musculo-skeletal system

Question 1

knee joint

Answer 1

hinge joint:

flexion:
agonist:
- hamstrings = biceps femoris, semimembranosus, semitendinosus

antagonist:
- quadriceps = rectus femoris, vastus lateralis, vastus medialis, vastus intermedius

extension:
(opposite)

Question 2

hip joint

Answer 2

ball and socket:

• flexion
• extension
• abduction
• adduction
• medial rotation
• lateral rotation

Question 3

shoulder joint

Answer 3

• flexion
• extension
• abduction
• horizontal flexion
• horizontal extension
• medial rotation
• lateral rotation

Question 4

motor neurons

Answer 4

specialised cells which transmit nerve impulses to muscle fibres causing them to contract + create movvement

Question 5

motor unit

Answer 5

motor neuron + associated muscle fibre

Question 6

action potential

Answer 6

1. nerve impulse initiated in the motor neuron cell body
2. nerve impulse conducted down the axon of the motor neuron by a nerve action potential to the synaptic cleft
3. neurotransmitter called Ach is secreted into the synaptic cleft to conduct the nerve impulse across the gap
4. if electrical charge is above threshold, the muscle fibre will contract
5. this happens in an ‘all or none’ fashion

Question 7

3 types of muscle fibres

Answer 7

• Type 1 ( slow oxidative)
• Type 2a ( fast oxidative glycolytic)
• Type 2b ( fast glycolytic)

Question 8

Type 1 muscle fibres

Answer 8

slow oxidative:

• high oxidative capacity
• high resistance to fatigue
• low force production
• slow contraction time
• high capillary density
• low glycolytic capacity
• e.g. marathon running, triathlon etc..

SMALLEST MOTOR UNITS NEEDED

Question 9

Type 2a muscle fibres

Answer 9

fast oxidative glycolytic:

• high oxidative capacity
• fast contraction time
• suited for lengthy anaerobic exercise e.g. basketball, football, rugby etc..
• medium resistance to fatigue
• high force production
• high glycolytic capacity
• medium capillary density

MEDIUM MOTOR UNITS NEEDED

Question 10

Type 2b muscle fibres

Answer 10

fast glycolytic:

• low oxidative capacity
• fastest contraction time
• suited for short anaerobic exercise e.g. 100m sprint, shotput etc..
• low resistance to fatigue
• highest force production
• high glycolytic capacity
• low capillary density

BIGGEST MOTOR UNITS NEEDED