CArdiovascular

Question 1

1. The most rapid conduction of electrical impulses occur in
   a. Atrial pathway
   b. AV node
   c. Bundle of His
   d. Purkinje system
   Ventricular muscle

Answer 1

D

Question 2

1. With regard to cardiac action potentials
   a. Cholinergic stimulation increases the slope of the pre-potential
   b. The resting membrane potential is increased by X stimulation
   c. Phase O and phase I are the steepest in the AV node
   d. The T wave is the surface ECG manifestation of phase I
   The action potential in the AV node is largely due to calcium fluxes

Answer 2

E

Question 3

1. With regard to the 12 lead ECG
   a. Lead II is at 90 degrees for vector analysis
   b. + 130 degrees is still a normal cardiac axis
   c. the standard limb leads record the potential difference between 2 limbs
   d. V2 is placed in the 3rd interspace
   e. Septal Q waves are predictable in V2

Answer 3

C

Question 4

1. With regard to the cardiac cycle
   a. Phase I represents atrial systole
   b. The aortic valve opens at the beginning of phase II
   c. The T waves of the ECG occur during phase IV
   d. The 2nd heart sound is due to mitral closure
   e. The C wave is due to tricuspid opening

Answer 4

A

Question 5

1. CO is decreased by
   a. Sleep
   b. Eating
   c. Pregnancy in the 1st trimester
   d. Sitting from a lying position
   e. All of the above

Answer 5

E

Question 6

1. myocardial contractility is decreased by all except
   a. acidosis
   b. barbiturates
   c. hypercarbia
   d. bradycardia
   e. glucagon

Answer 6

C

Question 7

1. The greatest percentage of the circulating blood volume is contained in the
   a. Capillaries
   b. Larger arteries
   c. Venules and veins
   d. Pulmonary circulation
   e. The heart

Answer 7

C

Question 8

1. The Poiuselle – Hagen formula tells us
   a. Longer tubes can sustain high flow rates
   b. Flow is directly proportional to resisance
   c. Flow will be doubled by a 20% increase in vessel diameter
   d. Why the venous capacitance system is important in CO
   Turbulent flow is predicted in high velocity vessels

Answer 8

C

Question 9

1. All of the following explain venous blood flow except
   a. Intrathoracic pressure variations
   b. The pumping action of the heart
   c. Skeletal muscle contraction
   d. Oncotic pressure gradient
   Smooth muscle contraction

Answer 9

D

Question 10

1. EDRF
   a. Shares a similar mechanism of action to GTN
   b. Activates adenylyl cyclase
   c. Is the common pathway in the action of adenosine and HA
   d. Antagonizes the action of thromboxane
   e. Is synthesised by a magnesium dependant enzyme

Answer 10

A

Question 11

1. All of the following produce vasodilation except
   a. Local K accumulation
   b. Systemic hypoxia
   c. Lactate
   d. Increase CO2 tension
   e. Decreased pH

Answer 11

B

Question 12

1. The c wave in the JVP 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

Answer 12

B

Question 13

1. 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 CO
   d. When the glottis is opened and intrathoracic pressure returns to normal
   e. If the patient has autonomic insufficiency

Answer 13

C

Question 14

1. which of the following is not part of the compensatory system activated by haemorrhage
   a. increased EPO secretion
   b. increased insulin secretion
   c. increased ADH secretion
   d. increased glucocorticoid secretion
   e. increased renin secretion

Answer 14

B

Question 15

1. The cardiac action potential is divided into 5 phases, which of the following statements are true
   a. Depolarization phase (0) rapid exit of Na out of cells
   b. Early rapid repolarisation phase (1) drop in membrane potential to -90mV
   c. Plateau phase (2) slow exit of Ca out of cell
   d. Terminal phase of rapid repolarisation (3) membrane potential returns to 0mV
   e. Period between action potentials (4) activation of Na/K pump

Answer 15

E

Question 16

1. Which of the following is false regarding the structures of the cardiac conduction system
   a. The SA node is located at the junction of the SVC and the R atrium
   b. The AV node is located in the R posterior portion of the interatrial septum
   c. The internodal pathways containing 3 bundles of atrial fibres that contain Purkinje type fibres
   d. The Purkinje type fibres are normally the only conducting pathways between the atria and the ventricles
   e. The bundle of His divides in a left and right bundle branch

Answer 16

D

Question 17

1. which of the following normally has the steepest prepotential
   a. SA node
   b. AV node
   c. Bundle of His
   d. Terminals of the Purkinje fibres
   e. Ventricular muscle mass

Answer 17

A

Question 18

1. Which of the following is false regarding physiological ECG intervals
   a. The duration of the P wave is normally < 0.1s
   b. The duration of the QRS complex is normally < 0.1s
   c. The duration of the PQ interval ranges between 0.12-0.2 s and is dependent on the frequency
   d. The QT interval starts with the end of the Q and ends with the beginning of the T wave and has an average duration of 0.4s
   e. The average duration of the ST interval is 0.32s

Answer 18

B

Question 19

1. which of the following is false regarding the pacemaker function of the cardiac conducting system
   a. in the normal human heart each beat originates in the SA node
   b. the heart rate in AV nodal block is approximately 45/min
   c. the heart rate in infranodal block is approximately between 15-35/min
   d. the atrial rate in AF is higher than the ventricular rate
   e. the HR is independent of the repiratory cycle

