Muscles

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What are the thick and thin filaments called? What appearance do they give?
Thick- myosin, Thin- actin. They give a striated appearance
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How are muscle fibres arranged?
They are composed of many myofibrils which contain sarcomeres. The sarcomeres contain actin and myosin
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How is actin and the proteins around it arranged?
Tropomyosin winds around actin. Troponin blocks actin's binding sites to prevent myosin attaching to them.
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Where are calcium ions stored and how are they released?
Stored in the sarcoplasmic reticulum. Neurotransmitter released from neurone which bind to receptors on the sarcolemma, so Na+ channels open. This depolarises the membrane, which travels down the t-tubules. Ca2+ released from sarcoplasmic reticulum
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What happens when calcium is released into the muscle fibre?
Calcium binds to troponin, changing it's shape, allowing tropomyosin to move and expose the binding sites on actin. Myosin heads bind to the active sites and the do the 'power stroke action'
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What role does ATP play in muscle contraction?
ATP is broken down into ADP and Pi when myosin performs the power stroke. Cross bridge is broken as new ATP binds to myosin. Also used in active transport of Ca2+ back into sarcoplasmic reticulum
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What happens to the relative length of the: Sarcomere, A band, I Band and H Band during muscle contraction?
Sarcomere: shorter. A band- same, I band- shorter, H band- shorter
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What is the A band?
the length of myosin filament
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What is the H band?
The length of myosin that is not overlapped by actin
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What is the I band?
The length of actin not overlapped by myosin
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What is a length of a sarcomere and how is is measured?
2.5 micrometers long. measured from Z line to Z line
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What are the respiratory substrates for skeletal muscle cells, smooth muscle cells and cardiac muscle cells?
Skeletal and smooth muscle- both glucose. Cardiac muscle respires fatty acids
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What nervous system is responsible for each muscle type?
Skeletal muscle- somatic nervous system. Cardiac and smooth muscle is controlled by the autonomic nervous system
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Card 2

Front

How are muscle fibres arranged?

Back

They are composed of many myofibrils which contain sarcomeres. The sarcomeres contain actin and myosin

Card 3

Front

How is actin and the proteins around it arranged?

Back

Preview of the front of card 3

Card 4

Front

Where are calcium ions stored and how are they released?

Back

Preview of the front of card 4

Card 5

Front

What happens when calcium is released into the muscle fibre?

Back

Preview of the front of card 5
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