Cardiovascular physiology

MCQs

24 th April 2012

You may do this paper as an open book exam but to get the most learning, please attempt without the book. This will

show you where your knowledge gaps are.

Physiology – Circulation MCQs

1. Which of the following is incorrect about B cells?a. Can bind directly to antigensb. B cells contact to helper T cells is not always required to produce full

activation and antibody formation c. Activated B cells can transform into memory B cells and plasma cellsd. Immunoglobulins are the secreted form of antigen-binding receptors on

the B cell membrane

2. Which of the following is incorrect about Platelets?a. Thrombopoietin is involved in regulation of platelet productionb. Membranes contain receptors for ADP and fibrinogenc. Aggregate at sites of vascular injuryd. alpha-granules contain non-protein substances like serotonin

3. With respect to ABO system, which is correct?a. Inherited as mendelian recessiveb. A and B antigens are complex oligosaccharides that terminate in a

terminal fructose moleculec. Antibodies against red cell agglutinogens are called agglutininsd. Type AB individuals develop anti-A and anti-B antibodies

4. Which of the following is not a congenital condition?a. Hageman traitb. Haemophilia Ac. Hypoprothrombinemiad. Parahemophilia

5. Which of the following has the slowest rate of conduction (m/s)?a. SA nodeb. Bundle of Hisc. Purkinje Systemd. Atrial pathways

6. With respect to the cardiac cycle, which of the following is false?a. End-diastolic ventricular volume is about 130mlsb. Ejection fraction is a valuable index of ventricular functionc. 60% of ventricular filling occurs passively during diastoled. Highest rate at which the ventricle can contract is theoretically 400/min

7. Which of the following will not increase cardiac output?a. Eatingb. Moderate changes in environmental temperaturec. Pregnancyd. exercise

8. Heterometric regulation of cardiac output relates to?a. Changes in cardiac muscle lengthb. Changes in contractilityc. Changes in muscle tensiond. Changes in systolic ventricular volume

9. The following all depress cardiac output except?a. Hypocapniab. Hypoxiac. Acidosisd. Procainamide

10. When considering oxygen consumption by the heart, which of the following is true?

a. Stroke work of the left ventricle is 9 times that of the right ventricleb. O2 consumption by the beating heart is about 6ml/100g/min at restc. Cardiac venous O2 tension is lowd. Increased preload causes a greater increase in cardiac O2 consumption

than an increase in afterload

11. Regarding capillaries, which is false?a. Total area of all capillary walls in the body exceeds 6300 m2 in the

adultb. Walls are made up of a single layer of endothelial cellsc. Junctions between skeletal endothelial cells can allow passage of

molecules up to 100 nm in diameterd. Pericytes warp around capillaries and can release vasoactive agents

12. The permeability of capillaries is expressed in terms of their hydraulic conductivity. Which of the following type of capillaries have the highest hydraulic conductivity?

a. Brainb. Skinc. Skeletal muscled. Lung

13. With respect to laminar flow in blood vessels, which is incorrect?a. There is a layer of blood in contact with blood vessel wall that does

not moveb. Turbulence occurs less frequently in anaemiac. Flow will not be turbulent if the Reynolds number (Re) is less than

2000d. Blood flows through vessels in a parabolic distribution

14. When considering viscosity and resistance of blood, which is false?a. haematocrit is the percentage of the volume of blood occupied by red

blood cellsb. whole blood is 1.8 times as viscous as waterc. vascular hindrance relates to the radius of the blood vesseld. viscosity is affected by the composition of plasma and the resistance

of cells to deformation

15. Which of the following does not cause an increase in interstitial fluid volume and oedema?

a. Substance Pb. Decrease in osmotically active substances in the interstitial spacec. Decreased plasma protein levelsd. Venous obstruction