Answer 19

E

Question 20

1. Which of the following regarding the cardiac vector is false?
   a. The normal direction of the mean QRS vector is normally between -30 and +110
   b. The mean QRS vector is indicating the electrical axis of the heart
   c. The QRS vector can be calculated from any 2 standard limb leads
   d. In LBBB the mean QRS vector is > +110
   e. The mean electrical axis is dependent on respiration and on the position of the body

Answer 20

D

Question 21

1. Which of the following is true regarding the electrical axis of the heart
   a. LAD, highest QRS lead I, negative QRS lead II
   b. LAD, highest QRS lead I, positive QRS lead II
   c. RAD, highest QRS lead III, negative QRS aVR
   d. RAD, negative QRS lead III, negative QRS aVR
   e. The electrical axis of the heart can be calculated from any unipolar chest lead

Answer 21

A

Question 22

1. Which ECG leads reflect the anterior surface of the heart
   a. I, aVL, V5-6
   b. II, III, aVF
   c. V1-4
   d. V1-2
   e. I, II, aVR

Answer 22

D

Question 23

1. What is false regarding the effect of K on the ECG
   a. ST degment depression is a sign of low K
   b. QT interval is prolonged in low K > 2.5
   c. Tall peaked T waves in high K are a sign of altered repolarisation
   d. In low K < 3.5 mmol/L a prominent U wave can be found
   e. In sever high K > 8.5 the P wave disappears

Answer 23

B

Question 24

1. What is false regarding the effects of electrolytes on the heart
   a. Low Ca causes prolonged ST segment and the QT interval
   b. High K is more rapidly fatal than low K
   c. Mg counteracts digitalis toxicity
   d. High K enhances digitalis toxicity
   e. Changes in Na concentration has no significant effect on the heart

Answer 24

D

Question 25

1. atrial flutter is characterized by a. an atrial rate slower than the ventricular rate b. flutter waves with a saw tooth appearance c. an atrial rate between 160-240 bpm d. doesn’t occur with an AV block e. carotid sinus massage can’t convert atrial flutter into the normal SR

Answer 25

B

Question 26

1. Which is false regarding AF a. Can be cardioverted by electrocardioversion b. Can cause acute heart failure c. Causes reduction in CO due to loss of the atrial kick d. Can be caused by hypothyroidism e. The ventricular rate can be lowered by digitalis die to its depression on AV conduction

Answer 26

D

Question 27

1. The absence of conduction of electrical impulses through the AV node, bundle of His or bundle branches, characterized by independent beating of the atria and ventricles is called a. SSS b. 2nd degree, type I block c. 3rd degree block d. 1st degree block e. 2nd degree, type II block

Answer 27

C

Question 28

1. Which is false regarding AV block a. 1st degree block is characterized by abnormally long PR intervals >0.2s and constant b. 2nd degree, type I (Wenckebachs) is characterized by progressive lengthening of the PR interval until a QRS complex fails to appear after a P wave c. 2nd degree, type II block is characterized by regularly or irregularly absent QRS complexes d. 3rd degree block is caused by a complete block of electrical impulses in one bundle branch and an intermittent block in the other bundle branch e. 3rd degree block can cause Adams Stokes syndrome due to intermittent ventricular asystole

Answer 28

D

Question 29

1. Which is false regarding the ECG changes in MI a. ST elevation of >1mm in limb leads is considered significant for MI b. ST depression of >1mm below baseline is considered a sign for severe myocardial ischaemia c. ST elevation of >0.5mm in chest leads is considered significant for MI d. An abnormal Q wave (>0.04 s wide, depth > ¼ height of succeeding R) is considered a sign of irreversible myocardial necrosis e. Acute LBBB is frequently caused by an anteroseptal MI

Answer 29

C

Question 30

1. Which is false regarding the cardiac cycle a. During late diastole, the tricuspid and mitral valves are open b. About 70% of the ventricular filling occurs passively during diastole c. Isovolumetric contraction starts with the opening of the aortic and pulmonary valves d. Isovolumetric relaxation ends when the ventricular pressure falls below the atrial pressure and the tricuspid and mitral valves open e. When the HR is increased the duration of diastole is shortened

Answer 30

C

Question 31

1. Which of the following is false regarding the cardiac cycle a. The atrial systole starts after the P wave of the ECG b. The ventricular systole starts near the end of the R wave of the ECG c. The ventricular systole end just after the T wave of the ECG d. The systolic pressure in the vascular system refers to the peak pressure reached during systole e. The diastolic pressure in the vascular system refers to the peak pressure reached during diastole

Answer 31

E

Question 32

1. Which of the following regarding volumes of the cardiac cycle is false a. EDV is ~ 130mL b. ESV is ~ 20mL c. SV is ~ 70-90mL in a resting man of average size in the supine position d. EF is the % of the ventricular volume ejected with each stroke e. SV in AF can be reduced up to 20%

Answer 32

B

Question 33

1. Which of the following regarding pressures is false a. RAP is ~ 10-15mmHg b. Peak LVP is about ~120mmHg c. Peak RVP is about 25mmHg d. CVP is about 0-8mmHg e. Pulmonary arterial pressure is about 5-25mmHg

Answer 33

A

Question 34

1. Which is false a. RAP resembles CVP b. The wedge pressure resemble LAP c. RAP resembles RVEDP d. SV = CO/HR e. Diastolic pressure in the left ventricle is about 40-80mmHg

