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fascia
bundle of muscle fibers (dense)
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Tendons
cordlike layer of connective tissue
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sarcomere
function of muscle fibers
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myofibril
bundel of filaments
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z line
separates sarcomeres (protine that borders)
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cross bridge
bridge between myosin & actin
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motor nueron
stimulates muscle- nerve cell that goes to muscle
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muscle tone
continuous partial state of contraction
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thereshold stimulus
minimum stimuls for a nueron to make a muscle contract
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describe the 4 characteristics of muscle tissue
- excitability- recieve & respond to a stimulus
- extensability- stretch beyond normal
- contractibility- shorten & thicken within stimulus is recieved
- elasticity- return to origional shape after extension or contraction
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describe the 3 functions of muscle tissue
- motion- whole or localized
- maintance of posture- maintains position
- heat production- enzymes function best at a certian temp and the body heat is from muscle contraction
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what advantages are there to a) whole body movement b) localized movement
- a) from one place to another
- b) movement of one part
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how are the fibers of skeletal muscle different from that of cardiac muscle?
- skeletal- striated, voluntary, movement of skeleton
- cardiac- heart, less striated, involuntary, pump blood
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what does the term smooth refer to in smooth muscle
no striations
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which types of muscles are voluntary?
skeletal
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what types of tissues are muscles composed of?
- muscle
- connective
- nervous
- vascular
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relationship between: epimysium, perimysium, and endomysium
- epimysium- covers entire muscle
- perimysium- covers bunches of fibers
- endomysium- covers individual fibers (cells)
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the outward extension of these froms what?
tendon
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what is the purpose of the tendon sheaths?
- to protect tendons
- reduce tension
- allignment of rind tissue
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what is tendenitis
inflamation of tendon sheaths
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what part of a muscle is considered to be the muscle cell?
muscle cell (fibers)
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why does a single muscle cell have many nuclei and mitochondria?
- length
- long and thin (more energy)
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do myofibrils and myofilaments run the entire length of a muscle cell?
myofibrils YES
myofilaments NO
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what are the differences between the myosin and the actin myofibrils?
myosin- thicker, entensions mosin
actin- thin myofilaments zlines
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what are troponin and tropmyosin, where are they found and what is their function?
protines associated with actin and myofilaments, prevents the binding of actin & myosin myofilaments by blocking myosin binding sites, found around actin
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what are the striations on skeletal muscle due to?
- alterating actin and myosin regions
- light/dark bands
- actin- thin myosin- thick
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what is the function unit of a muscle cell?
sacomere
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what is the function of acetylcholine and where is it produced?
nuerotrans mitter that alters heart contractions causing an impulse by duffusing across muscle
produces axon ends that stimulate muscle
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why to the motor nuerons of the eye innervate less muscle fibers?
fine motor control
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why arent all the muscle fibers of a muscle fired at the the same time
stamena ( so that other muscle fibers can rest)
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what is the function of muscle tone?
- posture
- coordination
- joint stability
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when a nervous impulse reaches the end of a motor anon what occurs?
acetylcholine is released (which diffuses across the neuromuscular junction and combines with recptor sites on the sarcolemma of the muscle fibers)
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when a muscle is stimulated by nerve what happends to the sarcolemma and the transverse tubules?
acetylcholine diffuses an impulse alone the sarcolemma membrane and than the impulse travels down the transverse tubules
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as a result of number 28 what next happends in the muscle and what is the result of this?
release of calcium ions combines with tropomin and tropomyosin causing them to move which result in the exposure of myosin binding sites on the actin
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when a myosin head comes in contact with a myosin-binding site on the actin, what happens?
releases energy, swivels/ bends to pull an actin myofilaments and the additional energy is released and give the myosin heads new energy
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what happends to the length of a sarcomere during contraction and extension?
it shortens & lenghtens
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what terminates a contracrtion?
absorption of calcium ions and transport back into the sacroplasmic reticulum for storage
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why does the body stiffen up after death?
muscle tone
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Can muscle cells partially contract?
NO thereshold
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Can muscles partially contact?
yes depends on # muscle fibers contract or dont (all or nothing)
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describe the 4 types of muscle contractions
twitch- one brief contraction, stimulus
tetanus- sustained contraction (results)
isotonic- contraction of a muscle under same tension
isometric- same length tension may increase not moving body parts
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most of the work you do with your muscles is of what type?
isometric and isotonic combination
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lifting a weight is what type of contraction?
isotonic
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trying to lift a weight is what type of contraction?
isometric
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what is atrophy, what is it due to, and what is the result of it?
- breakdown and weaking of muscle due to lack of use
- become weaker
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slow twitch
lots of myoglobin (RED)
contract slower
endurance (long distant running)
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fast twitch
low in myogobin (white)
glycogen
powerful brief contractions
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fast twitch fatigue resistant
lots of myoglobin (RED)
attract quickly (less endurance)
forceful sustained brief contraction sprinter
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endurance exercises
repitive running
bring heart rate up to 50% of max heart rate
benefits: increase capalaries, increase midocondria= more atp, more myoglibin produced
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resistance exercises
not repitive, running laps
exerting 75% max
increase amount of actin and myosin
making muscle stronger
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what affect does aging have on muscles
lose muscle tissue (age 30)
weaker
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