Physiomcq1 Cardiovascular Physiology

Front 1

CV01 In a normal cardiac cycle:

A. RA systole precedes LA systole

B. RV ejection precedes LV ejection in expiration

C. RV contraction precedes LV contraction in inspiration

D. Pulmonary valve closes after aortic in inspiration

E. Pulmonary valve closes before aortic in expiration

Back 1

CV01 [Mar96] [Jul97] [Mar99] [Feb00] [Jul01] [Jul02] [Feb04] In a normal cardiac cycle:

A. RA systole precedes LA systole TRUE

B. RV ejection precedes LV ejection in expiration TRUE

C. RV contraction precedes LV contraction in inspiration FALSE

D. Pulmonary valve closes after aortic in inspiration TRUE

E. Pulmonary valve closes before aortic in expiration FALSE

RA systole before LA systole and LV systole before RV systole (due to wave of depolarization)

However, ejection of RV before LV due to lower arterial pressures.

Expiration Aortic and Pulmonary close same time
Inspiration Aortic before Pulmonary

Front 2

In a normal cardiac cycle

A. RA ejection precedes LA ejection

B. RV contraction starts before LV contraction

C. LV ejection starts before RV ejection

D. Pulmonary valve closes before aortic valve

E. Aortic valve closes after pulmonary valve in ?expiration

Back 2

In a normal cardiac cycle

A. RA ejection precedes LA ejection TRUE

B. RV contraction starts before LV contraction FALSE

C. LV ejection starts before RV ejection FALSE

D. Pulmonary valve closes before aortic valve FALSE

E. Aortic valve closes after pulmonary valve in ?expiration FALSE

Front 3

With respect to the cardiac cycle:

A. Right ventricle starts ejecting before left ventricle

B. Pulmonary valve closes before aortic valve

C. Right & left atrial systole occur simultaneously

D. Peak aortic blood flow coincides with jugular venous c wave

E. Right ventricular ejection precedes left ventricular ejection

Back 3

With respect to the cardiac cycle:

A. Right ventricle starts ejecting before left ventricle FALSE

B. Pulmonary valve closes before aortic valve FALSE

C. Right & left atrial systole occur simultaneously FALSE

D. Peak aortic blood flow coincides with jugular venous c wave TRUE

E. Right ventricular ejection precedes left ventricular ejection FALSE

R atria contracts before L, L ventricle starts before R, but L valves opens last and closes first compared with R.(due to high systemic pressures and low pulmonary pressures. With inspiration more blood moves through lungs and PV close even later e.g. increased splitting of S2. Reversed splitting happens with delayed emptying (and thus delayed A2) of L ventricle e.g. AS.
Memory aid: with contracting, think how the conducting system works. With valves, think pressure difference in 2 systems.(systemic vs pulm)

Front 4

CV01b [Jul04] Physiological systole is defined as:

A. AV open to AV Close

B. MV close to MV open

C. MV close to AV Close

D. AV open to MV open

Back 4

CV01b [Jul04] Physiological systole is defined as:

A. AV open to AV Close

B. MV close to MV open

C. MV close to AV Close TRUE

D. AV open to MV open



Ventricular systole is from the closure of the atrioventricular valve to the closure of the semilunar valves. Diastole is from the closure of the semilunar valvue until the onset of atrial systole.

Front 5

CV02

Version 1: Normal jugular venous pressure c waves occur:

A. Just prior to atrial systole

B. Just after atrial systole

C. During ventricular systole

D. During expiration

E. ?

Back 5

CV02 [acd] [Jul98] [Jul99] [Apr01] [Jul02] [Feb04] [Jul04]

Version 1: Normal jugular venous pressure c waves occur:

A. Just prior to atrial systole

B. Just after atrial systole

C. During ventricular systole TRUE

D. During expiration

E. ?


3 waves of JVP
a : atrial kick
c : ventricular isovol contraction with buldging of tricuspid valve
v : atrial filling before tricuspid valve opens

Descends
x : btn c and v - right ventricular contraction pulling on AV fibrous ring, increased compliance of atrium
y : btn v and next a - movement of blood from atria to venticule

Front 6

Version 2: The ‘c’ wave in the JVP corresponds most closely with:

A. Peak aortic flow

B. Isovolumetric contraction

C. Isovolumetric relaxation

D. Closure of aortic valve

E. Closure of mitral valve

Back 6

Version 2: The ‘c’ wave in the JVP corresponds most closely with:

A. Peak aortic flow

B. Isovolumetric contraction TRUE

C. Isovolumetric relaxation

D. Closure of aortic valve

E. Closure of mitral valve

Front 7

CV04 [ad] [Jul98] [Jul01] In moderate exercise, the LV end-systolic volume is:

A. 10 mls

B. 30 mls

C. 70 mls

D. 120 mls

E. 140 mls

Back 7

ANSWER B

B. 30 mls TRUE

There is a non-linear increase in SV during exercise.

