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137 Cards in this Set
- Front
- Back
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the more movable bony attachment of the muscle
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insertion
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the less movable attachment to muscle:
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origin
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the prime mover of many skeletal muscle movement is _____
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agonist (flexor)
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flexors & extensors that act on the same joint to produce opposite actions are _____
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antagonistic muscles (extensor)
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when_____ muscles contract, it decreases the angle of the joint
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flexor
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when_____ muscles contract, it increases the angle of the joint
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extensor
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this muscle action moves limb away from the midline of the body
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abductor
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this muscle action moves insertion upwards
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levator
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this muscle action rotates a bone along its axis
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rotator
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this muscle action constricts an opening
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sphrinctor
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muscles are composed of _____ & have the same organelles as other cells
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muscle fibers
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unlike other cells in the body, skeletal muscle fibers contain multiple _____
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nuclei (multinucleated)
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why are skeletal muscle fibers multinucleated?
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because each fiber is formed from a fusion of embryonic cells
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the most distinctive feature of skeletal muscle fibers is their _____ appearance
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striated
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what are the striations in muscle fiber due to?
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protein arrangement: dark A bands & light I bands
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anisotropic stands for _____
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A bands: indicating the polarized light as it passes thru
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isotropic stands for _____
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I bands: indicating the polorized light as it passes thru
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each single muscle fiber is surrounded by a plasma mb called _______
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sarcolemma
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the sarcolemma is enveloped by a thin connective tissue layer called _______
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endomysium (endo=within)
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fasicles are ____ and covered by a connective tissue sheath called ______
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bundles of fibers covered by perimysium
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the _____ is continuous with the tendon and is the outer covering of a skeletal muscle
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epimysium
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each somatic motor neuron & all the muscle fibers its collateral branches innervate are collectively called _____
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motor unit
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when a somatic motor neuron is activated, all of the muscle fibers it innervates are stimulated to ____
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contract from AP
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many ____ allows for variability of strength via recruitment
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motor units (soda can)
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____ muscles have small motor units for fine motor control
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small muscles- sm motor units (eye)
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large strong muscles have ___ motor units and are more strong and less precise
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large (gastrocnemius)
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muscle cells are composed of many densely packed subunits called _____
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myofibrils
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each myofibril contains contractile protein subunits called _____
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myofilaments
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muscle fiber organelles are located _____
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betwe adjacent myofibrils (because myofibrils are so densely packed)
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muscle fiber has flattened peripherally located _____
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nuclei
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the muscle fiber plasma mb is _____
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sarcolemma
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the muscle fiber cytoplasm is ______
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sarcoplasm
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what part of the muscle fiber contains lots of glycogen stored for energy?
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sarcoplasm
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the ______ is comprised mainly of myofibrils and organelles
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sarcoplasm
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long protein bundles that occupy most of the cell:
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myofibrils
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what is a myofibril composed of?
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a bundle of myofilaments
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the Ca+ reserver of the muscle cell is ______
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sarcoplasmic reticulum (SER of muscle)
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the dilated sacs that Ca+ is reserved in muscle cells are called _____
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terminal cisternae (within sarcoplasmic reticulum)
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these mb infoldings in muscle cell carry the electrical impulses
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t-tubules
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AP at _______ stimulate ______to release Ca+
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t-tubules, Sacroplasmic reticulum
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protein microfilaments are aka as _____
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myofilaments
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_____ microfilaments contain hundreds of myosin protein, dark striation, & have golf club shape
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thick
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what forms the golf club shape of thick microfilaments?
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2 intertwined myosin proteins form tail and globular head
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______ filaments have 2 intertwined actin strands called F actin
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thin
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the F actin of thin filaments contains a string of subunits called _____
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G actin
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_____ contains an active site which can interact with myosin heads
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G actin
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_______ blocks actin & myosin interaction by blocking active sites on G actin
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tropomyosin
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tropomyosin contains smaller protein called ____
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troponin C complex
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_______ binds Ca+ and relieves inhibition allowing interaction & contraction
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troponin C
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the contractile proteins of thin filaments are ____ & ____
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actin & myosin
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the regulatory proteins of thin filaments are ____ & _____
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tropomyosin & troponin
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subunits that run from Z to Z
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sacromeres
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where is the Z disc/line located?
