Test
Muscles- Physiology MCQs PMU- 2nd Year
Preguntas del test (49)
1Thick filaments in skeletal muscle are composed of
- Aactin
- Bmyosin
- Ctroponin
- Dcalmodulin
- Etropomyosin
2During isotonic contraction of a skeletal muscle fibre:
- AThe sarcomere shortens
- BA-bands shorten
- CTension increases
- DFibres relax
- ENone of the above
3In skeletal muscle calcium facilitates contraction by binding to:
- Atropomyosin
- Bactin
- Ctroponin
- Dmyosin
- Ethe thick filament
4Motor unit’ refers to:
- Aa single motor neuron plus all the muscle fibres it innervates
- Ba single muscle fibre plus all the motor neurons that innervate it
- Call of the motor neurons supplying a single muscle
- Da pair of antagonistic muscles
- Eall of the muscles that affect the movement of any given joint
5During an isometric contraction of a skeletal muscle:
- Athe I-bands shorten and the A-bands stay the same length
- Bthe thick and thin filaments slide past each other
- Csarcomere length does not change
- Dtension does not change
- Enone of the above
6The cross bridge in the sacromere of skeletal muscle are made of:
- Aactin
- Bmyosin
- Ctroponin
- Dtropomyosin
- Emyelin
7With regard to knee jerk:
- Ait is a monosynaptic reflex
- Bthe impulse travels via type Ca afferent fibres
- Cthe Golgi body is an important component
- Dthe stimulus begins in the tendon
- Eit is a visceral reflex
8The most important contractile proteins are:
- Amyosin
- Btroponin
- Cactin
- Dtropomyosin
- Eall of the above
9Which role do Ca2+ ions play in the muscle contraction?
- Aexcitation-contraction coupling
- Bprevent the contraction
- Cform cross bridges
- Drelease energy for the contraction
- Eexcite the myofiber
10Smooth muscle is not cross striated because:
- Aof myosin and actin in the myofibril
- Bmyofibrils are in register with each other
- Cmyofibrils are not in register with each other
- Dit has gap junctions
- Eit is surrounded by a basal lamina
11lntercalated discs are most likely to be observed in:
- Alongitudinal section of skeletal muscle
- Btransverse section of skeletal muscle
- Ctransverse section of cardiac muscle
- Dlongitudinal section of cardiac muscle
- Etransverse section of smooth muscle
12During strong exercise, oxygen consumption is greatest in the:
- Abrain
- Bheart
- Cskeletal muscles
- Dliver
- Ekidneys
13An increase in force of a skeletal muscle contraction is initially achieved by:
- Arecruitment of nerve fibers
- Brecruitment of muscle fibers
- Crecruitment of motor units
- Dincreased intracellular calcium
- Eincreased lactic acid
14Which area of the sacromere consists only of myosin filaments?
- AI-bands
- BH-zone
- CA-bands
- DM-line
- EZ-disc
15Which muscle cell compound stores oxygen?
- Acreatine phosphate
- Bglycogen
- Chemoglobin
- Dmyoglobin
- Elipid droplets
16Smooth muscle is:
- Avoluntary and spindle shaped
- Bvoluntary and striated
- Cinvoluntary and spindle shaped
- Dinvoluntary and striated
- Einnervated by the somatic nervous system
17Skeletal muscle ls:
- Avoluntary and spindle shaped
- Bvoluntary and striated
- Cinvoluntary and spindle shaped
- Dinvoluntary and striated
- Einnervated by ANS
18Cardiac muscle is:
- Avoluntary and spindle shaped
- Bvoluntary and striated
- Cinvoluntary and spindle shaped
- Dinvoluntary and striated
- Einnervated by the somatic nervous system
19Which type of muscle cell is multinucleated?
- ACardiac
- BSmooth
- CSkeletal
- DCardiac and smooth
- ENone of the above
20What is an example of a smooth muscle?
- Amasseter (face)
- Bbladder
- Cheart
- Dpronator teres (forearm)
- Erectus abdominis (belly)
21How many actin filaments surround each myosin filament?
- Atwo
- Bfour
- Csix
- Deight
- Eseven
22The muscular system is controlled by which system?
- Athe cardiovascular system
- Bthe endocrine system
- Cthe nervous system
- Dthe respiratory system
- Ethe urinary system
23How many types of muscle are there?
- Atwo
- Bthree
- Cfour
- Dfive
- Esix
24The sacroplasmic reticulum stores:
- Acalcium ions
- Bchloride ions
- Csodium ions
- Dpotassium ions
- Ehydrogen ions
25Which of the following should affect the strength or force of skeletal muscle contraction?
- Athe number of muscle fibers at rest
- Bthe degree of muscle stretch
- Cthe series-elastic elememts
- Dstronger stimuli
- Econcentration of Na+
26Which of these is true of skeletal muscle:
- Aspindle-shaped cells
- Bunder involuntary control
- Cmany peripherally located nuclei per muscle fiber
- Dforms the walls of hollow internal organs
- Emay be autorhythmic
27Which of these is not a major property of muscle?
- Acontractility
- Belasticity
- Cexcitability
- Dextensibility
- Esecretability
28What is each myofibril made of?
