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Cardiovascular System- Physiology PMU- 2nd Year 2nd Sem

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Cardiovascular System- Physiology PMU- 2nd Year 2nd Sem

Question 1 of 146

1

The pacemaker of the heart is normally the:

Select one of the following:

  • sino-atrial node

  • atrio-ventricular node

  • bundle of Hiss

  • mitral valve

  • left ventricle

Explanation

Question 2 of 146

1

In electrocardiogram (ECG) the QRS complex represents:

Select one of the following:

  • depolarisation of the atria

  • repolarization of the atria

  • depolarisation of the ventricles

  • repolarization of the ventricles

  • delay at the AV node

Explanation

Question 3 of 146

1

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

Select one of the following:

  • heart murmur

  • stroke volume

  • cardiac output

  • blockage of conduction of electrical signals between the atria and the ventricles

  • none of the above

Explanation

Question 4 of 146

1

Cardiac output (C.O.) is the:

Select one of the following:

  • volume of blood pumped per minute by both ventricles

  • volume of blood flowing through the systemic circulation each minute

  • product of the number of heartbeats per minute and the volume pumped per beat

  • a and c

  • b and c

Explanation

Question 5 of 146

1

According to the Frank-Starling mechanism of the heart

Select one of the following:

  • 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 beats per minute

  • cardiac output increases with increased heart rate

  • stroke volume increases with increased venous return

  • both ventricles contact simultaneously

Explanation

Question 6 of 146

1

Distinguishing characteristics of the veins include the following

Select one of the following:

  • all veins carry deoxygenated blood

  • all veins carry blood towards the heart

  • all veins have thick elastic walls

  • a and b

  • b and c

Explanation

Question 7 of 146

1

During exercise, there is an increased flow of blood to

Select one of the following:

  • the brain

  • the kidneys

  • the muscles

  • b and c

  • a, b and c

Explanation

Question 8 of 146

1

Which of the following does not contribute to the increased stroke volume (SV) during exercise

Select one of the following:

  • increased contractility of the cardiac muscle

  • increased venous return

  • increased length of filling time during diastole

  • increased sympathetic stimulation of the ventricular muscle

  • increased end-diastolic volume

Explanation

Question 9 of 146

1

The aortic valve

Select one of the following:

  • 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 left ventricle during ventricular ejection

  • prevents backflow of blood into the aorta during injection

  • closes when the first heart sound is heard

Explanation

Question 10 of 146

1

In humans, blood loss causes

Select one of the following:

  • venous constriction

  • decreased blood flow to the skin

  • a fall in the cardiac output

  • splenic contraction

  • a, b and c

Explanation

Question 11 of 146

1

Angiotensin ll:

Select one of the following:

  • as an octapeptide

  • is produced mainly in the lungs

  • causes thirst

  • stimulates the secretion of the antidiuretic hormone (ADH)

  • all of the above

Explanation

Question 12 of 146

1

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

Select one of the following:

  • brain

  • heart muscle

  • skin

  • liver

  • kidney

Explanation

Question 13 of 146

1

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

Select one of the following:

  • 3.45 l.min-1

  • 4.55 l.min-1

  • 5.25 l.min-1

  • 8.0 l.min-1

  • 9.85 l.min-1

Explanation

Question 14 of 146

1

The ventricles are completely depolarized during which portion of the ECG?

Select one of the following:

  • PQ interval

  • QRS complex

  • QT interval

  • ST segment

  • T wave

Explanation

Question 15 of 146

1

Cardiac output (CO) of the right heart is what percentage of that of the left?

Select one of the following:

  • 25%

  • 50%

  • 75%

  • 100%

  • 125%

Explanation

Question 16 of 146

1

The action potential corresponds to which portion of the ECG?

Select one of the following:

  • P wave

  • PQ interval

  • QRS complex

  • ST segment

  • QT interval

Explanation

Question 17 of 146

1

Which effects are caused by sympathetic stimulation?

Select one of the following:

  • increased force of heart contraction

  • increased heart metabolism

  • increased heart conductibility

  • decreased excitability

  • a, b, and c

Explanation

Question 18 of 146

1

Which are the peculiarities of the action potential in cardiac muscle?

Select one of the following:

  • long duration (0.3 s)

  • short duration (0.01 s)

  • high amplitude

  • plateau

  • a, and d

Explanation

Question 19 of 146

1

Excitation from SA node to AV node is conducted by:

Select one of the following:

  • Nodal fibers

  • Internodal fibers

  • Atrial cardiac cells

  • His bundle

  • b, and c

Explanation

Question 20 of 146

1

When are all four valves closed?

