Med Student
Quiz by , created more than 1 year ago

Muscles- Physiology MCQs PMU

2667
31
0
Med Student
Created by Med Student about 7 years ago
Close

Muscles- Physiology MCQs PMU- 2nd Year

Question 1 of 49

1

Thick filaments in skeletal muscle are composed of

Select one of the following:

  • actin

  • myosin

  • troponin

  • calmodulin

  • tropomyosin

Explanation

Question 2 of 49

1

During isotonic contraction of a skeletal muscle fibre:

Select one of the following:

  • The sarcomere shortens

  • A-bands shorten

  • Tension increases

  • Fibres relax

  • None of the above

Explanation

Question 3 of 49

1

In skeletal muscle calcium facilitates contraction by binding to:

Select one of the following:

  • tropomyosin

  • actin

  • troponin

  • myosin

  • the thick filament

Explanation

Question 4 of 49

1

Motor unit’ refers to:

Select one of the following:

  • 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

Explanation

Question 5 of 49

1

During an isometric contraction of a skeletal muscle:

Select one of the following:

  • 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

Explanation

Question 6 of 49

1

The cross bridge in the sacromere of skeletal muscle are made of:

Select one of the following:

  • actin

  • myosin

  • troponin

  • tropomyosin

  • myelin

Explanation

Question 7 of 49

1

With regard to knee jerk:

Select one of the following:

  • 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

Explanation

Question 8 of 49

1

The most important contractile proteins are:

Select one of the following:

  • myosin

  • troponin

  • actin

  • tropomyosin

  • all of the above

Explanation

Question 9 of 49

1

Which role do Ca2+ ions play in the muscle contraction?

Select one of the following:

  • excitation-contraction coupling

  • prevent the contraction

  • form cross bridges

  • release energy for the contraction

  • excite the myofiber

Explanation

Question 10 of 49

1

Smooth muscle is not cross striated because:

Select one of the following:

  • 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

Explanation

Question 11 of 49

1

lntercalated discs are most likely to be observed in:

Select one of the following:

  • 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

Explanation

Question 12 of 49

1

During strong exercise, oxygen consumption is greatest in the:

Select one of the following:

  • brain

  • heart

  • skeletal muscles

  • liver

  • kidneys

Explanation

Question 13 of 49

1

An increase in force of a skeletal muscle contraction is initially achieved by:

Select one of the following:

  • recruitment of nerve fibers

  • recruitment of muscle fibers

  • recruitment of motor units

  • increased intracellular calcium

  • increased lactic acid

Explanation

Question 14 of 49

1

Which area of the sacromere consists only of myosin filaments?

Select one of the following:

  • I-bands

  • H-zone

  • A-bands

  • M-line

  • Z-disc

Explanation

Question 15 of 49

1

Which muscle cell compound stores oxygen?

Select one of the following:

  • creatine phosphate

  • glycogen

  • hemoglobin

  • myoglobin

  • lipid droplets

Explanation

Question 16 of 49

1

Smooth muscle is:

Select one of the following:

  • voluntary and spindle shaped

  • voluntary and striated

  • involuntary and spindle shaped

  • involuntary and striated

  • innervated by the somatic nervous system

Explanation

Question 17 of 49

1

Skeletal muscle ls:

Select one of the following:

  • voluntary and spindle shaped

  • voluntary and striated

  • involuntary and spindle shaped

  • involuntary and striated

  • innervated by ANS

Explanation

Question 18 of 49

1

Cardiac muscle is:

Select one of the following:

  • voluntary and spindle shaped

  • voluntary and striated

  • involuntary and spindle shaped

  • involuntary and striated

  • innervated by the somatic nervous system

Explanation

Question 19 of 49

1

Which type of muscle cell is multinucleated?

Select one of the following:

  • Cardiac

  • Smooth

  • Skeletal

  • Cardiac and smooth

  • None of the above

Explanation

Question 20 of 49

1

What is an example of a smooth muscle?

Select one of the following:

  • masseter (face)

  • bladder

  • heart

  • pronator teres (forearm)

  • rectus abdominis (belly)

Explanation

Question 21 of 49

1

How many actin filaments surround each myosin filament?

Select one of the following:

  • two

  • four

  • six

  • eight

  • seven

Explanation

Question 22 of 49

1

The muscular system is controlled by which system?

Select one of the following:

  • the cardiovascular system

  • the endocrine system

  • the nervous system

  • the respiratory system

  • the urinary system

Explanation

Question 23 of 49

1

How many types of muscle are there?

