4. MCQS Muscle Physiology

The tetanic muscle contraction is:

a) as strong as the single muscle contraction;

b) 7-8 times stronger than the single muscle contraction;

c) 3-4 times weaker than the single muscle contraction;

d) 3-4 times stronger than the single muscle contraction;

e) the weakest type of muscle contraction.

The tetanic muscle contraction is:

a) as strong as the single muscle contraction;

b) 7-8 times stronger than the single muscle contraction;

c) 3-4 times weaker than the single muscle contraction;

d) 3-4 times stronger than the single muscle contraction;

e) the weakest type of muscle contraction.

The duration of a single muscle contraction is:

a) equal to the duration of the action potential;

b) is shorter than the duration of the action potential;

c) depends on the latency period;

d) depends on the refractory period;

e) is longer than the duration of the action potential.

The duration of a single muscle contraction is:

a) equal to the duration of the action potential;

b) is shorter than the duration of the action potential;

c) depends on the latency period;

d) depends on the refractory period;

e) is longer than the duration of the action potential.

During isotonic contraction of a skeletal muscle fibre:

a) the sarcomere length changes;

b) both length and tension change;

c) tension increases;

d) fibres relax;

e) tension decreases.

During isotonic contraction of a skeletal muscle fibre:

a) the sarcomere length changes;

b) both length and tension change;

c) tension increases;

d) fibres relax;

e) tension decreases.

Every two bones flexibly connected by a joint form:

a) a kinematic chain;

b) a motor unit;

c) a statokinetic system;

d) a triad;

e) a kinematic pair.

Every two bones flexibly connected by a joint form:

a) a kinematic chain;

b) a motor unit;

c) a statokinetic system;

d) a triad;

e) a kinematic pair.

What is the function of the protein titin?

a) causes calcium to be released into the cytoplasm of the cell;

b) increases the amount of ATP produced;

c) aids in the orientation of myosin to actin;

d) leads to stronger contractions;

e) provides nutrition to the muscle cell.

What is the function of the protein titin?

a) causes calcium to be released into the cytoplasm of the cell;

b) increases the amount of ATP produced;

c) aids in the orientation of myosin to actin;

d) leads to stronger contractions;

e) provides nutrition to the muscle cell.

In which type of muscle contraction is there a change in both the length and the tension at the same time?

a) isotonic;

b) auxotonic.

c) isometric;

d) eccentric;

e) concentric;

In which type of muscle contraction is there a change in both the length and the tension at the same time?

a) isotonic;

b) auxotonic.

c) isometric;

d) eccentric;

e) concentric;

'Motor unit' refers to:

a) a single motor neuron plus all the muscle fibres it innervates;

b) a single muscle fibre plus all the motor neurons that innervate it;

c) all of the motor neurons supplying a single muscle;

d) a pair of antagonistic muscles;

e) all of the muscles that affect the movement of any given joint.

'Motor unit' refers to:

a) a single motor neuron plus all the muscle fibres it innervates;

b) a single muscle fibre plus all the motor neurons that innervate it;

c) all of the motor neurons supplying a single muscle;

d) a pair of antagonistic muscles;

e) all of the muscles that affect the movement of any given joint.

What method is used to record skeletal muscle bioelectrical activity?

a) electromyography (EMG);

b) electrocardiography (ECG);

c) electroneurogram (ENG);

d) electroencephalography (EEG);

e) echography.

What method is used to record skeletal muscle bioelectrical activity?

a) electromyography (EMG);

b) electrocardiography (ECG);

c) electroneurogram (ENG);

d) electroencephalography (EEG);

e) echography.

Thick filaments in skeletal muscle are composed of:

a) actin;

b) troponin;

c) myosin;

d) calmodulin;

e) tropomyosin.

Thick filaments in skeletal muscle are composed of:

a) actin;

b) troponin;

c) myosin;

d) calmodulin;

e) tropomyosin.

In skeletal muscle calcium facilitates contraction by binding to:

a) tropomyosin;

b) actin;

c) troponin;

d) myosin;

e) the thick filament.

