MUSCULOSKELETAL SYSTEM PHYSIOLOGY
QUESTION 1
Which of the following ions stimulates neurotransmitter secretion in the neuromuscular
junction?
a. Sodium
b. Potassium
c. Calcium
d. Magnesium
ANSWER:
C
QUESTION 2
Which of the following is correct sequence for events happening at neuromuscular junction?
A. Action potential in the motor neuron; depolarization of the muscle end plate; uptake of
Ca2+ into the presynaptic nerve terminal
B. Influx of Ca2+ into the presynaptic terminal; release of acetylcholine (ACh); depolarization
of the muscle end plate
C. Release of ACh; action potential in the motor neuron; action potential in the muscle
D. Influx of Ca2+ into the motor end plate; action potential in the motor end plate; action
potential in the muscle
ANSWER:
b
QUESTION 3
An action potential in the motor end plate rapidly spreads to the central portions of the
muscle cells by which of the following means?
a) Z-lines
b) sarcoplasmic reticulum
c) pore in the plasma membrane
d) transverse tubules
answer: D
QUESTION 4
Which of the following is the functions of tropomyosin in skeletal muscle?
A. Sliding on actin to produce shortening
B. Releasing Ca2 + after initiation of contraction
C. Binding to myosin during contraction
D. Acting by covering up the sites where myosin binds to actin
ANSWER: D