Select one of the following:

  • two

  • three

  • four

  • five

  • six

Explanation

Question 24 of 49

1

The sacroplasmic reticulum stores:

Select one of the following:

  • calcium ions

  • chloride ions

  • sodium ions

  • potassium ions

  • hydrogen ions

Explanation

Question 25 of 49

1

Which of the following should affect the strength or force of skeletal muscle contraction?

Select one of the following:

  • the number of muscle fibers at rest

  • the degree of muscle stretch

  • the series-elastic elememts

  • stronger stimuli

  • concentration of Na+

Explanation

Question 26 of 49

1

Which of these is true of skeletal muscle:

Select one of the following:

  • spindle-shaped cells

  • under involuntary control

  • many peripherally located nuclei per muscle fiber

  • forms the walls of hollow internal organs

  • may be autorhythmic

Explanation

Question 27 of 49

1

Which of these is not a major property of muscle?

Select one of the following:

  • contractility

  • elasticity

  • excitability

  • extensibility

  • secretability

Explanation

Question 28 of 49

1

What is each myofibril made of?

Select one of the following:

  • many muscle fibers

  • contains sacroplasmic reticulum

  • many sacromeres

  • contains T-tubules

  • is the same thing as a muscle fiber

Explanation

Question 29 of 49

1

Myosin myofilaments are

Select one of the following:

  • 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

Explanation

Question 30 of 49

1

The part of the sacrolemma that invaginates into the interior of skeletal muscle fibers is the

Select one of the following:

  • T-tubule system

  • Sacroplasmic reticulum

  • Myofibrils

  • Terminal cisternae

  • Mitochondria

Explanation

Question 31 of 49

1

Which of these events occurs during the lag (latent) phase of muscle contraction?

Select one of the following:

  • Cross-bridge movement

  • Active transport of Ca2+ into the sacroplasmic reticulum

  • Ca2+ binding to troponin

  • Sacromere shortening

  • Breakdown of ATP to ADP

Explanation

Question 32 of 49

1

Muscle contraction which cannot move weight because it is too heavy is:

Select one of the following:

  • isometric

  • isotonic

  • isokinetic

  • concentric

  • eccentric

Explanation

Question 33 of 49

1

Voluntary skeletal muscles in the leg are innervated

Select one of the following:

  • Postganglionic neurons

  • Somatic motor neurons

  • Preganglionic neurons

  • CNS fibers

  • All the above

Explanation

Question 34 of 49

1

A small motor unit would control which type of movement?

Select one of the following:

  • fast but brief

  • intense and strong

  • delicate and precise

  • sprinting

  • marathon running

Explanation

Question 35 of 49

1

Muscle fibers type 1 have only one of the following features:

Select one of the following:

  • slow onset of contraction

  • easily fatigued

  • many enzyme for glycolysis

  • a slow refractory period

  • low mitochondrial content

Explanation

Question 36 of 49

1

Muscle fibers type Ila are:

Select one of the following:

  • 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

Explanation

Question 37 of 49

1

Muscle fibers type IIb are:

Select one of the following:

  • 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

Explanation

Question 38 of 49

1

Muscle fibers type 1 are

Select one of the following:

  • 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

Explanation

Question 39 of 49

1

These bands of the sacromere do not shorten during contraction

Select one of the following:

  • A bands

  • H, I and M bands

  • Z discs and A bands

  • I bands

  • a and d

Explanation

Question 40 of 49

1

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

Select one of the following:

  • 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

Explanation

Question 41 of 49

1

The cross bridges of the sarcomere in skeletal muscle are components of:

Select one of the following:

  • actin

  • myosin

  • troponin

  • tropomyosin

  • titin

Explanation

Question 42 of 49

1

The function of tropomyosin in skeletal muscle In

Select one of the following:

  • 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

Explanation

Question 43 of 49

1

The cell membranes In skeletal muscle:

Select one of the following:

  • 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

Explanation

Question 44 of 49

1

A skeletal muscle fibre at rest:

Select one of the following:

  • 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

Explanation

Question 45 of 49

1

In skeletal muscle:

Select one of the following:

  • 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

Explanation

Question 46 of 49

1

Visceral smooth muscle differs from skeletal muscle in that

Select one of the following:

  • 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

Explanation

Question 47 of 49

1

A property shared by:

Select one of the following:

  • 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

Explanation

Question 48 of 49

1

The action potential of skeletal muscle:

Select one of the following:

  • 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

Explanation

Question 49 of 49

1

Smooth muscle need help of:

Select one of the following:

  • calmodulin for contraction

  • acetyl choline for contraction

  • K+ for contraction

  • monoamine oxidase for contraction

  • secondly molar for contraction

Explanation

Previous
Check answer
Next