Physiology of Musculoskeletal system mcqs, free questions on musculoskeletal system is available for you for free on Medicalfond
1. why slow fibers are called oxidative?
a.
It has dense capillaries
which carries oxygen
b.
It is fatigue resistant
and has high endurance so they are best suited from endurance type activities
c.
It cannot develop high
tension because their small diameter means they have myofibrils
d.
It contract slowly as a
result of its myosin ATPases work slowly
2. Which
one is false concerning thin myosin filament?
a.
The two strands of thin
filament are composed of repeating monomers of globular protein G-actin
b.
ADP molecules are the active
sites on the myosin filaments with which the cross bridges of the actin
filaments interact to cause muscle contraction
c.
The backbone of the thin
myofilament is a double stranded F-actin protein molecule
d.
Each tropomyosin molecule
extends a distance of seven G-actin monomers along the F-actin groove
3. All
are true concerning thick myofilaments, except?
a.
The form of myosin found
in human muscle is myosin-II with two globular heads and a long tail
b.
The light chain of thick
myofilament help control the function of the head during muscle contraction
c.
The S1 region of the thick
myofilaments is responsible for the enzymatic and chemical activity that
results in muscle contraction
d.
The regulatory light chain
is necessary for myosin to function and the essential light chain can be
phosphorylated during muscle activity and modulates muscle function
4. Which
of the following is not the function of titin?
a.
to keep myosin and actin
filaments centered within the sarcomere structure
b.
it may act as an elastic
band to keep filaments in an appropriate orientation so that the contractile
machinery of the sarcomere will work
c.
it facilitates the
structural deterioration of the sarcomere during muscle contraction
d.
it may help to prevent
overextension of the sarcomeres and maintain the central location of t he A
bands
5. Concerning
rigor mortis or contracture which is untrue?
a.
It is due to depleted ATP
and phosphocreatine stores
b.
During this rigor mortis,
the muscle becomes extremely rigid and contracted
c.
It occurs after death
d.
Calcium ion concentration
within sarcoplasm of muscle fiber increases
6. Of
the following lists, one is odd concerning properties of muscle fibers?
a.
Excitability
b.
Contractility
c.
Extensibility
d.
Flexibility
7. Which
one is correct arrangement concerning the formation of muscle?
a.
A
Myofilaments-----myofibrils------muscle fibers------muscle
fasciculi-----muscles
b.
Myofibrils------muscle fibers------
muscles ----myofilaments ----muscle fasciculi
c.
Muscle fibers------muscles
----myofibrils------muscle fasciculi-----myofilaments
d.
Muscles ----myofilaments-----muscle
fibers------muscle fasciculi---- myofibrils
8. As stated by sliding filament theory, during muscle contraction which
one happened from
the following lists?
a. Distance between Z discs decreases
b. Length of the A band decreases
c. Length of the H zone decreases
d. Length of the I band decreases
9. Why large amount of energy (ATP) is consumed during muscular
performance in skeletal muscle?
a.
To move the head
of myosin (power stroke) and to remove the head of myosin from actin
b.
Active Ca’’ pump
from sarcoplasm to sarcoplasm
c.
For Na-K'-pump in the membrane
d.
All the above
10. When the receptors bind acetylcholine, non-selective cation channels
open and this depolarizes
the muscle membrane in the endplate region. This depolarization is called
a. Excitatory postsynaptic potential or EPSP
b. Miniature endplate potentials or mepps
c. Inhibitory postsynaptic potential or IPSP
d. Endplate potential or EPP
11. For patient with suspected muscle tone problem the physiotherapists
order nerve stimulator in order to assess integrity of the muscle. If the
stimulator is set to deliver an increasing frequency of electric shocks
automatically, the relaxation time between successive twitches will get shorter
and shorter as the strength of contraction increases in amplitude. This effect
is
a.
Incomplete tetanus
b.
Summation
c.
Complete tetanus
d.
twitch
12. When you lift a weight by flexing your elbow joint, the force produced
by contraction of by your biceps brachii muscle is greater than the force
of gravity on the object being lifted. That means the tension produced by the
shortening muscle is just greater than the force (load) at each value, causing
the muscle to shorten. This type of muscle contraction
a.
Isometric contraction
b.
Isotonic contraction
c.
Concentric
contraction
d.
Eccentric
contraction
13. From the following lists, which area where multi-unit smooth muscle
is not found?
a.
The ciliary
muscle of the eye
b.
The iris muscle
of the eye
c.
The stomach
d.
The piloerector muscles
14. Concerning the length-tension
relationship of skeletal muscle which one is untrue?
a. When the sarcomeres are at a length of 2.0 to 2.25 um, there is maximal
tension
b. When the sarcomeres reach a length of about 3.6 um, the muscle produces
zero tension
c. At a sarcomere length of 1.25 um, the muscle produces zero force
d. None of the above 55.
15. Concerning the intrafusal fibers which one is odd?
a.
Intrafusal fibers contain myofibrils
along their entire length
b.
The nuclear bag fibers of
intrafusal fibers have their nuclei arranged in a loos aggregate in the central regions of the fibers
c.
The contractile apparatus in case
of intrafusal fibers, it is absent from the centre regions of the fiber
d.
The nuclear chain fibers of
intrafusal fibers have nuclei arranged in rows in the centre regions of the fibers
16. The skeletal muscle at rest obtain most of their energy from the aerobic
respiration of-
a.
Muscle glycogen
b.
Blood glucose
c.
Free fatty acids
d.
Muscle triglycerides
17. From the drugs listed below which one is known by inactive the
acetylcholinesterase in the synapses so that it no longer hydrolyzes
acetylcholine?
a.
Carbachol
b.
Neostigmine
c.
D-tubocurarine
d.
Methacholine
18. Which one is false concerning smooth muscle?
a.
Instead of Z disk, in smooth muscle
bodies thin and thick myofilaments are attached to dense
b.
The ratio of actin to myosin in
smooth muscle is 16 to 1
c.
In smooth muscles thin myofilament are
relatively short in size when compared with thin myofilaments of skeletal muscle
d.
The arrangement of the contractile
apparatus in smooth muscle cells is the one that is required for proper smooth
muscle function