physiology cardiovascular MCQ

The primary pacemaker of the heart at physiological condition is normally the:

Sino-atrial node

Atrio-ventricular node

Bundle of His

Mitral valve

Left ventricle

Sino-atrial node

Current caused by opening of which of the following channels contribute to the repolarization phase of the action potential of ventricular muscle fibers?

Na+ channels

Cl- channels

Ca2+ channels

K+ channels

HCO3- channels

K+ channels

In second degree heart block:

The ventricular rate is lower than the atrial rate

The ventricular ECG complexes are distorted

There is a high incidence of ventricular tachycardia

Stroke volume is decreased

Cardiac output is increased

The ventricular rate is lower than the atrial rate

On the electrocardiogram (ECG), the QRS complex represents:

Depolarization of the atria

Repolarization of the atria

Depolarization of the ventricles

Repolarization of the ventricles

Delay at the AV node

Depolarization of the ventricles

An ECG would be useful for determining a patient's:

Heart murmur

Stroke volume

Cardiac output

Blockage of conduction of electrical signals between the atria and ventricles

None of the above

Blockage of conduction of electrical signals between the atria and ventricles

According to the Frank-Starling mechanism of the heart:

With each systole the left ventricle ejects a larger volume of blood then the right ventricle

The intrinsic rate of the heart's pacemaker is 100 bpm

Cardiac output increases with increased heart rate

Stroke volume increases with the increase of the venous return

Both ventricles contract simultaneously

Stroke volume increases with the increase of the venous return

Within protodiastole of the ventricles:

AV valves are opened, SL valves closed

AV and SL valves are closed

AV and SL valves are opened

AV valves are closed, SL valves are closing

None of the upper mentioned are correct

AV valves are closed, SL valves are closing

During exercise, there is an increased blood flow to:

The brain

The kidneys

The muscles

The endocrine glands

Prostate gland

The muscles

During isovolumetric contraction:

AV valves are opened, SL valves are opened

AV valves are closed, SL valves are opened

AV valves are opened, SL valves are closed

AV valves are closed, SL valves are closed

Sometimes AV valves are opened, sometimes closed, depending on the end-diastolic volume (EDV)

AV valves are closed, SL valves are closed

The aortic valve:

Prevents the backflow of blood into the aorta during ventricular diastole

Prevents the backflow of blood into the left ventricle during ventricular diastole

Prevents the backflow of blood into the aorta during ventricular ejection

Prevents the backflow of blood into the aorta during ejection

Closes when the first heart sound is heard

Prevents the backflow of blood into the left ventricle during ventricular diastole

In humans, blood loss causes:

venous contraction

increased blood flow to the skin

a rise in the cardiac output

decrease erythropoietin production

increased hematocrit level

venous contraction

The heart sounds:

express the arterial wall fluctuations synchronous with the cardiac performance

register the cardiomyocytes bioelectrical activity during the cardiac cycle

reflect the volume of blood, which the heart ejects in the large and small circle per minute

are registered and analyzed via auscultation and phonocardiography

are registered via phlebography

are registered and analyzed via auscultation and phonocardiography

Which of the following organs has the greatest blood flow per 100g of tissue?

brain

heart muscle

skin

liver

kidney

kidney

If the heart rate is 70bt/min, cardiac output is closer to:

3.45l/min

4.55l/min

5.25l/min

8.01l/min

9.85l/min

5.25l/min

Which of ECG elements reflects the ventricular depolarization?

PQ interval

QRS complex

QT interval

ST segment

T wave

QRS complex

Cardiac output of the right heart is what percentage of the left?