In skeletal muscle calcium facilitates contraction by binding to:

a) tropomyosin;

b) actin;

c) troponin;

d) myosin;

e) the thick filament.

With regard to knee jerk:

a) it is a monosynaptic reflex;

b) the impulse travels via type Ca afferent fibres;

c) the Golgi body is an important component;

d) the stimulus begins in the tendon;

e) it is a visceral reflex.

With regard to knee jerk:

a) it is a monosynaptic reflex;

b) the impulse travels via type Ca afferent fibres;

c) the Golgi body is an important component;

d) the stimulus begins in the tendon;

e) it is a visceral reflex.

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

a) excitation-contraction coupling;

b) prevent the contraction;

c) form cross bridges;

d) release energy for the contraction;

e) excite the myofiber.

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

a) excitation-contraction coupling;

b) prevent the contraction;

c) form cross bridges;

d) release energy for the contraction;

e) excite the myofiber.

Smooth muscle is not cross striated because:

a) of myosin and actin in the myofibril;

b) myofibrils are in register with each other;

c) myofibrils are not in register with each other;

d) it has gap junctions;

e) it is surrounded by a basal lamina.

Smooth muscle is not cross striated because:

a) of myosin and actin in the myofibril;

b) myofibrils are in register with each other;

c) myofibrils are not in register with each other;

d) it has gap junctions;

e) it is surrounded by a basal lamina.

Intercalated discs are most likely to be observed in:

a) longitudinal section of skeletal muscle;

b) transverse section of skeletal muscle;

c) transverse section of cardiac muscle;

d) longitudinal section of cardiac muscle;

e) transverse section of smooth muscle.

Intercalated discs are most likely to be observed in:

a) longitudinal section of skeletal muscle;

b) transverse section of skeletal muscle;

c) transverse section of cardiac muscle;

d) longitudinal section of cardiac muscle;

e) transverse section of smooth muscle.

Cardiac muscle is:

a) voluntary and spindle shaped;

b) voluntary and striated;

c) involuntary and spindle shaped;

d) involuntary and striated;

e) innervated by the somatic nervous system.

Cardiac muscle is:

a) voluntary and spindle shaped;

b) voluntary and striated;

c) involuntary and spindle shaped;

d) involuntary and striated;

e) innervated by the somatic nervous system.

During an isometric contraction of a skeletal muscle:

a) the I-bands shorten and the A-bands stay the same length;

b) the thick and thin filaments slide past each other;

c) sarcomere length does not change;

d) tension does not change;

e) the sarcomere shortens.

During an isometric contraction of a skeletal muscle:

a) the I-bands shorten and the A-bands stay the same length;

b) the thick and thin filaments slide past each other;

c) sarcomere length does not change;

d) tension does not change;

e) the sarcomere shortens.

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

a) actin;

b) myosin;

c) troponin;

d) tropomyosin;

e) myelin.

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

a) actin;

b) myosin;

c) troponin;

d) tropomyosin;

e) myelin.

Which area of the sarcomere consists only of myosin filaments?

a) I-bands;

b) H-zone;

c) A-bands;

d) M-line;

e) Z-disc.

Which area of the sarcomere consists only of myosin filaments?

a) I-bands;

b) H-zone;

c) A-bands;

d) M-line;

e) Z-disc.

Which muscle cell compound stores oxygen?

a) creatine phosphate;

b) glycogen;

c) hemoglobin;

d) myoglobin;

e) lipid droplets.

Which muscle cell compound stores oxygen?

a) creatine phosphate;

b) glycogen;

c) hemoglobin;

d) myoglobin;

e) lipid droplets.

Smooth muscle is:

a) voluntary and spindle shaped;

b) voluntary and striated;

c) involuntary and spindle shaped;

d) involuntary and striated;

e) innervated by the somatic nervous system.

Smooth muscle is:

a) voluntary and spindle shaped;

b) voluntary and striated;

c) involuntary and spindle shaped;

d) involuntary and striated;

e) innervated by the somatic nervous system.

Skeletal muscle is:

a) voluntary and spindle shaped;

b) voluntary and striated;

c) involuntary and spindle shaped;

d) involuntary and striated;

e) innervated by ANS.