Select one of the following:

  • during isovolumetric ventricular contraction

  • during isovolumetric ventricular relaxation

  • during ventricular systole

  • during atrial diastole

  • a, and b

Explanation

Question 21 of 146

1

Effects of hypokalaemia:

Select one of the following:

  • short PQ interval

  • ventricular extrasystoles

  • elevated ST segments

  • long QRS interval

  • long QT interval

Explanation

Question 22 of 146

1

Hyperkalaemia:

Select one of the following:

  • causes a prolonged QT interval

  • prolongs the QRS

  • causes ST segment elevation

  • potentiates digoxin toxicity

  • causes loss of P wave

Explanation

Question 23 of 146

1

Left ventricular end-diastolic volume is:

Select one of the following:

  • 10 - 30 ml

  • 30 - 50 ml

  • 50 - 70 ml

  • 70 - 100 ml

  • 100 - 130 ml

Explanation

Question 24 of 146

1

Local metabolic control is most important in determining flow to the:

Select one of the following:

  • skin

  • lungs

  • skeletal muscles

  • kidneys

  • liver

Explanation

Question 25 of 146

1

The atrial component of ventricular filling is:

Select one of the following:

  • 5%

  • 10%

  • 30%

  • 50%

  • 80%

Explanation

Question 26 of 146

1

The lowest intrinsic discharge activity resides in the:

Select one of the following:

  • SA node

  • AV node

  • Bundle branches

  • Purkinje fibers

  • Ventricular fibers

Explanation

Question 27 of 146

1

Slowest conduction (velocity) occurs in the:

Select one of the following:

  • Atrium

  • AV node

  • Bundle of His

  • Purkinje fibers

  • Ventricular muscle

Explanation

Question 28 of 146

1

Which one of the following causes vasodilatation:

Select one of the following:

  • TXA2

  • Serotonin (5-HT)

  • Endothelin

  • Neuropeptide Y

  • VIP

Explanation

Question 29 of 146

1

The highest oxygen extraction is found in the:

Select one of the following:

  • carotid body

  • heart

  • kidneys

  • brain

  • lungs

Explanation

Question 30 of 146

1

The fastest conduction velocity is found in the:

Select one of the following:

  • SA node

  • Atrial muscle

  • AV-node

  • Bundle of His

  • Ventricular conduction system (Purkinje system)

Explanation

Question 31 of 146

1

Oxygen consumption at rest is the highest in the:

Select one of the following:

  • brain

  • heart

  • liver

  • kidneys

  • skeletal muscles

Explanation

Question 32 of 146

1

Coronary blood flow is:

Select one of the following:

  • dominant in the left coronary artery in 60% of people

  • better supply to subendocardium during systole

  • better supply to subendocardium during diastole

  • better supply to left ventricle during systole

  • left > right during systole

Explanation

Question 33 of 146

1

The velocity of blood flow is greatest in:

Select one of the following:

  • capillaries

  • pulmonary vein during diastole

  • small arteries

  • inferior vena cava

  • the aorta

Explanation

Question 34 of 146

1

Arterial baroreceptor afferents:

Select one of the following:

  • reach the spinal cord via sympathetic nerves

  • utilize glycine as a neurotransmitter

  • primary synapse in C1 area of the medulla

  • activate GABA inhibitory interneurons

  • excite autonomic efferents in the anterolateral horn

Explanation

Question 35 of 146

1

Isovolumetric contraction is associated with:

Select one of the following:

  • immediate increase in heart rate due to cardiac sympathetics

  • cardiac output increased/unchanged

  • increased systolic blood pressure and decreased diastolic blood pressure

  • does not work

  • decrease stroke volume

Explanation

Question 36 of 146

1

Baroreceptors are not located in:

Select one of the following:

  • carotid sinus

  • carotid body

  • right atrium

  • aortic arch

  • large veins

Explanation

Question 37 of 146

1

The volume of blood is the greatest in the:

Select one of the following:

  • systemic capillaries

  • large veins

  • small arteries

  • the liver

  • the lungs

Explanation

Question 38 of 146

1

The standard ECG setting is:

Select one of the following:

  • speed 50 mm.s-1 50 mm/mv

  • speed so mm.s-1 25 mm/mV

  • speed 25 mm.s-1 25 mm/mV

  • speed 25 mm.s-1 50 mm/mV

  • none of the above

Explanation

Question 39 of 146

1

Long term control of tissue blood flow includes:

Select one of the following:

  • adenosine

  • nitric oxide

  • change in tissue vascularity

  • oxygen tension at the precapillary sphincter

  • aldosterone

Explanation

Question 40 of 146

1

Turbulence is more likely with:

Select one of the following:

  • small tube diameter

  • high density fluid

  • increased tube length

  • increased viscosity

  • none of the above

Explanation

Question 41 of 146

1

The following would directly increase heart rate

Select one of the following:

  • sympathetic stimulation

  • parasympathetic stimulation

  • decreased blood pressure

  • b, and c

  • none of the above

Explanation

Question 42 of 146

1

At any given time the largest amount of blood in the body is carried by:

Select one of the following:

