skeletal and muscular systems (quiz)

Question 1

Give an example of a movement in the sagittal plane

Answer 1

Tumble turn in swimming
Somersault in gymnastics

Question 2

Give an example of a movement in the frontal plane

Answer 2

Lateral raises
Cartwheel in gymnastics

Question 3

Give an example of a movement in the transverse plane

Answer 3

Pirouette in dance
Pivot in netball
Arm action to throw a discus

Question 4

Compare isotonic and isometric muscle contractions. (2)

Answer 4

isometric contraction there isno change in muscle length
isotonic contraction causes a change in length of muscle

Question 5

Describe the structure of a motor unit. (1)

Answer 5

Consists of a motor neuroneanda number of muscle fibres

Question 6

What is the ‘all or none’ law? (1)

Answer 6

When stimulated all the fibres within a motor unit contract completely or not at all

Question 7

What is the effect of stimulating more motor units? (1)

Answer 7

Increased force of contraction

Question 8

Explain how a motor unit is stimulated to cause muscular contraction. (4)

Answer 8

Nerve impulse from CNS traveldownthe motor neuron
Action potential
Release of sodium causes depolarisation
at neuromuscular junction neurotransmitterissecreted
impulse crosses synaptic clefttomuscle fibres
If the impulse is abovethreshold
all muscle fibres in motor unit will contract or not at all

Question 9

Explain, using sporting examples, how the predominance of each muscle fibre type in performers may impact on their performance. (3)

Answer 9

Slow twitch for endurance .
E.g. footballer can last 90 minutes without fatigue
Fast oxidative glycolytic for muscular endurance.
E.g. gymnast can complete a strenuous floor routine without tiring
Fast glycolytic twitch for power.
E.g. High jumper can produce explosive strength needed to jump over bar.
Mix of fibre types would benefit a games player, providing a combination of speed, muscular endurance and stamina

Question 10

Explain the recruitment of muscle fibre types during exercise of differing intensities. (4)

Answer 10

Slow oxidative fibres (T1) recruited for aerobic work. eg marathon / long distance becauseslow oxidative fibres have high fatigue resistance and high aerobic capacity becausethey have high density of mitochondria and a high myoglobin content
Fast oxidative glycolytic fibres (2a) recruited during high intensity exercise. eg team sports / 400m / 800m becausefast oxidative glycolytic have high force of contraction andmoderate fatigue resistance becauselarge neuron and moderate myoglobin store
Fast glycolytic fibres (2b) recruited during very high intensity. eg. shot put / 100m / sprint for ball becausefast glycolytic have fast speed and high force of contraction becauseFG fibres have high phosphocreatine store and large neurons
Slow oxidative fibres are recruited first then as intensity increases, fast oxidative glycolytic fibres and finally fast glycolytic fibres are subsequently recruited.