Circulation
1. Regarding the rapid control of blood pressure all of the following are true EXCEPT:
a. Noradrenaline and adrenaline are secreted in response to a fall in blood pressure - true
b. Vasopressin is released from the supraoptic nuclei – ADH or vasopressin is made in the cell
bodies in the SON, but the axons project to the posterior pituitary for release of the hormone.
c. The renin angiotensin system is brought into play - true
d. The kidneys bring the blood pressure to near normal – via the atrial reflexes (the volume reflex) ->
dilatation of afferent glommerular ateriole -> rise in GFR. Also signals from atria to hypothalamus ->
ADH causing reduced reabsorption of fluid in the renal tubule, increasing urine output and reducing
blood volume. Also, release of atrial natriuretic peptide increases urine output and thus reduces
blood volume.
e. The baroreceptor mechanism operates best during fluctuations of blood pressure - true
2. Which of the following pairs are correctly matched?
a. Bradykinin – vasoconstriction
b. Vasopressin – vasodilation
c. Noradrenaline – vasoconstriction
d. Nitric oxide – vasoconstriction
e. Prostacyclin – vasoconstriction
3. With regards to heart sounds
a. The first heart sound is caused by closure of the aortic valve – of the AV valves
b. The second heart sound is caused by closure of the aortic and mitral valves – of the aortic and
pulmonary
c. The fourth heart sound can be heard when the ventricle is hypertrophied – also when the arial
pressure is high
d. The third heart sound is always pathological – heard in many normal young individuals
e. The third heart sound is due to rapid ventricular ejection – caused by rapid ventricular filling
4. Regarding changes in cardiac function during strenuous exercise
a. Oxygen usage may increase up to 10 times – correct
b. Cardiac output it less than 6.4L/min – may be up to 20.9L/min
c. Stroke volume may double – stroke volume levels off (shortening diastole)
d. A-V difference is ten times greater than at rest – maybe 3-4x
e. Pulse rate is between 60 and 100 beats/min – up to 170+
5. All of the following are characteristics of haemoglobin EXCEPT:
a. It contains four haem moieties
b. It has a lower affinity for oxygen in its relaxed state – up to 500x higher w/ more binding sites exp
c. It contains 38 histidine residues
d. When fully saturated it carries 1.39mL of O2 per gram haemoglobin
e. Each molecule of adult haemoglobin contains 2 α and 2 β polypeptide chains
6. Regarding factors which affect arteriolar calibre
a. kinins cause vasoconstriction - dilate
b. serotonin causes vasodilation - constrict
c. histamine causes vasoconstriction - dilate
d. lactate causes vasoconstriction - dilates
e. neuropeptide Y causes vasoconstriction - true
7. On standing the typical cardiovascular response is
a. an increase in total peripheral resistance by 75% - Increased peripheral SNS activity stimulates
arteriolar vasoconstriction – increasing the TPR by 1:1.4 (i.e. 40%)
b. an increase in stroke volume by 10% - venous return will drop, thus cardiac output
c. an increase in cardiac output by 50%
d. a decrease in central bloodpool by 400ml – this is the main issue with standing, and why the
reflexes exist to maintain BP. Note BP = CO x resistance, so BP = SV X HR x resistance. Thus on
standing, the stroke volume drops (because reduced venous return/EDV) but there is a decrease in
vagal stimulation and increase in sympathetic stimulation -> increase HR and increased peripheral
resistance so it balances out.