Skeletal muscle is:

a) voluntary and spindle shaped;

b) voluntary and striated;

c) involuntary and spindle shaped;

d) involuntary and striated;

e) innervated by ANS.

Which type of muscle cell is multinucleated?

a) cardiac;

b) smooth muscles;

c) skeletal;

d) cardiac and smooth;

e) connective tissue.

Which type of muscle cell is multinucleated?

a) cardiac;

b) smooth muscles;

c) skeletal;

d) cardiac and smooth;

e) connective tissue.

What is an example of a smooth muscle?

a) masseter (face);

b) bladder;

c) heart;

d) pronator teres (forearm);

e) rectus abdominis (belly).

What is an example of a smooth muscle?

a) masseter (face);

b) bladder;

c) heart;

d) pronator teres (forearm);

e) rectus abdominis (belly).

How many actin filaments surround each myosin filament?

a) two;

b) four;

c) six;

d) eight;

e) seven.

How many actin filaments surround each myosin filament?

a) two;

b) four;

c) six;

d) eight;

e) seven.

The muscular system is controlled by which system?

a) the cardiovascular system;

b) the endocrine system;

c) the nervous system;

d) the respiratory system;

e) the urinary system.

The muscular system is controlled by which system?

a) the cardiovascular system;

b) the endocrine system;

c) the nervous system;

d) the respiratory system;

e) the urinary system.

Which protein is not involved in skeletal muscles contraction?

a) myosin;

b) troponin;

c) actin;

d) tropomyosin;

e) myoglobin.

Which protein is not involved in skeletal muscles contraction?

a) myosin;

b) troponin;

c) actin;

d) tropomyosin;

e) myoglobin.

The neuromuscular synapses are:

a) only excitatory;

b) only inhibitory;

c) neither excitatory nor inhibitory;

d) excitatory or inhibitory depending on the receptors;

e) excitatory or inhibitory depending on the neurotransmitter

The neuromuscular synapses are:

a) only excitatory;

b) only inhibitory;

c) neither excitatory nor inhibitory;

d) excitatory or inhibitory depending on the receptors;

e) excitatory or inhibitory depending on the neurotransmitter

The sarcoplasmic reticulum stores:

a) calcium ions;

b) chloride ions;

c) sodium ions;

d) potassium ions;

e) hydrogen ions.

The sarcoplasmic reticulum stores:

a) calcium ions;

b) chloride ions;

c) sodium ions;

d) potassium ions;

e) hydrogen ions.

Which of these is true of skeletal muscle:

a) spindle-shaped cells;

b) under involuntary control;

c) many peripherally located nuclei per muscle fiber;

d) forms the walls of hollow internal organs;

e) may be autorhythmic.

Which of these is true of skeletal muscle:

a) spindle-shaped cells;

b) under involuntary control;

c) many peripherally located nuclei per muscle fiber;

d) forms the walls of hollow internal organs;

e) may be autorhythmic.

Which of these is not a major property of muscle?

a) contractility;

b) elasticity;

c) excitability;

d) extensibility;

e) secretability.

Which of these is not a major property of muscle?

a) contractility;

b) elasticity;

c) excitability;

d) extensibility;

e) secretability.

Mysoin myofilaments are:

a) attached to the Z-disk;

b) found primarily in the I-band;

c) thinner than actin myofilaments;

d) absent from the H-zone;

e) attached to filaments that form the M-line.

Mysoin myofilaments are:

a) attached to the Z-disk;

b) found primarily in the I-band;

c) thinner than actin myofilaments;

d) absent from the H-zone;

e) attached to filaments that form the M-line.

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

a) T-tubule system;

b) sarcoplasmic reticulum;

c) myofibrils;

d) terminal cisternae;

e) mitochondria.

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

a) T-tubule system;

b) sarcoplasmic reticulum;

c) myofibrils;

d) terminal cisternae;

e) mitochondria.

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

a) cross-bridge movement;

b) active transport of Ca2+ into the sarcoplasmic reticulum;

c) Ca2+ binding to troponin;

d) sarcomere shortening;

e) breakdown of ATP to ADP.