16. The following are all vasodilators excepta. Potassiumb. Adenosinec. Lactated. Decreased CO2 tension

17. Regarding Nitric Oxide (NO), which is true?a. Nitric oxide synthase (NOS) 1 is found in macrophages and immune

cellsb. NOS 1 and NOS 3 are activated by intracellular calcium concentrationsc. NO is activated in the presence of haemoglobind. Platelet aggregation inhibits NO release

18. Which of the following is a stimulator of endothelin-1 secretion?a. Angiotensin IIb. Nitric oxidec. PGE2d. Prostacyclin

19. All of the following will cause vasoconstriction of arterioles except:a. Endothelin-1b. Decreased local temperaturec. Circulating Na-K ATPase inhibitord. Decreased discharge of noradrenergic vasomotor nerves

20. Increased baroreceptor discharge produces all of the following except:a. Vasodilationb. Venodilationc. Drop in blood pressured. Tachycardia

21. Heart Rate is not slowed by:a. Fearb. Increased intracranial pressurec. hypoxiad. expiration

22. Which of the following tissues has the highest oxygen consumption (ml/100g/min)?

a. Brainb. Skinc. Skeletal muscled. kidney

23. Regarding Cerebrospinal fluid (CSF), which of the following is false?a. Bulk Flow of CSF into venous blood is unidirectionalb. In adults, free communication appears to occur between brain

interstitial fluid and CSFc. Osmolality of CSF is less than plasmad. 50-70% of CSF is formed in the choroid plexuses

24. All of the following are referred to collectively as the circumventricular organs except:

a. Neurohypophysisb. Anterior pituitaryc. Area postremad. Subfornical organ

25. Concerning dynamics of blood flow, all are true except:a. Arterioles are the major site of blood flow resistanceb. The probability of turbulence within a vessel can be expressed as the

Reynold’s numberc. Forward flow is continuous because of vessel wall recoil during systoled. Veins are capacitance vessels and small arteries and arterioles are

resistance vessels

26. Considering vasodilator metabolites, which is correct?a. Nitric oxide synthase (NOS) in immune cells is activated by cytokines

instead of calciumb. Endothelin receptors are coupled via G protein to adenylyl cyclasec. Vasopressin, angiotensin II and bradykinin are all vasodilatorsd. Atrial natiuretic peptide (ANP) is released in response to hypovolaemia

27. Regarding the normal physiology of the heart, which is true?a. The end diastolic ventricular volume is about 90 mlsb. The ejection fraction is approximately 85% c. The end-systolic ventricular volume is approximately 50mls

d. Peak right ventricular pressure is about 120 mmHg

28. Regarding the normal ECG, which is false?a. The PR interval is 0.18 secondsb. QT interval is 0.8 secondsc. Ventricular repolarisation occurs during the ST intervald. Right axis deviation is when the electrical axis falls to the right of

+110 degrees

29. All of the following are true with respect to human immunoglobulins functions except for:

a. A function of IgG is complement activationb. A function of IgD is localised protection in external secretionsc. Antigen recognition by B cells is not a function of IgAd. Histamine release is a function of IgE

30. Regarding hypertension, which of the following is false?a. Plasma renin levels can be low in up to 25% of patients with essential

hypertensionb. The incidence of atherosclerosis increases in hypertensionc. Coarctation of the thoracic aorta increases rennin secretion and

increases peripheral resistanced. Estrogen increases angiotensin secretion which can lead to

hypertension

31. Which of the following are not compensatory reactions activated by haemorrhage?

a. Increased secretion of vasopressinb. Increased secretion of erythropoietinc. Venodilationd. Vasoconstriction

32. All of the following are types of obstructive shock except:a. Congestive heart failureb. Pulmonary embolismc. Cardiac tumourd. Cardiac tamponade

33. Which of the following is not increased with isotonic exercise?a. diastolic pressureb. Total peripheral resistancec. Oxygen consumptiond. Cardiac output

34. Regarding foetal circulation, which is false?a. 55% of foetal cardiac output goes through the placentab. Haemoglobin F binds 2,3-DPG more effectively than Haemoglobin Ac. By age 4 months post-partum, 90% of circulating haemoglobin is

