muscle contractions 2 Flashcards
What is a network of internal membranes that runs through the sarcoplasm called
The sarcoplasmic reticulum
What does the sarcoplasmic reticulum do
The sarco plasmic reticulum stores and rele ases calcium ions that are needed for muscle contraction
What do muscle fibres contain alot of
M uscle fibres have lots of mit ocho ndria to provide
the ATP that’s needed for muscle contraction.
What is multinucleate
M uscle fibres are multinuclea te (contain many nucle i).
What are myofibrils
M uscle fibres have lots of long, cylin drical organelles c alle d myofibrils. They’re made up of proteins and are highly sp ecialised for co ntraction.
What do myofibrils contain
Myofibrils Contain Thick Myosin Filaments and Thin Actin myofilaments hat move past each other to make muscles co ntract
What are thick myofuilaments are made of
Thick myofilaments are made of the protein myosin.
What are thin filaments made of
Thin myofilaments are made of the protein actin
If you look at a myofibril under an electron microscope what will you see
If you look at a myofibril under an electron microsco pe, yo u’ll see a pattern of alternating dark and light bands:
When looking at myofibril under an electron microscope what are the dark bands mad eof
Dark bands contain the thick myosin filaments and some overlapping thin actin filaments — these are calle d A-band
f you look at myofibril under a microscope what are the light bands made of
Light bands contain thin actin filaments o nly — these are calle d I-bands
What is a myofibril made up of
A myofibril is made up of many short units calle d sarcomeres., A myofibril is made up of many short units calle d sarcomeres.
What is the sliding filament theory
The theory explaining muscle contraction,
Myosin and actin filaments slide over one another to make the sarcomeres contract — the myofilaments themselves don’t contract. the myofilaments themselves don’t contract. The simultaneous contractio n of lots of sarcomeres means the myofibrils and muscle fibres contract. Sarcomeres return to their original length as the muscle relaxes.
What do myosin filaments contain
Myosin filaments have glo bular heads that are hinged, so they can move backand forth. 2) Each myosin head has a binding site for actin and a binding sit e for ATP.
What do actin filaments contain
Actin filaments have binding sites for myosin heads, calle d actin-myosin binding sites