Answer 34

E

Question 35

1. Which is false a. The dicrotic notch in the aortic pressure curve is caused by the closure of the aortic valve b. Venous pressure is lower during inspiration than during expiration c. The a wave in the JVP is due to atrial systole d. The c wave in the JCP is produced by the bulging of the tricuspid valve into the atria e. The v wave is caused by the rise in atrial pressure due to the closing of the tricuspid valve

Answer 35

E

Question 36

1. Which of the following is false regarding heart murmurs a. Murmurs are caused by turbulent blood flow b. AS produces a systolic murmur loudest over the base of the heart c. MR produces a diastolic murmur loudest over the apex, with radiation to the axilla d. MR can produce a 3rd heart sound e. PS produces a systolic murmur loudest over the 2nd/3rd intercostals space left of parasternal

Answer 36

C

Question 37

1. Regarding CO, which is false a. In a resting, supine man ~ 5.0L/min b. Can be measured with the direct Fick method c. Is dependant on preload, contractility, afterload and HR d. Can be calculated CO = VO2/CaO2-CvO2 x 10 e. Pregnancy decreases CO

Answer 37

E

Question 38

1. During exercise a man consumes 1.8 L of oxygen per minute. His arterial oxygen content is 190mL/L and the oxygen content of his mixed venous blood is 134mL/L. His CO is approximately a. 3.2L/min b. 16L/min c. 32L/min d. 54L/min e. 160mL/min

Answer 38

C

Question 39

1. Starling’s law of the heart a. Does not operate in the failing heart b. Does not operate during exercise c. Explains the increase in the HR produced by exercise d. Explains the increase in the CO that occurs when venous return is increased e. Explains the decrease in the EDV when venous return is increased

Answer 39

D

Question 40

1. Starling’s law describes the relationship of a. HR/SV b. HR/EDV c. Afterload/EDV d. SV/EDV e. Preload/SV

Answer 40

D

Question 41

1. The Frank Starling curve a. Describes the myocardial contractility b. Is shifted upwards and to the left during increased preload c. Is shifted upwards and to the left during increased afterload d. Is shifted downwards and to the right in cardiac insufficiency e. Is shifted upwards and to the left during noradrenaline administration

Answer 41

C

Question 42

1. he oxygen consumption of the heart – which is false a. Is increased by tachycardia b. Is dependent on the contractile state of the myocardium c. Volume work produces a greater increase in oxygen consumption than pressure work d. Is increased by increased stroke volume An increase in afterload causes a greater increase in oxygen consumption than an increase in preload

Answer 42

C

Question 43

1. The EDV a. Is increased by increased total blood volume b. Is decreased by AF c. Is decreased by an increased CVP d. Is decreased in cardiogenic shock e. Is decreased when standing

Answer 43

E

Question 44

1. Which is false a. Rhythmicity in the SA node is primarily due to increased permeability to K b. The AV node delays passage of the impulse from the atria to the ventricles by approximately 0.13s c. The velocity of electrical impulse conduction through the atria is approximately equal to that through the ventricular muscle fibres d. The transmission time from endocardial to epicardial surface is approximately equal to that of the entire Purkinje system e. Action potentials can travel both ways through all tissues of the heart except the AV node

Answer 44

A

Question 45

1. Vagal stimulation of the SA node a. Leads to increased conductance of Ca ions into the cell b. Leads to increased conductance of K ion into the cell c. Leads to increased intracellular cAMP d. Decreases the slope of the prepotential (phase 4 of the cardiac action potential) e. Inhibits the β1 receptors directly

Answer 45

D

Question 46

1. Which is true a. The resting membrane potential of ventricular muscle fibres is greater than that of the SA node b. The resting membrane potential of ventricular muscle fibres is greater than that of average resting peripheral nerve fibres c. The resting membrane potential of Purkinje fibres is less than that of the AV node d. The resting membrane potential of the SA node is equal to the AV node e. The resting membrane potential of average resting peripheral nerves is less than that of the SA node

Answer 46

D

Question 47

1. Which is correct a. ACh increases cardiac conducting system fibres permeability to K which increases the slope of phase 4 and so increases the heart rate b. Noradrenaline increases Na and Ca permeability therefore increases HR by decreasing the negativity of the resting membrane potential and by increasing the slope of phase 4 (prepotential) c. The AV node and the Purkinje fibres do not function as the cardiac pacemakers because background X stimulation reduces their rate of firing to below the rate of the SA node d. Nicotinic receptors in the SA node are responsible for increasing the resting HR in smokers e. None of the above

Answer 47

B

Question 48

1. Carotid sinus massage sometimes stops SVT because a. It decreases sympathetic discharge to the SA node b. It increases X discharge to the SA node c. It increases X discharge to the conducting tissue between the atria and the ventricles d. It decreases sympathetic discharge to the conducting tissue between the atria and the ventricles e. It increases the refractory period of the ventricular myocardium

Answer 48

C

Question 49

1. In 2nd degree heart block a. The ventricular rate is lower than the atrial rate b. The ventricular ECG complexes are distorted c. There is a high incidence of VT d. Stroke volume is decreased e. CO is increased

Answer 49

A

Question 50

1. The work performed by the left ventricle is substantially greater than that performed by the right ventricle, because in the left ventricle a. Contraction is slower b. The wall is thicker c. The SV is greater d. The preload is greater e. The afterload is greater

Answer 50

E

Question 51

1. The fourth heart sound is caused by a. Closure of the aortic and pulmonary valves b. Vibrations in the ventricular wall during systole c. Ventricular filling d. Closure of the mitral and tricuspid valves e. Regurgitant flow in the vena cava

