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38 Cards in this Set
- Front
- Back
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all-or-none response applies to what?
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single muscle fiber
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process of activating more and more motor units is called?
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motor recruitment
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staircase effect AKA treppe
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contractions become stronger as muscle is repeatedly stimulated b/c of calcium ion buildup in sarcoplasm
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a sustained contraction
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tetanus
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lockjaw is caused by?
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pathological tetanus
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isotonic contraction
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muscle shortens, tension is constant
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isometric contraction
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muscle does NOT shorten, tension increases
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two types of smooth muscle
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-multi-unit
-visceral (single-unit) |
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visceral smooth muscle cells are arranged how?
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in wraparound sheets
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what is calmodulin?
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used in smooth muscle instead of troponin & tropomyosin for excitation-contraction coupling
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what causes smooth muscle to contract?
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nervous input from the ANS
hormones substances produced w/in tissue stretching |
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intercalated discs contain what kind of junctions?
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gap junctions
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pacemaker cells
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specialized cardiac cells that display rhythmic excitatory activity
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first class levers
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fulcrum between out-force & in-force
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give 3 examples of first class levers in the human body
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lifting head; straightening arm @ elbow; walking (foot & ankle)
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second class levers
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out-force in the middle
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third class levers
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in-force in the middle
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example of third class lever in human body?
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flexing forearm @ elbow
-third class levers are the most common type in the human body |
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advantage of lever system?
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large movement of limb w/ small degree of muscle shortening
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disadvantage of lever system?
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mechanical disadvantage- must exert much more force
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flexor/extensor
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decrease/increase angle @ a joint
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abductor/adductor
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move bone away/closer to the midline
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levator/depressor
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produce an upward/downward movement
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supinator/pronator
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turn palm up/down
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sphincter
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decrease size of an opening
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tensor
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make a body part more rigid
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rotator
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move a bone around its longitudinal axis
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agonist/antagonist
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prime mover/ relaxor
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"helper" muscles
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synergists
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satellite cells
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stem cells that divide and form myoblasts that can make new muscle cells to replace damaged ones
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muscular hyperplasia
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forming new muscle fibers from satellite cells
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muscular hypertrophy
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increase in size of muscle fibers (happens when you exercise)
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muscular atrophy
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wasting away of muscles
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myasthenia gravis
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type of muscular atrophy
antibodies against acetylcholine receptors form |
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Duchenne muscular dystrophy
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type of muscular atrophy caused by a mutation in the gene for dystrophin
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how is myasthenia gravis treated?
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with anticholinesterase drugs that reduce enzymatic breakdown of acetylcholine at the neuromuscular junction
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force exerted by a muscle is proportional to what?
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its cross-sectional area
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t/f, increasing the volume of a muscle increases the amount of work it can do?
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true
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