Muscle Contraction

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  • Created by: Molly
  • Created on: 23-03-14 16:41
What are the three types of muscles?
Cardiac muscles - in the heart. Smooth muscle - walls of blood vessels and gut. Skeletal muscle - attached to bone and is voluntary.
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What are myofibrils?
Fibres of muscle.
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What are the 2 types of protein fillaments in myofibrils?
Actin and myosin.
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What is the structure of actin?
Thinner and consists of two strands twisted around each other.
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What is the structure of myosin?
Which is thicker and consists of long, rod shaped fibres with bulbed heads that project to the side.
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Why do myofibrils appear striped?
Because they have alternating light and dark coloured bands.
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What are the light bands?
Isotropic bands, they are lighter because the myosin and actin do not over lap here.
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What are the dark bands?
Anistotropic bands, dark coloured because the actin and myosin do overlap in this region.
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What is the centre of the A band?
The H-zone.
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What is the Z line?
At the centre of each isotropic band.
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What is the sarcomere?
The distance between adjacent z lines.
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What happens to the sarcomere when a muscle contracts?
The sarcomere shortens.
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What are the two proteins found in muscle?
Tropomyosin - forms fibrous strands around the actin filament. Troponin - a globular protein.
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What are the two types of muscle fibre?
Slow twitch fibres and fast twitch fibres.
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What do slow twitch fibres do?
Contrast slowly and provide less powerful contractions over a long period of time. They are important in endurance work e.g. long distance running.
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What do fast twitch fibres do?
contract rapidly and produce powerful contractions but only for a short period of time.
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Other cards in this set

Card 2

Front

What are myofibrils?

Back

Fibres of muscle.

Card 3

Front

What are the 2 types of protein fillaments in myofibrils?

Back

Preview of the front of card 3

Card 4

Front

What is the structure of actin?

Back

Preview of the front of card 4

Card 5

Front

What is the structure of myosin?

Back

Preview of the front of card 5
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