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Quiz von Med Student , aktualisiert more than 1 year ago
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Frage 1
Frage
Thick filaments in skeletal muscle are composed of
Antworten
-
actin
-
myosin
-
troponin
-
calmodulin
-
tropomyosin
Frage 2
Frage
During isotonic contraction of a skeletal muscle fibre:
Antworten
-
The sarcomere shortens
-
A-bands shorten
-
Tension increases
-
Fibres relax
-
None of the above
Frage 3
Frage
In skeletal muscle calcium facilitates contraction by binding to:
Antworten
-
tropomyosin
-
actin
-
troponin
-
myosin
-
the thick filament
Frage 4
Frage
Motor unit’ refers to:
Antworten
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a single motor neuron plus all the muscle fibres it innervates
-
a single muscle fibre plus all the motor neurons that innervate it
-
all of the motor neurons supplying a single muscle
-
a pair of antagonistic muscles
-
all of the muscles that affect the movement of any given joint
Frage 5
Frage
During an isometric contraction of a skeletal muscle:
Antworten
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the I-bands shorten and the A-bands stay the same length
-
the thick and thin filaments slide past each other
-
sarcomere length does not change
-
tension does not change
-
none of the above
Frage 6
Frage
The cross bridge in the sacromere of skeletal muscle are made of:
Antworten
-
actin
-
myosin
-
troponin
-
tropomyosin
-
myelin
Frage 7
Frage
With regard to knee jerk:
Antworten
-
it is a monosynaptic reflex
-
the impulse travels via type Ca afferent fibres
-
the Golgi body is an important component
-
the stimulus begins in the tendon
-
it is a visceral reflex
Frage 8
Frage
The most important contractile proteins are:
Antworten
-
myosin
-
troponin
-
actin
-
tropomyosin
-
all of the above
Frage 9
Frage
Which role do Ca2+ ions play in the muscle contraction?
Antworten
-
excitation-contraction coupling
-
prevent the contraction
-
form cross bridges
-
release energy for the contraction
-
excite the myofiber
Frage 10
Frage
Smooth muscle is not cross striated because:
Antworten
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of myosin and actin in the myofibril
-
myofibrils are in register with each other
-
myofibrils are not in register with each other
-
it has gap junctions
-
it is surrounded by a basal lamina
Frage 11
Frage
lntercalated discs are most likely to be observed in:
Antworten
-
longitudinal section of skeletal muscle
-
transverse section of skeletal muscle
-
transverse section of cardiac muscle
-
longitudinal section of cardiac muscle
-
transverse section of smooth muscle
Frage 12
Frage
During strong exercise, oxygen consumption is greatest in the:
Antworten
-
brain
-
heart
-
skeletal muscles
-
liver
-
kidneys
Frage 13
Frage
An increase in force of a skeletal muscle contraction is initially achieved by:
Antworten
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recruitment of nerve fibers
-
recruitment of muscle fibers
-
recruitment of motor units
-
increased intracellular calcium
-
increased lactic acid
Frage 14
Frage
Which area of the sacromere consists only of myosin filaments?
Antworten
-
I-bands
-
H-zone
-
A-bands
-
M-line
-
Z-disc
Frage 15
Frage
Which muscle cell compound stores oxygen?
Antworten
-
creatine phosphate
-
glycogen
-
hemoglobin
-
myoglobin
-
lipid droplets
Frage 16
Frage
Smooth muscle is:
Antworten
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voluntary and spindle shaped
-
voluntary and striated
-
involuntary and spindle shaped
-
involuntary and striated
-
innervated by the somatic nervous system
Frage 17
Frage
Skeletal muscle ls:
Antworten
-
voluntary and spindle shaped
-
voluntary and striated
-
involuntary and spindle shaped
-
involuntary and striated
-
innervated by ANS
Frage 18
Frage
Cardiac muscle is:
Antworten
-
voluntary and spindle shaped
-
voluntary and striated
-
involuntary and spindle shaped
-
involuntary and striated
-
innervated by the somatic nervous system
Frage 19
Frage
Which type of muscle cell is multinucleated?
