11.2 Movement Flashcards Preview

Biology 6. Human Physiology > 11.2 Movement > Flashcards

Flashcards in 11.2 Movement Deck (42)
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1
Q

Explain the role of calcium ions in muscle contraction

A
  • Ca2+ ions are released when a nerve impulse arrives at the muscle
  • Ca2+ ions are released from a sarcoplasmic reticulum
  • binding sites for myosin heads are exposed
  • this allows cross bridges between myosin and actin to form
2
Q

What are antagonistic muscles?

A

Movement of the body requires muscles to work in antagonistic = opposite pairs. This means one muscle relax (extend) while the other flex/contract (shorten). Eg. Triceps extends when biceps flex.

3
Q

Explain the role of ATP in the contraction of skeletal muscles

A
  • ATP binds to the myosin head
  • ATP binding causes cross-bridges to break/heads detach from binding site
  • ATP broken down/hydrolysed to ADP + P (Phosphate) causing myosin heads attach to binding sites on actin filaments further along sarcomere
  • head with ADP + P attaches to binding site on the actin that are further from the centre of the sarcomere than the previous site
  • The ADP and phosphate are released and the heads push the actin in wards towards centre of the sarcomere (power stroke)
4
Q

Outline how skeletal muscle contracts (5 marks)

A
  • tropomyosin blocks the binding sites on actin
  • calcium ions are released from the sarcoplasmic reticulum (motor neuron signal);
  • Calcium ions bind to troponin
  • they expose the myosin binding sites (on actin) / cause movement of blocking molecules/troponin;
  • ATP hydrolysis into ADP +P;
  • cross-bridges form between actin and myosin molecules using ADP +P;
  • phosphate released;
  • myosin myofilament is used to move the head and pull actin towards centre of sarcomere;
  • ADP is released from the myosin head as it moves.
  • ATP provides energy to release myosin from binding site;
  • action can be repeated further along the molecule;
5
Q

Explain how nerve impulses are transmitted along and between neurons (9 marks)

A
  • the resting potential of cell is negative inside compared with outside; - stimulation causes depolarization/reversal of charge on each side; - due to Na+ channels opening / Na+ flowing into the cell; - which causes an action potential; - K+ channels open / K+ flows out of the cell; - sodium potassium pump restores resting potential; - transmitted between neurons across a synapse; - neurotransmitter released into synaptic cleft; - diffuse across cleft to postsynaptic membrane; - where they bind to receptors; - influx of Na+ into cell; - which may initiate action potential;
6
Q

How do bones and exoskeletons facilitate movement?

A

Provide an anchorage for muscles and by acting as levers

7
Q

What determines the class of lever?

A

Effort force, a pivot point called fulcrum, and resultant force

8
Q

How many pairs of appendages does a grasshopper have?

A

Three like all insects

9
Q

Annotate the parts of an insects leg

A

Tibia, Tarsus, and Fermur with massive muscles

10
Q

What is point called where the bones meet?

A

joint

11
Q

what is articulation?

A

joints allowing bones to move in relation to one another

12
Q

What do most articulated joints have?

A

Cartilage, synovial fluid and joint capsule

13
Q

What do to biceps do?

A

Flex the joint

14
Q

What do triceps do?

A

Extend the joint

15
Q

What does synovial fluid do?

A

Fills a cavaty in the joint between cartilages, lubricates the joint and prevents

16
Q

What does the joint-capsule do?

A

Tough ligamentous, that seals the joint and hold in the synovial fluid and prevents dislocation

17
Q

What does cartilage do?

A

smooth tissue that covers regions of bone in the joint to prevent friction and absorbs shock (that may cause bone fracture)

18
Q

To what is the radius bone attached to?

A

Biceps

19
Q

To what is the ulna bone attached to?

A

Triceps

20
Q

What are different kinds of synovial joint structures? (Give example for each)

A

Hinge joint = Knee (only allows two movement) Pivot Joint= Neck/knee when flexed Ball and socket joint = Shoulder/Hip

21
Q

What is the movement of joints away from the body called?

A

abduction

22
Q

What is movement of joint TOWARD the body called?

A

adduction

23
Q

What are skeletal muscles?

A

muscles used to move the body attached to bones, also known as striated muscle

24
Q

What are striated muscles composed off?

A

Muscle fibres (strings inside a muscle) with many nuclei

25
Q

What is plasma membrane called that surrounds a muscle fibre?

A

Sarcolemma

26
Q

Why are muscle fibres much longer than normal cells?

A

embryonic muscle cells fuse together

27
Q

What is the muscle fibre version of an endoplasmic reticulum?

A

Sarcoplasmic reticulum. It extends through the fibre and wrapes around all myofibrils and carry signals

28
Q

What does the sarcoplasmic reticulum store?

A

Calcium

29
Q

Where does the ATP come from in muscle fibres for muscle contractions?

A

Mitochondria between myofibrils

30
Q

What are muscle fibres composed of?

A

Many myofibrils

31
Q

What is each myofibril made of?

A

contractable sarcomeres

32
Q

Draw labelled diagram of structure of sarcomere

A
  • two z-lines
  • myosin filaments should with heads
  • actin filament should be connected to z-lines
  • light and dark band labelled
33
Q

How is the contraction of skeletal muscles achieved?

A

Contraction occurs by sliding of actin and myosin filaments. Myosin filaments pull the actin filaments inwards, towards centre of sarcomere. This shortens each sarcomere and overall length of muscle fibre

34
Q

What causes the sliding for muscle contraction?

A

Myosin filaments have heads that can bind to special sites on actin filaments, creating cross bridges. They can exert force on actin using ATP and pull them towards centre of sarcomere

35
Q

What is tropomyosin?

A

a protein that blocks the binding site of actin in a relaxed muscle.

36
Q

What happens when a signal is released to a muscle fibre?

A

the sarcoplasmic reticulum releases calcium ion

37
Q

What happens when calcium ions are released during muscle contraction?

A

Calcium ions bind to troponin. This moves tropomyosin out of the way and exposes actin binding sites to myosin.

38
Q

What is required for myosins to be ready to bind?

A

must have converted ATP into ADP and phosphate attached to the myosin head

39
Q

What have some of the classic experiments of muscle research depended on?

A

flourescence because it can be detected in light microscope and captured on film bcause of electromagnetic radiation

40
Q

How were researchers able to demonstrate the ATP dependence of myosin-actin interaction?

A

By attaching flourescent dye to myosin molecules

41
Q

Annotate a diagram of a human elbow

A
  • ulna
  • radius bone
  • humerus bone
  • triceps
  • biceps
  • cartilage
  • synovial fluid
  • joint-capsule
42
Q

Which band shortens during muscle contraction?

A

the LIGHT band