the muscular system

Question 1

functions

Answer 1

• movement
• posture
• body function

Question 2

movement

Answer 2

• kicking, throwing, walking
• muscles contract and relax around joints and bones which allows movement to occur

Question 3

posture

Answer 3

• abdominal and back muscles hold the body upright

Question 4

body functions

Answer 4

• the digestive system is surrounded by smooth muscles and utilizes muscle contractions
• the diaphragm assists in breathing
• cardiac muscles pump the heart
• skeletal muscles moves the body

Question 5

types of muscle

Answer 5

• skeletal (voluntary control)
• smooth (involuntary control)
• cardiac (involuntary control)

Question 6

types of muscle contraction

Answer 6

tension develops in a muscle
- isotonic
- isometric
- isokinetic

Question 7

isotonic contraction

Answer 7

• controlled lengthening and shortening of the muscle
• concentric
• eccentric
• motion occurs

Question 8

concentric

Answer 8

• tension develops while muscle shortens
• causes joint movement

Question 9

eccentric

Answer 9

• tension develops while muscle lengthens
• controls joint movement

Question 10

isometric contraction

Answer 10

• tension develops in muscle but there is no change in muscle length
• static contraction
• no movement occurs at the joint
• stops joint movement
• holding a plank, pushing a wall

Question 11

reciprocal inhibition

Answer 11

• the relationship of muscles working in pairs
• when two muscles work together to create a movement
• one contracts (shortens) whilst the other relaxes (lengthens)
• agonist
• antagonist

Question 12

agonist

Answer 12

• is the muscle that is pulling
• prime mover
• directly responsible for the movement at a joint

Question 13

antagonist

Answer 13

• is the muscle that is relaxing
• muscle that is relaxing
• has the opposite action to the agonist

Question 14

points of attachment for muscles

Answer 14

• origin
• insertion

Question 15

origin

Answer 15

the site where a muscle is attached to a stable bone which the muscles pull again

Question 16

insertion

Answer 16

where the muscle attaches to a bone that is moved by the action of the muscle

Question 17

stabilisers

Answer 17

the muscles which provide support across joints

Question 18

muscle arrangement

Answer 18

• muscle
• muscle fibre
• myofibril
• sarcomere
• actin - myosin

Question 19

features of muscles

Answer 19

• nervous control: nerves control muscle action
• contractility: muscles contract and become thicker
• extensibility: muscles have the capacity to stretch when force is applied
• elasticity: muscles can return to their original size and shape once stretched
• atrophy: muscles can decrease in size as a result of injury, illness or lack of exercise
• hypertrophy: muscles can increase in size with an increase in activity

Question 20

myofibril

Answer 20

• the part of the muscle containing filaments
• it runs the length of the muscle fibre and contains actin and myosin filaments

Question 21

sarcomere

Answer 21

• the functional unit of the myofibril
• divided into I, A and H bands
• when the muscle contracts, the h-zone and the i band both decrease as the z lines are pulled together

Question 22

z line

Answer 22

separates each sarcomere

Question 23

h zone

Answer 23

the centre of the sarcomere

Question 24

i bands

Answer 24

where the actin filaments align

Question 25

a band

Answer 25

where the myosin filaments align

Question 26

actin

Answer 26

a thin contractile filament containing 'active' or 'binding' sites.

Question 27

myosin

Answer 27

a thick contractile protein filament with protrusions known as myosin heads

Question 28

what causes actin filaments to move?

Answer 28

- the actin filament slides over the myosin - the myosin filaments contain tiny globular heads, called cross bridges which attach to the actin filaments and pull on them to create movement

Question 29

atp

Answer 29

- Adenosine TriPhosphate - energy for the body - ATP > ADP releases energy

Question 30

slow twitch muscle fibres

Answer 30

- type 1 - red in colour - used for aerobic, endurance activities - small fibre size

Question 31

fast twitch oxidative

Answer 31

- type 2a - pinkish colour - anaerobic (long term) - medium fibre size

Question 32

fast twitch glycolytic

Answer 32

- type 2b - white colour - anaerobic (short term) - large fibre size.

Question 33

(activation) all or nothing principle

Answer 33

states that when the electrical impulse reaches a certain threshold all of the fibres of that motor unit will contract at the same time and as forcefully as possible

Question 34

(recruitment) size principle

Answer 34

motor units are recruited in order from smallest to largest depending on the intensity of the force being applied