Answer 51

C

Question 52

1. RAP a. May fall to as little as -10mmHg at rest, but rarely more b. May be 6cm of blood normally c. Will tend to fall with venoconstriction d. Increases with exercise Increases with inspiration

Answer 52

B

Question 53

1. During the cardiac cycle a. Systole is the period of ventricular contraction (ie between the 1st and 2nd heart sounds) b. The SV is increased by increasing the EDV, not the EF c. Ventricular contraction commences at the R wave and is not completed until the end of the T wave d. Diastole is the period between opening and closure of the AV valves e. JVP waves occur at – a atrial systole, c ventricular systole, v just prior to opening the AV valves

Answer 53

C

Question 54

1. Which is true a. Starlings law of the heart explains homometric regulation of CO b. Compliance is reduced by scarring resulting in reduced heterometric response to preload c. Afterload promotes sarcomeres shortening while preload opposes it d. β1 receptor stimulation results in further sarcomeres shortening and ultimately to increased CO e. increased venous tone decreases the myocardial sarcomeres length

Answer 54

B

Question 55

1. The lumen diameter of vessels, heart chambers and alveoli is important because a. Resistance is inversely proportional to the square of the radius b. The wall tension necessary to balance transmural pressure is inversely proportional to the radius c. Velocity is equal to flow for any given diameter d. Flow and resistance are both related reciprocally to the radius to the power of 4 e. Alveoli collapse in the absence of surfactant because their diameter decreases in expiration and the wall tension increases

Answer 55

D

Question 56

1. Which of the following statements regarding cardiovascular regulatory mechanisms is true a. The Cushing reflex is characterized by hypertension and tachycardia as cerebral interstitial fluid accumulates when raised intracranial pressure compromises cerebral blood flow b. Increased Baroreceptor discharge from the carotid sinus and aorta elevates BP and HR via increased sympathetic discharge c. NA, A, Angiotensin II and ADH are all hormones responsible for local tissure blood flow autoregulation d. In general, tissue blood flow is regulated according to the needs of the tissue, CO is regulated according to the sum of tissue blood flow and BP is regulated independently of either local blood flow or CO e. Increased CVP produces the same sympathetic response from atrial stretch receptors as elevated BP produces from carotid sinus baroreceptors

Answer 56

D

Question 57

1. The EF represents a. The % blood remaining in the ventricle following systole b. The % of atrial volume ejected into the ventricles with atrial systole c. Aortic blood flow d. The % of ventricular volume ejected with each stroke e. LVP

Answer 57

D

Question 58

1. Regarding the CO, which is false a. Resting CO correlates with the body surface area b. CO is not affected by moderate changes in environmental temperature c. Heterometric regulation is changing contractility of the heart muscle fibres independent of length d. The output per square metre of body surface is the cardiac index e. CO is not affected by sleep

Answer 58

C

Question 59

1. Regarding blood flow a. In the blood vessels is normally turbulent b. Turbulent flow is silent c. The small arteries and arterioles are referred to as the capacitance vessels d. The average velocity of blood is highest in the capillaries e. Blood flow and resistance in vivo are markedly affected by small changes in the caliber of vessels

Answer 59

E

Question 60

1. In the cardiac action potential a. Initial rapid depolarization is due to opening of voltage gated K channels b. Phase 2 is due to opening of Na channels c. Phase 3 is due to the opening of K channels d. Extracellular potassium concentration is not important e. The magnitude is affected by external sodium concentration

Answer 60

E

Question 61

1. cardiac muscle contraction a. is in its absolute refractory period in the latter half of phase 3 and phase 4 b. shows decrease in the number of cross bridges between actin and myosin (during descending limb of Starling’s curve) c. shows greater inotropism when catecholamines act on β1 adrenergic receptors d. shows increased contraction when digoxin stimulates Na/K ATPase e. in Duchenne’s muscular dystrophy, shows hypertrophy but does not lead to cardiac failure

Answer 61

C

Question 62

1. In the cardiac cycle a. Right ventricular contraction occurs before the left b. Phase II commences with the opening of the AV valves c. Phase IV is isovolumetric relaxation d. During inspiration the pulmonary valves close before the aortic e. The duration of systole is more variable than diastole

Answer 62

C

Question 63

1. Regarding the heart sounds a. The 3rd heart sound is heard 1/3 way through diastole in many normal young individuals b. A 4th heart sound can be heard in some individuals with low atrial pressure c. The 1st heart sound is loud when the heart rate is slow d. The interval between the aortic and pulmonary valves is decreased during inspiration e. The 2nd heart sound is normally lower pitched and longer than the first

Answer 63

A

Question 64

1. cerebral circulation a. is highly variable with posture b. is constant across approximately 100-200mmHg c. is variable due to the closed box nature of the cranium d. is approximately 750mL/min e. has the same flow/weigh as the kidney

Answer 64

D

Question 65

1. Regarding the ECG a. The U wave is believed to be due to papillary muscle repolarisation b. The PR interval is the time taken for atrial repolarisation c. Lead III is the vector between the right arm and left leg d. LBBB is defined by cardiac axis > 30 degrees e. Lead V5 is placed in the 4th ICS MCL

Answer 65

A

Question 66

1. increased Baroreceptor discharge a. inhibits GABA secreting neurons in the medulla b. inhibits X stimulation of the heart c. inhibits tonic discharge of vasoconstrictor nerves d. is inversely proportional to pressure change e. passes via efferent nerves in IX and X nn