- Amany muscle fibers
- Bcontains sacroplasmic reticulum
- Cmany sacromeres
- Dcontains T-tubules
- Eis the same thing as a muscle fiber
29Myosin myofilaments are
- Aattached to the Z-disk
- Bfound primarily in the I band
- Cthinner than actin myofilaments
- Dabsent from the H zone
- Eattached to filaments that form the M-line
30The part of the sacrolemma that invaginates into the interior of skeletal muscle fibers is the
- AT-tubule system
- BSacroplasmic reticulum
- CMyofibrils
- DTerminal cisternae
- EMitochondria
31Which of these events occurs during the lag (latent) phase of muscle contraction?
- ACross-bridge movement
- BActive transport of Ca2+ into the sacroplasmic reticulum
- CCa2+ binding to troponin
- DSacromere shortening
- EBreakdown of ATP to ADP
32Muscle contraction which cannot move weight because it is too heavy is:
- Aisometric
- Bisotonic
- Cisokinetic
- Dconcentric
- Eeccentric
33Voluntary skeletal muscles in the leg are innervated
- APostganglionic neurons
- BSomatic motor neurons
- CPreganglionic neurons
- DCNS fibers
- EAll the above
34A small motor unit would control which type of movement?
- Afast but brief
- Bintense and strong
- Cdelicate and precise
- Dsprinting
- Emarathon running
35Muscle fibers type 1 have only one of the following features:
- Aslow onset of contraction
- Beasily fatigued
- Cmany enzyme for glycolysis
- Da slow refractory period
- Elow mitochondrial content
36Muscle fibers type Ila are:
- Aslow-twitch, glycolytic, fatigable resistant
- Bfast-twitch, oxidative-glycolytic, relatively fatigue resistant
- Cfast-twitch, glycolytic, fatigable
- Dslow-twitch, oxidative, fatigue resistant
- Efast-twitch, oxidative, fatigable
37Muscle fibers type IIb are:
- Aslow-twitch, glycolytic, fatigable resistant
- Bfast-twitch, oxidative-glycolytic, relatively fatigue resistant
- Cfast-twitch, glycolytic, fatigable
- Dslow-twitch, oxidative, fatigue resistant
- Efast-twitch, oxidative, fatigable
38Muscle fibers type 1 are
- Aslow-twitch, glycolytic, fatigable resistant
- Bfast-twitch, oxidative-glycolytic, relatively fatigue resistant
- Cfast-twitch, glycolytic, fatigable
- Dslow-twitch, oxidative, fatigue resistant
- Efast-twitch, oxidative, fatigable
39These bands of the sacromere do not shorten during contraction
- AA bands
- BH, I and M bands
- CZ discs and A bands
- DI bands
- Ea and d
40The role of transverse tubules in skeletal muscle fibers is to:
- Aconnect the sacromeres to each other
- Bbind the myofibrils
- Cspread the action potential quickly
- Dconnect the sacrolemma to the sacroplasmic reticulum
- Ebind to the receptors- dihydropyridine receptors
41The cross bridges of the sarcomere in skeletal muscle are components of:
- Aactin
- Bmyosin
- Ctroponin
- Dtropomyosin
- Etitin
42The function of tropomyosin in skeletal muscle In
- Asliding on actin to produce shortening
- Breleasing Ca2+ after initiation of contraction
- Cbinding to myosin during contraction
- Dcovering up the actin binding sites of myosin at rest
- Ereleasing Na+ after contraction
43The cell membranes In skeletal muscle:
- Aare impermeable to fat-soluble substances
- Bare more permeable to sodium than to potassium ions
- Cbecome more permeable to glucose in the presence of insulin
- Dbecome less permeable to potassium in the presence of insulin
- Eare ligand dependent
44A skeletal muscle fibre at rest:
- Apresents with a membrane which is positively charged on the inside with respect to the outside
- Bcontains intracellular stores of calcium ions
- Cis normally innervated by more than one motor neuron
- Dbecomes more excitable as its resting membrane potential increase in absolute value
- Ebecomes less excitable as the extracellular ionized calcium levels fall
45In skeletal muscle:
- Acontraction occurs when its pacemaker cells depolarize sufficiently to reach the threshold for firing
- Bcalcium is taken up by the sarcotubular system when it contracts
- Cactin and myosin filaments shorten when it contracts
- Dthe sarcomeres shorten during contraction
- Econtraction strength is related to the influx of K+ ions
46Visceral smooth muscle differs from skeletal muscle in that
- Ait contracts when stretched
- Bit is not paralyzed when its motor nerve supply is cut
- Cits cells have unstable resting membrane potentials
- Dexcitation depends more on influx of extracellular calcium than release of calcium from endoplasmic reticulum
- Eall of the above
47A property shared by:
- Askeletal and cardiac muscles is their striated microscopical appearance
- Bcardiac and visceral smooth muscles is their spontaneous activity when denervated
- Cskeletal and cardiac ventricular muscles is their stable resting membrane potential
- Dall types of muscles is that contraction strength is related to their initial length
- Eall of the above
48The action potential of skeletal muscle:
- Ahas a prolonged plateau phase
- Bspreads inwards to all parts of the muscle via T tubules
- Cis longer than the action potential of cardiac muscle
- Dis not essential for muscle conduction
- Ehas different amplitudes
49Smooth muscle need help of:
- Acalmodulin for contraction
- Bacetyl choline for contraction
- CK+ for contraction
- Dmonoamine oxidase for contraction
- Esecondly molar for contraction
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- Muscles- Physiology MCQs PMU
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