musclar system [contractions] - unit 3 Flashcards
how many muscles in human body?
600+
muscles are made of
skeletal muscle cells/fivers. they are the biggest in the body.
4 CT coverings associated with muscles
endomysium, perimysium, epimysium, and deep facia
type of CT covering. areolar CT covering individual skeletal muscle cells which bind neighboring cells.
endomysium
type of CT covering. dense irregular CT that packages bundles of Skeletal muscle cells into “fascicles”
perimysium
type of CT covering. dense irregular CT that covers the entire skeletal muscle
epimysium
type of CT covering. dense irregular CT that packages/surround multiple cells.
deep facia
Dense irregular CT cord that connects skeletal muscle cells to bone
tendons
tendon term. bone that skeletal muscle is bounded to/anchored to.
origin
tendon term. bone that moves when the muscle contracts
insertion
type of CT covering. body movement that muscle provides when it contracts.
action
skeletal muscle cell structure. plasma membrane.
sarcolemma
skeletal muscle cell structure. stores Ca2+ and releases it into myofibrils upon electrical stimulation. its surrounds myofibrils.
sarcoplasmic reticulum
skeletal muscle cell structure. cytoplasm.
sacroplasm
skeletal muscle cell structure. pits/invaginations of sarcolemma that extend deep into the cell to SR. they conduct/transmit electricity from sarcolemma to SR.
Transverse Tubules (T-Tubles)
skeletal muscle cell structure. part of cytoskeleton. cylindrical structures that spam length of cell which contain contractile protein machinery of cell. give cell its striated appearance.
myofibrils
Myofibril structure: zig-zag shaped proteins that anchor thin filaments
z-discs
Myofibril structure: made of striated-like proteins called “actin” twisted together. myosin heads of myosin proteins bind and pull on them. (generates contraction force)
thin filaments
Myofibril structure: covers thin filaments and blocks myosin heads from binding. it binds to Ca2+ released from SR and folds over to expose thin filaments. (triggers contraction force)
troponin-Tropomyosin Complex
Myofibril structure: bundles of myosin that bind to ATP and break it down to recharge heads.
Thick Filaments
contraction step __. electricity transmitted from T-Tubles to SR stimulate Ca2+ release into neighboring myofibrils. Troponin-Tropomysoin bind Ca2+ and fold over to expose thin filaments to thick filaments. Myosin heads with ADP bind to it.
1
contraction step __. myosin heads release ADP, bends/twists neck to generate contraction force.
2
contraction step ___. myosin heads bind ATP to detach/release from thin filaments.
3
contraction step ___. myosin heads break down ATP into ADP+P and use energy released to recharge+recock heads.
4
(for contractions) if electricity ____ to stimulate cell/SR then Ca2+ release will continue converting into myofibrils. Troponin-Tropomyosin continues to bind Ca2+
continues
(for contractions) if electricity ___ then SR pumps Ca2+ into itself and diffuse it out of myofibril. Troponin-Tropomyosin releases Ca2+ and block thin filaments.