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