Haemoglobin Ad. Blood in the umbilical vein is believed to be 80% saturated with

oxygen

35. Which of the following is incorrect of cutaneous circulation?a. Contraction of precapillary sphincters causes White Reactionb. Triple response is lost after total sympathectomyc. Reactive hyperaemia can be prevented if limb circulation is occluded

in an atmosphere of 100% O2.d. When skin appears cold and blue, the arterioles are constricted and

capillaries are dilated

36. Regarding brain metabolism, which is false?a. Oxygen, glucose and glutamine are utilised for brain metabolismb. Occlusion of blood supply to the brain can cause unconsciousness in as

little as 10 secondsc. Parkinsonism can occur due to hypoxia of the basal gangliad. Respiratory quotient of cerebral tissue is 0.95-0.99

37. When considering venous circulation, which of the following is incorrect?a. Pressure in the venules is higher than in large veinsb. Drop in venous pressure during expiration aids venous returnc. Venous flow is pulsatile close to the heartd. Heartward movement of blood is decreased in patients with varicose

veins

38. The opening of which channel completes the pre-potential for pacemaker cells?

a. Ca+2 T channel b. K+ channel c. Na-K ATPase channel d. Ca+2 L channel

39. Regarding systole and diastole, which is false? a. cardiac muscle can contract and repolarise faster with higher heart rates b. diastole shortens more than systole at high heart rates c. theoretically, ventricles could contract up to 400 times per minute d. ventricular filling is always adequate up to a heart rate of 180

40. Which of the following is incorrect with respect to heart sounds? a. S1 is caused by vibrations from the closure of AV valves b. S4 can be heard with high atrial pressures c. S4 can be heard in patients with ventricular hypertrophy d. S2 is caused by the closure of AV valves

41. Which of the following is incorrectly paired? a. aortic stenosis systolic murmur b. pulmonary insufficiency systolic murmur c. mitral stenosis diastolic murmur d. tricuspid stenosis diastolic murmur

42. Which of the following will not decrease End Diastolic Volume? a. intrapericardial tumour b. myocardial infarction c. infiltrative disease of the myocardium d. increase in the normal negative intrathoracic pressure

43. Which of the following changes in cardiac function has only a minimal rise with isometric exercise?

a. O2 usage (ml/min) b. pulse rate (per min) c. cardiac output (L/min) d. Stroke volume (mls)

44. Regarding bone marrow, which is incorrect? a. normally 85% of cells in the marrow are white blood cell producing

myeloid type b. yellow marrow = fat infiltrated marrow c. haematopoietic stem cells = capable of producing all blood cell types d. progenitor cells = committed stem cells

45. Which of the following proteins is not part of the fibrinolytic system? a. fibrin b. plasmin c. thrombomodulin d. tissue plasminogen activator

46. Which of the following blood vessels has the largest approximate total cross- sectional area (cm2)?

a. vena cava b. venule c. arteriole d. vein

47. Which of the following does not lead to an increase in interstitial fluid volume? a. venular constriction b. gravity c. incompetent heart valves d. increased plasma protein levels

48. Which of the following will lead to arteriolar dilation?a. thromboxane A2b. decreased local pHc. neuropeptide Yd. circulating Na+K+ATPase inhibitor

49. Neurons located in the Rostal Ventrolateral Medulla (RVLM) are a major contributor to neural control of the vascular system. Which of the following would not lead to excitatory inputs to the RVLM?

a. pain pathwaysb. carotid and aortic chemoreceptorsc. carotid and aortic baroreceptorsd. somatosympathetic reflex

50. Regarding peripheral chemoreceptors, which is false?a. chemoreceptor discharge can lead to Mayer wavesb. chemoreceptors are primarily activated by reduction in PaCO2c. increased vagal nerve activity is a direct effect of chemoreceptor activationd. chemoreceptors exert their main effect on respiration