  • veins

  • capillary beds

  • arterioles

  • aorta

  • vena cava

Explanation

Question 43 of 146

1

The pacemaker of the heart is:

Select one of the following:

  • AV node

  • Purkinje fibers

  • AV bundle

  • SA node

  • None of the above

Explanation

Question 44 of 146

1

The T wave in an ECG indicates:

Select one of the following:

  • Resting potential

  • Atrial depolarization

  • SA node excitation

  • Ventricle repolarization

  • Purkinje excitation

Explanation

Question 45 of 146

1

End diastolic volume in human is about

Select one of the following:

  • 140 ml

  • 50 ml

  • 70 ml

  • 100ml

  • 200ml

Explanation

Question 46 of 146

1

Major functions of the lymphatic system are?

Select one of the following:

  • provide route for return of extracellular fluid

  • act as drain off for inflammatory response

  • render surveillance, recognition , and protection against foreign materials via lymphocytes, phagocytes, and antibodies

  • a, and c

  • a, b, and c

Explanation

Question 47 of 146

1

Blood pressure is the measure of:

Select one of the following:

  • pressure exerted by the blood on the walls of the blood vessels

  • pressure exerted by the blood on the arteries

  • pressure exerted by the blood on the veins

  • pressure exerted by the blood on the aorta

  • none of the above

Explanation

Question 48 of 146

1

Systolic Pressure is:

Select one of the following:

  • an average of 120 mm Hg

  • lowers steadily during ventricle systole

  • the highest when blood is being pumped out of the left ventricle into the aorta

  • an average of 80 mm Hg

  • a, and c

Explanation

Question 49 of 146

1

The working myocardium:

Select one of the following:

  • is a functional syncitium

  • is comprised of cells whose cytoplasm communicates

  • plays the role of pacemaker of the heart

  • is comprised of cells, connected by structures that impede the ion flow

  • reacts to threshold irritants with different number of excited fibers

Explanation

Question 50 of 146

1

The heart rate at rest is:

Select one of the following:

  • 100 - 140 beats.min-1

  • 40 - 60 beats.min-1

  • approximately 50 beats.min-1

  • 60-90 beats.min-1

  • 20-40 beats.min-1

Explanation

Question 51 of 146

1

The full compensatory pause is typical of:

Select one of the following:

  • the atrial extrasystoles only

  • both the atrial and the ventricular extrasystoles

  • the ventricular extrasystoles only

  • extrasystoles during atrial fibrillation

  • extrasystoles during atrial flutter

Explanation

Question 52 of 146

1

The duration of the cardiac cycle depends on:

Select one of the following:

  • stroke volume

  • the time one systole to occur

  • the time one diastole to occur

  • the heart rate

  • the cardiac paused

Explanation

Question 53 of 146

1

The rhythm of the heart is determined by:

Select one of the following:

  • the bundle of His

  • the atrioventricular node

  • the sinus node

  • the Purkinje fibers

  • the Ieft and right bundle branches

Explanation

Question 54 of 146

1

The increased heart rate is called:

Select one of the following:

  • tachipnoe

  • bradycardia

  • atrial fibrillation

  • atrial flutter

  • tachycardia

Explanation

Question 55 of 146

1

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

Select one of the following:

  • 60-90 beats.min-1

  • 20-40 beats.min-1

  • approximately 75 beats.min-1

  • 40-60 beats.min-1

  • 8-120 beats.min-1

Explanation

Question 56 of 146

1

Automaticity is characteristic of:

Select one of the following:

  • the cardiac muscle only

  • the striated muscles

  • some neurons and smooth muscle cells

  • all excitable tissues

  • the smooth muscle cells only

Explanation

Question 57 of 146

1

The action potential of the cardiomyocytes passes through:

Select one of the following:

  • slow depolarization and quick repolarization

  • rapid depolarization and slow repolarlzation

  • quick de- and repolarizations

  • slow de- and repolarizations

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

Explanation

Question 58 of 146

1

P wave of the electrocardiogram reflects:

Select one of the following:

  • repolarization of the atria

  • depolarization of the ventricles

  • depolarization of the atria

  • hyperpolarization of the atria

  • the time necessary for the impulse originating in SA. node to reach the Purkinje fibers

Explanation

Question 59 of 146

1

Asynchronic contraction of the ventricles:

Select one of the following:

  • is a phase of the ventricular systole

  • is a phase of the ventricular diastole

  • begins with closing the S.L. valves

  • begins with opening the S.L. valves

  • begins with opening the A.V. valves

Explanation

Question 60 of 146

1

In the complete atriovenrticular block:

Select one of the following:

  • the conductivity at the bundle of His is fully interrupted

  • there is a complete independence of the atrial and ventricular ECG stages

  • the atrial waves indicate normal heart rate, but the rate of ventricular ones is 20-40 beats.min-1