e. a decrease intra-abdominal vascular resistance – it will increase because intra-abdominal pressure
will rise
8. with regard to the calibre of arterioles, the following substance causes vasoconstriction
a. nitric oxide - dilates
b. kinins - dilates
c. histamine - dilates
d. angiotensin II – constricts (as the name implies)
e. VIP - dilates
9. regarding the cardiac cycle
a. closure of the A-V valve occurs at the start of isovolumic relaxation – at the start of isovolumetric
contraction
b. closure of the aortic valve occurs at the end of isovolumic contraction – at the start of isovolumetric
relaxation
c. V-wave corresponds with ventricular antiaction – V wave is the rise in atrial pressure prior to the
tricuspid valve opening
d. A wave corresponds with atrial contraction - correct
e. Jugular venous pressure demonstrates a dicrotic notch – the carotid/arterial wave form has a
dicrotic notch caused by the aortic valve snapping shut at the end of systole causing an occilation
10. causes of increased interstitial fluid volume and oedema include all of the following
EXCEPT:
a. arteriolar dilation
b. decreased plasma protein level
c. histamine
d. increased lymph flow – clears oedema
e. venular constriction
11. the decreased tension developed in cardiac muscle at high levels of stretch (descending
limb of Starling curve) is caused by
a. decreasing available calcium
b. decrease in the number of cross bridges between actin and myosin
c. increased muscarinic transmission associated with high diastolic intraventricular pressures
d. disruption of myocardial fibres – The Frank-Starling curve has a "descending limb" at high filling
volumes. In this region further stretching of the cardiac fibres leads to a break down in their structural
integrity and subsequent drop in cardiac output. A catastrophe would occur: The diminished cardiac
output would be unable to pump away all the blood that fills the ventricle during diastole. As the blood
accumulates, the cardiac output falls still further until cardiac failure occurred.
e. mechanical closure of calcium channels
12. at an arterial blood pressure of 70mmHg
a. carotid sinus receptors are strongly stimulated – the stretch receptors will be very weakly
stimulated, they are stimulated by high pressures not low
b. carotid body receptors are strongly stimulated – they will be poorly perfused and therefore
activated by a reduction in PO2 (stagnant anoxia). These receptors are responsible for the Mayer
Waves seen in hypotension: 20-40s fluctuations in BP as feedback is looped.
c. central nervous system ischaemia response is activated - <40mmHg
d. both carotid body and carotid sinus receptors are strongly stimulated
e. none of the above are true
13. The c wave of the jugular venous pressure corresponds to
a. Atrial systole – a wave
b. Rise in atrial pressure point prior to tricuspid opening – v wave
c. Aortic valve snapping shut – the dicrotic notch of carotid/arterial pulse
d. Bulging of the tricuspid valve into the atrium – correct, during isovolumetric ventricular contraction
e. Atrial diastole
14. with respect to the cardiac cycle and the ECG
a. the start of systole is marked by the P wave
b. the PR interval represents atrial relaxation
c. the ST segment represents absolute refractory period of the ventricles - The T wave represents the
repolarization (or recovery) of the ventricles. The interval from the beginning of the QRS complex to
the apex of the T wave is referred to as the absolute refractory period. The last half of the T wave is
referred to as the relative refractory period (or vulnerable period).
d. the T wave is synchronous with the third heart sound
e. none of the above
15. vascular compliance
a. is equal to increase in pressure divided by increase in volume – C = ΔV/ΔP
b. is the same as vascular distensibility - Compliance is a measure of the tendency of a hollow organ
to resist recoil toward its original dimensions upon removal of a distending or compressing force. It is
the reciprocal of "elastance". Distensibility is simply the ability to stretch and hold more volume. They
are elated, but not the same.
c. is 24 times greater in a vein than a corresponding artery - Venous compliance is approximately 30
times larger than arterial compliance
d. is increased by sympathetic stimulation in the arterial system - decreased
e. is increased by sympathetic stimulation in the venous system - decreased
16. factors affecting the activity of the vasomotor area in the medulla are
a. inhibitory inputs from carotid and aortic chemoreceptors – excitatory inputs
b. direct stimulation by CO2 – correct, also hypoxia directly stimulates
c. excitatory inputs from the carotid, aortic and cardiopulmonary baroreceptors - inhibitory
d. excitatory inputs from lungs - inhibitory
e. inhibitory input from cortex via hypothalamus – excitatory or inhibitory?
17. regarding Frank-Starling curves
a. the extent of afterload is proportionate to end diastolic volume
b. cardiac muscle fibres are lengthened by decreased ventricular compliance
c. contractility of myocardium is increased on standing – this is correct because the drop in BP ->
decreased baroreceptor stimulation -> decreased inhibition of RVLM -> increased sympathetic
response -> increased HR and contractility
d. sympathetic stimulation shifts the length/tension curve upward and to the right – upward and to the
left
e. increased negative intrathoracic pressure increases contractility - Contractility describes the ability
of the myocardium to contract in the absence of any changes in preload or afterload. In other words,
it is the "power" of the cardiac muscle. The most important influence on contractility is the
sympathetic nervous system. as per Ganong: lung inflation afferents + cardiopulmonary
baroreceptors (venous return) inhibits the RVLM -> reduces sympathetic stimulation (lowers
BP/HR)… however studies do show the contractility increases, likely through reduced vagal
stimulation.
