Muscles Skeletal Contraction

Question 1

When the sarcomere is at rest, what blocks the active sites on the actin filament?
A. troponin
B. myosin
C. tropomyosin
D. calcium ions
E. adenosine triphosphate (ATP)

Answer 1

C

Question 2

Which of the following most accurately describes the ‘sliding filament’ mechanism?
A. Thick filaments pull thin filaments to create sliding
B. Thin filaments pull thick filaments to create sliding
C. Both the thick and thin filaments pull to create sliding
D. Thick filaments pull thick filaments to create sliding
E. Thin filaments pull thin filaments to create sliding

Answer 2

A

Question 3

What substance is released across the synaptic cleft at the neuromuscular junction?
A. calcium
B. chloride
C. acetylcholine
D. adrenalin
E. noradrenalin

Answer 3

C

Question 4

Which ion is responsible for initiating skeletal muscle contraction?
A. Sodium
B. Calcium
C. Potassium
D. Chloride
E. Magnesium

Answer 4

B

Question 5

What causes the tropomyosin to re cover the binding sites on actin filament?
A. Release of acetylcholine by somatic motor neurons
B. Action potential traveling down the T-tubules
C. Increase in availability of calcium in the muscle cell
D. Decrease in availability of calcium in the muscle cell
E. Opening of the RyR channels on the sarcoplasmic reticulum

Answer 5

D