51. The Dromotropic effect is:a. sympathetic impulses causing increased heart rateb. sympathetic impulses causing increased contractile forcec. sympathetic impulses increasing rate of transmission in the cardiac

connective tissued. parasympathetic impulses causing increased contractile force

52. Regarding lymphatics, which is the incorrect statement?a. initial lymphatics have valves to help with fluid flowb. tissue fluid enters initial lymphatics via loose junctions between endothelial

cells that form the wallsc. fluid within initial lymphatics is massaged by muscle contractions of the

associated organsd. 25 -50% of circulating plasma protein is returned to the bloodsteam daily

via the lymphatics

53. When considering transportation across capillary walls, which is false?a. diffusion is more important than filtrationb. diffusion depends upon Starling Forcesc. Flow limited exchange means that diffusion can be increased by increasing

blood flow through the tissued. capillary filtration coefficient is proportional to the permeability of the

capillary wall and the area available for filtration

54. Which of the following statements regarding capillaries is incorrect?a. pericytes are wrapped around the outside and are contractileb. sinusoidal capillaries of the liver are extremely porousc. pre-capillary sphincters are unresponsive to vasoconstrictor

moleculesd. kidney endothelial cells are attenuated to form gaps called fenestrations

55. Which of these is not a Vitamin K dependent clotting factor?a. Factor IXb. Prothrombinc. Protein Cd. Factor XII

56. Regarding circulatory changes in exercise which is true?  a. fall in tissue pO2 and rise in pCO2 help increase skeletal muscle blood flow

b. a decrease in accumulated potassium increases skeletal muscle blood flowc. the maximum heart rate achieved in exercise increases with aged. training will decrease VO2max (maximal oxygen consumption)

 57. In Myocardial infarction which is false?

a. accelerated opening of potassium channels is responsible in part for ST segment elevation in the infarcted muscleb arrhythmias occuring in the first 30 mins after infarction are usually due to reentry mechanismsc. Q waves and poor R wave progression are late signs of infractiond. endocardial lesions lead to interruption of symphathetic nerve fibres

 58. Regarding components of blood which is false?

a. Granulocytes can contain neutrophils, eosinophils and basophilsb. erythrocytes are derived from megakaryocytesc. neutrophils make up around 50 to 70% of circulating white cellsd. splenectomy can lead to thrombocytosis

 

59. Regarding clotting factors which is true?a. a deficiency in factor VIII explains the haemorrhagic tendency in liver

diseaseb. the vitamin K dependent clotting factors include II, V and VIIc. Christmas disease is the deficiency of factor IXd. Factor VIII deficiency has sex linked inheritance

 

60. Flow along collecting lymphatics is aided by all the following except:a. lymphatic vessel valvesb. negative intrathoracic pressure during expirationc. suction affect of high velocity flow of blood in veinsd. smooth muscle peristaltic action

 

61. Regarding the blood-brain barrier, which statement is true?a. glucose diffuses rapidly across the BBBb. P-gylcoprotein is required to transport certain drugs into the brainc. Kernicterus occurs when the BBB is immatured. Movement of H2O and CO2 is subject to regulation

62. According to the Munro-Kellie doctrine, the volume within the cranium must remain relatively constant. Regarding this, which of the following statements is false?

a. a rise in venous pressure decreases cerebral blood flow b. acceleration upwards causes a drop in brain arterial pressure c. straining or valsalva manoeuvres cause an increase in brain venous pressured. any change in venous pressure causes a compensatory change in ICP

63. Which of the following statements regarding brain metabolism is true?a. glutamine is converted to glutamate with ammoniab. glucose enters the brain actively by GLUT-2 transporterc. Insulin is required by most cerebral cells to utilise glucosed. during starvation, up to 30% of normal glucose uptake is converted to amino acids, lipids and proteins

64. Regarding the electrical events that occur during ECG intervals, which is correct?a. PR atrial depolarization and conduction through AV nodeb. QRS ventricular depolarization and atrial depolarizationc. QT ventricular depolarization and atrial repolarizationd. ST ventricular depolarization

