Straighterline A&P 1 Cumulative Final: StraighterLine A&P 1:
Questions & Answers
Which of the following statements concerning the structure of muscle tissue is correct?
a) Skeletal muscle has the same structure as cardiac muscle
b) Smooth muscle cells have no striations as they lack myosin filaments
c) Smooth muscle has a system of T-tubules.
d) The myofibrils of skeletal muscle are surrounded by the sarcoplasmic reticulum. - ANSWER:d
Which of the following statements concerning the role of Ca2+ in the contraction of skeletal muscle is
correct?
a) The mitochondria act as a store of Ca2+ for the contractile process
b) Ca2+ entry across the plasma membrane is important in sustaining the contraction of skeletal muscle
c) A rise in intracellular Ca2+allows actin to interact with myosin
d) The tension of a skeletal muscle fibre is partly regulated by G proteins. - ANSWER:c
Which of the following statements concerning cardiac muscle is correct?
a) The force of contraction is increased by circulating adrenaline
b) Heart muscle contracts in response to action potentials in the autonomic nerve fibres
,c) The action potential has the same duration as that of skeletal muscle
d) All of the Ca2+required for contraction enters a myocyte during the plateau phase of the action
potential - ANSWER:a
Skeletal muscle has a system of T-tubules while smooth muscle does not. True or false?
a) True
b) False - ANSWER:a
All muscle cells contain actin and myosin. True or false?
a) True
b) False - ANSWER:a
The functional unit of contractile system in striated muscle is
a) myofibril
b) cross bridges
c) Z band
d) sarcomere - ANSWER:d
The contractile protein of skeletal muscle involving ATPase activity is
a) actin
b) myosin
,c) troponin
d) tropomyosin - ANSWER:b
Which of the following is a component of actin filaments of a sarcomere?
a) myosin and troponin
b) troponin and actin
c) actin and myosin
d) troponin, tropomyosin and actin - ANSWER:d
Muscle fatigue sets in due to non availability of
a) calcium
b) ATP
c) actin binding site
d) Mg cofactor - ANSWER:b
Muscles get fatigue due to accumulation of
a) lactic acid
b) ATP
c) phosphate molecules
, d) carbon dioxide - ANSWER:a
Which one of the following sets of ions are necessary in the chemical events for muscle contraction?
a) Na+ and K+
b) Ca+ and Mg++ ions
c) Na+ and Ca++ ions
d) Na+ and Mg++ ions - ANSWER:b
Light band has which of the following filament protein?
a) myosin
b) actin
c) myosin and actin
d) none of these - ANSWER:b
Upon stimulation of skeletal muscles calcium is immediately made available for binding to troponin from
a) blood
b) sarcoplasmic reticulum
c) lymph
d) bone - ANSWER:b
Which of the following statements about the structure of skeletal muscle is correct?