Antworten
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Cardiac
-
Smooth
-
Skeletal
-
Cardiac and smooth
-
None of the above
Frage 20
Frage
What is an example of a smooth muscle?
Antworten
-
masseter (face)
-
bladder
-
heart
-
pronator teres (forearm)
-
rectus abdominis (belly)
Frage 21
Frage
How many actin filaments surround each myosin filament?
Antworten
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two
-
four
-
six
-
eight
-
seven
Frage 22
Frage
The muscular system is controlled by which system?
Antworten
-
the cardiovascular system
-
the endocrine system
-
the nervous system
-
the respiratory system
-
the urinary system
Frage 23
Frage
How many types of muscle are there?
Antworten
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two
-
three
-
four
-
five
-
six
Frage 24
Frage
The sacroplasmic reticulum stores:
Antworten
-
calcium ions
-
chloride ions
-
sodium ions
-
potassium ions
-
hydrogen ions
Frage 25
Frage
Which of the following should affect the strength or force of skeletal muscle contraction?
Antworten
-
the number of muscle fibers at rest
-
the degree of muscle stretch
-
the series-elastic elememts
-
stronger stimuli
-
concentration of Na+
Frage 26
Frage
Which of these is true of skeletal muscle:
Antworten
-
spindle-shaped cells
-
under involuntary control
-
many peripherally located nuclei per muscle fiber
-
forms the walls of hollow internal organs
-
may be autorhythmic
Frage 27
Frage
Which of these is not a major property of muscle?
Antworten
-
contractility
-
elasticity
-
excitability
-
extensibility
-
secretability
Frage 28
Frage
What is each myofibril made of?
Antworten
-
many muscle fibers
-
contains sacroplasmic reticulum
-
many sacromeres
-
contains T-tubules
-
is the same thing as a muscle fiber
Frage 29
Frage
Myosin myofilaments are
Antworten
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attached to the Z-disk
-
found primarily in the I band
-
thinner than actin myofilaments
-
absent from the H zone
-
attached to filaments that form the M-line
Frage 30
Frage
The part of the sacrolemma that invaginates into the interior of skeletal muscle fibers is the
Antworten
-
T-tubule system
-
Sacroplasmic reticulum
-
Myofibrils
-
Terminal cisternae
-
Mitochondria
Frage 31
Frage
Which of these events occurs during the lag (latent) phase of muscle contraction?
Antworten
-
Cross-bridge movement
-
Active transport of Ca2+ into the sacroplasmic reticulum
-
Ca2+ binding to troponin
-
Sacromere shortening
-
Breakdown of ATP to ADP
Frage 32
Frage
Muscle contraction which cannot move weight because it is too heavy is:
Antworten
-
isometric
-
isotonic
-
isokinetic
-
concentric
-
eccentric
Frage 33
Frage
Voluntary skeletal muscles in the leg are innervated
Antworten
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Postganglionic neurons
-
Somatic motor neurons
-
Preganglionic neurons
-
CNS fibers
-
All the above
Frage 34
Frage
A small motor unit would control which type of movement?