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in the center of each I band
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the I band extends from _____ to ______
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each of thick filament of 1 sacromere to next
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where is the H zone located?
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the light center region of A band where thin filaments dont reach/overlap
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the area of thick filaments & region of overlap betw thick & thin filaments together is called:
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A band
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this area defines sacromere boundries
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Z disc
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distance betw this area shortens when contraction occurs
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Z disc
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this are contains elastic components of connectin & anchors thin filaments
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Z disc
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the protein filaments in center of thick filaments is called _____
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M line
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this anchors thick filaments:
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M line
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the elastic protein that runs thru thick filament is _____
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titin
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the _____ of the thick filaments contribute to elastic recoil
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titin
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the sliding filament theory is when ______
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sacromere (z-z) shortens, which then shortens myofibrils toward the origin to contract
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which bands shorten during contraction?
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I and H bands only
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which bands do not shorten but instead move closer together?
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A bands
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shortening of sacromeres is caused by myosin cross bridges that pull ____ or ____
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thin actin filaments over thick
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many _____ are needed to slide filaments
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cross bridges
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what are cross bridges?
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myosin head of thick filament interaction forms binding site on actin
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what are the characteristics that allow cross bridges to pull actin toward the center
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orientation of heads on each side of sacromere is opposite
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the _____ has an actin binding site, ATP binding site, & serves as ATPase to hydrolyze ATP
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myosin head of thick filament
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what happens after myosin head hydrolyzes ATP into ADP and P?
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the myosin head becomes "cocked" (activated & changes orientation) to bind actin
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after the myosin head is cocked, what must happen before interaction to occur
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tropomyosin must be moved
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after binding of filaments occur, what allows actin to be pulled toward the center?
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power stroke
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when are the bound ADP and P released?
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after power stroke
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what happens after ADP and P are released?
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new ATP binds- required for release of myosin from actin
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what is required for release of myosin cross bridge from actin?
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binding of new ATP to myosin head
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contraction resulting from lack of ATP when muscle dies is called ______
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rigor mortis
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temporal summation
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increase freq, build of of Ca in sarcoplasm, more actin & myosin interr, stronger force
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increase voltage, more motor units activated, maximum all motor units & muscle fibers contract, stronger contraction
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motor unit summation
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the staircase effect
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phoenomenon treppe- as freq of stimulus increases each twitch successively gets stronger
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incomplete tetanus
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stimulus auto delivers electric shocks with increasing freq, relaxation time betw gets shorter, & strength of contraction increases in amplitude
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fusion freq of stimulation, no visable relaxation betw twiches, smooth & sustained contraction
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complete tetanus
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recoil, tendons, not allowing muscle to relax, going into complete tetanus as a result of temporal summation
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series elastics
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relationship betwe the load & force of contraction
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force velocity curve. no load=easy contract, heavy load=harder & takes more time to contract
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all contractions begins ____ , generates tension, then converts to isotonic
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isometric
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isometric means ______
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muscle develops tension but does not shorten (iso=same metric=length)
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if a muscle is fixed, it shortens with a constant load
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isotonic iso=same tonic=tension
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quick contract & quick relax
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twitch
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staircase- as freq increases each twitch gets stronger
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treppe
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no relax, same
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complete tetanus
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short relax, high strength & high amplitude
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incomplete tetanus
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the heavier the load the longer it takes to contract
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force velocity curve
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optimal resting length allows _____
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maximal contraction 80%-120% when myosin & actin overlap ech other fully
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if length tension is stretched 75% _____
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75% less binding sites, 60% no binding sites
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if length tension is 175% _______
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too far away, no binding sites, no contraction
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cells generates ATP thu _____ or ______
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glucose or oxidative phosphorolation (preferred)
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goal of glycolysis
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to generate pyruvate & shuttle into krebs
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goal of krebs
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to produce cofactors needed to make ATP which are shuttled into electron transport
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_____ generates a lot of ATP but oxygen is needed
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electron transport (oxadative phosphorolation)
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taking pyruvate turning into lactic acid
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anaerobic respiration (not preferred bc can only be done short period of time)
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aerobic respiration
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lactic acid turning into pyruvate oxygen required ETC lots of ATP generated
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during exercise how do we generate ATP
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take glucose from glycogen and put it thru ETC
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when is increased insertion of glucose transporters?