25%

50%

75%

100%

125%

100%

During the ventricular filling:

AV valves are opened, SL valves are opened

AV valves are closed, SL valves are opened

AV valves are opened, SL valves are closed

AV valves are closed, SL valves are closed

None of the above

AV valves are opened, SL valves are closed

In complex heart block:

Fainting may occur because the atria are unable to pump blood into the ventricles

Ventricular fibrillation is common

The atrial rate is lower than the ventricular rate

The atrial rate is the same as the ventricular rate

Fainting may occur because of prolonged periods during which the ventricles fail to contract

Fainting may occur because of prolonged periods during which the ventricles fail to contract

The work performed by the left ventricle is substantially grater than that performed by the right ventricle, because in the left ventricle:

The contraction is slower

The wall is thicker

The stroke volume is greater

The preload is greater

The afterload is greater

The afterload is greater

Starling's law of the heart:

Does not operate in the failing heart

Does not operate during exercise

Explains the increase in heart rate produced by exercise

Explains the increase in cardiac output that occurs when venous return is increased

Explains the increase in cardiac output when the sympathetic nerves supplying the heart are stimulated

Explains the increase in cardiac output that occurs when venous return is increased

Which effect(s) is/are caused by sympathetic stimulation?

Increased strength of heart contraction

Decreased heart metabolism

Decreased heart conductibility

Decreased excitability

The heart is resistant to sympathetic stimulation

Increased strength of heart contraction

Which are the peculiarities of the cardiomyocytes' action potential?

Long duration (0.3s) and the presence of plateau phase

Short duration (0.01s) and the presence of plateau phase

High amplitude and short absolute refractory period

Lack of absolute refractory period

Lack of after potentials

Long duration (0.3s) and the presence of plateau phase

The integral of the valves of blood pressure during one cardiac cycle is defined as:

Pulse pressure

The systolic blood pressure

The diastolic blood pressure

Mean arterial blood pressure

Closer in valve to the systolic blood pressure

Mean arterial blood pressure

The duration of the cardiac cycle depends on:

The stroke volume

The time needed one systole to occur

The time needed one diastole to occur

The heart rate

The cardiac pause

The heart rate

Hypokalaemia causes:

Short PQ interval

Ventricular extrasystoles

Elevated ST segment

Prolonged QRS interval

Prolonged QT interval

Ventricular extrasystoles

Hyperkalaemia causes:

Causes a prolongued QT interval

Prolongs the QRS complex

Causes ST segment elevation

Potentiates digoxin toxicity

Causes lack of P wave

Prolongs the QRS complex

Left ventricular end-diastolic volume is:

10-30 ml

30-50 ml

50-70 ml

70-100 ml

100-130ml

100-130ml

The automatic activity of 20-40 imp.min^ -1 is typical for the:

The bundle of His

The A-V node

The sino-atrial node

The cells of Purkinje

the left and right ventricular branches

the cells of the Purkinje

The end diastolic volume (EDV):

Depends on the stroke volume

is directly proportional to the venous return to the heart

Doesn't depend on length and strength, developed by the ventricular myocardium

Increases when the blood pressure in aorta increases

Doesn't depend on atrial systole and diastole

is directly proportional to the venous return to the heart

Which of the following factors is not a vasoconstrictor:

Noradrenaline (norepinephrine)

Vasopressin

Serotonin

Angiotensin

Atria natriuretic peptide

atrial natriuretic peptide

The slowest conduction (velocity) is characteristics for:

Atria

AV node

Bundle of His

Prukinje fibres

Ventricular muscle

AV node

Effect on α- and β-adrenergic receptors has:

Noradrenaline (norepinephrine)

Adrenaline (epinephrine)

Atropine

Angiotensin II

serotonin

adrenaline (epinephrine)

In a patient with mitral stenosis one would expect to hear:

Continuous murmur

A systolic murmur loudest over the base of the heart

a diastolic murmur, with loudest intensity over the apex of heart

a diastolic murmur loudest over the base of heart

Systolic murmur over the apex of heart

a diastolic murmur, with loudest intensity over apex of heart

The activity of the peripheral chemoreceptors increases when:

The mean arterial blood pressure is increased

PO2 in blood is decreased

PCO2 in blood is decreased

H+ concentration is decreased

There is hypothermia

pO2 in blood is decreased

Oxygen consumption at rest is the highest in the:

Brain

Heart

Liver

Kidneys

Skeletal muscles

heart

The coronary blood flow is:

Dominant in the left coronary artery in 60% of people

Not decreased during systole in the left ventricle better delivered to subendocardium during systole

Not suspended during systole in the right coronary artery

Better delivered to left ventricle during systole

Suspended during systole in the right coronary artery

not suspended during systole in the right coronary artery

The second heart sound is:

Prolonged of low frequency and strong in intensity

Strong, of low frequency and weak

Short, of high frequency and weak

Prolonged of high frequency and strong

Short, of high frequency and strong in intensity

short, of high frequency and weak

If on ECG, P wave is missing, but QRS complex and T wave are normal, the pacemaker is located in:

SA node

AV node

Bundle of His

Purkinje fibres

Ventricular fibres

AV node

The isovolumetric contraction is:

A part of the ejection phase of ventricular contraction

a part of the ventricular contraction phase

a part of ventricular diastole

The rapid filling phase of ventricular diastole

The slow filling phase of ventricular diastole

a part of the ventricular contraction phase

The vascular baroreceptors register the change in:

The systolic blood pressure

The diastolic blood pressure

PCO2 in blood

The mean arterial arterial blood pressure (MAP)

PO2 in blood

the mean atrial blood pressure (MAP)

The asynchronous contraction is:

A phase of the ventricular systole

A phase of the ventricular diastole

Starts of the S-L valves closure

Ends with S-L valves opening

Starts with A-V valves opening

a phase of the ventricular systole

The standard ECG bipolar leads are:

a VR, a VL and a VF

I, II and III

V1 to V6

II and V2

All ECG leads are bipolar

I, II and III

Which of the following is not increased during exercise:

Stroke volume

Total peripheral resistance

Systolic blood pressure

Heart rate

Muscle blood flow

total peripheral resistance

The peripheral baroreceptors trigger:

Pressor and depressor reflexes

Only pressor reflexes

Long term regulation of arterial blood pressure

Only depressor reflexes

Reflex of Bainbridge

pressor and depressor reflexes

The following would directly increase the heart rate:

Sympathetic stimulation

Parasympathetic

Decreased blood pressure

H1-receptors stimulations

Increased atrial natriuretic peptide (ANP) concentration

sympathetic stimulation

The long-term regulation of arterial blood pressure is:

nerve-reflex

Carried out by pressor and depressor baroreceptive reflexes

Humoral and restores the volume of blood

Carried out by depressor chemoreceptive reflexes

Carried out by ventral medial hypothalamus

Humoral and restores the volume of blood

The physiological pacemaker of the heart is:

AV node

Purkinje fibres

AV bundle

SA node

hypothalamus

SA node

The T wave in ECG indicates:

resting potential

Atrial depolarization

SA node excitation

Ventricular repolarization

Purkinje fibres excitation

ventricular repolarization

The end diastolic volume in humans in about:

140 ml

50 ml

70 ml

100 ml

200 ml

140 ml

Increased vagal tone causes:

Hypertension

Tachycardia

Bradycardia

Increase in cardiac output

Increase in stroke volume

bradycardia

The dicrotic notch on aortic pressure cure is caused by the:

Closure of mitral valve

Closure of tricuspid valve

Closure of aortic valve

Closure of pulmonary valve

Opening of atrioventricular valve

closure of aortic valve

For the peripheral resistance of the blood flow in a definite region, of highest significance is:

The viscosity of blood

The length of the vessels

the laminar blood flow in the vessels

The radius of the vessels

The venous valves

the radius of the vessels

The working myocardium:

is a functional syncitium

is comprised of cells whose cytoplasm communicates

Plays a role of pacemaker of the heart

Is comprised of cells, connected by structures that impede the ion

Reacts to threshold stimuli with different number of excited fibres

is a functional syncitium

The heart rate at rest is:

100-140 bt min-1

40-60 bt min-1

Approximately 50 bt min-1

60-90 bt min-1

20-40 bt min-1

60-90 bt min-1

The full compensatory pause is typical of:

