Muscles- Physiology MCQs PMU- 2nd Year

Med Student
Quiz by Med Student , updated more than 1 year ago
Med Student
Created by Med Student about 3 years ago
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Muscles- Physiology MCQs PMU

Resource summary

Question 1

Question
Thick filaments in skeletal muscle are composed of
Answer
  • actin
  • myosin
  • troponin
  • calmodulin
  • tropomyosin

Question 2

Question
During isotonic contraction of a skeletal muscle fibre:
Answer
  • The sarcomere shortens
  • A-bands shorten
  • Tension increases
  • Fibres relax
  • None of the above

Question 3

Question
In skeletal muscle calcium facilitates contraction by binding to:
Answer
  • tropomyosin
  • actin
  • troponin
  • myosin
  • the thick filament

Question 4

Question
Motor unit’ refers to:
Answer
  • 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

Question 5

Question
During an isometric contraction of a skeletal muscle:
Answer
  • 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

Question 6

Question
The cross bridge in the sacromere of skeletal muscle are made of:
Answer
  • actin
  • myosin
  • troponin
  • tropomyosin
  • myelin

Question 7

Question
With regard to knee jerk:
Answer
  • 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

Question 8

Question
The most important contractile proteins are:
Answer
  • myosin
  • troponin
  • actin
  • tropomyosin
  • all of the above

Question 9

Question
Which role do Ca2+ ions play in the muscle contraction?
Answer
  • excitation-contraction coupling
  • prevent the contraction
  • form cross bridges
  • release energy for the contraction
  • excite the myofiber

Question 10

Question
Smooth muscle is not cross striated because:
Answer
  • 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

Question 11

Question
lntercalated discs are most likely to be observed in:
Answer
  • 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

Question 12

Question
During strong exercise, oxygen consumption is greatest in the:
Answer
  • brain
  • heart
  • skeletal muscles
  • liver
  • kidneys

Question 13

Question
An increase in force of a skeletal muscle contraction is initially achieved by:
Answer
  • recruitment of nerve fibers
  • recruitment of muscle fibers
  • recruitment of motor units
  • increased intracellular calcium
  • increased lactic acid

Question 14

Question
Which area of the sacromere consists only of myosin filaments?
Answer
  • I-bands
  • H-zone
  • A-bands
  • M-line
  • Z-disc

Question 15

Question
Which muscle cell compound stores oxygen?
Answer
  • creatine phosphate
  • glycogen
  • hemoglobin
  • myoglobin
  • lipid droplets

Question 16

Question
Smooth muscle is:
Answer
  • voluntary and spindle shaped
  • voluntary and striated
  • involuntary and spindle shaped
  • involuntary and striated
  • innervated by the somatic nervous system

Question 17

Question
Skeletal muscle ls:
Answer
  • voluntary and spindle shaped
  • voluntary and striated
  • involuntary and spindle shaped
  • involuntary and striated
  • innervated by ANS

Question 18

Question
Cardiac muscle is:
Answer
  • voluntary and spindle shaped
  • voluntary and striated
  • involuntary and spindle shaped
  • involuntary and striated
  • innervated by the somatic nervous system

Question 19

Question
Which type of muscle cell is multinucleated?
Answer
  • Cardiac
  • Smooth
  • Skeletal
  • Cardiac and smooth
  • None of the above

Question 20

Question
What is an example of a smooth muscle?
Answer
  • masseter (face)
  • bladder
  • heart
  • pronator teres (forearm)
  • rectus abdominis (belly)

Question 21

Question
How many actin filaments surround each myosin filament?
Answer
  • two
  • four
  • six
  • eight
  • seven

Question 22

Question
The muscular system is controlled by which system?
Answer
  • the cardiovascular system
  • the endocrine system
  • the nervous system
  • the respiratory system
  • the urinary system

Question 23

Question
How many types of muscle are there?
Answer
  • two
  • three
  • four
  • five
  • six

