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189 Cards in this Set
- Front
- Back
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Contraction produces _________.
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tension
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What is tension?
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the force exerted by a muscle on the load (the object to be moved)
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_________ produces tension.
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Contraction
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What term is described:
" the force exerted by a muscle on the load (the object to be moved) " |
tension
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True or false:
different principles apply to contraction of a single fiber and a whole muscle |
false
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True or false:
the same principles apply to contraction of a single fiber and a whole muscle |
true, the same principles apply to contraction of a single fiber and a whole muscle
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The load, when referring to muscle mechanics, refers to what?
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the object to be moved
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True or false:
Contraction does not always shorten a muscle |
true, contraction does NOT always shorten a muscle
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What are the two types of contractions?
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isometric and isotonic
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What is isometric contraction?
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no shortening; muscle tension develops but does not exceed the load
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What type of contraction is best described:
" no shortening " |
isometric contraction
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What type of contraction is best described:
" muscle tension develops but does not exceed the load " |
isometric contraction
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What is isotonic contraction?
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muscle shortens because muscle tension exceeds the load
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What type of contraction is best described:
" muscle shortens " |
isotonic contraction
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What type of contraction is best described:
" muscle tension exceeds the load " |
isotonic contraction
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In isotonic contraction, why does muscle shorten?
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Because muscle tension exceeds the load
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The force and duration of contraction vary in response to what?
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stimuli of different frequencies and intensities
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The _______ and _______ of contraction vary in response to stimuli of different frequencies and intensities?
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Force and duration
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During isotonic contractions, muscle develops enough tension to do what?
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to overcome the load
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In isotonic contractions, changes in _________ and the load moving occurs.
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length
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During ________ contraction, the load is moved.
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isotonic
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_________ contractions are either concentric or eccentric.
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Isotonic
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What are the types of isotonic contractions?
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concentric and eccentric
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During _________ contractions, the muscle shortens and does work.
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concentric contractions
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What are concentric contractions?
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when the muscle shortens and does work
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During ________ contractions, the muscle contracts as it lengthens.
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eccentric contractions
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What are eccentric contractions?
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when the muscle contracts as it lengthens
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During isometric contractions, the load is ______ than the tension the muscle is able to develop.
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greater
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Relate the load and the tension during isometric contractions.
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The load is greater than the tension the muscle is able to develop
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During isometric contractions, tension ________ to the muscle's capacity, but the muscle neither shortens nor lengthens.
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increases
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Relate the tension and muscle capacity during isometric contractions.
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During isometric contractions, tension increases to the muscle's capacity
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During ________ contractions, the muscle neither shortens nor lengthens.
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isometric contractions
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During isometric contractions, what happens to muscle length?
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nothing
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State all the types of contractions of the quadriceps that occur when you perform a knee bend.
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- flexing knee = eccentric
- holding squat = isometric - extending knee = concentric |
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flexing your knee is an example of a/an __________ contraction
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eccentric
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holding your squat is an example of a/an ________ contraction
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isometric
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extending your knee is an example of a/an _________ contraction
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concentric
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________ muscle responses are aka variations in the degree of muscle contraction
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graded muscle responses
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What is/are required for proper control of skeletal movement?
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graded muscle responses
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Graded muscle responses are required for what?
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for proper control of skeletal movement
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How are muscle responses graded?
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- changing the frequency or strength of the stimulation
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How is greater muscle force generated?
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by increasing the firing rate of motor neurons
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True or false:
greater muscle force is generated by having a stronger impulse |
false
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True or false:
greater muscle force is generated by increasing the firing rate of motor neurons |
true; greater muscle force is generated by increasing the firing rate of motor neurons
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What is the threshold stimulus?
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stimulus strength at which the first observable muscle contraction occurs
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A muscle contracts more vigorously as what happens to stimulus strength?
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as stimulus strength is increased above the threshold
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As stimulus strength is increased above the threshold, what happens to a muscle?
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a muscle contracts more vigorously
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the force exerted by a contracting muscle on an object is known as _______
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tension
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contraction force is precisely controlled by ___________
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recruitment (multiple motor unit summation)
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____________ is precisely controlled by recruitment (multiple motor unit summation).
