarcomere
what two proteins make up the striated pattern of muscle?
actin (lighter)
myosin (darker)
[…] on either side of the sarcomere holds the actin protein in a structured form
z lines
what protein makes up the I band?
actin
what protein makes up the H band?
myosin
I band is connected to the
Z line
what protein makes up the A band?
actin and myosin
contains ATP and actin binding sites
myosin head
protein responsible for turning on muscle contraction
troponin
binds troponin to tropomyosin
Tn-T
binds calcium during contraction
Tn-C
inhibitory protein on tropomyosin when there is no Ca++
Tn-I
actin and myosin interacting to generate force is known as the
cross bridge
steps of the cross bridge cycle
1) ATP hydrolysis
2) Calcium binding troponin C
3) actin-myosin bind
4) working stroke occurs
5) sliding filament
5) new ATP comes in to release actin and myosin
you have to have […] to release the actin-myosin binding
new ATP
action potential is spread down […] to allow muscle fibers to move in concert
t tubules
action potential moving down the t tubules triggers […] release from inside muscle
Ca++
contraction will continue to occur as long as […] is present
calcium
**there is a system that reuptakes the calcium in order to keep intracellular calcium low
what bands change in length as the sarcomere contracts?
H and I shorten
[…] facilitates the release of actin from myosin
ATP
what causes rigor mortis?
lack of ATP for release of actin from myosin
maximal tension is generated when sarcomere length is
optimal
**if given a graph, optimal region is where plateau is seen
force generation […] as sarcomere length […]
increases
decreases
force generated by a muscle is a function of its […]
velocity
the rate that cross bridges form between actin and myosin is referred to as
rate of constants
force generated by a muscle depends on the number of […] attached
cross bridges
because the rate of constant attachment doesn’t change, as filaments slide past each other faster, force […]
decreases
**less cross bridges attach
as filament velocity decreases more cross bridges attach generating […]
greater force
prolonged eccentric muscle contractions cause
disorganization of myofibrillar proteins around the Z disk
CK levels demonstrated a delayed increase following […] contraction
eccentric
proteins on the thin filament [3]
actin
troponin
tropomyosin
anchoring proteins that help maintain the length of thick and thin filaments
titin (thick)
nebulin (thin)
type 1 fibers have [more/less] mitochondria than type II
more
what type of fibers primarily utilize aerobic respiration
type I
what type of fibers have a slow contraction speed?
type I
type I fibers generate [more/less] power than type II
less
what type of fiber primarily uses anaerobic respiration?
type II
what type of fiber fatigues more easily?
type II
what type of fibers are fast?
type II
what type of fibers are slow?
type I
what type of fiber uses oxidative phosphorylation to produce a sustained contraction?
type I
what type of training produces type I fibers?
endurance training
what type of training produces type II fibers?
resistance training, sprinting
