Chapter 10 Muscle Tissues Notes Flashcards
6 functions of skeletal muscle
produce skeletal movement maintain position support soft tissues guard openings maintain temp store nutrients
dense layer of connective tissue that surrounds entire skeletal muscle
epimysium
delicate connective tissue that surrounds skeletal muscle fibers and ties adjacent muscle fibers together
endomysium
bundle of collagen fibers at the end of a skeletal muscle that attaches the muscle to bone
tendon
advantage of having many nuclei in a skeletal muscle fiber
large amount of proteins can quickly grow/repair
skeletal muscle fibers are formed by embryonic cells called
myoblasts
repeating unit of a skeletal muscle fiber
sarcomeres
interactions between actin and myosin filaments of the sarcomere are responsible for
contractions
cross-bridges are portions of
actin filaments
active sites are blocked by
tropomyosin
narrow space between synaptic terminal and muscle fiber
synaptic cleft
active sites on the actin become available for binding after
calcium bonds to receptor
two protein molecules connected by myosin cross-bridges during muscle contraction
myosin
actin
rapid rise and fall in force produced by a muscle fiber after a single action potential
twitch
contraction in which muscle fibers do not shorten
isometric contraction
at peak levels of muscle exertion the mitochondria can supply
1/3 of ATP needed
after heavy exercise, of energy reserves in a muscle are depleted, this occurs
oxygen debt
type of muscle fiber that is most resistant to fatigue
slow fiber
muscular force can be adjusted to match different loads by
- more/larger motor units
- increase frequency/action potential
the cytoplasm of neuromuscular terminal contains vesicles filled with molecules of the neurotransmitter
ACH
aerobic metabolism provides _____ percent of the ATP demands of a resting muscle cell
95%
large diameter, densely packed myofibrils, large glycogen reserves, and few mitochondria are characteristics of
fast fibers
when hormone directly stimulates growth of muscle tissue, leading to increased muscle mass
testosterone
because skeletal muscle contractions demand large quantities of ATP, skeletal muscles have the following adaptations:
blood vessels
mitochondria
after death, muscle fibers run out of ATP and calcium begins to leak from the sarcoplasmic reticulum into the sarcoplasm
rigor mortis
large motors are found in ______ muscles, and small motors are found in ______ muscles
larger
smaller
what would happen if blood flow decrease to a muscle
lack oxygen
shift to glycosis
fatigue
pyruvic acid to lactic acid
__ myosin head binds ATP molecule and detaches from actin
__ free myosin head splits ATP
__ calcium ion is releases from sarcoplasmic reticulum
__ myosin cross-bridges bind to actin
__ myosin head pivots toward center of sarcomere
__ calcium ion binds to troponin
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