SEHS 4.1 Neuromuscular Junction Quiz

The diagram shows a motor unit. Which is X?

• Dendrite

• Motor end plate

• Axon

• Cell body

Which correctly identifies functions of slow twitch (type I) muscle fibres?

• Small force - Maintain contractions for a long time

• Moderate force - Fatigue quickly

• Large force - Maintain contractions for a long time

• Small force - Fatigue quickly

The diagram shows a motor unit. What structure is labelled X?

• Nucleus

• Cell body

• Axon

• Motor end plate

What are the predominant muscle fibre characteristics of an elite 100 m sprinter’s gastrocnemius?

• High Capillary supply, High Contraction force, Low Glycogen content

• High Capillary supply, Low Contraction force, High Glycogen content

• Low Capillary supply, High Contraction force, High Glycogen content

• Low Capillary supply, Low Contraction force, High Glycogen content

Which correctly identifies functions of slow twitch (type 1) muscle fibres?

• small force generation, maintain contractions for a long time

• moderate force generation, fatigue quickly

• large force generation, maintain contractions for a long time

• small force generation, fatigue quickly

Which occurs during concentric muscle contraction?

• Z lines move apart

• H zone increases in size

• A band remains constant

• Sarcomere lengthens

The diagram shows a neuromuscular junction. What does X represent?

• Calcium ions

• Sodium ions

• Cholinesterase

• Acetylcholine

The predominant muscle fibre type in the gastrocnemius muscle of an elite 200m sprinter is:

• Type I

• Type IIa

• Type IIb

• Type IIx

What is the function of calcium ions during muscle contraction?

• Calcium ions move across the synapse to initiate a nerve impulse on the muscle cell.

• Calcium ions bind to troponin, causing tropomyosin to move, allowing actin and myosin to bind.

• Calcium ions bind to the myosin head following contraction, allowing detachment of myosin from actin.

• Calcium ions cause ATP molecules stored in the sarcoplasmic reticulum to be released, initiating contraction.

The diagram shows a motor unit. Acetylcholine acts in which area?

• A

• B

• C

• D