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74 Cards in this Set

  • Front
  • Back
Where do the thick and thin filaments overlap?
A Band
What is the functional contractile unit of a myofibril?
sacromere
Where are only thin filaments found?
I Band
What is the end of the sarcoplasmic reticulum, a t-tubule and the end of the other sarcoplasmic reticulum?
triad
What hydrolyzes ATP to relase energy?
ATPase
Where are only thick filaments found?
H Zone
After the calcium moves the TTC away from the binding sites on actin, what happens?
myosin heads attach to form the cross-bridge
What is the thick filament made of?
myosin
What happens when calcium is released?
binding site is open
What are the rod-like protein molecules that run parallel within the myofibril?
myofiliments
when atp binds to myosin head and cross bridge releases
cross-bridge detachment
What is the modified endoplasmic reticulum?
sarcoplasmic reticulum
What contains ATPase?
myosin
What releases calcium and takes it back up?
sarcoplasmic reticulum
What happens when the myosin head is cocked?
atp is hydrolyzed to release energy (to reposition head to create a new cross bridge)
Actin is actually the what site?
binding
Myosin has a natural and unnatural -.
sitting position
What is the repeated series of light and dark bands created by the myofiliments?
striations
What is required to move the TTC away from the binding sites on actin?
calcium
What is a muscle's ability to receive/respond to stimuli?
excitability/irritability
When the thin filaments are pulled toward the center of the sacromere by the thick filaments
power stroke
What are the four functional characteristics of muscles?
excitability
contractility
extensibility
elasticity
What happens when CA is taken up by the SR?
muscle relaxes
What is the electrical signal called which stimulates cells in the muscle to contract?
response
A high level of CA, muscle is.....
contracted
What are three stimuli that are associated with muscle excitablility/irritability?
chemical (neurotransmitter)
hormone
change in pH
Four effects of contraction/ca release on sarcomeres?
-shorten, muscle shortens
-z lines slide toward each other
-I bands shorten
-h zone disappears
What is a muscle's ability to shorten?
contractility
What is a nerve and all the fibers it serves?
motor unit
What are the two types of myofiliments?
thick and thin
When the myofibril contracts, what comes closer together?
the Z lines
What is a muscle's ability to be stretched?
extensibility
If the stimulus is constant, time between contractions short and Ca levels increase or decrease?
increase
What is a muscle's ability to resume resting length after being stretched?
elasticity
Why can't tetanus occur indefinitely?
run out of atp, causing muscle fatigue
What is the boundary line between sacromeres?
Z Line
How do you get a muscle to send more force?
send more stimuli
What are thin filaments made of?
actin, tropomyosin and troponin
Stronger stimuli causes what?
mulitple unit summation
What attaches to the tropomyosin to form a complex?
troponin
What is sustained contraction?
tetanus
Skeletal attachment, movable bone?
insertion
"cramps" due to the lack of atp
contractures
What covers the binding sites on the filament for the myosin heads?
tropomyosin
Increasing stimuli causes more muscle fibers- motor units to act, called what?
recruitment
When the TTC moves out of the way and the myosin heads attach to the actin, what is this called?
cross-bridge
What helps to produce smooth and controlled contractions?
stronger stimuli
The normal function of skeletal muscle depends on what?
nerves and rich blood supply
What is recruitment?
letting some cells work, some rest
What are three characteristics of skeletal muscle?
highly innervated
lots of blood supply
branch of at least one nerve
What is treppe?
when repeated stimuli cause 2nd contraction to be stronger than 1st
Skeletal attachment, less movable bone?
origin
What helps with muscle fatigue (some cells at tetanus, some at resst)?
stronger stimuli
Sacro-
Myo-
muscle
Treppe: limit based on what?
filaments running out of room to slide within sarcomere
Skeletal muscle attachment must have what two things?
a tendon and aponeuroses
type of muscle fiber recruited depends on what?
need
What are associated with myofibrils?
t-tubules
What is when muslces change length and move something?
isotonic contraction
What element is extremely important in contraction?
calcium
What is an ex of isotonic contraction?
lifting weights
What attaches the muscle to the bone?
tendon
What is when muscles contract but there is no shortening/lengthening?
isometric contraction
What are tendons made of?
connective tissue
What is an ex of isometric contraction?
pushing on a wall
What controls contraction?
the sarcoplasmic reticulum
how many types of muscle fiber is a motor unit comprised of?
one
type of muscle fiber recruited depends on what?
need
What occurs because the muscle hasn't fully relaxed before the onset of the second stimulus?
rapid stimulation
Stimuli in rapid succession will produce what?
a second twitch stronger than the first ("summation")
What causes wave summation and tetanus?
rapid stimulation
physical inability to conract
muscle fatigue
Can tetanus occur indefinitely?
no
muscles are made up of how many types?
three