The atrial extrasystoles only

Both the atrial and the ventricular extrasystoles

The ventricular extrasystoles only

Extrasystoles during atrial fibrillation

Extrasystoles during atrial flutter

The ventricular extrasystoles only

56. The duration of the cardiac cycle depends on:

The stroke volume (SC)

The time needed one systole to occur

The time needed one diastole to occur

The heart rate

The cardiac pause

The heart rate

The rhythm of the heart is determined by:

a) the bundle of His

b) the AV node

c) the SA node

d) the Purkinje fibers

e) the left and right bundle branches.

the SA node

The increased heart rate is called:

a) tachypnoea

b) bradycardia

c) atrial fibrillation

d) atrial flutter

e) tachycardia

tachycardia

When the rhythm is determined by the AV node, the heart rate is:

a) 60-90 bt·min -1

b) 20-40 bt-min-1

c) approximately 75 bt-min-1

d) 40-60 bt-min-1

e) 8-120 bt-min-1

40-60 bt-min-1

Automaticity is characteristic for:

a) the cardiac muscle only

b) the striated muscles

c) conducting system cells, some neurons and smooth muscle cells

d) all excitable tissues

e) the smooth muscle cells only

conducting system cells, some neurons and smooth muscle cells

The action potential of the cardiomyocites is characterized by:

a) slow depolarization and quick repolarization

b) rapid depolarization and slow repolarization

c) rapid de- and repolarizations

d) slow de- and repolarizations

e) period of current electrical activity, expressed as slow waves and spike potentials

rapid depolarization and slow repolarization

P wave of the ECG reflects:

a) repolarization of the atria

b) depolarization of the ventricles

c) depolarization of the atria

d) hyperpolarization of the atria;

e) the time necessary for the impulse originating in S.A. node to reach the purkinje fibers

depolarization of the atria

Asynchronous contraction of the ventricles:

a) is a phase of the ventricular systole

b) is a phase of the ventricular diastole

c) begins with closing the S-L valves

d) begins with opening the S-L valves

e) begins with opening the A-V valves

is a phase of the ventricular systole

When there is a complete atrioventricular block:

a) the conductivity at the bundle of His is fully interrupted and complete independence of the atrial and ventricular ECG stages

b) there is a not complete independence of the atrial and ventricular ECG stages

c) the atrial waves indicate normal heart rate, but the rate of ventricular ones is over 100 bt min-1

d) the duration of PQ interval is 0.12-0.20 s

e) left and right ventricles are not contracting simultaneously

the conductivity at the bundle of His is fully interrupted and complete independence of the atrial and ventricular ECG stages

The stroke volume of the heart at rest is:

a) 60-90 bt-min 1;

b) approximately 70 ml

c) 5.2L

d) 0.500L

e) 100-140 mmH

approximately 70 ml

The electrical axis of the heart is determined by:

a) the vectorial sum of QRS complexes in the standard leads

b) the vectorial sum of QRS complexes in the precordial leads

c) the vector's direction of the electrical forces of the ventricular muscle tissue

d) the supine or straight position of the body

e) the vector's direction of the electrical forces of the atrial muscle tissue.

the vectorial sum of QRS complexes in the standard leads

67. The augmented unipolar leads are:

a) 1, II and III;

b) aVR, aVL and aVF

c) VI, V2 and V3

d) V4, V5 and V6;

e) I, aVR and V1

aVR, aVL and aVF

The auscultation of the mitral valve is performed at:

a) II sternal intercostal space, right of the sternum

b) V intercostal space, 2 cm medial to the midclavicular line

c) IV sternal intercostal space, right of the sternum

d) II sternal intercostal space, left of the sternum

e) III sternal intercostal space, left of the sternum

V intercostal space, 2 cm medial to the midclavicular line

The 'plateau'-phase of the cardiomyocytes' action potential is due to.