18. regarding coronary blood flow
a. in most people, the left coronary artery supplies the sinoatrial node – (R)CA
b. coronary blood flow occurs only during systole - diastole
c. coronary blood flow is about 15% of cardiac output – 5% of output, 11% O2 consumption
d. the coronary sinus drains into the right atrium - correct
e. B1 receptors in the arterial wall cause vasoconstriction – vasodilation (alpha receptors
vasocontrict, sympathetic stimulation -> vasodilation because of metabolites from increased
HR/contractility, however if b-blocked it would cause vasocontriction)
19. Regarding Starlins forces
a. Capillary pressure at the arteriole end is 15mmHg - depends
b. Hydrostatic pressure exceeds oncotic pressure throughout the capillary
c. Capillary pressure at the venule end is 5mmHg - depends
d. Interstitial colloid osmotic pressure is usually negligible
e. Capillary filtration coefficient decreases with capillary permeability
20. concerning capillary fluid exchange
a. venule constriction reduces filtration pressure - increases
b. hypoproteinaemia decreases fluid shift out of capillaries - increases
c. lymphoedema fluid has a low protein count – high, caused my inadequate lymph draininage
d. substance P increases capillary permeability – after noxious stimuli, via the axon reflex
e. kinins reduce capillary permeability – histamine and bradykinin increase
21. Regarding Starlings forces
a. Hydrostatic pressure gradient is the only force involved
b. Interstitial fluid pressure remains the same
c. Osmotic pressure gradient is not involved
d. Total diffusion is not flow limited
e. Transfer for substances that do not reach equilibrium is diffusion limited
22. during the cardiac cycle
a. ventricular systole starts with opening of the aortic valve
b. rapid ejection occurs at the end of systole
c. phase 3 corresponds to ventricular ejection
d. with a rate of 75bpm, diastole is 0.27 seconds
e. the V wave relates to rise in atrial pressure before the closure of the tricuspid valve
23. With regards to cerebral blood flow
a. Autoregulation is not a typical feature
b. It is increased with raised intracranial pressure
c. It is unaffected by sympathetic stimulation
d. It is maintained at normal flow limits with arterial pressures ranging from 35 to 160mmHg
e. It is maintained in times of increased intracranial pressure by the Cushing reflex
24. the vasomotor centre receives
a. excitatory inputs from the lungs
b. excitatory and inhibitory inputs from the carotic chemoreceptors
c. direct stimulation from the heart
d. excitatory input from the kidneys
e. inhibitory input from the pain pathways
25. the slowest conduction speed in cardiac tissue is found in
a. Purkinje system
b. AV node
c. Ventricular muscle
d. Bundle of His
e. Atrial pathways
26. circulatory changes in exercise include
a. total cessation of skeletal muscle blood flow at 50% of its maximal tension – 70%
b. a drop in stroke volume with isotonic muscle contraction
c. a decrease in venous return
d. “rebound” hypotension post-exercise <- due to metabolites
e. An initial bradycardia at the start of isometric muscle contraction
27. the plateau phase of the cardiac action potential is due to the opening of
a. calcium channels
b. sodium channels
c. chloride channels
d. potassium channels
e. hydrogen channels
28. which of the following changes will produce a transient decrease in cerebral blood flow