65. Which of the ECG findings is not associated with a K+ of 2.0?a. upright T waveb. U wavec. ST segment depressiond. PR prolongation

66. Regarding the cardiac cycle, which is true?a. during isovolumetric contraction all of the heart valves are closed b. v waves occur in phase 3 of the cycle c. the peak right ventricular pressure is 30mmHg in systole d. left ventricular pressure exceeds aortic pressure throughout systole   

67. Regarding cardiac output, which of the following is correct?a. sleep reduces cardiac output b. rapid arrhythmias decrease cardiac output c. eating decreases cardiac output d. standing increases cardiac output  

 

68. Which of the follwing is false of the heart murmurs?a. aortic stenosis is systolic murmurb. tricuspid stenosis is often a diastolic murmurc. pulmonary regurgitation is a an early systolic murmurd. mitral prolapse is heard as a systolic murmur  

69. Which is true regarding hypovolemic shock?a. lactic acidosis increases myocardial contractility b. moderate haemorrhage is a blood loss of 5-15mL/kg with increased heart ratec. in severe blood loss bradycardia is never a featured. warm peripheries, rapid pulse, thirst, restlessness are all signs  

70.  When considering cardiac contractility, which is false? a. Catecholamines increase contractility via adrenergic receptors and G protein signalling b. Caffeine increases contractility by prolonged intracellular cAMP presence c. Digitalis increases contractility by activating adenylyl cyclase d. Hypoxia, acidosis and procainamide depress contractility

71. Which of the following has the lowest proportion of blood flow to the organ in ml/100g/min in a resting state?

a. heart muscleb. kidneysc. liverd. brain

72. Which of the following has the highest percentage of total oxygen consumption at rest?

a. kidneysb. brainc. liverd. heart muscle

73. Which of the following is false regarding Cerebrospinal fluid (CSF)?a. about 50 -70% of the CSF is formed in the choroid plexusb. the concentration of glucose in the CSF is higher than in plasmac. the extracellular fluid in humans makes up about 15% of the brain volumed. in humans, the rate of CSF production is about 550ml/day

74. Which of the following about foetal circulation is true?a. the blood in the umbilical vein is approximately 80% saturatedb. the ductus arteriosus constricts within 24 hours after birth c. the ductus closure can be produced by drugs that enhance the effect of cyclooxygenased. uterine blood flow increases 40 fold during the course of pregnancy

75. Arteriole constriction is produced by which of the following?a. increased CO2b. decreased local pHc. Endothelin – 1d. decreased sympathetic nerve discharge

76. Which is true with regard to the pathways involved in medullary control of the cardiovascular system?

a. the RVLM is sometimes called a vasomotor areab. inflation of the lungs causes vasoconstriction and increased blood pressurec. inhibitory inputs affecting activity of the RVLM include the somatosympathetic reflexd. prolonged severe pain causes vasoconstriction and fainting

77. Which is false with regard to baroreceptors?a. the carotid sinus and aortic arch receptors monitor the arterial circulationb. baroreceptors are chemoreceptors which are activated by reduction in PaO2c. Cardiopulmonary receptors are low-pressure, volume receptorsd. arterial baroreceptors are located in the tunica adventitia of the vessel wall\

78. Endothelin-1 is:a. not found in the brain or kidneysb. stored in secretory granulesc. inhibited by insulind. stimulated by Angiotensin II and catecholamines

79. With regard to natriuretic hormones, which is true?a. ANP is secreted by the heartb. BNP does not act on the kidneysc. Natriuretic hormones are released in response to hypovolemoad. Natriuretic hormones act by augmenting the action of vasoconstrictor agents

80. Regarding brain metabolisma. Cerebral Metabolic Rate for O2 (CMRO2) is approximately 10% of total body resting O2 consumptionb. vegetative structures of the brain are more sensitive to hypoxia than the cerebral cortexc. glucose utilisation at rest is inversely proportional to blood flow and O2 consumption of the brain at restd. glutamate-glutamine conversion in the brain is the opposite reaction to that which occurs in the kidney

81. Which of the following is a correct statement regarding heart failure? a. It occurs when the heart is unable to pump enough blood to meet the

needs of the tissues.b. It is never associated with sudden death.c. In systolic failure ejection fraction is maintained.d. In diastolic failure stroke volume is reduced.