  • the duration of PQ interval is 0.12-0.20 s

  • a, b, and c

Explanation

Question 61 of 146

1

The stroke volume of the heart at rest is:

Select one of the following:

  • 60 - 90 beats.min-1

  • approximately 70 ml

  • 5.2 l

  • 0.500 I

  • 100-140 mmHg

Explanation

Question 62 of 146

1

The electrical axes of the heart is determined by:

Select one of the following:

  • the vectorial sum of QRS complexes in the standard leads

  • the vectorial sum of QRS complexes in the precordial leads

  • the vector's direction of the electrical forces of the ventricular muscle tissue

  • the supine or straight position of the body

  • the vector's direction of the electrical forces of the atrial muscle tissue

Explanation

Question 63 of 146

1

The augmented unipolar leads are

Select one of the following:

  • 1st, 2nd and 3rd

  • aVR, aVL and aVF

  • answers a, and b

  • V1, V2, V3, V4, V5 and V6

  • b, and d

Explanation

Question 64 of 146

1

The auscultation of the mitral valve is performed at:

Select one of the following:

  • 2nd sternal intercostal space, right of the sternum

  • 5th intercostal space, 2 cm inside of the medioclavicular line

  • 4th sternal intercostal space, right of the sternum

  • 2nd sternal intercostal space, left of the sternum

  • 3rd sternal intercostal space, left of the sternum

Explanation

Question 65 of 146

1

The phase 'plateau' of the cardiomyocytes action potentials is due to:

Select one of the following:

  • outflow of K+ from the cells

  • inflow of Na+ into the cells

  • inflow of K+ into the cells

  • slow inflow of Ca2+ into the cells

  • inflow of Na+ into the cells and outflow of K+ from the cells

Explanation

Question 66 of 146

1

The extrasystoles are:

Select one of the following:

  • increased heart rate of 250-230 imp-min-1

  • disturbances in conductivity

  • disturbances in excitability

  • extraordinary, only currently interrupting the cardiac rhythm, contractions of the cardiac muscle

  • c, and d

Explanation

Question 67 of 146

1

The electrical axes of the heart is of the indifferent type when the angle with the isoelectric line is:

Select one of the following:

  • +60 to +90 degrees

  • +30 to +60 degrees

  • from -90 degrees upward

  • +30 to -30 degrees

  • from -30 degrees downwards

Explanation

Question 68 of 146

1

Which of the following is not a vasoconstrictor:

Select one of the following:

  • norepinephrine

  • epinephrine

  • serotonin

  • angioitensin II

  • kinins

Explanation

Question 69 of 146

1

At rest the diastolic arterial pressure is:

Select one of the following:

  • 90-95 mmHg

  • 140-160 mmHg

  • 60-90 mmHg

  • 100-140 mmHg

  • 75 mmHg

Explanation

Question 70 of 146

1

Which of the following doesn't affect blood pressure:

Select one of the following:

  • cardiac output (C.O.)

  • minute respiratory volume

  • viscosity of blood

  • total peripheral vessel resistance

  • the volume of blood

Explanation

Question 71 of 146

1

Throughout the isovolumetrtc relaxation of the ventricles:

Select one of the following:

  • A.V. valves are opened, S.L. valves - opened

  • A.V. valves are closed, S.L. valves - opened

  • A.V. valves are opened, S.L. valves - closed

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

  • None of the above

Explanation

Question 72 of 146

1

The first heart sound is:

Select one of the following:

  • systolic, result of the ventricular contractions

  • systolic, result of the A.V. valves closing

  • systolic, result of the S.L valves closing

  • diastolic, result of the A.V. valves closing

  • a, and b

Explanation

Question 73 of 146

1

Cardiac output (C.O.) depends on:

Select one of the following:

  • vital capacity (VC)

  • stroke volume (SV)

  • heart rate (HR)

  • the preload and afterload

  • b, c and d

Explanation

Question 74 of 146

1

The intracardial regulation of the heart is carried out by:

Select one of the following:

  • integrated reflexes

  • neural regulatory mechanisms

  • humoral factors

  • adaptation to changes in venous return or resistance in the aorta

  • the automaticlty

Explanation

Question 75 of 146

1

The heart stops in diastole because of:

Select one of the following:

  • increased level of Ca2+ in the extracellular fluid

  • increased levels of catecholamines

  • increased levels of glucocorticoids

  • increased concentration of K+ the extracellular fluid

  • increased secretion of T3 and T4

Explanation

Question 76 of 146

1

The peripheral chemoreceptors trigger:

Select one of the following:

  • pressor and depressor reflexes

  • pressor reflexes only

  • the quick regulation of arterial blood pressure

  • depressor reflexes only

  • Hering-Breuer reflex

Explanation

Question 77 of 146

1

The pulse pressure is:

Select one of the following:

  • closer in value to the systolic than to the diastolic pressure

  • mean arithmetic of systolic and diastolic pressures

  • closer in value to the diastolic than to the systolic pressure

  • the difference between systolic and diastolic pressure

  • one third of the mean arterial pressure

Explanation

Question 78 of 146

1

The cardiovascular center is situated in:

Select one of the following:

  • hypothalamus

  • mesencephalon

  • the cortex

  • medulla oblongata

  • C8 - Th1-2 spinal cord segments

Explanation

Question 79 of 146

1

In the pulmonary circulation blood leaves the:

Select one of the following:

  • right ventricle and goes directly to the aorta

  • right ventricle and moves to the lungs

  • right atrium and goes directly to the left ventricle

  • right atrium and goes directly to the lungs

  • left ventricle and moves to the lungs

Explanation

Question 80 of 146

1

In the systemic circulation, blood leaves the:

Select one of the following:

  • left ventricle and goes directly to the aorta

  • right ventricle and goes directly to the aorta

  • right ventricle and moves to the lungs

  • lungs and moves to the left atrium

  • right atrium and goes directly to the lungs

Explanation

Question 81 of 146

1

The cardiac cycle includes all of the following events except:

Select one of the following:

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

  • the closing and opening of the heart valves during each heart beat

  • the number of times the heart beats in one minute

  • the changes in pressure gradients in all chambers of the heart

  • the changes in blood volume in all chambers of the heart

Explanation

Question 82 of 146

1

Which of the following chemicals does not regulate blood pressure?

Select one of the following:

  • ADH

  • Atrial natriuretic peptide

  • Angiotensin II

  • Nitric acid

  • Epinephrine

Explanation

Question 83 of 146

1

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

Select one of the following:

  • arterioles

  • arteries

  • veins

  • capillaries

  • venules

Explanation

Question 84 of 146

1

Arterial blood pressure increases in response to all but which of the following?

Select one of the following:

  • increasing stroke volume

  • increasing heart rate

  • rising blood volume

  • falling blood volume

  • all of the above

Explanation

Question 85 of 146

1

The inferior vena cava brings blood from the lower regions of the body empties into the:

Select one of the following:

  • left atrium

  • right atrium

  • aorta

  • left ventricle

  • right ventricle

Explanation

Question 86 of 146

1

The pacemaker of the heart is the;

Select one of the following:

  • Purkinje fibers

  • The bundle branches

  • Bundle of His

  • AV node

  • SA node

Explanation

Question 87 of 146

1

The tricuspid valve is located between the:

Select one of the following:

  • right and left atria

  • right and left ventricles

  • right atrium and right ventricle

  • left atrium and left ventricle

  • right ventricle and the aorta

Explanation

Question 88 of 146

1

When the mitral valve closes, it prevents the backflow of blood from the:

Select one of the following:

  • left atrium into the left ventricle

  • left ventricle into the left atrium

  • right atrium into the right ventricle

  • left ventricle into the aorta

  • right ventricle into the pulmonary trunk

Explanation

Question 89 of 146

1

The vessels that carry oxygen to the myocardial cells are called:

Select one of the following:

  • aortic arteries

  • pulmonary arteries

  • pulmonary veins

  • coronary veins

  • coronary arteries

Explanation

Question 90 of 146

1

The myocardium functions as a functional syncytium due to:

Select one of the following:

  • the presence of striations in the myocardium

  • branching of myocardlal cells

  • the presence of gap junctions

  • the presence of desmosomes

  • higher concentration of Ca2+

Explanation

Question 91 of 146

1

Autorhythmic cardiac cells are found In all the following location except the:

Select one of the following:

  • SA node

  • Interatrial septum

  • Purkinje cells

  • AV node

  • His bundle

Explanation

Question 92 of 146

1

Coronary blood flow to the left ventricle increases during:

Select one of the following:

  • early systole

  • myocardial hypoxia

  • hypothermia

  • stimulation of parasympathetic nerves in the heart

  • AV block

Explanation

Question 93 of 146

1

Local metabolic activity is the chief factor determining the rate of blood flow to the:

Select one of the following:

  • heart

  • skin

  • glands

  • lung

  • kidney

Explanation

Question 94 of 146

1

The pressure:

Select one of the following:

  • drop along large veins is similar to that along large arteries

  • drop across the hepatic penal bed is similar to that across the splenic vascular bed

  • in the hepatic portal vein exceeds that in the inferior vena cava

  • drop across the vascular bed in the foot is greater when a subject is in the vertical than when he is in the horizontal position

  • in foot veins is higher when walking than when standing still

Explanation

Question 95 of 146

1

The second heart sound differs from the first heart sound in that it is

Select one of the following:

  • related to turbelence set up by valve closure

  • longer lasting than the first sound

  • higher in frequency

  • occasionally in split

  • heard when the ventricles are contracting

Explanation

Question 96 of 146

1

Pulmonary vascular resistance is

Select one of the following:

  • is equal to that offered by the systemic circuit

  • decreased when alveolar oxygen pressure fails

  • expressed in units of volume flow per unit time per unit pressure gradients

  • decreased during exercise

  • regulated reflexvely by sympathetic vasoconstrictor nerves

Explanation

Question 97 of 146

1

Veins:

Select one of the following:

  • contain most of the blood volume

  • have a histaminergic vasodilator innervation

  • receive nutrition from vas vasorum arising from their lumen

  • respond to distension by dilation of their smooth muscle

  • do not contain valves

Explanation

Question 98 of 146

1

In the heart:

Select one of the following:

  • the left atrial wall is about three times thicker than the right atrial wall

  • systolic contraction normally begins in the left atrium

  • excitation spreads directly from atrial muscle cells to ventricular muscle cells

  • atrial and ventricular muscle contracts simultaneously in systole

  • the contracting ventricles shorten from apex to base

Explanation

Question 99 of 146

1

When measuring blood pressure by the auscultatory method:

Select one of the following:

  • the sounds that are heard are generated in the heart

  • the cuff pressure at which the first sounds are heard indicate systolic pressure

  • the cuff pressure at which the loudest sounds are heard indicate diastolic pressure

  • systolic pressure estimations tend to be lower than those made by the palpatory method

  • wider cuff's are required for smaller arms

Explanation

Question 100 of 146

1

The absolute refractory period in the ventricles:

Select one of the following:

  • is the period when the ventricles are completely still excitable

  • corresponds to the period of ventricular depolarization

  • corresponds approximately to the period of ventricular relaxation

  • is shorter than the corresponding period in atrial muscle

  • decreases during parasympathetic stimulation of the heart

Explanation

Question 101 of 146

1

Vascular resistance:

Select one of the following:

  • increases by 50 per cent When the vascular radius is halved

  • is related to the thickness of the wall of the vessel

  • is related to the vessel’s length

  • is affected by blood Hb concentration

  • is greater in the capillary bed than in the arteriolar bed

Explanation

Question 102 of 146

1

Sympathetic drive to the heart is increased:

Select one of the following:

  • in exercise

  • in relaxed position

  • in normotension

  • when parasympathetic drive is decreased

  • during a vasovagal attack

Explanation

Question 103 of 146

1

Hyperaemia in skeletal muscle during exercise is normally associated with:

Select one of the following:

  • release of sympathetic vasoconstrictor tone in the exercising muscles

  • capillary dilation due to relaxation of capillary smooth muscle

  • a fall in arterial pressure

  • reflex vasoconstriction in other vascular beds

  • an increase in venous pressure

Explanation

Question 104 of 146

1

Sinuatrial node cells are:

Select one of the following:

  • found in both atria

  • innervated by the somatic nerves

  • unable to generate impulses when completely denervated

  • connected to the AV node by fine bundles of purkinje tissue

  • able to generate impulses because their membrane potential is unstable

Explanation

Question 105 of 146

1

The first heart sound corresponds in time with:

Select one of the following:

  • closure of the aortic and pulmonary valves

  • the P wave of the electrocardiogram

  • a decline in atrial pressure

  • a rise in ventricular pressure

  • the A wave in central venous pressure

Explanation

Question 106 of 146

1

The velocity of blood flow:

Select one of the following:

  • in capillaries is low because they offer high resistance to flow

  • in veins is greater than in venules

  • can fall to zero in the ascending aorta during systole

  • is lower towards the centre of large blood vessels than at the periphery

  • in the circulation falls as the haematocrit falls

Explanation

Question 107 of 146

1

The strength of contraction of left ventricular muscle increases when:

Select one of the following:

  • end-diastolic ventricular filling pressure

  • serum potassium levels rise

  • blood calcium levels fall

  • blood magnesium levels fall

  • peripheral resistance is decreased

Explanation

Question 108 of 146

1

During isometric ventricular contraction:

Select one of the following:

  • the entry and exit valves of the ventricle are closed

  • pressure in the aorta rises

  • pressure in the atria falls

  • left coronary blood flow is going up

  • the rate of rise in pressure is greater in the right than in the left ventricle

Explanation

Question 109 of 146

1

Cardiac output:

Select one of the following:

  • is normally expressed as the output of one ventricle in liters/minute

  • is about 2.0 l at rest

  • is about 10.0 l at rest

  • rises in a cold environment

  • does not increase in exercise following denervatlon of the heart

Explanation

Question 110 of 146

1

In the brachial artery:

Select one of the following:

  • Pulse waves travel at the same velocity as blood

  • Pulse pressure falls with decreasing elasticity of the wall

  • Pressure rises markedly when the artery is occluded distally

  • Pressure falls when the arm is raised above head level

  • Pulse pressures have a smaller amplitude than aortic pulse pressures

Explanation

Question 111 of 146

1

Arterioles offer more resistance to flow than other vessels since they have:

Select one of the following:

  • thicker muscular walls

  • richer sympathetic innervation

  • smaller internal diameters

  • a smaller total cross-sectional area

  • a greater pressure drop along their length

Explanation

Question 112 of 146

1

In the denervated heart, left ventricular stroke work increases when:

Select one of the following:

  • the end-diastolic length of the ventricular fibres increase

  • peripheral resistance decreases

  • blood volume falls

  • right ventricular output decreases

  • the veins dilate

Explanation

Question 113 of 146

1

With increasing distance from the heart, arterial:

Select one of the following:

  • walls contain relatively more smooth muscle than elastic tissue

  • flow has a greater tendency to be turbulent

  • mean pressure tends to decrease slightly

  • pulse pressure tends to increase slightly

  • pO2 falls appreciably

Explanation

Question 114 of 146

1

In the estimation of cardiac output using the Fick principle:

Select one of the following:

  • pulmonary blood flow is measured

  • the pO2 of arterial and mixed venous blood are measured

  • oxygen uptake is estimated from alveolar pO2 measurements

  • pulmonary arterial blood is sampled to measure the oxygen in venous blood

  • pulmonary venous blood is sampled to measure the oxygen in arterial blood

Explanation

Question 115 of 146

1

Systemic hypertension may be caused by:

Select one of the following:

  • hypoxia due to chronic respiratory failure

  • excessive secretion of aldosterone

  • excessive secretion of insulin

  • myocardial thickening (hypertrophy) of the left ventricle

  • the rapid cardiac action of ventricular fibrillation

Explanation

Question 116 of 146

1

Peripheral differs from central circulatory failure in that:

Select one of the following:

  • hypovolaemia is unusual

  • it leads to underperfusion of the tissues

  • cardiac output is usually normal

  • central venous pressure is high

  • ventricular function is usually normal

Explanation

Question 117 of 146

1

In atrial fibrillation:

Select one of the following:

  • the electrocardlagram shows no evidence of atrial activity

  • ventricular rate is lower than atrial rate

  • respiratory sinus arrhythmia can usually be seen

  • the ventricular rate is higher than atrial rate

  • the QRS complexes have an abnormal configuration

Explanation

Question 118 of 146

1

Pain due to poor coronary blood flow (angina) may be relieved by:

Select one of the following:

  • Cutting the parasympathetic nerve trunks supplying the heart

  • Infecting CaCl2

  • Providing the patient with a cold environment

  • β-adrenoceptor stimulating drugs

  • Drugs causing peripheral vasodilation

Explanation

Question 119 of 146

1

Aortic valve incompetence may cause:

Select one of the following:

  • increase in arterial pulse pressure

  • systolic murmurs in the aortic valve area

  • hypertrophy of right ventricular muscle

  • decreased myocardial blood flow

  • right ventricular failure

Explanation

Question 120 of 146

1

Ventricular extrasystoles:

Select one of the following:

  • are usually associated with a normal QRS complex

  • from the same focus have similar QRS complexes

  • usually occur following a compensatory pause

  • can‘t be detected by ECG

  • indicate serious heart disease

Explanation

Question 121 of 146

1

Pulmonary embolism (blood clots impacting in lung blood vessels) usually decreases:

Select one of the following:

  • pulmonary vascular resistance

  • left atrial pressure

  • right atrial pressure

  • ventilation to perfusion ratios in the affected lung

  • pO2 in pulmonary venous blood

Explanation

Question 122 of 146

1

Hardening of the arterial walls tends to raise:

Select one of the following:

  • Arterial compliance

  • Systolic arterial pressure

  • Diastolic arterial pressure

  • Peripheral resistance

  • The frequency of breathing

Explanation

Question 123 of 146

1

Left ventricular failure tends to cause an increase in:

Select one of the following:

  • right atrial pressure

  • Ieft ventricular ejection fraction

  • pulmonary capillary pressure

  • lung compliance

  • pulmonary oedema when the patient stands up

Explanation

Question 124 of 146

1

In otherwise healthy people, local tissue death follows obstruction of:

Select one of the following:

  • an internal carotid artery

  • a renal artery

  • a femoral artery

  • a brachial artery

  • the hepatic portal vein

Explanation

Question 125 of 146

1

The part of the circulation pumping blood to and from the lungs is known as the _____ circulation.

Select one of the following:

  • systemic

  • pulmonary

  • coronary

  • respiratory

  • hepatic

Explanation

Question 126 of 146

1

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

Select one of the following:

  • 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

Explanation

Question 127 of 146

1

The valve between the right ventricle and the vessel that leaves it is the _____ valve.