Question 24

Question
The sacroplasmic reticulum stores:
Answer
  • calcium ions
  • chloride ions
  • sodium ions
  • potassium ions
  • hydrogen ions

Question 25

Question
Which of the following should affect the strength or force of skeletal muscle contraction?
Answer
  • the number of muscle fibers at rest
  • the degree of muscle stretch
  • the series-elastic elememts
  • stronger stimuli
  • concentration of Na+

Question 26

Question
Which of these is true of skeletal muscle:
Answer
  • spindle-shaped cells
  • under involuntary control
  • many peripherally located nuclei per muscle fiber
  • forms the walls of hollow internal organs
  • may be autorhythmic

Question 27

Question
Which of these is not a major property of muscle?
Answer
  • contractility
  • elasticity
  • excitability
  • extensibility
  • secretability

Question 28

Question
What is each myofibril made of?
Answer
  • many muscle fibers
  • contains sacroplasmic reticulum
  • many sacromeres
  • contains T-tubules
  • is the same thing as a muscle fiber

Question 29

Question
Myosin myofilaments are
Answer
  • 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

Question 30

Question
The part of the sacrolemma that invaginates into the interior of skeletal muscle fibers is the
Answer
  • T-tubule system
  • Sacroplasmic reticulum
  • Myofibrils
  • Terminal cisternae
  • Mitochondria

Question 31

Question
Which of these events occurs during the lag (latent) phase of muscle contraction?
Answer
  • Cross-bridge movement
  • Active transport of Ca2+ into the sacroplasmic reticulum
  • Ca2+ binding to troponin
  • Sacromere shortening
  • Breakdown of ATP to ADP

Question 32

Question
Muscle contraction which cannot move weight because it is too heavy is:
Answer
  • isometric
  • isotonic
  • isokinetic
  • concentric
  • eccentric

Question 33

Question
Voluntary skeletal muscles in the leg are innervated
Answer
  • Postganglionic neurons
  • Somatic motor neurons
  • Preganglionic neurons
  • CNS fibers
  • All the above

Question 34

Question
A small motor unit would control which type of movement?
Answer
  • fast but brief
  • intense and strong
  • delicate and precise
  • sprinting
  • marathon running

Question 35

Question
Muscle fibers type 1 have only one of the following features:
Answer
  • slow onset of contraction
  • easily fatigued
  • many enzyme for glycolysis
  • a slow refractory period
  • low mitochondrial content

Question 36

Question
Muscle fibers type Ila are:
Answer
  • 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

Question 37

Question
Muscle fibers type IIb are:
Answer
  • 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

Question 38

Question
Muscle fibers type 1 are
Answer
  • 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

Question 39

Question
These bands of the sacromere do not shorten during contraction
Answer
  • A bands
  • H, I and M bands
  • Z discs and A bands
  • I bands
  • a and d

Question 40

Question
The role of transverse tubules in skeletal muscle fibers is to:
Answer
  • 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

Question 41

Question
The cross bridges of the sarcomere in skeletal muscle are components of:
Answer
  • actin
  • myosin
  • troponin
  • tropomyosin
  • titin

Question 42

Question
The function of tropomyosin in skeletal muscle In
Answer
  • 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

Question 43

Question
The cell membranes In skeletal muscle:
Answer
  • 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

Question 44

Question
A skeletal muscle fibre at rest:
Answer
  • 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

Question 45

Question
In skeletal muscle:
Answer
  • 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

Question 46

Question
Visceral smooth muscle differs from skeletal muscle in that
Answer
  • 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

Question 47

Question
A property shared by:
Answer
  • 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

Question 48

Question
The action potential of skeletal muscle:
Answer
  • 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

Question 49

Question
Smooth muscle need help of:
Answer
  • calmodulin for contraction
  • acetyl choline for contraction
  • K+ for contraction
  • monoamine oxidase for contraction
  • secondly molar for contraction
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