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contraction force
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What is another term for recruitment?
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multiple motor unit summation
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What is another term for multiple motor unit summation?
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recruitment
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Recruitment brings what?
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more and more muscle fibers into action
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The multiple motor unit summation brings what?
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more and more muscle fibers into action
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The force of contraction is affected by:
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- number of muscle fibers stimulated (recruited)
- relative size of the fibers - frequency of stimulation - degree of muscle stretch |
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If a large number of muscle fibers are activated, what happens to contractile force?
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contractile force increases
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If large muscle fibers are involved, what happens to contractile force?
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contractile force increases
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If there is a high frequency of stimulation, what happens to contractile force?
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contractile force increases
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If a muscle and sarcomere are stretched to slightly over a hundred percent of resting length
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contractile force increases
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The velocity and duration of contraction are influenced by what things?
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- muscle fiber type
- load - recruitment |
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The ________ and ________ of contraction are influenced by muscle fiber type, load and recruitment
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velocity and duration
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The muscle fiber type is classified according to what two characteristics?
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2 functional characteristics:
- speed of contraction - metabolic pathways for ATP synthesis |
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Speed of contraction is slow or fast, depending on what?
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- speed at which myosin ATPases split AtP
- pattern of electrical activity of the motor neurons - How quickly calcium is moved from cytosol into sarcoplasmic reticulum |
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_______ fibers use aerobic pathways
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oxidative
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________ fibers use anaerobic glycolysis
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glycolytic
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oxidative fibers use ________ pathways
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aerobic
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glycolytic fibers use _____________
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anaerobic glycolysis
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What is the only energy source used directly for contractile services?
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ATP
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Available stores of ATP are depleted in how much time?
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4-6 seconds
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How is ATP regenerated?
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- direct phosphorylation of ADP by creatine phosphate
- anaerobic pathway (glycolysis) - aerobic respiration |
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Direct phosphorylation of ADP by creatine phosphate, glycolysis, and aerobic respiration are three methods of what?
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regenerating ATP
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ADP is phosphorylized by ___________
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creatine phosphate
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What does creatine phosphate do?
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phosphorylzes ADP
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ATPases do what?
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split ATP
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Anaerobic pathways are at ______ percent of maximum contractile activity
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seventy
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________ pathways are at seventy percent of maximum contractile activity
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Anaerobic
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During anaerobic pathways (70% maximum contractile activity), what happens to blood vessels?
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bulging muscles compress blood vessels
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During anaerobic pathways (70% maximum contractile activity), what do bulging muscles do?
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compress blood vessels
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During ________ pathways, oxygen delivery is impaired.
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anaerobic
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During anaerobic pathways, what delivery is impaired?
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oxygen delivery
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During anaerobic pathways, pyruvic acid is converted into what?
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lactic acid
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During anaerobic pathways, ________ is converted into lactic acid
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pyruvic
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lactic acid diffuses into the__________
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bloodstream
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lactic acid is used as what?
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fuel by the liver, kidneys, and heart
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Eventually, lactic acid is converted back into ________ by the liver
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pyruvic acid
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What converts lactic acid back into pyruvic acid?
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liver
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Eventually, ________ is converted back into pyruvic acid by the liver
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lactic acid
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Aerobic pathways produce ______ of ATP during rest and light to moderate exercise
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95%
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What pathway is best described:
" produces 95% of ATP during rest and light to moderate exercise " |
aerobic pathways
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What are the fuel options for aerobic pathways?
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stored glycogen, then bloodborne glucose, pyruvic acid from glycolysis and free fatty acids
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" stored glycogen, then bloodborne glucose, pyruvic acid from glycolysis and free fatty acids "
describe what? |
the fuel options for an aerobic pathway
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What are the three types of muscle fibers?
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- slow oxidative fibers
- fast oxidative fibers - fast glycolytic fibers |
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What are the types of oxidative fibers?
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slow and fast
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What are the types of glycolytic fibers?
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only fast
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Describe what the influence of load is.