Answer 66

C

Question 67

1. Myocardial contractility is increased by a. X stimulation b. Hypoxia c. Acidosis d. Digitalis e. Loss of myocardium

Answer 67

D

Question 68

1. CO is increased by a. Sleep b. Moderate change in environmental temperature c. Eating d. Rapid arrhythmia e. Sitting or standing from lying position

Answer 68

C

Question 69

1. Myocardial contractility is decreased by a. Acidosis b. Quinidine c. Hypoxia d. Hypercapnia e. All of the above

Answer 69

E

Question 70

1. Coronary blood flow a. Occurs predominantly in systole b. Is increased with rising venous pressure c. Is 20% of total CO d. Is most likely to be compromised subendocardially e. Is inceased by CO2/H+/K+ and cyanide

Answer 70

D

Question 71

1. with respect to baroreceptors a. barcoreceptor stimulation causes bradycardia and a drop in BP b. impulses generated in the baroreceptors excite the tonic discharge of vasoconstrictor nerves c. impulses generated in baroreceptors inhibit the X innervation of the heart d. positive pressure ventilation has no effect on Baroreceptor discharge e. any drop in systemic arterial pressure increases the inhibitory discharge in the buffer nerves and there is a compensatory rise in BP

Answer 71

A

Question 72

1. All of the following factors will cause vasodilation in skeletal muscle except a. Nitric oxide b. Acidosis c. Potassium d. Adenosine e. Lactate

Answer 72

D

Question 73

1. Angiotensin II a. Has less aldosterone effects as angiotensin III b. Increases diastolic BP c. Penetrates the BBB d. Has the same pressor activity of angiotensin I e. Excess angiotensin II upregulates AT1A receptors

Answer 73

B

Question 74

1. With respect to the vasomotor centre of the brain a. Increased Baroreceptor discharge causes increased X discharge from the vasomotor area b. A decrease in vasomotor discharge causes an increase in systemic vascular resistance c. Neurons synapse with the preganglionic neurons in the lateral white columns of the spinal cord d. Is inhibited by input from the carotid chemoreceptor e. Is excited by input from the aortic baroreceptors

Answer 74

A

Question 75

1. HR is increased by all except a. Hypoxia b. Decreased activity of the baroreceptors c. Fever d. Bainbridge reflex Expiration

Answer 75

E

Question 76

1. The law of La Place predicts the following except a. Increased myocardial work in dilate CMP b. The protection of capillaries against rupture c. The relationship between transmural tension and wall tension d. The pattern of intravesical pressure/volume curve e. The failure of alveoli to collapse in expiration

Answer 76

E

Question 77

1. Increased Baroreceptor discharge acts via the medulla to a. Increase HR b. Increase SV c. Increase vessel diameter d. Increase BP e. Increase renin

Answer 77

C

Question 78

1. In the coronary circulation a. Blood flow is maximal during systole b. 45-50% of O2 is extracted c. lactate is a vasodilator d. β adrenergic receptors mediated vasoconstriction e. the ostia of coronary arteries are shut during systole

Answer 78

C

Question 79

1. During exercise a. Regional blood flow to the skin remains unchanged b. Diastolic pressures tend to rise more than systolic pressure c. O2 consumption of skeletal muscle usually triples d. Blood flow to the brain increases e. CO increases 50 fold

Answer 79

A

Question 80

1. regarding conduction in the heart a. stimulation of right X inhibits the AV node b. the rate of discharge of the SA node is independent of temperature c. depolarization of ventricular muscle starts on the right d. the speed of conduction is fastest in ventricular muscle e. the SA node and the AV node exhibit the same speed of conduction

Answer 80

E

Question 81

1. In the cardiac action potential a. The resting membrane potential is -70mV b. The initial depolarization is due to Ca influx c. The plateau is due to the IKI current d. The initial rapid repolarisation is due to the closure of Na channels e. cAMP decreased the active transport of Ca to the sarcoplasmic reticulum thus accelerating relaxation and shortening of the cycle

Answer 81

D

Question 82

1. A decrease in the length of ventricular cardiac muscle fibres can be brought about by a. Stronger atrial contraction b. Increase in total blood volume c. Increase in venous tone d. Standing e. Increase in negative intrathoracic pressure

Answer 82

D

Question 83

1. Resting blood flow a. To the liver = 10% CO b. To the heart = 5% CO c. To the brain = 30% CO d. To the skin = 20% CO The skeletal muscle = 40% CO

Answer 83

B

Question 84

1. Regarding the cardiac cycle a. SV is normally 50mL b. Contraction of the left atrium precedes the right atrium c. The c wave of the JVP corresponds to movement of the closed tricuspid valve d. LVP immediately falls after opening of the aortic valve e. At rapid heart rates, systole shortens more than diastole

Answer 84

C

Question 85

1. With respect to BP control a. The stress relaxation mechanism is one of the immediate responses b. Angiotensin acts by increasing venous tone c. Baroreceptors are activated over the course of hours d. The renin angiotensin system is vital in controlling the effect of excess Na intake e. Renal responses precede capillary fluid shifts

Answer 85

D

Question 86

1. With respect to cardiac muscle action potential a. As HR increase the QRS duration decreases b. The absolute refractory period last from phase 0 to half way through phase 4 c. Relative refractory period begins halfway through phase 3 d. Phase 1 is due to opening of voltage gated Na channels e. Voltage gated Ca channels are activated at -50mV

