WorksheetsMuscular System Test A
Total questions: 40
Worksheet time: 44mins
Myoglobin ________.
breaks down glycogen
is a protein involved in the direct phosphorylation of ADP
stores oxygen in muscle cells
produces the end plate potential
After nervous stimulation stops, what prevents ACh in the synaptic cleft from continuing to stimulate contraction?
calcium ions returning to the terminal cisternae
the tropomyosin blocking the myosin once full contraction is achieved
acetylcholinesterase breaks apart the ACh
the action potential stops going down the overloaded T tubules
What does excess postexercise oxygen consumption represent?
amount of oxygen needed for aerobic activity to accomplish the same amount of work
the difference between the amount of oxygen needed for totally aerobic muscle activity and the amount actually used
the amount of oxygen equal to the oxygen already used
the amount of oxygen taken into the body immediately after the exertion
What is the functional unit of a skeletal muscle called?
a sarcomere
the sarcoplasmic reticulum
a myofibril
a myofilament
What is the role of tropomyosin in skeletal muscles?
Tropomyosin is the chemical that activates the myosin heads.
Tropomyosin serves as a contraction inhibitor by blocking the myosin binding sites on the actin molecules.
Tropomyosin serves as a contraction inhibitor by blocking the actin binding sites on the myosin molecules.
Tropomyosin is the receptor for the motor neuron neurotransmitter.
Which muscle cells have the greatest ability to regenerate?
skeletal
cardiac
smooth
no muscle can regenerate
Most skeletal muscles contain ________.
muscle fibers of the same type
a mixture of fiber types
a predominance of slow oxidative fibers
a predominance of fast oxidative fibers
The strongest muscle contractions are normally achieved by ________.
increasing stimulus above the threshold
increasing stimulus above the treppe stimulus
increasing the stimulation up to the maximal stimulus
recruiting small and medium muscle fibers
What structure in skeletal muscle cells functions in calcium storage?
sarcoplasmic reticulum
mitochondria
intermediate filament network
myofibrillar network
Immediately following the arrival of the stimulus at a skeletal muscle cell there is a short period called the ________ period during which the neurotransmitter is released by exocytosis, diffuses across the synaptic cleft, and binds to its receptors.
contraction
relaxation
latent
refractory
Creatine phosphate functions in the muscle cell by ________.
forming a temporary chemical compound with myosin
forming a chemical compound with actin
inducing a conformational change in the myofilaments
storing energy that will be transferred to ADP to resynthesize ATP
Which of the following is a factor that affects the velocity and duration of muscle contraction?
number of muscle fibers stimulated
size of the muscle fibers stimulated
load on the fiber
muscle length
Which of the following would be recruited later in muscle stimulation when contractile strength increases?
motor units with the longest muscle fibers
many small motor units with the ability to stimulate other motor units
large motor units with small, highly excitable neurons
motor units with larger, less excitable neurons
What structure in skeletal muscle cells functions in calcium storage?
sarcoplasmic reticulum
mitochondria
intermediate filament network
myofibrillar network
What muscle is primarily responsible for preventing foot drop?
extensor digitorum longus
tibialis anterior
extensor hallucis longus
fibularis tertius
Which of the following is NOT a muscle primarily involved in the breathing process?
diaphragm
external intercostal
internal intercostal
latissimus dorsi
What is the main factor that determines the power of a muscle?
the length
the shape
the number of neurons innervating it
the total number of muscle fibers (cells) available for contraction
When the term biceps, triceps, or quadriceps forms part of a muscle's name, what does it tell you about the muscle?
The muscle has two, three, or four origins, respectively.
The muscle is able to change direction twice, three times, or four times faster than other muscles, respectively.
The muscle has two, three, or four functions, respectively.
The muscle has two, three, or four insertions, respectively.
Which of the following muscles is involved in producing horizontal wrinkles in the forehead?
the medial pterygoid
the zygomaticus major
the frontal belly of the epicranius
the temporalis
Which of the following muscles is involved in crossing one leg over the other to produce the cross-legged position?
the gastrocnemius
the sartorius
all of the hamstrings
the quadriceps femoris
Which of the following is NOT a member of the hamstrings?
gracilis
semitendinosus
semimembranosus
biceps femoris
Which of the following best describes the orbicularis oris?
