IB Biology Sub-topic B3.3 Definitions

This page contains our IB Biology definitions for sub-topic B3.3. By learning each one of these definitions, you will fully cover the content for IB Biology 'Muscle & motility'.
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anchorage

A stationary point during contraction

antagonistic muscles

A pair of muscles that exert forces in opposite directions to one another

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articular joint

A connection between bones

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insertion

A point that moves during contraction

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ligament

A connective tissue that attaches bone to bone to keep them together and in place, only allowing movement in certain directions

muscle contraction

The sliding of actin and myosin filaments over each other to pull the ends of each sarcomere together and shorten the entire muscle fiber

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muscle fiber

A large multinucleated cell that composes skeletal muscle

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Myofibrils

Long contractile fibers within a muscle cell

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Sarcolemma

The plasma membrane of a muscle fiber

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sarcomere

The smallest contractile unit of a myofibril

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Sarcoplasmic Reticulum

A network of tubules in muscle fibers that stores calcium ions and coordinates muscle contraction

skeletal muscle

Muscle attached to bone

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synovial joint

A moving connection between bones, but it only allows movement in certain directions

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tendon

A connective tissue that attaches muscle to bone

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