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An increased load leads to a decreased latent period, leading to a decreased contraction and a decreased duration of contraction
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An increased load leads to a/an _______ latent period
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increased latent period
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A decreased load leads to a/an _______ latent period
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decreased latent period
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an increased load leads to a/an _________ contraction
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decreased
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a decreased load leads to a/an _________ contraction
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increased
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An increased load leads to a/an ________ duration of contraction
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decreased
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A decreased load leads to a/an _______ duration of contraction
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increased
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Describe the influence of recruitment
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Recruitment leads to a faster contraction and increased duration of contraction
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Recruitment leads to a _________ contraction
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longer
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recruitment does what to the duration of contraction?
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increases it
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aerobic exercise is also known as ___________ exercise
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endurance
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aerobic exercise leads to what microscopically?
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- increased muscle capillaries
- increased number of mitochondria - increased myoglobin synthesis |
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Relate aerobic exercise and muscle capillaries?
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aerobic exercise leads to an increase in muscle capillaries
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Relate aerobic exercise to the number of mitochondria
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aerobic exercise leads to an increase in mitochondria
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Relate aerobic exercise to myoglobin synthesis
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aerobic exercise leads to an increase in myoglobin synthesis
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Aerobic exercise results in greater what on a macroscopic level?
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endurance, strength, and resistance to fatigue
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Aerobic exercise may convert _______ into fast oxidative fibers
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fast glycolytic fibers
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Aerobic exercise may convert fast glycolytic fibers into _____________
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fast oxidative fibers
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Aerobic exercise may convert __________ into __________
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fast glycolytic fibers ; fast oxidative fibers
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Resistance exercise is typically __________
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anaerobic
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Muscle hypertrophy is due to what?
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an increase in fiber size
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Anaerobic exercise results in _______ mitochondria
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increased
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Anaerobic exercise results in _______ myofilaments
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increased
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Anaerobic exercise results in _______ glycogen stores
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increased
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Anaerobic exercise results in _______ connective tissue
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increased
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Smooth muscle is found where?
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in walls of most hollow organs (except the heart)
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What type of tissue is best described:
" in the walls of most hollow organs (except the heart) " |
smooth muscle
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Smooth muscle is usually in what two layers?
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longitudinal and circular
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______ muscle is usually in two layers; longitudinal and circular
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Smooth
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What layer of smooth muscle is best described:
" muscle fibers run parallel to long axis of organ " |
longitudinal
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In the longitudinal layer of smooth muscle, where do muscle fibers run?
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parallel to long axis of origin
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In the circular layer of smooth muscle, where do muscle fibers run ?
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around the circumference of organ
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What layer of smooth muscle is best described:
" muscle fibers run around circumference of organ " |
circular
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Smooth muscle has what shaped fibers?
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spindle-shaped fibers
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Compare skeletal muscle fibers and smooth muscle fibers
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smooth muscle fibers are spindle shaped, and thinner and shorter than skeletal muscle fibers
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True or false:
skeletal muscle fibers are longer than smooth muscle fibers |
true
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True or false:
smooth muscle fibers are longer than smooth muscle fibers |
false
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True or false:
smooth muscle fibers are thinner than skeletal muscle fibers |
true
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Smooth muscle fibers are ______ and _____ than skeletal muscle fibers
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thinner and shorter
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What connective sheath(s) characterizes smooth muscle?
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endomysium only
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______ muscle is characterized only by endomysium.
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smooth
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______ muscle has a less developed sarcoplasmic reticulum than in skeletal muscle
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smooth
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______ muscle has a more developed sarcoplasmic reticulum than in smooth muscle
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skeletal
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What are caveolae?
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pouchlike infoldings of sarcolemma with calcium in them, characteristic of smooth muscle
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cavaeolae are characteristic of what specific type of muscle?
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smooth
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What term is best described by the following statement:
" pouchlike infoldings of sarcolemma with calcium in them, characteristic of smooth muscle" |
cavaeolae
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Since smooth muscle lack striations, they also lack what?
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sarcomers, myofibrils, or T tubules
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How do you know smooth muscle contain sarcomeres?
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They don't have striations
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Smooth muscle cells have ______ nerves.
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lots of ; innervated
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What are varicosities?
