Muscle Flashcards
(47 cards)
Muscle that has striped appearance is described as being _____________.
a. elastic
b. nonstriated
c. excitable
d. striated
d. striated
Which element is important in directly triggering contraction?
a. sodium (Na+)
b. Calcium (Ca+)
c. Potassium (K+)
d. Chlorine (Cl-)
b. Calcium (Ca+)
Which of the following properties is not common to all three muscle tissues?
a. Excitability
b. need for ATP
c. at rest, uses shielding protein to cover actin binding sites
d. elasticity
c. At rest, uses shielding to cover actin binding sites.
The correct order for the smallest to largest unit of organization in the muscle tissues is
a. fascicle, filament, muscle fiber, myofibril
b. filament, myofibril, muscle fiber, fascicle
c. muscle fiber, fascicle, filament, myofibril
d. myofibril, muscle fiber, filament, fascicle
b. Filament, Myofibril, muscle fiber, fascicle
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
Muscle relaxation occurs when ____________.
a. calcium ions are actively transported out of the sarcoplasmic reticulum.
b. calcium ions diffuse out of the sarcoplasmic reticulum
c. calcium ions are actively transported into the sarcoplasmic reticulum.
d. calcium ions diffuse into the sarcoplasmic reticulum
c. calcium ions are actively transported into the sarcoplasmic reticulum
During muscle contraction, the crossbridge 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
Thin and thick filaments are organized functional units called ____________.
a. myofibrils
b. myofilaments
c. t-tubules
d. sarcomeres
d. sarcomeres
During which phase of a twitch in a muscle fiber is tension the greatest?
a. resting phase
b. repolarization phase
c. contraction phase
d. relaxation phase
c. Contraction phase
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
A sprinter would experience muscle fatigue sooner than a marathon runner due to ___________________.
a. anaerobic metabolism in the muscles of a sprinter
b. anaerobic metabolism in the muscles of the marathon runner
c. aerobic metabolism in the muscles of the sprinter
d. glycolysis in the muscles of the marathon runner
a. anaerobic metabolism in the muscles of the sprinter
What aspect of creatine phosphate allows it to supply energy to the muscles?
a. ATPase activity
b. phosphate bonds
c. carbon bonds
d. hydrogen bonds
b. phosphate bonds
Drug X blocks ATP regeneration from ADP and phosphate. How will muscle cells respond to this drug?
a. by absorbing ATP from the bloodstream
b. by using ADP as an energy source
c. by using glycogen as an energy source
d. none of the above
d. None of the above
The muscles of a professional sprinter are more likely to have ________.
a. 80 percent fast-twitch muscle fibers and 20 percent slow-twitch muscle fibers
b. 20 percent fast-twitch muscle fibers and 80 percent slow-twitch muscle fibers
c. 50 percent fast-twitch muscle fibers and 50 percent slow-twitch muscle fibers
d. 40 percent fast-twitch muscle fibers and 60 percent slow-twitch muscle fibers.
b. 20 percent fast-twitch muscle fibers and 80 percent slow-twitch muscle fibers
The muscles of a professional marathon runner are most likely to have _________.
a. 80 percent fast-twitch muscle fibers and 20 percent slow-twitch muscle fibers.
b. 20 percent fast-twitch muscle fibers and 80 percent slow-twitch muscle fibers
c. 50 percent fast-twitch muscle fibers and 50 percent slow-twitch muscle fibers
d. 40 percent fast-twitch muscle fibers and 60 percent slow-twitch muscle fibers
d. 40 percent fast-twitch muscle fibers and 60 percent slow-twitch muscle fibers
Which of the following statements is true?
a. fast fibers have a small diameter
b. fast fibers contain loosely packed myofibrils
c. fast fibers have large glycogen reserves
d. fast fibers have many mitochondria
c. fast fibers have large glycogen reserves
Which of the following statements is false?
a. slow fibers have a small network of capillaries
b. slow fibers contain the pigment myoglobin
c. slow fibers contain a large number of mitochondria
d. slow fibers contract for extended periods
a. slow fibers have a small network of capillaries
Cardiac muscles differ from skeletal muscles in that they ____________.
a. are striated
b. utilize aerobic metabolism
c. contain myofibrils
d. contain intercalated discs
d. contain intercalated discs
If cardiac muscle cells were prevented from undergoing aerobic metabolism, they ultimately would _____________.
a. undergo glycolysis
b. synthesize ATP
c. stop contracting
d. start contracting
c. stop contracting
Smooth muscles differ from skeletal and cardiac muscles in that they ____________.
a. lack myofibrils
b. are under voluntary control
c. lack myosin
d. lack actin
a. lack myofibrils
Which of the following statements describes smooth muscle cells?
a. They are resistant to fatigue.
b. They have a rapid onset of contractions.
c. They cannot exhibit tetanus.
d. They primarily use anaerobic metabolism
a. they are resistant to fatigue