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

a) cross-bridge movement;

b) active transport of Ca2+ into the sarcoplasmic reticulum;

c) Ca2+ binding to troponin;

d) sarcomere shortening;

e) breakdown of ATP to ADP.

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

a) isometric;

b) isotonic;

c) isokinetic;

d) concentric;

e) eccentric.

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

a) isometric;

b) isotonic;

c) isokinetic;

d) concentric;

e) eccentric.

A small motor unit would control which type of movement?

a) fast but brief;

b) intense and strong;

c) delicate and precise;

d) sprinting;

e) marathon running.

A small motor unit would control which type of movement?

a) fast but brief;

b) intense and strong;

c) delicate and precise;

d) sprinting;

e) marathon running.

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

a) slow onset of contraction

b) easily fatigued;

c) many enzymes for glycolysis;

d) a slow refractory period;

e) low mitochondrial content.

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

a) slow onset of contraction

b) easily fatigued;

c) many enzymes for glycolysis;

d) a slow refractory period;

e) low mitochondrial content.

Muscle fibers type IIa are:

a) slow-twitch, glycolytic, fatigable resistant;

b) fast-twitch, oxidative-glycolytic, relatively fatigue resistant;

c) fast-twitch, glycolytic, fatigable;

d) slow-twitch, oxidative, fatigue resistant;

e) fast-twitch, oxidative, fatigable.

Muscle fibers type IIa are:

a) slow-twitch, glycolytic, fatigable resistant;

b) fast-twitch, oxidative-glycolytic, relatively fatigue resistant;

c) fast-twitch, glycolytic, fatigable;

d) slow-twitch, oxidative, fatigue resistant;

e) fast-twitch, oxidative, fatigable.

Muscle fibers type IIb are:

a) slow-twitch, glycolytic, fatigable resistant;

b) fast-twitch, oxidative-glycolytic, relatively fatigue resistant;

c) fast-twitch, glycolytic, fatigable;

d) slow-twitch, oxidative, fatigue resistant;

e) fast-twitch, oxidative, fatigable.

Muscle fibers type IIb are:

a) slow-twitch, glycolytic, fatigable resistant;

b) fast-twitch, oxidative-glycolytic, relatively fatigue resistant;

c) fast-twitch, glycolytic, fatigable;

d) slow-twitch, oxidative, fatigue resistant;

e) fast-twitch, oxidative, fatigable.

Muscle fibers type I are:

a) slow-twitch, glycolytic, fatigable resistant;

b) fast-twitch, oxidative-glycolytic, relatively fatigue resistant;

c) fast-twitch, glycolytic, fatigable;

d) slow-twitch, oxidative, fatigue resistant;

e) fast-twitch, oxidative, fatigable.

Muscle fibers type I are:

a) slow-twitch, glycolytic, fatigable resistant;

b) fast-twitch, oxidative-glycolytic, relatively fatigue resistant;

c) fast-twitch, glycolytic, fatigable;

d) slow-twitch, oxidative, fatigue resistant;

e) fast-twitch, oxidative, fatigable.

These bands of the sarcomere do not shorten during contraction:

a) A-bands;

b) H-, I-, and M-bands;

c) Z-discs and A-bands;

d) I-bands;

e) Z-discs.

These bands of the sarcomere do not shorten during contraction:

a) A-bands;

b) H-, I-, and M-bands;

c) Z-discs and A-bands;

d) I-bands;

e) Z-discs.

The smooth muscles are innervated by:

a) a-motor neurons in the spinal cord;

b) y-motor neurons;

c) pseudounipolar neurons in the spinal ganglia;

d) postganglionic neurons of the ANS;

e) preganglionic neurons of the ANS.

The smooth muscles are innervated by:

a) a-motor neurons in the spinal cord;

b) y-motor neurons;

c) pseudounipolar neurons in the spinal ganglia;

d) postganglionic neurons of the ANS;

e) preganglionic neurons of the ANS.

The function of tropomyosin in skeletal muscle is:

a) sliding on actin to produce shortening;

b) releasing Ca2+ after initiation of contraction;

c) binding to myosin during contraction;

d) covering up the active sites of actin at rest;

e) releasing Na+ after contraction.

