muscles

Question 1

what are the 3 types of muscle

Answer 1

• skeletal
• cardiac
• smooth

Question 2

what are muscles made up of

Answer 2

tiny muscle fibres called myofobrils

Question 3

how do myofibrils make up muscles

Answer 3

grouped into a single muscle fibre which are further grouped into bundles of muscle fibres which are grouped into muscle tissue

Question 4

what makes up a muscle fibre

Answer 4

• sarcolemma
• nucleus
• sarcomeres (make up a myofibril)
• mitochondria

Question 5

what’s the membrane called in a muscle fibre

Answer 5

sarcomere

Question 6

what’s the ER called in a muscle fibre

Answer 6

sarcoplasmic reticulum

Question 7

what filaments make up a scaromere

Answer 7

myosin & actin

Question 8

main neurotransmitter in muscles

Answer 8

acetylcholine

Question 9

what does acetylcholine do

Answer 9

• acts as an excitatory neurotransmitter at neuromuscular junctions connecting motor neurones with skeletal muscle

Question 10

what acts as the post synaptic membrane when talking about muscles

Answer 10

the sarcolemma (muscle fibre membrane)

Question 11

how is a muscle fibre contracted

Answer 11

same stages as chokinergic synapses - neurotransmitter and sodium ions lead to depolarisation of the sarcolemma

Question 12

what type of neurotransmitters do u find in the neuromuscular junction

Answer 12

only excitatory

Question 13

what neurones are involved

Answer 13

only motor neurones

Question 14

does the action potential carry on at the sarcolemma?

Answer 14

no

Question 15

what does acetylcholine do in neuromuscular junctions

Answer 15

binds to receptors on membrane of muscle fibres

Question 16

structure of myosin filament

Answer 16

• thick
• long rod shaped tails
• bulbous heads

Question 17

structure of actin filaments

Answer 17

• thin
• consists of 2 strands twisted around one another
• binding sites

Question 18

what does tropomyosin do

Answer 18

wrap around actin, covering up its binding sites

Question 19

what wraps around actin

Answer 19

tropomyosin

Question 20

what do calcium ions do

Answer 20

cause tropomyosin to change shape and pull away from the binding sites on actin

Question 21

how is a muscle contracted

Answer 21

• calcium moves tropomyosin
• myosin head attaches to actin binding sites
• myosin changes angle pulling actin filament along
• ADP is released & ATP fixes to myosin head, moving it away from actin binding site
• ATP hydrolysed back to ADP by ATPase provides energy to move myosin head back to its normal position

Question 22

the 3 ways ATP is supplied to a skeletal muscle

Answer 22

• aerobic respiration in mitochondria by slow twitch fibres
• anaerobic respiration by fast twitch fibres
• creatine phosphate - enzyme converts this to ADP v quickly

Question 23

what are fast twitch muscle fibres

Answer 23

fibres with many mitochondria, often found in muscles requiring endurance

Question 24

what are slow twitch muscle fibres

Answer 24

few mitochondria, rich in glycogen

Question 25

type of work performed for FT fibres

Answer 25

strength & fast movements (speed)

Question 26

type of work performed for ST fibres

Answer 26

endurance & stamina

Question 27

type of athletes for each type of muscle fibre

Answer 27

• FT = sprinters

* ST = marathon runners

Question 28

number of blood cells each type of muscle fibre has

Answer 28

• FT = few

* ST = many

Question 29

energy released in each muscle fibre

Answer 29

• FT = small amounts quickly

* ST = large amount slowly

Question 30

type of respiration each muscle fibre carries out

Answer 30

• FT = anaerobic

* ST = aerobic

Question 31

numbers of mitochondria in muscle fibres

Answer 31

• FT= few

* ST = lots