It closes, purses, and protrudes the lips.
It pulls the lower lip down and back.
It draws the eyebrows together.
It closes the eye.
Tennis players often complain about pain in the arm (forearm) that swings the racquet. What muscle is usually strained under these conditions?
the triceps brachii
the anconeus
the brachioradialis
the flexor digitorum profundus
Which muscle(s) is (are) contracted to exhale forcibly?
diaphragm alone
internal intercostals and rectus abdominus
external intercostals and diaphragm
rectus abdominis and diaphragm
Paralysis of which of the following would make an individual unable to flex the thigh?
biceps femoris
vastus medialis
soleus
iliopsoas and rectus femoris
Which of the following muscles serves as a common intramuscular injection site, particularly in infants as the buttocks and arm muscles are poorly developed?
the vastus intermedius
the vastus medialis
rectus femoris
the vastus lateralis
Which of the following surrounds an individual muscle cell?
perimysium
endomysium
epimysium
fascicle
Rigor mortis occurs because ________.
the cells are dead
sodium ions leak into the muscle causing continued contractions
no ATP is available to release attached actin and myosin molecules
proteins are beginning to break down, thus preventing a flow of calcium ions
What is the functional role of the T tubules?
stabilize the G and F actin
enhance cellular communication during muscle contraction
hold cross bridges in place in a resting muscle
synthesize ATP to provide energy for muscle contraction
During vigorous exercise, there may be insufficient oxygen available to completely break down pyruvic acid for energy. As a result, the pyruvic acid is converted to ________.
a strong base
stearic acid
hydrochloric acid
lactic acid
When a muscle is unable to respond to stimuli temporarily, it is in which of the following periods?
relaxation period
refractory period
latent period
fatigue period
In an isotonic contraction, the muscle ________.
changes in length and moves the "load"
does not change in length but increases tension
never converts pyruvate to lactate
rapidly resynthesizes creatine phosphate and ATP
An anaerobic metabolic pathway that results in the production of two net ATPs per glucose plus two pyruvic acid molecules is ________.
the citric acid cycle
glycolysis
hydrolysis
the electron transport chain
What is the most distinguishing characteristic of muscle tissue?
It is composed of multiple cells working together.
the ability to respond to nervous stimulation
its cells' inability to reproduce by mitosis
the ability to transform chemical energy into mechanical energy to move the body
What part of the sarcolemma contains acetylcholine receptors?
motor end plate
end of the muscle fiber
part adjacent to another muscle cell
any part of the sarcolemma
The oxygen-binding protein found in muscle cells is ________.
hemoglobin
ATP
myoglobin
immunoglobin
During muscle contraction, myosin cross bridges attach to which active sites?
myosin filaments
actin filaments
Z discs
thick filaments
A muscle that opposes, or reverses, a particular movement is a(n) ________.
antagonist
fixator
synergist
agonist (prime mover)
Myasthenia gravis is a disease that is believed to be caused by autoimmune disorder, resulting in the loss of ACh receptors at the motor end plate of muscle fibers. Which of the following is likely to be a symptom of myasthenia gravis?
weakness of muscle
seizures and uncontrollable muscle movement
coma and loss of voluntary muscle movement
dehydration with headache
The 100-meter dash is a quick and short run requiring explosive speed. On completion of the dash, the runners will continue to breathe hard for several seconds to minutes even though they are no longer running. Which of the following is the best explanation for why this is so?
The runners' use of stored oxygen, glucose, and creatine phosphate is being replenished and this requires a prolonged increase of oxygen intake.
Since the exercise was mostly aerobic exercise, the runners' bodies have not yet realized the run is over.
The runners' fast oxidative muscles are so slow to utilize oxygen, they only begin aerobic respiration by the time the run has finished.
Slow oxidative fibers are recruited last and have only started to work at completion of the run.
