what does the SR store correct answers proteins and calcium
what is the role of the transverse tubules in the muscle fiber correct answers allow inside of muscle to communicate with the outside of the muscle
how is a sarcomere measured correct answers from z-disc to z-disc
what is conta...
GMS 6474 final exam
what does the SR store correct answers proteins and calcium
what is the role of the transverse tubules in the muscle fiber correct answers allow
inside of muscle to communicate with the outside of the muscle
how is a sarcomere measured correct answers from z-disc to z-disc
what is contained in the I band of the sarcomere & what color is the band correct
answers thin filaments
titin
z-disc
light (isotropic)
what is contained in the A band of the sarcomere & what color is the band correct
answers thick filaments
thin filaments
dark (scatters light)
what is contained in the H zone & what color is the band correct answers thick
filaments
light
no barbs or myosin
middle zone of the sarcomere
what is contained in the M line correct answers in the middle of the sarcomere, middle
of H zone
thick filaments
myomesin
what does titin do in the sarcomere correct answers structural protein
how many zones can you see when the sarcomere is relaxed correct answers all zones
can be seen in relaxed state
how many zones can be seen when the sarcomere is contracted correct answers
sarcomere shortens
I band shortens
H zone disappears
thick and thin filaments overlap DONT shorten
what is the contractile unit of skeletal muscle correct answers the sarcomere
,what is the main component of the thick filaments correct answers myosin
have heavy and light chains
motor heads that move it along the thin filament
what is the largest protein in the body correct answers titin
what are the main components of the thin filaments correct answers actin (where
myosin binds)
troponin (moves tropomyosin when Ca2+ is present)
tropomyosin (covers actin active site)
nebulin (sets thin filament length)
CapZ (anchors actin to Z-line on z-disc side)
Tropomodulin (on end of actin, in middle of sarcomere)
alpha-actinin (anchors actin to z-line)
what does desmin do in the sarcomere correct answers interacts with alpha-actinin to
anchor z-disc to sarcolemma
what does dystrophin do in the sarcomere correct answers connects sarcomere to
sarcolemma
stabilizes the sarcolemma to prevent damage during contractions
1st step of cross-bridge cycle correct answers BINDING
activated myosin binds to actin
ADP and Pi are still bound to myosin
2nd step of cross bridge cycle correct answers POWER STROKE
myosin head swivels
movement of actin filament
ADP and Pi released from myosin
(Pi is released first, before ADP is released)
3rd step of cross bridge cycle correct answers DISSOSCIATION
ATP binds to myosin
Actin and myosin dissociate (cross bridge detaches)
4th step of cross bridge cycle correct answers ACTIVATION
ATP hydrolysis energy activates myosin head
ADP and Pi remain bound to myosin
if Ca2+ still present, cycle continues
how does Ca2+ effect the cross bridge cycle correct answers Ca2+ is needed for the
troponin to move the tropomyosin off the actin
when Ca2+ runs out, the cross bridge cycle will stop
troponin has 4 Ca2+ binding sites
, how does Ca2+ get into the cell to trigger the cross bridge cycle correct answers
through the RyR channels, which are activated by the DHPR channel mechanical
change IN SKELETAL MUSCLES
what are the two roles of ATP in the cross bridge cycle correct answers release from
rigor state
re-energize/reactivate myosin heads for next cycle
what resequesters Ca2+ to end muscle contraction correct answers SERCA
where is the sarcoplasmic reticulum located correct answers wrapped around the
sarcomeres and throughout the myofibrils
what is the role of the sarcoplasmic reticulum in muscle cells correct answers stores
Ca2+ that is needed for contraction
what are the components of the triad in the muscle cell correct answers sarcoplasmic
reticulum
t-tubule
what is the role of the triad in the muscle cell correct answers communication center
what are the two main receptors in the triad correct answers dihydropyridine receptors
(DHPR)
ryanodine receptors (RyR)
what is the role of the DHPR in the triad correct answers voltage sensor
sense when action potential is moving down t-tubule
what is the role of the RyR in the triad correct answers Ca2+ release channel
what kind of pennate muscle fiber formation has the most force production correct
answers multipennate
what muscle fiber arrangement is best for speed correct answers when they are
stacked on top of each other (like a building)
what muscle fiber arrangement is best for strength correct answers when they are next
to each other (like a trailer)
have more tension
what kind of muscle contraction action has the most tension correct answers isometric
contraction
how many endplates do muscle fibers have correct answers one endplate per muscle
fiber
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