The function of tropomyosin in skeletal muscle is:

a) sliding on actin to produce shortening;

b) releasing Ca2+ after initiation of contraction;

c) binding to myosin during contraction;

d) covering up the active sites of actin at rest;

e) releasing Na+ after contraction.

The cell membranes in skeletal muscle:

a) are impermeable to fat-soluble substances;

b) are more permeable to sodium than to potassium ions;

c) become more permeable to glucose in the presence of insulin;

d) become less permeable to potassium in the presence of insulin;

e) are ligand dependent.

The cell membranes in skeletal muscle:

a) are impermeable to fat-soluble substances;

b) are more permeable to sodium than to potassium ions;

c) become more permeable to glucose in the presence of insulin;

d) become less permeable to potassium in the presence of insulin;

e) are ligand dependent.

A skeletal muscle fibre at rest:

a) presents with a membrane which is positively charged on the inside with respect to the outside;

b) contains intracellular stores of calcium ions;

c) is normally innervated by more than one motor neurone;

d) becomes more excitable as its resting membrane potential increase in absolute value;

e) becomes less excitable as the extracellular ionized calcium levels fall.

A skeletal muscle fibre at rest:

a) presents with a membrane which is positively charged on the inside with respect to the outside;

b) contains intracellular stores of calcium ions;

c) is normally innervated by more than one motor neurone;

d) becomes more excitable as its resting membrane potential increase in absolute value;

e) becomes less excitable as the extracellular ionized calcium levels fall.

In skeletal muscle:

a) contraction occurs when its pacemaker cells depolarize sufficiently to reach the threshold for firing;

b) calcium is taken up by the sarcotubular system when it contracts;

c) actin and myosin filaments shorten when it contracts;

d) the sarcomeres shorten during contraction;

e) contraction strength is related to the influx of K+ ions.

In skeletal muscle:

a) contraction occurs when its pacemaker cells depolarize sufficiently to reach the threshold for firing;

b) calcium is taken up by the sarcotubular system when it contracts;

c) actin and myosin filaments shorten when it contracts;

d) the sarcomeres shorten during contraction;

e) contraction strength is related to the influx of K+ ions.

The action potential of skeletal muscle:

a) has a prolonged plateau phase;

b) spreads inwards to all parts of the muscle via T-tubules;

c) is longer than the action potential of cardiac muscle;

d) is not essential for muscle conduction:

e) has different amplitudes.

The action potential of skeletal muscle:

a) has a prolonged plateau phase;

b) spreads inwards to all parts of the muscle via T-tubules;

c) is longer than the action potential of cardiac muscle;

d) is not essential for muscle conduction:

e) has different amplitudes.

Smooth muscle need help of:

a) calmodulin for contraction;

b) acetylcholine for contraction;

c) K+ for contraction;

d) monoamine oxidase for contraction;

e) secondary messenger for contraction.

Smooth muscle need help of:

a) calmodulin for contraction;

b) acetylcholine for contraction;

c) K+ for contraction;

d) monoamine oxidase for contraction;

e) secondary messenger for contraction.

The sarcomere is:

a) the principal protein in the skeletal muscle;

b) the basic functional unit of the smooth muscle;

c) the main energy source of muscle contraction;

d) the basic functional unit of the skeletal muscle fibre;

e) the main proprioceptor.

The sarcomere is:

a) the principal protein in the skeletal muscle;

b) the basic functional unit of the smooth muscle;

c) the main energy source of muscle contraction;

d) the basic functional unit of the skeletal muscle fibre;

e) the main proprioceptor.

The types of muscles in the human body are:

a) skeletal, voluntary and smooth;

b) striated, smooth and cardiac;

c) involuntary, smooth and striated;

d) striated, smooth and skeletal;

e) cardiac and smooth.

The types of muscles in the human body are:

a) skeletal, voluntary and smooth;

b) striated, smooth and cardiac;

c) involuntary, smooth and striated;

d) striated, smooth and skeletal;

e) cardiac and smooth.