Answer 86

C

Question 87

1. Oxygen debt a. Can be measured during exercise b. Trained athletes are able to incur a greater oxygen debt for the same level of exertion as an untrained athlete c. Is proportional to the degree of aerobic metabolism d. Is used to replenish phosphoylcreatine stores and replace oxygen from myoglobin e. Can occur in severe chronic respiratory disease

Answer 87

D

Question 88

1. With respect to depolarization of the heart a. Atrial depolarization is complete in 100 ms b. AV nodal delay is 10 ms c. AV nodal delay is lengthened by increasing sympathetic stimulation d. Ventricular muscle depolarizes from the right e. The last area to be depolarized is the posterobasal portions of the RV

Answer 88

A

Question 89

1. The normal ECG a. The average QT is 450ms b. There is no Q wave in V1 c. The normal axis is between -10 and 110 degrees d. T wave coincides with the diastolic blood pressure e. P wave coincides with the venous a wave

Answer 89

B

Question 90

1. Isovolumetric ventricular contraction a. Is responsible for the venous v wave b. Causes rapid rise in intraventricular pressure c. Lasts half a second d. Causes the opening of the AV valves e. Decreases the atrial pressure

Answer 90

B

Question 91

1. the CO a. is correlated with body surface area b. is a product of the HR and EDV c. can be calculated by using p-aminohippuric acid d. is decreased during sleep e. is decreased during eating

Answer 91

A

Question 92

1. All of the following factors may increase EDV except a. Maximal inspiration b. Hypervolaemia c. Exercise d. Standing up e. Adrenaline

Answer 92

D

Question 93

1. The oxygen consumption of the heart a. Basal consumption is about the same as skeletal muscle b. While beating is about 9mL/100g/min at rest c. An increase in preload causes more consumption than an increase in afterload d. Is decreased by increased EDP e. Increased consumption can be partially compensated by increased oxygen extraction

Answer 93

B

Question 94

1. The flow in a blood vessel is a. Inversely proportional to the radius b. Inversely proportional to the pressure difference between the arterial and venous end c. Inversely proportional to the length d. Proportional to the diameter e. Proportional to the viscosity

Answer 94

C

Question 95

1. With respect to arterial pressure a. Pulse pressure is the difference between arterial and venous pressure b. In the lying position the arterial pressure in the foot is higher than the arterial pressure in the head c. Dicrotic notch is causes by the closure of the AV valves d. Dicrotic notch is not present in the pulmonary circulation e. Pulmonary arterial pressure is approximately 25/10 mmHg

Answer 95

E

Question 96

1. All of the following changes occur at birth except a. Pulmonary vascular resistance falls to less than 20% b. Increase in peripheral resistance c. Closure of the foramen ovale within a few hours d. Closure of the ductus arteriosus within a few hours e. Negative intrapleural pressure of -30 to -50 mmHg in the first few gasps

Answer 96

D

Question 97

1. HR is accelerated by a. Grief b. Increased Baroreceptor activity c. Increased atrial stretch receptor activity d. Expiration e. A direct effect on angiotensin

Answer 97

C

Question 98

1. The rate of the pacemaker cells in the heart can be slowed by all of the following except a. More negative diastolic potential b. Reduction of the slope of diastolic depolarization c. More positive threshold potential d. Prolongation of the action potential e. Increased phase 4 depolarisation slope

Answer 98

E

Question 99

1. which of the following is true concerning the heart a. increased volume of work is the product of heart rate and stroke volume b. cardiac work is the product of HR and SV c. the heart in its resting state gains 60% of its caloric requirements d. the work of the left ventricle is twice that of the right due to higher pressures in the systemic circulation e. increased preload has a greater effect on O2 consumption of the heart than increased afterload

Answer 99

C

Question 100

1. Of the following which is correct a. The normal cardiac index is 3.2 b. Increased HR with exercise in a transplanted heart is due to heterometric regulation c. Increased HR with exercise in a transplanted heart is due to homometric regulation d. The normal EF is 65% e. All of the above

Answer 100

E

Question 101

1. Which of the following does not cause an increase in CO a. Eating b. Moderate increase in environmental temperature c. Pregnancy d. Exercise e. Anxiety

Answer 101

B

Question 102

1. blood flow a. in the RCA is greater in systole than in diastole b. is increased in the cerebral circulation by hyperventilation c. is greater in the epicardial arteries than in the subendocardial arteries at the LV in diastole d. is lower towards the centre than the periphery of large vessels e. in the LCA is decreased by moderate hypoxaemia

Answer 102

C

Question 103

1. myocardial contractility is increased by all of the following except a. activation of adenylyl cyclase b. X stimulation c. Digoxin d. Mobilization of Ca from longitudinal tubule systems e. None of the above

Answer 103

B

Question 104

1. all of the following are true for venule walls except a. are slightly thinner than capillaries b. are thin and easily distended c. contain relatively little smooth muscle d. venoconstriction is caused by noradrenergic nerves and NA e. all are correct

Answer 104

A

Question 105

a. It can be easily measured using Poiseulle-Hagen formula, even though blood is not a perfect fluid b. Viscosity is a function of the haematocrit c. Blood flow is normally laminar d. Velocity is proportion to flow divided by the area e. Critical closing pressure occurs when capillary pressure exceeds tissue pressure