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GLUT4 during exercise so can break down glucose and generate ATP
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how does increases to help generate ATP?
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increase GLUT4, gluconeogenesis, amount of glucose used, increase breakdown of glycogen
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what is inhibited to help generate ATP?
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synthesis of glycogen
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what can be used to make ATP?
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fatty acid, phosphocreatine, and myoglobin
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how does phosphocreatine help make ATP?
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donates a P to ADP to make ATP
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what can be done to buy time anaerobically?
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metobolize ATP from phosphocreatine or myoglobin (gazelle)
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what is the oxygen reserver?
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myoglobin
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if muscle fatigue occurs when sustained max contraction & all motor units recruited ______
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K+ accumulation depolarizes mb, unable to fire AP for 60 sec
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if muscle fatigue occurs during exercise _____
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increase of lactic acid, lowers pH, glycogen gets depleted, & SR reduces ability to release Ca+
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if trained muscles frequently, they will _____
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adapt to increase need for efficiently (exercise adaption)
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what will a decrease in all of the following allow to occur? # of fast glycolytic & oxidative fibers, rate of glycogen depletion, & production of lactic acid
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exercise adaption to increase need for efficiency
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what will need to increase in order for exercise adaption?
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size & # of mitochondria, myoglobin, intramuscular triglyceride, ability to obtain ATP from oxidative phos, & ability to extract O2 from blood
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skeletal muscle is postmitotic this means ____
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limited repair
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______cells can proliferate following an injury. some repair possible but declines with age
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satellite (stem) cells
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where can smooth muscle be found?
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hollow organs like bladder, bronchioles, and bvs
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smooth musc is circular only in _______&_____
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bvs and bronchioles
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sm musc is circular & longitudinal in ______
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hollow organs
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when can myosin & actin interr in smooth muscle?
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always bc myosin is vertically stacked (myosin heads along entire length) & cross bridges at entire thick filament length
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there is a lot more ____ than ___ in sm musc
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more actin than myosin 16:1
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long thin filaments in sm musc attach to either ____ or _____
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pm or dense bodies
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in sm muscl Ca+ binds with ____
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calomodulin
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Ca+/calomodulin complex activates ______
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MLCK
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MLCK phosphorolates ______
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MLC
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MLC activates _____
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ATPase action on myosin which causes myosin & actin to cross bridge
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what increases MLCK activity in sm musc excitation contraction coupling?
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more Ca+
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sm musc lacks _____
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sarcomeres, troponin, striations, and has less SR (so Ca+ enters via VGCCs depolarization)
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single unit sm muscl are joined by ______
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gap juncts which allows for functional synctium so muscles work in synchronous way
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neurons of the ANS contain _____ near cells with gap junctions & functional syncytium
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varicosites
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what would occur if Ca chs in cm musc were blocked?
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bvs would dilate allowing more bf. used for hypertension
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what is it called when a muscle contracts in response to stretch?
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myogenic activity (bladder)
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multiunit sm musc require ______
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nerve stimulation
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which sm musc lacks gap juncts?
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multiunit sm musc
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in ___ contraction can occur without AP
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sm musc (if Ca enters contraction can occur) slow & sustained but energy eff
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what must happen in order for relaxation to occur in sm musc?
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phosphate must be taken away from myosin chain by myosin phosphotase or myosin ATPase pump
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