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42 Cards in this Set

  • Front
  • Back
locomotion
movement of the body
excitable
nervous tissue and muscle tissue
action potential
electrical impulses that (in this case) cause contraction
extensible
muscle tissue can stretch
elasticity
muscle tissue can recoil back to original shape and size
Muscle tissue is
elastic
extensible
excitable
Epimysium
covering of skeletal muscle organ as a whole
Perimysium
the connective tissue between each muscle fascicle
Endomysium
the connective tissue between each muscle fiber (cell)
sarcolemma
cell membrane of a muscle fiber
sarcoplasm
the cytoplasm of surrounding individual muscle fiber cells
T tubules
connects sarcolemma to interior of muscle fiber
pass contraction stimuli to deeper regions of muscle fiber
myofibrils
thousands of rods of proteininside each muscle fiber
sarcoplasmic reticulum
modified endoplasmic reticulum that stores calcium ions
surrounds each myofibril
terminal cisternae
large calcium ion sotrage chambers which lie adjacent to transverse tubules
triad
sandwich made of a t-tubule, plus terminal cisterna on either side
Actin
THIN filament (3000)
Myosin
THICK filament (1500)
sarcomere
repeating patterns of actin and myosin along a myofibril
Z line
where thin actin connects to one another at the END of a sarcomere
Actinin
what makes up a Z line
I band
area newar Z line that contains only thin filaments
A band
area containing both thin and thick filaments located between I bands in a sarcomere
zone of overlap
where thick and thin bind during muscle contraction
H zone
middle region of an A band and contains ONLY THICK filaments
Four proteins that make up actin strands
G actin
F actin
nebulin
active sites
G actin
spherical molecules like pearls on a necklace
F actin
300-400 G actins twist together
Nebulin
"string of a necklace" that holds beads "g-actins" in place
tropomyosin
follows twisted actin strands and blocks active sites to regulate muscle contraction
troponin
holds tropomyosin in position and has binding sites for calcium ions
two strands of myosin
two intertwined tail regions and two globular head regions
titin
protein that attaches thick filament to the Z line on end of sarcomere
Muscular dystrophies
inherited diseases that cause changes in muscle proteins that result in progressive weakening and deterioration of skeletal muscles
DMD (Duchenne
starts in childhood and fatal with cardiac and respiratory failure by age of 20

mutation of gene for muscle protein dystrophin part of anchoring complex that attaches thin filaments to sarcolemma

calcium channels remain open in absence of dystrophin

located on X chromosome mothers can be carriers and 50% chance to pass on to male offspring
motor neuron
nerve cell controlling skeletal muscle fiber
ACh
chemical released by motor neuron
Neuromuscular junction/ myoneural junction
where motor neuron and muscle fiber meet
synaptic vesicles
store ACh at end of synaptic knob/terminal
Synaptic cleft
small gap that separates knob from a folded area of sarcolemma called motor end plate
AChE
esterase- breaks down ACh to prevent over stimulation of muscle fiber
Muscle contraction
AP travels down neuron and raches synaptic knob and vesicles release ACh into synaptic cleft. ACh diffuses across cleft and binds to ACh receptors embedded in sarcolemma at motor end plate of muscle fiber. Binding causes sarcolemma to generate an action potential. Spread down T tubules causing calcium ions to be released from sarcoplasmic reticulum into sarcoplasm of muscle fiber. Calcium ions bind to troponin which moves tropomyosin and exposes active sites on G actins. Myosin heads attach at active sites and ratchet thin filaments inward. Thin filaments slide into H zone and sarcomere shorterns