1. Skeletal muscles physiology BCQs
1. intracellular fluid between the myofibrils is:
a) sarcomere b) sarcoplasm
c) cytoplasm d) matrix
2. about____ of the body is skeletal muscle:
a) 10% b) 25%
c) 40% d) 50%
3. Regarding the skeletal muscle fibers:
a) voluntary b) striated
c) Innervated by single motor nerve
d) intercalated disc
4. sarcolema is a:
a) true plasma membrane b) encloses muscles
c) plasma membrane + polysaccharide
d) attached directly to bones
5. the portion of myofibril between two successive
Z discs is called:
a) sarcoplasm b) sarcomere
c) sarcolema d) myofilament
e) muscle filament
6. these are the dark bands:
a) A-bands b) I - bands
c) H - zone d) Z disc
7. the length of myosin filament is:
a) 1.6 µm b) 2 µm
c) 1.6 nm d) 2 nm
Physiology BCQs Dr. Sajid Ali Talpur

2. 8. how many myosin and actin filaments are there
in myofibril of skeletal muscle:
a) 1000 : 2000 b) 2000 : 1000
c) 1500 : 3000 d) 3000 : 1500
9. it remains constant during the contraction
throughout its length:
a) A-bands b) I - bands
c) H - zone d) A.O.T
10. it contains only myosin filament:
a) A-bands b) I - bands
c) H - zone d) M line
11. it has only actin filament:
a) A-bands b) I - bands
c) H - zone d) Z disc
12. myosin filaments are connected to Z discs
through:
a) connexin protein b) myosin molecules
c) tightin proteins d) actin filament
13. each myosin molecule is consist of polypeptide
chains:
a) 2 b) 4
c) 6 d) 8
14. polypeptide chains in the myosin molecules are
as:
a) 3 heavy : 3 light b) 2 heavy : 4 light
Physiology BCQs Dr. Sajid Ali Talpur

3. c) 4 heavy : 2 light d) 5 heavy : 1 light
15. Ca++ ions are present in ______for muscles:
a) sarcomere b) sarcoplasm
c) sarcoplasmic reticulum
d) E.R
16. the molecular weight of light and heavy chains
of myosin molecules is:
a) 200, 2000 b) 2000, 20000
c) 20000,200000 d) 200000, 2000000
17. the myosin filament contains about ____myosin
molecules:
a) 20 b) 200
c) 2000 d) 20000
18. troponin is consist of_____subunit proteins:
a) 2 b) 3
c) 4 d) 6
19. the inhibitory effect of troponin tropomyosin
complex on actin filament is itself inhibited by:
a) Na ions b) Ca ions
c) K ions d) Mg ions
20. in the motor end plate the nerve fiber____the
sarcolema:
a) penetrates b) touches
c) does not touch
d) may be any of them
Physiology BCQs Dr. Sajid Ali Talpur

4. 21. the common enzyme present in the synaptic
cleft is:
a) acetylinase b) acetylencholinase
c) acetylcholinesterase d) neurotransmirase
22. about ___ vesicles of acetylcholine are released
into the synaptic cleft on the arrival of nerve
impulse at the neuromuscular junction:
a) 125 b) 130
c) 135 d) 140
23. acetylcholine receptors contain:
a) alpha subunits
b) alpha and beta subunits
c) alpha, beta and delta subunits
d) alpha, beta, delta and gamma subunits
24. the skeletal muscles are fatigued because of the
accumulation of:
a) malic acid b) lactic acid
c) oxalic acid d) CO2
e) A.O.T
25. to reach the action potential at the deep
myofibrils the skeletal muscle fibers use:
a) trnsmition tubules b) transistor tubules
c) transverse tubules d) transmitter tubules
Physiology BCQs Dr. Sajid Ali Talpur

5. Answer Key:
1 B 2 C 3 D
4 C 5 B 6 A
7 A 8 C 9 A
10 C 11 B 12 C
13 C 14 B 15 C
16 C 17 B 18 B
19 B 20 C 21 C
22 A 23 D 24 B
25 C
Physiology BCQs Dr. Sajid Ali Talpur