Answer 105

E

Question 106

1. Which is incorrect a. The law of LaPlace explains the difference between intraluminal and transmural pressure b. The smaller the radius of a blood vessel the lower the wall tension to balance distention pressure c. Veins are referred to as capacitance vessels and arterioles as resistance vessels d. The recoil effect in blood vessels is known as Windkessel effect e. The mean pressure is the average pressure in the cardiac cycle and is calculated as diastolic pressure plus 1/3 pulse pressure

Answer 106

A

Question 107

1. concerning the capillaries, which is false a. 5% circulating blood is in the capillaries at any one time b. transport of substances from the capillaries into the tissues occurs via fenestrations, vesicular transport and cytoplasmic transport c. the rate of transport along a capillary depends on Starling forces d. oncotic and filtration pressure gradients are the same for all capillaries e. transit time from arteriolar end to venular end averages 1-2 s

Answer 107

D

Question 108

1. All the following regarding lymphatics are true except a. The normal lymph flow is 2-4L/d b. The 2 types of lymph vessels are interstitial and collecting c. Collecting lymphatics have valves and smooth muscles in their walls d. Flow in the collecting lymphatics is aided by skeletal muscle movements e. Functions of the lymphatics are recycling of protein and transport of long chain FFA

Answer 108

B

Question 109

1. The volume of fluid in interstitial space is dependent on all of the following except a. Capillary pressure b. Capillary filtration coefficient c. The cross sectional area of the capillary bed d. The ratio of pre-capillary to post capillary venular resistance e. The oncotic pressure

Answer 109

C

Question 110

1. causes of increased interstitial fluid volume and oedema include all except a. arteriolar constriction and venular dilation b. increased venous pressure c. decreased plasma protein level d. venous obstruction e. substance P

Answer 110

A

Question 111

1. factors increasing blood flow through the venous system includes which a. fluctuations in negative pressure during expiration b. intra-abdominal pressure rises during expiration due to abdominal muscle contraction c. the absence of valves in the system d. contractions of skeletal muscle e. the high cross sectional area of the great veins

Answer 111

D

Question 112

1. concerning venous pressure, which is false a. because sagittal sinus veins have rigid walls and cannot collapse, the pressure in the upright position is sub-atmospheric b. the CVP is normally 4-6mmHg, but varies with respiration c. CVP rises during negative pressure breathing d. Elevated CVP occurs with expanded blood volume e. Peripheral venous pressure rises with increasing distance from the heart

Answer 112

C

Question 113

1. During the ST segment of the ECG, there is a. No current flow, all myocardial membranes positive outside, negative inside b. Normal current flow of repolarisation c. Inability of damaged myocardium to depolarize if ST segments are elevated d. Current flow if other than on zero potential line e. If elevated, current flow during diastole

Answer 113

E

Question 114

1. As a % of total body volume, which is correct a. 40% in pulmonary circulation b. 13% in systemic arteries c. 20% in the systemic arterioles and capillaries d. 30% in veins e. none of the above

Answer 114

B

Question 115

1. action potential initiation in the SA and AV nodes results from a. Na influx b. K influx c. Ca influx d. Na and Ca influx e. Increased K conductance

Answer 115

C

Question 116

1. Which is not correct about the reflex mechanisms acting on the circulation a. The baroreceptors in the carotid bodies are stimulated when the BP increases b. The Bainbridge reflex causes increases in HR c. The Cushing reflex is a special CNS ischaemic response resulting from raised ICP d. The maximum firing per change in pressure of the carotid baroreceptors occurs at a MAP of 90mmHg e. IX is involved in the Baroreceptor reflex

Answer 116

A

Question 117

1. when the X fibres to nodal tissue is stimulated a. the membrane becomes hyperpolarized b. the slope of the prepotential is decreased c. ACh decreases conductance to Ca via muscarinic receptors d. ACh increases the permeability of nodal tissues to K via muscarinic receptors e. All of the above are true

Answer 117

E

Question 118

1. HR is accelerated by a. Decreased activity of the baroreceptors in the left ventricle b. Increased activity of baroreceptors in the pulmonary circulation c. Increased intracranial pressure d. Expiration e. Increased activity of the baroreceptors in the arteries

Answer 118

A

Question 119

1. Regarding coronary blood flow a. Systolic blood flow in subendocardial arteries is greater than in the epicardial b. Less than 50% of oxygen is removed during passage when in resting state c. The coronary circulation is well supplied by parasympathetic vasodilatory fibres d. Sympathetic vasoconstrictory fibres predominate in epicardial vessels e. None of the above

Answer 119

D

Question 120

1. regarding isometric ventricular relaxation a. it occurs in late diastole b. ventricular filling occurs c. intraventricular pressure remains constant during this phase d. it ends when the AV valves close e. it ends when the AV valves open

Answer 120

E

Question 121

1. local vasoconstriction results from a. increased K b. increased Mg c. increased Na d. decreased pH e. increased Ca

Answer 121

E

Question 122

1. lymph flow a. on average 500mL/h into the circulation b. proportional to interstitial fluid pressure c. increased with decreased interstitial fluid protein d. decreased with contraction of muscles e. decreased with raised capillary pressure

Answer 122

B

Question 123

1. regarding Starling forces operating in the capillaries a. there is a net outward force of about 0.3mmHg b. the filtration co-efficient describes the rate of plasma proteins being filtered from the microcirculation c. rate of filtration is roughly equal in the different tissues of the body d. mean capillary pressure is normally greater than plasma colloid osmotic pressure e. lymphatics play no role in maintaining equilibrium of the forces