Antworten
-
fast but brief
-
intense and strong
-
delicate and precise
-
sprinting
-
marathon running
Frage 35
Frage
Muscle fibers type 1 have only one of the following features:
Antworten
-
slow onset of contraction
-
easily fatigued
-
many enzyme for glycolysis
-
a slow refractory period
-
low mitochondrial content
Frage 36
Frage
Muscle fibers type Ila are:
Antworten
-
slow-twitch, glycolytic, fatigable resistant
-
fast-twitch, oxidative-glycolytic, relatively fatigue resistant
-
fast-twitch, glycolytic, fatigable
-
slow-twitch, oxidative, fatigue resistant
-
fast-twitch, oxidative, fatigable
Frage 37
Frage
Muscle fibers type IIb are:
Antworten
-
slow-twitch, glycolytic, fatigable resistant
-
fast-twitch, oxidative-glycolytic, relatively fatigue resistant
-
fast-twitch, glycolytic, fatigable
-
slow-twitch, oxidative, fatigue resistant
-
fast-twitch, oxidative, fatigable
Frage 38
Frage
Muscle fibers type 1 are
Antworten
-
slow-twitch, glycolytic, fatigable resistant
-
fast-twitch, oxidative-glycolytic, relatively fatigue resistant
-
fast-twitch, glycolytic, fatigable
-
slow-twitch, oxidative, fatigue resistant
-
fast-twitch, oxidative, fatigable
Frage 39
Frage
These bands of the sacromere do not shorten during contraction
Antworten
-
A bands
-
H, I and M bands
-
Z discs and A bands
-
I bands
-
a and d
Frage 40
Frage
The role of transverse tubules in skeletal muscle fibers is to:
Antworten
-
connect the sacromeres to each other
-
bind the myofibrils
-
spread the action potential quickly
-
connect the sacrolemma to the sacroplasmic reticulum
-
bind to the receptors- dihydropyridine receptors
Frage 41
Frage
The cross bridges of the sarcomere in skeletal muscle are components of:
Antworten
-
actin
-
myosin
-
troponin
-
tropomyosin
-
titin
Frage 42
Frage
The function of tropomyosin in skeletal muscle In
Antworten
-
sliding on actin to produce shortening
-
releasing Ca2+ after initiation of contraction
-
binding to myosin during contraction
-
covering up the actin binding sites of myosin at rest
-
releasing Na+ after contraction
Frage 43
Frage
The cell membranes In skeletal muscle:
Antworten
-
are impermeable to fat-soluble substances
-
are more permeable to sodium than to potassium ions
-
become more permeable to glucose in the presence of insulin
-
become less permeable to potassium in the presence of insulin
-
are ligand dependent
Frage 44
Frage
A skeletal muscle fibre at rest:
Antworten
-
presents with a membrane which is positively charged on the inside with respect to the outside
-
contains intracellular stores of calcium ions
-
is normally innervated by more than one motor neuron
-
becomes more excitable as its resting membrane potential increase in absolute value
-
becomes less excitable as the extracellular ionized calcium levels fall
Frage 45
Frage
In skeletal muscle:
Antworten
-
contraction occurs when its pacemaker cells depolarize sufficiently to reach the threshold for firing
-
calcium is taken up by the sarcotubular system when it contracts
-
actin and myosin filaments shorten when it contracts
-
the sarcomeres shorten during contraction
-
contraction strength is related to the influx of K+ ions
Frage 46
Frage
Visceral smooth muscle differs from skeletal muscle in that
Antworten
-
it contracts when stretched
-
it is not paralyzed when its motor nerve supply is cut
-
its cells have unstable resting membrane potentials
-
excitation depends more on influx of extracellular calcium than release of calcium from endoplasmic reticulum
-
all of the above
Frage 47
Frage
A property shared by:
Antworten
-
skeletal and cardiac muscles is their striated microscopical appearance
-
cardiac and visceral smooth muscles is their spontaneous activity when denervated
-
skeletal and cardiac ventricular muscles is their stable resting membrane potential
-
all types of muscles is that contraction strength is related to their initial length
-
all of the above
Frage 48
Frage
The action potential of skeletal muscle:
Antworten
-
has a prolonged plateau phase
-
spreads inwards to all parts of the muscle via T tubules
-
is longer than the action potential of cardiac muscle
-
is not essential for muscle conduction
-
has different amplitudes
Frage 49
Frage
Smooth muscle need help of:
Antworten
-
calmodulin for contraction
-
acetyl choline for contraction
-
K+ for contraction
-
monoamine oxidase for contraction
-
secondly molar for contraction
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