BSC 2085: Muscular System
Muscle fatigue is caused by ________.
a) buildup of ATP and lactic acid levels
b) exhaustion of energy reserves and buildup of lactic acid levels
c) buildup of ATP and pyruvic acid levels
d) exhaustion of energy reserves and buildup of pyruvic acid levels - ✔️✔️b)
exhaustion of energy reserves and buildup of lactic acid levels
The correct order for the smallest to the largest unit of organization in muscle tissue is
________.
a) fascicle, filament, muscle fiber, myofibril
b) filament, myofibril, muscle fiber, fascicle
c) muscle fiber, fscicle, filament, myofibril
d) myofibril, muscle fiber, filament, fascicle - ✔️✔️b) filament, myofibril, muscle fiber,
fascicle
Muscle that has a striped appearance is described as being ________.
a) elastic
b) nonstriated
c) excitable
d) striated - ✔️✔️d) striated
Which element is important in directly triggering contractions?
a) sodium (Na+)
b) calcium (Ca++)
c) potassium (K+)
d) chloride (Cl-) - ✔️✔️b) calcium (Ca++)
Which of the following properties is not common to all three muscle tissues?
a) excitability
b) the need for ATP
c) at rest, uses shielding proteins to cover actin-binding sites
d) elasticity - ✔️✔️c) at rest, uses shielding proteins to cover actin-binding sites
Depolarization of the sarcolemma means ________.
a) the inside of the membrane has become less
negative as sodium ions accumulate
b) the outside of the membrane has become less
negative as sodium ions accumulate
c) the inside of the membrane has become more
negative as sodium ions accumulate
, d) the sarcolemma has completely lost any electrical
charge - ✔️✔️a) the inside of the membrane has become less negative as sodium ions
accumulate
In relaxed muscle, the myosin-binding site on actin is
blocked by ________.
a) titin
b) troponin
c) myoglobin
d) tropomyosin - ✔️✔️d) tropomyosin
According to the sliding filament model, binding sites on actin open when ________.
a) creatine phosphate levels rise
b) ATP levels rise
c) acetylcholine levels rise
d) calcium ion levels rise - ✔️✔️d) calcium ion levels rise
The cell membrane of a muscle fiber is called ________.
a) myofibril
b) sarcolemma
c) sarcoplasm
d) myofilament - ✔️✔️b) sarcolemma
During muscle contraction, the cross-bridge detaches
when ________.
a) the myosin head binds to an ADP molecule
b) the myosin head binds to an ATP molecule
c) calcium ions bind to troponin
d) calcium ions bind to actin - ✔️✔️b) the myosin head binds to an ATP molecule
Thin and thick filaments are organized into functional units called ________.
a) myofibrils
b) myofilaments
c) T-tubules
d) sarcomeres - ✔️✔️b) myofibrils
A sprinter would experience muscle fatigue sooner than a marathon runner due to
________.
a) anaerobic metabolism in the muscles of the
sprinter
b) anaerobic metabolism in the muscles of the
marathon runner
c) aerobic metabolism in the muscles of the sprinter
Muscle fatigue is caused by ________.
a) buildup of ATP and lactic acid levels
b) exhaustion of energy reserves and buildup of lactic acid levels
c) buildup of ATP and pyruvic acid levels
d) exhaustion of energy reserves and buildup of pyruvic acid levels - ✔️✔️b)
exhaustion of energy reserves and buildup of lactic acid levels
The correct order for the smallest to the largest unit of organization in muscle tissue is
________.
a) fascicle, filament, muscle fiber, myofibril
b) filament, myofibril, muscle fiber, fascicle
c) muscle fiber, fscicle, filament, myofibril
d) myofibril, muscle fiber, filament, fascicle - ✔️✔️b) filament, myofibril, muscle fiber,
fascicle
Muscle that has a striped appearance is described as being ________.
a) elastic
b) nonstriated
c) excitable
d) striated - ✔️✔️d) striated
Which element is important in directly triggering contractions?
a) sodium (Na+)
b) calcium (Ca++)
c) potassium (K+)
d) chloride (Cl-) - ✔️✔️b) calcium (Ca++)
Which of the following properties is not common to all three muscle tissues?
a) excitability
b) the need for ATP
c) at rest, uses shielding proteins to cover actin-binding sites
d) elasticity - ✔️✔️c) at rest, uses shielding proteins to cover actin-binding sites
Depolarization of the sarcolemma means ________.
a) the inside of the membrane has become less
negative as sodium ions accumulate
b) the outside of the membrane has become less
negative as sodium ions accumulate
c) the inside of the membrane has become more
negative as sodium ions accumulate
, d) the sarcolemma has completely lost any electrical
charge - ✔️✔️a) the inside of the membrane has become less negative as sodium ions
accumulate
In relaxed muscle, the myosin-binding site on actin is
blocked by ________.
a) titin
b) troponin
c) myoglobin
d) tropomyosin - ✔️✔️d) tropomyosin
According to the sliding filament model, binding sites on actin open when ________.
a) creatine phosphate levels rise
b) ATP levels rise
c) acetylcholine levels rise
d) calcium ion levels rise - ✔️✔️d) calcium ion levels rise
The cell membrane of a muscle fiber is called ________.
a) myofibril
b) sarcolemma
c) sarcoplasm
d) myofilament - ✔️✔️b) sarcolemma
During muscle contraction, the cross-bridge detaches
when ________.
a) the myosin head binds to an ADP molecule
b) the myosin head binds to an ATP molecule
c) calcium ions bind to troponin
d) calcium ions bind to actin - ✔️✔️b) the myosin head binds to an ATP molecule
Thin and thick filaments are organized into functional units called ________.
a) myofibrils
b) myofilaments
c) T-tubules
d) sarcomeres - ✔️✔️b) myofibrils
A sprinter would experience muscle fatigue sooner than a marathon runner due to
________.
a) anaerobic metabolism in the muscles of the
sprinter
b) anaerobic metabolism in the muscles of the
marathon runner
c) aerobic metabolism in the muscles of the sprinter
