Which of the following is NOT a major
function of skeletal muscle?
1.
2.
3.
4.
Maintaining body temperature
Lining hollow organs
Maintaining posture
Storing nutrient reserves
How are epimysium, perimysium, and
endomysium interrelated?
1. All three surround skeletal muscle fibers
2. All three contain capillaries and nerves
3. All three contain satellite cells that function in
the repair of muscle tissue
4. All three unite at the ends of skeletal muscles
to form tendons
How would severing the tendon attached to a
muscle affect the muscle’s ability to move a
body part?
1. Uncontrolled movement would result from
a severed tendon.
2. Movement would be greatly exaggerated
with no tendon.
3. No movement is possible without a muscle
to bone connection.
4. Limited movement would result.
Myofibrils are organized into repeating
subunits called ____?
1.
2.
3.
4.
T-Tubules
Z lines
Sarcomeres
Sarcoplasmic reticulum
The A band is comprised of which of the
following subunits?
1.
2.
3.
4.
I-Band, terminal cisternae, and the Z-Line
M-Line, H-Zone, and zone of overlap
Thin filaments, titin, and the Z-Line
Sarcoplasmic reticulum and T-Tubules
Why does skeletal muscle appear striated when
viewed through a microscope?
1. Z. Lines and myosin filaments align within
the tissue.
2. Glycogen reserves are linearly arranged.
3. Capillaries regularly intersect the
myofibers.
4. Actin filaments repel stain, appearing
banded.
Where would you expect the greatest
concentration of Ca2+ in resting skeletal
muscle to be?
1.
2.
3.
4.
In T. Tubules
Surrounding the mitochondria
Within sarcomeres
In cisternae of the sarcoplasmic
reticulum
In what ways does the appearance of a
sarcomere change during contraction of a
skeletal muscle fiber?
1. Zones of overlap get larger; H. Zone gets
wider; A bands shorten
2. Titin molecules are relaxed; M. Line
disappears
3. Z. Lines move closer together; I bands and
4. H. Zones get smaller
5. None of these is correct
Which of these describes the
neuromuscular junction?
1.
2.
3.
4.
The surface containing membrane receptors that
bind acetylcholine
Special intercellular connection between axon
branches and a skeletal muscle fiber
The link between generation of an action
potential and the start of muscle contraction
A propagated change in membrane potential that
travels the length of an axon
How would a drug that blocks acetylcholine
release affect muscle contraction?
1.
2.
3.
4.
Contraction would be prevented.
Contraction would be slowed.
The speed of contraction would increase.
The strength of contraction would
increase.
What would you expect to happen to a
resting skeletal muscle if the sarcolemma
suddenly became very permeable to Ca2+?
1.
2.
3.
4.
increased strength of contraction
decreased cross bridge formation
decreased ability to relax
both 1 and 3
Predict what would happen to muscles if a
pesticide that inhibits acetylcholinesterase were
present at the motor end plate.
1. Muscle would lose strength.
2. Muscle would be unable to contract.
3. Muscle would lock in a state of
contraction.
4. Muscle would contract repeatedly.
What is excitation–contraction coupling and
where does it occur?
1.
2.
3.
4.
The same as rigor mortis/in the SR
Pivoting of myosin heads/cross-bridges
The release of ACh/at motor end plates
The link between generation of an action
potential and the start of muscle contraction/at
triads
Why does a muscle that has been
overstretched produce less tension?
1. Few cross-bridges form, causing weak
contraction.
2. Cross-bridges cannot be formed.
3. Actin and myosin cease to be stimulated by
acetylcholine.
4. The increased amount of Ca2+ in the
sarcoplasm causes the muscle to relax
completely.
What is a motor unit? Why would you
need a small motor unit to control
movements of the fingers?
1.
2.
3.
4.