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swelling of the ANS nerve fibers that store and release neurotransmitters
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What term is best described:
" swelling of the ANS nerve fibers that store and release neurotransmitters" |
varicosities
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Varicosities are swellings of _______ nerve fibers that store and release neurotransmitters
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ANS
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Varicosities are swellings of ANS nerve fibers that do what
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store and release neurotransmitters
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True or false:
smooth muscle contraction is fast |
false
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true or false:
smooth muscle contraction is slow |
true
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true or false:
smooth muscle contractions are synchronized |
true
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true or false:
smooth muscle contractions are asynchronized |
falsee
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Some ____________ have cells that are self-excitatory
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smooth muscles
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Self-excitatory means what?
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can depolarize without external stimuli
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Being self-excitatory means that the cells can ______ without external stimuli
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depolarize
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Being self-excitatory means that the cells can depolarize without what?
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external stimuli
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smooth muscle contractions have _______ energy requirements than skeletal muscle contractions
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lower
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skeletal muscle contractions have ______ energy requirements than smooth muscle contractions
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higher
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Moderate constant contraction for homeostasis is called what?
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smooth muscle tone
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What is smooth muscle tone?
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moderate constant contraction for homeostasis
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What type of muscle is characterized by moderate constant contraction for homeostasis?
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smooth muscle
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What is peristalsis?
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alternating contractions and relaxations of smooth muscle layers that mix and squeeze substances through the organ
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What term is best described:
" alternating contractions and relaxations of smooth muscle layers that mix and squeeze substances through the organ " |
peristalsis
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When the longitudinal layer contracts, what happens to the organ during peristalsis?
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organ dilates and shortens
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During peristalsis, what is going on with the longidtudinal layer when the organ dilates and shortens?
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longitudinal layer contracts
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During peristalsis, what is going on when the organ constricts and elongates?
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the circular layer contracts
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When the longitudinal layer ______; organ dilates and shortens in peristalsis
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contracts
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When the circular layer ________; organ constricts and elongates in peristalsis
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contracts
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In peristalsis, when does the organ dilate and shorten?
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when the longitudinal layer contracts
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In peristalsis, when does the organ constrict and elongate?
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when the circular layer contracts
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What is the stress-relaxation response?
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- responds to stretch only briefly, then adapts to new length
- retains ability to contract on demand - enables organs such as the stomach and bladder to temporarily store contents |
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The stress-relaxation response enables organs like the stomach and bladder to do what?
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to temporarily store contents
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What enables organs like the stomach and bladder to temporarily store contacts?
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the stress-relaxation response
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The stress-relaxation response retains the ability to what?
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to contract on demand
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What is hyperplasia?
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the ability of smooth muscle cells to divide and thus increase in numbers
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What term is best described:
" the ability of smooth muscle cells to divide and thus increase in numbers" |
hyperplasia
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Estrogen's effects on uterus at puberty and during pregnancy is an example of _________
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hyperplasia
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State an example of hyperplasia
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estrogen's effects on uterus at puberty and during pregnancy
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What are the two types of smooth muscle?
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single unit and multiunit
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What is another term for visceral smooth muscle?
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single unit smooth muscle
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The most common type of smooth muscle is ________.
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single unit
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What type of smooth muscle is best described:
" in walls of all hollow organs except heart" |
single unit smooth muscle
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What type of smooth muscle is best described:
" sheets contract rhythmically as a unit " |
single unit smooth muscle
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What type of smooth muscle is best described:
" arranged in opposing sheets and exhibit stress-relaxation response " |
single-unit smooth muscle
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What are gap junctions?
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when sheets contract rhythmically as a unit
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Multiunit smooth muscle is located where?
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in large airways, large arteries, arrector pili muscles and iris of eye
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Multiunit smooth muscle have what type of contractions?
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graded contractions
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What type of smooth muscle is best described:
" fewer junctions " |
multiunit smooth muscle
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What type of smooth muscle is best described:
" graded contractions occur in response to neural stimuli " |
multiunit smooth muscle
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What is the sliding filament theory of contraction?
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during contraction, the thin filaments slide past the thick ones
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