a. a decrease in intracranial pressure
b. an increase in cardiac output
c. dilation of cerebral arterioles
d. a rise in mean venous pressure at brain level
e. decreased blood viscosity
29. the biggest influence of blood flow in a tube is
a. viscosity
b. systolic pressure
c. length of vessel
d. radius of vessel
e. diastolic pressure
30. With a K+ of 8.5meq/L the ECG usually
a. Shows a prominent U wave
b. Shows no evidence of atrial activity
c. Has T wave inversion
d. Is completely normal
e. Will have a QRS interval of approximately 0.06 seconds
31. Which factors increase myocardial contractility?
a. Hypoxia
b. Hypercapnia
c. Acidosis
d. Digitalis
e. Decreased cAMP
32. vasodilating hormones include all of the following EXCEPT:
a. VIP
b. Atrial natriuretic peptide
c. Vasopressin
d. Bradykinin
e. Kalidin
33. lymph
a. protein content is lower than plasma <- and 25-50% circulating returned each day (2-4L drain)
b. drains into blood via SVC
c. is clear after a fatty meal
d. doesn’t contain clotting factors
e. contains circulating neutrophils
34. arteriolar dilatation in muscle is mediated by all except
a. histamine
b. kinins
c. circulating adrenaline
d. circulating noradrenaline
e. atrionatriuretic factor
35. during exercise
a. the amount of blood in the arterial portion of the circulation may increase by as much as 30%
b. blood flow to the brain is increased
c. blood flow to the kidney is increased
d. blood flow to the brain is decreased
e. the oxyhaemoglobin dissociation curve (for blood in the muscular bed) is decreased in proportion
to the CO2 level
36. what is common to all capillary beds?
a. All are patent
b. Are 10-20mm in diameter
c. Have a continuous basement membrane
d. Have intracellular fenestration
e. ?
37. with regard to lymph
a. has no clotting factors
b. its protein content depends on the area it is from
c. is not dependent on the colloid pressure of the capillary
d. ?
e. ?
38. during isovolumetric contraction
a. mitral valve opens
b. decreased aortic pressure
c. may have reversed flow in the aorta
d. ?
e. ?
39. flow through a narrow tube is proportional to
a. viscosity
b. length
c. average pressure in the tube
d. pressure gradient
e. ?
40. regarding cardiac output in exercise
a. it can increase 200%
b. it can increase 500%
c. it can increase 700%
d. it can increase 300%
e. it can increase 400%
41. in exercise in a fit healthy young male
a. stroke volume increases less than 200%
b. stroke volume increases more than 300%
c. stroke volume increases more than 400%
d. stroke volume increases more than 700%
e. ?
42. regarding the blood supply of the heart
a. the heart receives 15% of CO at rest
b. left ventricular supply may be decreased by tachycardia
c. ?
d. ?
e. ?
43. regarding granulocytes
a. all have cytoplasmic grancules
b. basophils are identical to mast cells
c. eosinophils phagocytose viruses
d. neutrophils have a half life of 4 days
e. ?
44. regarding the Rhesus antigen system
a. Rh positive individuals have C, D and E antigens
b. 50% of caucasians are D+
c. Do not develop anti-D antibodies without prior exposure of D –ve individuals to D +ve red cells
d. ?
e. ?
45. the major cause of oedema is
a. increased hydrostatic pressure
b. increased lymph flow
c. increased intravascular oncotic pressure
d. ?
e. ?
46. Regarding capillaries
a. Arterioles have a lower ratio of smooth muscle to diameter than large arteries
b. Capillary flow is regulated by precapillary sphincters on metarterioles
c. Have the largest corss-sectional area
d. Contain 8% of the total blood volume
e. ?
47. the slowest conducting type of cardiac tissue is
a. bundle of His
b. ventricular muscle
c. Purkinje system
d. Atrial pathways
e. AV node
48. the part of the CVS with the largest total cross sectional area is
a. arteries
b. large veins
c. capillaries
d. arterioles
e. venules
49. with respect to the cardiac action potential
a. the plateau phase of repolarisation may be up to 200 times longer than the depolarisation phase
b. unlike the nerve action potential there is no overshoot
c. ?
d. ?
e. ?
50. cardiac output is changed accordingly in all of the following circumstances except
a. increased by up to 700% in exercise
b. increased on eating
c. decreased by sleep
d. ?
e. ?