The resting tension in a muscle/so it would not
involve muscle fibers of adjoining fingers
Muscle fibers controlled by a single motor
neuron/need precise control
The addition of one twitch to another/need
twitches to cover a large area
None of these is correct
How is it possible for a skeletal muscle to
contract without shortening?
1.
2.
3.
4.
Through eccentric contractions, the muscle
lengthens
Through concentric contractions, the muscle
does not change length
Through isometric contraction, the muscle
remains the same length
1 and 3 are correct
What is the mechanism by which ATP is
continuously synthesized in muscle cells?
1.
2.
3.
4.
Through the reaction of ADP with creatine
Primarily aerobic metabolism in mitochondria
Primarily glycolysis in the cytoplasm
2 and 3 are correct
What are the structural and functional
distinctions of fast fibers (white muscle fibers)?
1.
2.
3.
4.
They contract in 0.01 sec, are large in diameter,
and use anaerobic metabolism.
They use aerobic metabolism, have numerous
mitochondria, and have high myoglobin content.
They are capable of mitotic division and their
contractions use ATP in small amounts.
They are the least abundant fiber type and use
aerobic metabolism.
Why would a sprinter experience muscle
fatigue before a marathon runner?
1.
2.
3.
4.
Marathon running uses ATP for only a short time,
while sprinting uses ATP indefinitely.
Marathon runners muscles depend on stored
glycogen, therefore they do not fatigue.
Sprinting involves anaerobic endurance, whereas
running a marathon depends more upon
availability of substrates for aerobic respiration.
None of these is correct.
Which activity would be more likely to
create an oxygen debt: swimming laps or
lifting weights?
1.
2.
3.
4.
swimming laps
lifting weights
both 1 and 2
neither 1 nor 2
Which type of muscle fibers would predominate in the
large leg muscles of someone who excels at
endurance activities, such as cycling and why?
1.
2.
3.
4.
Fast fibers/because they have large glycogen
reserves
Slow fibers/because they have extensive
capillary networks
Nonvascular fibers/because they use both
aerobic and anaerobic metabolism
Intermediate fibers/because they have more
neuromuscular junctions
Which type of muscle fibers would you expect to
predominate in the large leg muscles of someone who
excels at endurance activities, such as cycling or longdistance running and why?
1.
2.
3.
4.
Fast fibers/large glycogen reserves
Slow fibers/extensive capillary networks
Nonvascular fibers/use both aerobic and
anaerobic metabolism
Intermediate fibers/more neuromuscular
junctions
What structural characteristics distinguish cardiac
muscle tissue from skeletal muscle tissue?
Cardiac muscle cells ___.
1.
2.
3.
4.
Are larger and usually have one nucleus
Have intercalated discs, short T tubules and no
triads
Are dependent on anaerobic metabolism
Contact each other at tight junctions
What feature of cardiac muscle tissue allows
the heart to act as a functional syncytium?
1.
2.
3.
4.
striations
intercalated discs
gap junctions
short T tubules without triads
Two cardiologist are talking about functional
characteristics of cardiac muscle tissue. Which of
the following descriptions would they use?
1.
2.
3.
4.
Special gap junctions, no wave summation, contracts
without neural stimulation
Spindle-shaped, non-striated, thick filaments
scattered, involuntary
Ca2+ from SR, rapid fatigue, functional syncytium
Cardiologists would not use any of this terminology
Why are cardiac and smooth muscle
contractions more affected by changes in
extracellular Ca2+ than are skeletal muscle
contractions?
1.
2.
3.
4.
Extracellular Ca2+ inhibits actin.
Cross-bridges are formed extracellularly.
Most calcium for contractions comes from
SR stores.
Most calcium for contractions comes from
extracellular fluid.
Smooth muscle can contract over a wider
range of resting lengths than skeletal muscle
can. Why?
1.
2.
3.
4.
Smooth muscle sarcomeres are longer.
Actin and myosin filament arrangement is
less organized in smooth muscle.
Smooth muscle cells are shorter.
Smooth muscle actin is longer.