contraction Flashcards
when is muscle contraction initiated
when an action potential arrives at a neuromuscular junction from a motor neurone
where does the depolarisation spread
along t tubules and into the sarcoplasm
what does depolarisation of the t tubules stimulate
the sarcoplasmic reticulum
what does the SR release
Ca2+ ions into sarcoplasm
what do ca2+ ions bind to
a protein attached to tropomyosin
what does the binding of Ca2+ ions cause
the protein to change shape
what does the altering of the protein cause
tropomyosin to be moved so the actin myosin binding site is no longer blocked by tropomyosin
what is the bond called between the actin and myosin
actin-myosin cross bridge
what does the myosin head do once the binding site is no longer blocked
binds to the actin filament
what do Ca2+ ions activate
ATP hydrolase
what is ATP hydrolase
enzyme that hydrolyses ATP to ADP and inorganic phosphate
what does the process of ATP hydrolase cause
the release of energy that can power muscle contraction
what does the energy released from ATP cause
the myosin head to bend
what does the movement of the myosin head cause
the actin filament to slide past the myosin filament
what happens after the actin filament has slid past the myosin filament
the actin-myosin bridge is broken