Answer 123

D

Question 124

1. regarding the cardiac cycle a. in tachycardia, the duration of systole is shortened relatively more than diastole b. the v wave is caused by the bulging of tricuspid valve into the atria c. the 3rd heart sound is due to rapid ventricular emptying d. the EDV ~ 180mL e. isovolumetric relaxation occurs after the closure of the aortic and pulmonary valves

Answer 124

E

Question 125

1. The action potential of cardiac pacemaker cells a. Is not affected by calcium current b. Is mainly due to sodium influx c. Shows decreased prepotential slope with sympathetic stimulation d. Exhibits a prepotential initially caused by decreased K efflux e. Show no spontaneous rhythmicity

Answer 125

D

Question 126

1. arteriolar constriction is caused by a. kinins b. decreased NA discharge c. circulating angiotensin I d. circulating Na/K ATPase inhibitor e. decreased pH

Answer 126

D

Question 127

1. factors affecting the vasomotor area in the medulla are a. inhibitory inputs from carotid and aortic chemoreceptors b. direct stimulation by CO2 c. excitatory inputs from the carotid, aortic and cardiopulmonary baroreceptors d. excitatory inputs from the lungs e. inhibitory inputs from cortex via the hypothalamis

Answer 127

B

Question 128

1. regarding cardiovascular regulatory mechanisms, which is false a. decreases in O2 tensions and increases in local CO2 concentrations lead to coronary artery dilation b. circulating vasoconstrictors hormones include angiotensin II and aldosterone c. vasomotor control is mediated by the Baroreceptor reflex d. increased Baroreceptor activation slows down the HR e. the vasomotor area is stimulated by hypoxia and pCO2

Answer 128

B

Question 129

1. Pouiselle’s equation states a. Flow is proportional to density b. Viscosity multiplied by flow is proportional to the pressure gradient c. Flow is inversely proportional to the radius d. Flow is not related to the length of the tube e. Flow is proportional to the radius

Answer 129

B

Question 130

1. After 1L of blood is lost a. The haematocrit increases immediately b. Iron reabsorption is not increased c. Equals loss of 35% plasma volume d. Plasma protein synthesis is not increased

Answer 130

B

Question 131

1. 5% dextrose IV distributes predominantly to a. intracellular compartment b. interstitial compartment c. extracellular compartment d. intravascular compartment e. transcellular fluid

Answer 131

A

Question 132

1. Regarding CO in exercise a. It can increase up to 200% b. It can increase up to 500% c. It can increase up to 700% d. It can increase up to 300% e. It can increase up to 400%

Answer 132

C

Question 133

1. In exercise in a fit healthy young male a. SV increases less than 200% b. SV increases more than 300% c. SV increases more than 400% d. SV increases more than 700%

Answer 133

A

Question 134

1. regarding blood vessels a. arterioles have a lower ratio of smooth muscle to diameter than have large arteries b. capillary flow is regulated by precapillary sphincters and meta-arterioles c. capillaries have the largest cross-sectional area d. capillaries contain 8% of the total blood volume

Answer 134

D

Question 135

1. the slowest conducting type of cardiac tissue is a. bundle of His b. ventricular muscle c. Purkinje system d. Atrial pathway e. AV node

Answer 135

E

Question 136

1. 2,3 DPG levels increase in all of the following except a. chronic hypoxia b. androgens c. natriuresis d. none of the above

Answer 136

?

Question 137

1. with respect to the cardiac action potential a. the plateau of repolarisation phase may be up to 200 times longer than the depolarization phase b. unlike the nerve action potential, there is no overshoot

Answer 137

A

Question 138

1. 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 fenestrations

Answer 138

C

Question 139

1. 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 capillaty

Answer 139

B

Question 140

1. flow through a narrow tube is proportional to a. viscosity b. length c. average pressure in the tube d. pressure gradient

Answer 140

D

Question 141

1. A subject is injected with a substance that caused: increase in HR, no change in BP, did not impair ejaculation, decreased sweating, papillary dilation – it was most likely a. Nicotinic antagonist b. Nicotinic agonist c. α blocker d. muscarinic antagonist

Answer 141

D

Question 142

1. if the autonomic nerve supply is removed from the heart a. HR 150 bpm b. HR 40 bpm c. Decreased contractility

Answer 142

C

Question 143

1. regarding the cardiac muscles a. there are no Z bands b. resembles skeletal muscle c. intercalated discs are loosely attached d. gap junctions resist the flow of ions

Answer 143

B

Question 144

1. with the loss of 1L of blood a. haematocrit falls immediately b. iron resorption is not increased c. this equals 40% of plasma volume loss d. Baroreceptors increase parasympathetic output e. RBC mass normalizes within 2 weeks

Answer 144

E

Question 145

1. The R wave of the ECG is due to a. Ca influx b. Cl influx c. Na influx d. K efflux e. Cl efflux

Answer 145

C

Question 146

1. the systemic circulation peripherally has a. decreased RBC size b. decreased pH c. increased Cl d. decreased HCO3

Answer 146

B

Question 147

1. which of the following have a specific β effect on smooth muscle contraction a. adrenaline b. noradrenaline c. isoprenaline

Answer 147

C

Question 148

1. Which of the following is a compensatory response to shock a. Decreased ADH b. Increased thoracic pumping

Answer 148

B