Topic 11.2 Flashcards

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1
Q

Exoskeletons

A
  • External skeletons that surround and protect most of the body surface of animals
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2
Q

How do bones and exoskeletons facilitate movement

A
  • Provide an anchorage for muscles
  • Act as levers
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3
Q

Give one example of an antagonistic pairs and explain

A
  • Biceps and triceps
  • When biceps contracts, tricepts relaxes
  • the arm bends
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4
Q

Name another animal that uses antagonistic pairs of muscles

A
  • Grasshoppers use antagonistic pairs of muscles to produce a powerful jump
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5
Q

Annotate the following diagram of the human elbow

A

Refer to picture

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6
Q

Cartilage

A
  • Tough, smooth tissue that covers the regions of bone in the joint
  • Prevents contract between regions of bone that might otherwise rub together
  • Prevents friction
  • Absorbs shocks that might cause bones to fracture
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7
Q

Synovial fluid

A
  • Fills the cavity in the joint between the cartilages on the ends of the bones
  • Lubricates the joint
  • Prevent the friction
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8
Q

Joint capsule

A
  • Tough ligamentous covering to the joint
  • Seals the joint and holds in the synovial fluid
  • Prevent dislocation
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9
Q

Tendon

A

Connects muscle to bones

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10
Q

Ligaments

A

Connects bone to bone

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11
Q

Hinge joint

A
  • ie. knee joint
  • only allows two movements (flexion/bending and extension/straightening)
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12
Q

Ball and socket joint

A
  • ie. the hip joint
  • has greater range of movement
  • can flex, extend, rotate and move sideways/back
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13
Q

Label abduction and adduction in the following diagram

A

Refer to picture

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14
Q

Label the following diagram of a muscle fibre

A

Refer to picture

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15
Q

Skeletal muscle

A
  • multinucleate
  • contain specialized endoplasmic reticulum
  • called skeletal muscle because are attached to bones
  • called striated muscle because when their structure is viewed using a microscope, stripes are visible
  • composed of bundles of muscle cells known as muscle fibres
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16
Q

Muscle fibre

A
  • makes up skeletal muscle
  • although a single plasma membrane called the sarcolemma surrounds each muscle fibre, there are many nuclei present and muscle fibres are much longer than typical cells
  • a modified version of the endoplasmic reticulum, called the sarcoplasmic reticulum, extends throughout the muscle fibre
  • contains many myofibrils
  • between myofibrils are large numbers of mitochondia which provide ATP for contraction
17
Q

Sarcoplasmic reticulum

A
  • extends throughout the muscle fibre
  • wraps around every myofibril, conveying the signal to contract to all parts of the muscle fibre at once
  • stores calcium
18
Q

Myofibrils

A
  • within each muscle fibre, there are many parallel, elongated structures called myofibrils
  • have alternating light and dark bands, which give stiated muscle its stripes
  • in the centre of each light band is a disc-shaped structure referred to as the Z-line
  • made up of contractile sarcomeres
19
Q

Sarcomere

A
  • many sarcomeres makes up a myofibril
  • consists of a regular arrangement of two types of protein filaments: thin actin filaments and thick myosin filaments
20
Q

Draw a labelled draigram of the structure of a sarcomere

A

Refer to picture

21
Q

Draw the structure of a sarcomere in relaxed muscle and the structure after the muslce contracts

A

Refer to picture

22
Q

Identify the contracted and the relaxed sarcomere

A

Refer to picture

23
Q

Explain how skeletal muscle contracts

A
  • muscles/fibres/myofibrils contain (repeating) units called sarcomeres;
  • muscle/sarcomeres contain actin filaments and myosin filaments;
  • actin fibres are thin AND myosin fibres are thick;
  • arriving action potential causes release of calcium ions;
  • from sarcoplasmic/endoplasmic reticulum;
  • calcium ion binds to troponin;
  • causing troponin and tropomyosin to move (on actin);
  • ATP binds to myosin heads releasing them/breaking cross bridges;
  • ATP hydrolysed/split into ADP + Pi;
  • ATP/energy causes myosin heads to change shape/swivel/become cocked;
  • myosin heads bind/form cross-bridges to (exposed) actin binding sites;
  • myosin heads swivel/move actin (releasing ADP + Pi);
  • myosin filaments move actin filaments towards centre of sarcomere;
  • sliding of filaments/actin and myosin shortens the sarcomere