Muscles

Question 1

How do muscles act?

Answer 1

In opposite (antagonistic) pairs in an incompressible skeleton

Question 2

How can a limb move in both directions?

Answer 2

By using antagonistic pairs because muscles can only pull

Question 3

What is the contracting muscle called?

Answer 3

Agonist

Question 4

What is the relaxed muscle called?

Answer 4

Antagonist

Question 5

What do ligaments do?

Answer 5

Attach bones to bones

Question 6

What do tendons do?

Answer 6

Attach bones to muscles

Question 7

When do skeletal muscles contact?

Answer 7

Contract voluntarily

Question 8

What do skeletal muscles have lots of?

Answer 8

Mitochondria

Question 9

What are skeletal muscles made up of?

Answer 9

Long cylindrical cells called muscle fibres (multinucleated)

Question 10

What do muscle fibres contain?

Answer 10

Long organelles called myofibrils

Question 11

What do myofibrils contain?

Answer 11

Myofilaments

Question 12

What are 2 examples of myofilaments?

Answer 12

Actin and Myosin

Question 13

How is myosin represented?

Answer 13

• Dark- Thick

Question 14

How is actin represented?

Answer 14

• Light- Thin

Question 15

What is the H-zone?

Answer 15

Overlapped myosin

Question 16

What is the A-band?

Answer 16

• All myosin- Appears dark- Anchor

Question 17

What is the I-band?

Answer 17

• Actin only- Doesn’t include overlap with myosin- Light in colour

Question 18

What is the sarcomere?

Answer 18

Between z-lines

Question 19

What does the sliding filament theory say about relaxed muscles?

Answer 19

• Actin-myosin binding site is blocked by trypomyosin- This prevents an actin-myosin cross bridge being formed

Question 20

What does the sliding filament theory say about contracting muscles?

Answer 20

• Calcium ions cause trypomyosin to move out of the binding site allowing the actin-myosin cross bridge to form- Calcium ions activate ATPase (ATP -> ADP + Pi)- ATP is used to:Change the shape of the myosin head (power stroke) (continues as long as the binding site is openDetach the myosin headReturn the myosin head to rest (recovery stroke)Re-absorb calcium ions into the sarcoplasmic reticulum by active transport

Question 21

What happens to the sarcomere during contraction?

Answer 21

Becomes shorter

Question 22

What happens to the I-band during contraction?

Answer 22

Becomes shorter

Question 23

What happens to the H-zone during contraction?

Answer 23

Becomes shorter

Question 24

What happens to the A-band during contraction?

Answer 24

Remains the same

Question 25

What is the fastest way to make ATP?

Answer 25

Phosphocreatine

Question 26

How is phosphocreatine used to generate ATP?

Answer 26

PCr + ADP -> ATP + Cr

Question 27

Where does PCr come from?

Answer 27

In cells

Question 28

Why is phosphocreatine the fastest way to make ATP?

Answer 28

It is a short and simple reaction

Question 29

When are PCr / Cr used?

Answer 29

During high intensity short duration activity because PCr/Cr stores are used up quickly

Question 30

Is phosphocreatine aerobic or anaerobic?

Answer 30

Anaerobic

Question 31

Does phosphocreatine produce lactic acid?

Answer 31

No, it is alactic

Question 32

What are two slow ways of producing ATP?

Answer 32

- Anaerobic respiration- Aerobic respiration

Question 33

What does anaerobic respiration produce?

Answer 33

- 2ATP (glycolysis)- Lactate (causes muscle fatigue)

Question 34

What does aerobic respiration produce?

Answer 34

- Lots of ATP (mainly made by oxidative phosphorylation)- No harmful waste products

Question 35

At what speed do slow twitch muscle fibres contract?

Answer 35

Slowly

Question 36

At what speed do fast twitch muscle fibres contract?

Answer 36

Fast

Question 37

At what speed do slow twitch muscle fibres relax?

Answer 37

Slow

Question 38

At what speed do fast twitch muscle fibres relax?

Answer 38

Fast

Question 39

What is the force of contraction of slow twitch muscle fibres?

Answer 39

Low

Question 40

What is the force of contraction of fast twitch muscle fibres?

Answer 40

High

Question 41

How quickly do slow twitch muscle fibres fatigue?

Answer 41

Slowly (they are resistant)

Question 42

How quickly do fast twitch muscle fibres fatigue?

Answer 42

Very quickly

Question 43

How do slow twitch muscle fibres respire?

Answer 43

Anaerobically (little aerobic respiration)

Question 44

How do fast twitch muscle fibres respire?

Answer 44

Aerobically (little anaerobic respiration)

Question 45

What do slow twitch muscle fibres have lots of?

Answer 45

- Mitochondria- Blood vessels- Myoglobin

Question 46

What do fast twitch muscle fibres have few of?

Answer 46

- Mitochondria- Blood vessels- Myoglobin

Question 47

What intensity of activity are slow twitch muscle fibres best for?

Answer 47

Low intensity and long duration e.g. marathon

Question 48

What intensity of activity are fast twitch muscle fibres best for?

Answer 48

High intensity and short distance e.g. sprint/long jump