51. all of the following produce vasodilatation except
a. local K+ accumulation
b. systemic hypoxia
c. lactate
d. increased CO2 tension
e. decreased pH
52. the c wave of the jugular venous pulse is due to
a. the rise in atrial pressure before the tricuspid valve opens in diastole
b. transmitted pressure due to tricuspid bulging in isovolumetric contraction
c. atrial systole
d. atrial contraction against a closed tricuspid valve in complete heart block
e. the increase in intrathoracic pressure during expiration
53. during the Valsalva manoeuvre bradycardia occurs
a. at the onset of straining
b. as the intrathoracic pressure reaches a maximum
c. as a result of an initial increase in cardiac output
d. when the glottis is opened and intrathoracic pressure returns to normal
e. if the patient has autonomic insufficiency
54. which of the following are not part of the compensatory mechanisms activated by haemorrhage
a. increased erythropoietin secretion
b. increased insulin secretion
c. increased vasopressin secretion
d. increased glucocorticoid secretion
e. increased renin secretion
55. the most rapid conduction of electrical impulses occurs in
a. atrial pathways
b. AV node
c. Bundle of His
d. Purkinje system
e. Ventricular muscle
56. with regard to cardiac action potentials
a. cholinergic stimulation increases the slope of the prepotential
b. the resting membrane potential is increased by vagal stimulation
c. phase 0 and phase 1 are steepest in the AV node
d. the T wave is the surface ECG manifestation of phase 1
e. the action potential in the AV node is largely due to calcium fluxes
57. with regard to the 12 lead ECG
a. lead II is at 90° for vector analysis
b. +130° is still a normal cardiac axis
c. The standard limb leads record the potential difference between 2 limbs
d. V2 is placed in the left 3rd interspace
e. Septal Q waves are predictable in V2
58. with regard to the cardiac cycle
a. phase 1 represents atrial systole
b. the aortic valve opens at the beginning of phase 2
c. the T wave of the ECG occurs during phase 4
d. the second heart sound is due to mitral valve closure
e. the c wave is due to tricuspid valve opening
59. cardiac output is decreased by
a. sleep
b. eating
c. pregnancy in the first trimester
d. sitting from a lying position
e. all of the above
60. myocardial contractility is decreased by all of the following EXCEPT:
a. acidosis
b. barbiturates
c. hypercarbia
d. bradycardia
e. glucagon
61. the greatest percentage of the circulating blood volume is contained within
a. capillaries
b. larger arteries
c. venules and veins
d. pulmonary circulation
e. the heart
62. The Poiseuille-Hagen formula tells us that
a. Longer tubes can sustain higher flow rates
b. Flow is directly proportional to resistance
c. Flow will be doubled by a 20% increase in vessel diameter
d. Why the venous capacitance system is important in cardiac output
e. Turbulent flow is predicted in high velocity vessels
63. all of the following explain venous blood flow EXCPT
a. intrathoracic pressure variations
b. the pumping action of the heart
c. skeletal muscle contraction
d. oncotic pressure gradient <e. smooth muscle contraction - ?
64. endothelium derived relaxing factor
a. shares a similar mechanism of action to glyceryl trinitrate
b. activates adenyl cyclase
c. is the common pathway in the action of adenosine and histamine
d. antagonises the action of thromboxane
e. is synthesised by a magnesium dependent enzyme
65. the R wave of the ECG is due to
a. calcium influx
b. chloride influx
c. sodium influx
d. potassium influx
e. chloride efflux
66. haemoglobin
a. the globin portion is a porphyrin
b. the difference between haemoglobin and myoglobin is haem
c. fetal haemoglobin has no beta chains
d. ?
e. ?
67. Regarding Poiseuille-Hagen flow in vessels, the flow in a vessel is proportional to
a. Pressure difference between the two ends
b. Radius
c. Viscosity
d. ?
e. ?
68. with respect to isovolumetric contraction of the ventricle it is associated with
a. decreasing aortic pressure
b. aortic back flow
c. open mitral and tricuspid valves
d. open aortic and pulmonary valves
e. none of the above
69. which of the following organs receives the largest amount of the blood’s circulation per kg of
tissue
a. heart
b. kidney
c. brain
d. liver
e. adrenal
70. a fit young man goes from sitting to running with full exertion. His stroke volume will increase by
a. 400%
b. 700%
c. 2000%
d. Less than 200%
e. 1000%
71. with respect to the cardiac cycle
a. ?
b. ?
c. ?
d. Isovolumetric contraction phase immediately follows the phase of atrial systole
e. ?
72. which of the following is a compensatory response to shock
a. decreased ADH
b. ?
c. ?
d. Increased thoracic pumping
e. ?
73. lymph
a. has an increased protein content compared with plasma
b. has a differing protein in different areas
c. fats cannot enter lymph
d. has no lymphocytes
e. contains no clotting factors
74. Which of the following is true regarding Starling’s law of the heart
a. It relates stroke volume to afterload
b. Changes in myocardial contractility do not influence the Frank Starling curve
c. Explains the increase in heart rate produced by exercise
d. Explains the increase in cardiac output that occurs when venous return is increased
e. Acidosis improves contractility