a) outflux of K+ from the cells

b) influx of Na+ into the cells

c) influx of K+ into the cells

d) slow influx of Ca2+ into the cells

e) influx of Na+ into the cells and outflow of K from the cells

slow influx of Ca2+ into the cells

The electrical axis of the heart is of indifferent type when a-angle is:

a) from +60 to +90 degrees

b) from +30 to +60 degrees

c) from -90 degrees upward

d) from +30 to -30 degrees

e) from -30 degrees downward

from +30 to +60 degrees

Which of the following factors is not a vasoconstrictor:

a) norepinephrine (noradrenaline)

b) epinephrine (adrenaline)

c) serotonin

d) angioitensin II

e) kinins

kinins

At rest the diastolic arterial pressure is:

a) 90 - 95 mmHg

b) 140 - 160 mmHg

c) 60 - 90 mmHg

d) 100 - 140 mmHg

e) 75 mmHg

60 - 90 mmHg

Which of the following doesn't affect the gradient of the blood pressure

a) cardiac output (C.O.)

b) minute respiratory volume (MRV)

c) viscosity of blood

d) total peripheral vessel resistance

e) the volume of blood

minute respiratory volume (MRV)

When the viscosity of the blood is increased, which of the following is increased?

Mean blood pressure (MBP)

Radius of the resistance vessels

Radius of the capacitance vessels

Central venous pressure

Capillary blood flow

Radius of the resistance vessels

Throughout the isovolumetric relaxation of the ventricles:

a) A-V valves are opened, S-L valves are opened

b) A-V valves are closed, S-L valves are opened

c) A-V valves are opened, S-L valves are closed

d) A-V valves are closed, S-L valves are closed

e) none of the above

A-V valves are closed, S-L valves are closed

Why is the dilator response to injected acetylcholine changed to a constrictor response when the endothelium is damaged?

More Na+ is generated

More bradykynin is generated

The damage lowers the pH of the remaining layers of the artery

The damage augments the production of endothelin-1 by the endothelium

The damage interferes with the production of NO by the endothelium

The damage interferes with the production of NO by the endothelium

The first heart sound is:

a) systolic, result of the ventricular contractions and A-V valves closing

b) systolic, result of the A-V valves opening

c) systolic, result of the S-L valves closing

d) diastolic, result of the A-V valves closing

e) diastolic, result of S-L valves closing

systolic, result of the ventricular contractions and A-V valves closing

Cardiac output (C.O.) depends on:

a) Vital Capacity (VC)

b) Stroke Volume (SV), Heart Rate (HR) and pre- and afterload

c) Heart Rate (HR)

d) the preload and afterload only

e) Stroke Volume (SV) only

Stroke Volume (SV), Heart Rate (HR) and pre- and afterload

Which of the following has the highest total cross-sectional area in the body

Arteries

Arterioles

Capillaries

Venules

veins

Capillaries

When the radius of the resistance vessels is increased, which of the following is increased?

Systolic blood pressure (SBP)

Diastolic blood pressure (DBP)

Viscosity of the blood

Hematocrit

Capillary blood flow

Capillary blood flow

The intracardial regulation of the heart is carried out by:

a) integrated reflexes

b) neural regulatory mechanisms

c) humoral factors

d) adaptation to changes in venous return or the change in peripheral resistance

e) the automaticity

adaptation to changes in venous return or the change in peripheral resistance

The heart would stop in diastole because of:

a) increased level of Ca2+ in the extracellular fluid

b) increased levels of catecholamines

c) increased levels of glucokorticoids

d) increased concentration of K+ in the extracellular fluid (above 8 mmol 11)

e) increased secretion of T3 and T4.

increased concentration of K+ in the extracellular fluid (above 8 mmol 11)

If the vagus nerve innervating the heart is blocked, then

The heart rate would decrease

The stroke volume would decrease

The cardia output would decrease

The heart rate would increase

The heart activity would remain unchanged

The heart rate would increase

The plateau phase of the action potential of the contractile myocardiocytes is due to:

The slow movement of Na+ across the cell membrane

The influx of Ca2+

The increased membrane permeability to K+

The increased membrane permeability to Na+

A decrease in Ca2+ diffusing across membrane

The influx of Ca2+

When the heart rate is 60 bt-min ", the duration of thee cardiac cycle is:

a) 0.5 s.

b) 0.8 s.

c) 1 s.

d) 0.2 s.

e) 60 s.