Select one of the following:

  • tricuspid AV

  • bicuspid AV

  • mitral

  • pulmonary semilunar

  • aortic semilunar

Explanation

Question 128 of 146

1

If the connections between the parasympathetic division of the ANS and the heart were cut, then

Select one of the following:

  • heart rate would decrease

  • stroke volume would decrease

  • cardiac output would decrease

  • heart rate would increase

  • heart activity would remain unchanged

Explanation

Question 129 of 146

1

Fenestrated capillaries:

Select one of the following:

  • have pores in their walls

  • are located in most tissue

  • permit only one-way exchange of materials

  • have a layer of smooth muscle in their walls

  • are found in the liver and kidneys

Explanation

Question 130 of 146

1

Absolute refractory period in the heart:

Select one of the following:

  • corresponds to the duration of relaxation

  • lasts till half of cardiac contraction

  • shorter than refractory period in skeletal muscle

  • lasts till cardiac contraction

  • last only 10 ms

Explanation

Question 131 of 146

1

First heart sound occurs during the period of:

Select one of the following:

  • isometric relaxation

  • isotonic relaxation

  • isovolumetric contraction

  • isovolumetric relaxation

Explanation

Question 132 of 146

1

Which of these vessels does not have sympathetic control:

Select one of the following:

  • cerebral

  • splanchnic

  • cardiac

  • cutaneous

  • muscle

Explanation

Question 133 of 146

1

Blood brain barrier is made up of:

Select one of the following:

  • astrocytes

  • oligodendrocytes

  • oligodendroglia

  • microglia

  • others

Explanation

Question 134 of 146

1

Positive bathmotropic effect on heart is produced by:

Select one of the following:

  • stimulation of vagus nerve

  • stimulation of sympathetic nerves

  • atropin

  • sectioning of vagus

  • K+

Explanation

Question 135 of 146

1

Which of the following conducting systems has the slowest conducting velocity:

Select one of the following:

  • SA node

  • Atrial muscle

  • Purkinje fibres

  • AV node

  • Hiss bundle

Explanation

Question 136 of 146

1

In heart, within physiological limits the force of contraction is directly proportional to the:

Select one of the following:

  • Pacemaker activity

  • AV nodal delay

  • Initial length of the cardiac muscle

  • Respiratory rate

  • ST-segment

Explanation

Question 137 of 146

1

The diacrotic notch on aortic pressure curve is caused by:

Select one of the following:

  • closure of mitral valve

  • closure of tricuspid valve

  • closure of atrial valve

  • closure of pulmonary valve

  • opening the atrial valve

Explanation

Question 138 of 146

1

The PR interval of ECG corresponds to:

Select one of the following:

  • ventricular repolarization

  • atrial repolarization and conduction through AV node

  • repolarization of AV node and bundle of His

  • depolarization of SA node

Explanation

Question 139 of 146

1

Increased vagal tone causes:

Select one of the following:

  • hypertension

  • tachycardia

  • bradycardia

  • increase in cardiac output

  • increase in stroke volume

Explanation

Question 140 of 146

1

Which of the following is not increased during exercise;

Select one of the following:

  • stroke volume

  • total peripheral resistance

  • systolic BP

  • heart rate

  • muscle blood flow

Explanation

Question 141 of 146

1

Which of the following takes longest time to return to normal after 1L of blood is removed from a normal individual:

Select one of the following:

  • number of RBC in peripheral blood

  • plasma volume

  • renin secretion

  • blood pressure

  • number of WBC in peripheral blood

Explanation

Question 142 of 146

1

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

Select one of the following:

  • continuous murmur

  • a systolic murmur loudest over the base of heart

  • a diastolic murmur loudest over the apex of heart

  • a diastolic murmur loudest over the base of heart

  • systolic murmur over the apex of heart

Explanation

Question 143 of 146

1

The ‘S' wave in ECG is below isoelectric line because of:

Select one of the following:

  • repolarization of ventricles

  • change in direction of the impulse when the base of the ventricles are getting depolarised

  • depolarisation of apex of heart

  • repolarisation of apex of heart

  • depolarisation of atria

Explanation

Question 144 of 146

1

Lymph flow from the foot is:

Select one of the following:

  • increased when an individual rises from the supine to standing position

  • increased by massaging the foot

  • increased when capillary permeability is decreased

  • decreased by exercise

  • decreased by massaging the foot

Explanation

Question 145 of 146

1

The "T" wave in ECG is above the isoelectric line because of:

Select one of the following:

  • depolarisation of ventricles

  • depolarisation of bundle of His

  • change in the direction of repolarisation from the wave of depolarization of the ventricles

  • repolarisation of purkinje fibres

  • depolarisation of atria

Explanation

Question 146 of 146

1

Restoration of the blood volume after haemorrhage is aided by:

Select one of the following:

  • contraction of venous reservoirs

  • a fall in capillary pressure in certain vascular beds

  • arteriolar vasodilation

  • mobilization of intracellular fluid into the circulation

  • in increase in the osmotic pressure of the plasma proteins

Explanation