82. Which is incorrect with regards to cardiac output (CO)?a. CO is affected by Cardiac Rate (CR) or Stroke Volume (SV) or both.b. CO is decreased during exercise.c. CR and SV may be affected by neural input to cardiac myocytes.d. CR and SV may be affected by hormonal input to cardiac myocytes.

83. Which is true of the cardiac cycle? a. Late in diastole the atrioventricular (AV) valves are closed.b. The rate of filling declines as the ventricles contract.c. 70% of ventricular filling occurs passively during diastole.d. Isometric ventricular contraction lasts about 0.5 seconds.

84. With regards to the heart sounds, which is correct? a. The first sound is caused by closure of the aortic and pulmonary

valves.b. The second sound is caused by closure of the mitral and tricuspid

valves.c. Murmurs are primarily normal sounds.d. Aortic stenosis produces a systolic murmur.

85. Starling’s law of the heart: a. Explains the relationship between contractility and preload of the heart.b. Does not apply in heart failure.c. Causes Frank-Starling Curve to shift upward and to the left as

contractility is decreased.d. Causes Frank-Starling Curve to shift downward and to the right with

sympathetic stimulation.

86. Which organ has the greatest blood flow per 100g of tissue?a. Kidneysb. Liverc. Braind. Heart

87. Which is incorrect regarding the blood-brain barrier?a. It is due to tight junctions between endothelial cells and between

epithelial cells in the choroid plexus.b. It prevents both free and protein-bound steroids from entering the

brain.c. Diffusion of glucose into CSF is enhanced by GLUT transporters.d. A variety of drugs cross the cerebral capillaries but are immediately

transported back out again.

88. Which of the following is true about coronary blood flow?a. Flow to the coronary arteries supplying the atria and right ventricle is

significantly reduced during systole.b. Flow to the subendocardial portion of the left ventricle occurs only

during diastole.c. Left ventricular coronary flow is increased in tachycardia.d. A low diastolic aortic pressure increases the coronary blood flow.

89. When is the pressure difference between the heart and aorta the least?a. Right ventricle during systoleb. Right ventricle during diastolec. Left ventricle during systoled. Left ventricle during diastole

90. Which vessel usually has the lowest pO2?a. Umbilical veinb. Umbilical arteryc. Maternal uterine veind. Maternal femoral vein

91. Which of the following DOES NOT cause increased interstitial fluid oedema ? a. Substance P b. Inadequate lymph flow c. Heart failure d. Increased plasma protein

  

92. Regarding haematopoiesis in adults, which is false?a. Extramedullary haematopoiesis can occur in the liver and spleen b. Bone marrow in the tibia becomes largely inactive by age 20 c. 90% of cells in marrow belong to the myeloid series d. 25% of red marrow cells are maturing red cells

 93. In the development of blood cells which is the incorrect pairing?

a. GM-CSF : RBC b. IL3 : basophil c. IL5: basophil d. M-CSF : monocyte

  

94. Regarding haemoglobin, which is true ?a. UV light therapy is used to break down Bilirubin into biliverdin for

haemolytic jaundice in infants b. Carboxyhaemoglobin is formed by a reaction between carbon dioxide

and haemoglobin

c. Adult haemoglobin consists of 3 alpha chains and 1 beta chain d. Methaemoglobin is produced after oxidative stress

 95. Regarding Red Blood cell antigens, which is the true statement?

a. Red blood cell antigens are called agglutinogens b. Type O blood contains anti-A and anti-B agglutinins c. Plasma from AB blood type will agglutinate with red cells type A, B

and AB d. Blood type AB is the least common blood type