1 s

The pulse pressure (PP) is:

a) closer in value to the systolic than to the diastolic pressure.

b) mean arithmetic of systolic and diastolic pressures:

c) closer in value to the diastolic than to the systolic pressure.

d) the difference between the systolic and diastolic pressure-

e) one third of the mean arterial pressure

the difference between the systolic and diastolic pressure

Left ventricular failure tends to cause an increase in

Right atrial pressure

Left ventricular ejection fraction

Pulmonary capillary pressure

Lung compliance

Pulmonary oedema when the patient stands up

Pulmonary capillary pressure

Which of the following factors doesn't play role in the formation of the Effective Filtration Pressure (EFP) in the capillaries

The hemodynamic pressure

The coloid osmotic pressure of plasma protein

The inteapleural pressure

The tissue fluid pressure

The interstitial coloid osmotic pressure

The inteapleural pressure

The cardiovascular centre is situated in:

a) hypothalamus.

b) mesencephalon:

c) the cortex.

d) medulla oblongata.

e) C-Th1-2 spinal cord segments

medulla oblongata

In the pulmonary circulation blood leaves the:

a) right ventricle and goes directly to the aorta.

b) right ventricle and moves to the lungs

c) right atrium and goes directly to the left ventricle

d) right atrium and goes directly to the lungs

e) left ventricle and moves to the lungs

right ventricle and moves to the lungs

The velocity of arterial pulse conduction

Depends on the blood flow velocity

Is equal for the big and small arteries

Depends on the arterial wall pecularities

Doesn't depend on age

In lower in the smaller arteries

Depends on the arterial wall pecularities

Hardening of the arterial walls tends to raise

Arterial compliance

Systolic arterial pressure

Diastolic arterial pressure

Peripheral resistance

The frequency of breathing

Systolic arterial pressure

In the systemic circulation, the blood leaves the:

a) left ventricle and goes directly to the aorta

b) right ventricle and goes directly to the aorta

c) right ventricle and moves to the lungs

d) lungs and moves to the left atrium

e) right atrium and goes directly to the lungs.

left ventricle and goes directly to the aorta

The mean arterial blood pressure (MAP) is about

Close in value to systolic, rather than the diastolic

The average of systolic and diastolic blood pressure

The diastolic plus one third of the pulse pressure

The difference between the systolic and diastolic pressures

The systolic plus one thrid of the diastolic pressure

The diastolic plus one third of the pulse pressure

The cardias cycle includes all of the following except events:

a) the movement of impulses from the SA node to all regions of the heart wall

b) the closing and opening of the heart valves during each heartbeat

c) the number of times the heart beats in one minute

d) the changes in pressure gradients in all chambers of the heart

e) the changes in blood volume in all chambers of the heart.

the number of times the heart beats in one minute

Which of the following substances does not participate in the regulation of blood pressure?

a) ADH

b) atrial natriuretic peptide (ANP)

c) angiotensin II

d) nitric acid

e) epinephrine (adrenaline).

nitric acid

The cardiac output (C.O.)

The volume of blood, pumped by the tight ventricle per minute

The volume of blood, flowing through the systemic circulation per minute

Is a function of stroke volume and heart rate

The volume of blood ejected by the right ventricle

The volume of blood ejected by the left ventricle

Is a function of stroke volume and heart rate

In atrial fibrillation

The electrocardiogram shows no evidence of atrial activity

The ventricular rate is lower than atrial rate

Respiratory sinus arrhythmia can usually be registered

The ventricular rate is higher than arterial rate

The QRS complex has abnormal configuration

The ventricular rate is lower than atrial rate

Exchange of nutrients and gases between the blood and tissue cells is the main function of the:

a) arterioles

b) arteries

c) veins

d) capillaries

e) venules.

capillaries

In the heart, (within physiological limits) the strength of contraction is directly proportional to the:

a) pacemaker activity.

b) A-V nodal delay

c) initial length of the cardiac muscle

d) respiratory rate

e) ST segment.

initial length of the cardiac muscle