Adequate stimuli of the smooth muscle are:

a) mechanical overload/stretching, temperature changes and chemical substances;

b) electrical stimulation and slow stretching;

c) electrical and osmotic stimuli;

d) only electrical stimuli;

e) only stretching.

Adequate stimuli of the smooth muscle are:

a) mechanical overload/stretching, temperature changes and chemical substances;

b) electrical stimulation and slow stretching;

c) electrical and osmotic stimuli;

d) only electrical stimuli;

e) only stretching.

A lot of electrical synapses and autorhythmicity have:

a) skeletal muscles;

b) all smooth muscles;

c) visceral type of smooth muscles;

d) multi-unit smooth muscles;

e) all extensors.

A lot of electrical synapses and autorhythmicity have:

a) skeletal muscles;

b) all smooth muscles;

c) visceral type of smooth muscles;

d) multi-unit smooth muscles;

e) all extensors.

Red muscle fibers are:

a) only type I;

b) only IIa;

c) type I and IIa;

d) only IIb;

e) all muscle fiber types.

Red muscle fibers are:

a) only type I;

b) only IIa;

c) type I and IIa;

d) only IIb;

e) all muscle fiber types.

White muscle fibers are:

a) only type I;

b) only IIa;

c) type I and IIa;

d) only IIb;

e) all muscle fiber types.

White muscle fibers are:

a) only type I;

b) only IIa;

c) type I and IIa;

d) only IIb;

e) all muscle fiber types.

Muscle contraction in which the muscle lengthens is called:

a) concentric;

b) eccentric;

c) isotonic;

d) isometric;

e) auxotonic.

Muscle contraction in which the muscle lengthens is called:

a) concentric;

b) eccentric;

c) isotonic;

d) isometric;

e) auxotonic.

Muscle contraction in which the muscle shortens is called:

a) concentric;

b) eccentric;

c) isotonic;

d) isometric;

e) auxotonic.

Muscle contraction in which the muscle shortens is called:

a) concentric;

b) eccentric;

c) isotonic;

d) isometric;

e) auxotonic.

The neurotransmitter released from the final endings of the motoneurons innervating skeletal muscles is:

a) serotonin;

b) norepinephrine;

c) acetylcholine;

d) glycine;

e) adrenaline.

The neurotransmitter released from the final endings of the motoneurons innervating skeletal muscles is:

a) serotonin;

b) norepinephrine;

c) acetylcholine;

d) glycine;

e) adrenaline.

The number of muscle fibres in a motor unit determines:

a) its maximum contraction force;

b) the contraction speed;

c) whether or not the muscle contractions are 'concentric' or 'eccentric';

d) whether or not the muscle contactions are isometric or isotonic;

e) whether or not the muscle contractions are single or tetanic.

The number of muscle fibres in a motor unit determines:

a) its maximum contraction force;

b) the contraction speed;

c) whether or not the muscle contractions are 'concentric' or 'eccentric';

d) whether or not the muscle contactions are isometric or isotonic;

e) whether or not the muscle contractions are single or tetanic.

What is each myofibril made of?

a) many muscle fibers.

b) contains sarcoplasmic reticulum;

c) many sarcomeres;

d) contains T-tubules;

e) is the same thing as a muscle fiber.

What is each myofibril made of?

a) many muscle fibers.

b) contains sarcoplasmic reticulum;

c) many sarcomeres;

d) contains T-tubules;

e) is the same thing as a muscle fiber.

The motor units of the skeletal muscles are composed of:

a) fast- and slow-twitch muscle fibres;

b) type I and type II muscle fibres;

c) type I and type IIb (white) fibres;

d) uniform fibre type;

e) three different types of muscle fibres.

The motor units of the skeletal muscles are composed of:

a) fast- and slow-twitch muscle fibres;

b) type I and type II muscle fibres;

c) type I and type IIb (white) fibres;

d) uniform fibre type;

e) three different types of muscle fibres.

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

a) slow onset of contraction

b) easily fatigued;

c) many enzymes for oxidation;

d) a slow refractory period;

e) high mitochondrial content.

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

a) slow onset of contraction

b) easily fatigued;

c) many enzymes for oxidation;

d) a slow refractory period;

e) high mitochondrial content.