Increased LVEDV due to increased venous return

-Decreased LVESV due to increased emptying due to increased sympathetic activity

Front 8

CV03b [Mar97] [Jul00] [Apr01] Left ventricular end-diastolic volume is:

A. 10-30 mls

B. 30-50 mls

C. 50-70 mls

D. 70-120 mls

E. 120-150 mls

Back 8

CV03b [Mar97] [Jul00] [Apr01] Left ventricular end-diastolic volume is:

A. 10-30 mls

B. 30-50 mls

C. 50-70 mls

D. 70-120 mls

E. 120-150 mls TRUE

Front 9

CV03 [Mar96] [Mar99] [Feb04] In a normal heart at rest the LV end-systolic volume is:

A. 10 to 30 ml

B. 50 to 70 mls

C. 120 to 150 ml

D. ?80 - 100 ml

Back 9

CV03 [Mar96] [Mar99] [Feb04] In a normal heart at rest the LV end-systolic volume is:

A. 10 to 30 ml

B. 50 to 70 mls TRUE

C. 120 to 150 ml

D. ?80 - 100 ml

Front 10

CV05 [Mar96] [Feb00] [Jul00] Effect of tilting table from flat to head up include:

A. Decreased activation of RAS

B. Changes to skin blood flow occur immediately

C. ?

D. ?

E. None of the above

Back 10

CV05 [Mar96] [Feb00] [Jul00] Effect of tilting table from flat to head up include:

A. Decreased activation of RAS

B. Changes to skin blood flow occur immediately TRUE

C. ?

D. ?

E. None of the above


Baroreceptors include those in the auricles of the heart and vena cavae, but the most sensitive baroreceptors are in the carotid sinuses and aortic arch. The carotid sinus baroreceptors are innervated by the glossopharyngeal nerve (CN IX); the aortic arch baroreceptors are innervated by the vagus nerve (CN X). Baroreceptor activity travels along these nerves, which contact the nucleus of the solitary tract (NTS) in the brainstem.

The NTS sends excitatory fibers (glutamatergic) to the caudal ventrolateral medulla (CVLM), activating the CVLM. The activated CVLM then sends inhibitory fibers (GABAergic) to the rostral ventrolateral medulla (RVLM), thus inhibiting the RVLM. The RVLM is the primary regulator of the sympathetic nervous system, sending excitatory fibers (glutamatergic) to the sympathetic preganglionic neurons located in the intermediolateral nucleus of the spinal cord. Hence, when the baroreceptors are activated (by an increased blood pressure), the NTS activates the CVLM, which in turn inhibits the RVLM, thus inhibiting the sympathetic branch of the autonomic nervous system leading to a decrease in blood pressure. Likewise, low blood pressure causes an increase in sympathetic tone via "disinhibition" (less inhibition, hence activation) of the RVLM.

The NTS also sends excitatory fibers to the Nucleus ambiguus (vagal nuclei) that regulate the parasympathetic nervous system, aiding in the decrease in sympathetic activity during conditions of elevated blood pressure.

Front 11

CV06 [Mar96] The best site to measure mixed venous pO2 is:

A. Superior vena cava

B. Radial Artery

C. Pulmonary artery

D. Pulmonary vein

E. Femoral Artery

Back 11

ANSWER C

True mixed venous bloood collected from pul artery using Swan Ganz. After mixing of blood from IVC, SVC and coronary sinus.

Front 12

CV07 [ad] [Jul98] [Jul99] [Apr01] Changes with raised intracerebral pressure (ICP):

A. BP increase, HR decrease, RR decrease

B. BP increase, HR increase, RR decrease

C. BP decrease, HR increase, RR increase

D. BP increase, HR decrease, RR increase

E. No change in BP or HR

Back 12

CV07 [ad] [Jul98] [Jul99] [Apr01] Changes with raised intracerebral pressure (ICP):

A. BP increase, HR decrease, RR decrease TRUE

B. BP increase, HR increase, RR decrease

C. BP decrease, HR increase, RR increase

D. BP increase, HR decrease, RR increase

E. No change in BP or HR

Front 13

CV08 [Mar96] [Jul97] [Mar98] [Apr01] With increased heart rate: (OR: “With moderate tachycardia:”

A. Myocardial oxygen demand increases

B. Ratio of systole to diastole increases

C. Vascular filling is unchanged

D.Prolonged AP

E.Decrease in diastolic filling

F. Decrease in coronary perfusion

G. None of the above

Back 13

CV08 [Mar96] [Jul97] [Mar98] [Apr01] With increased heart rate: (OR: “With moderate tachycardia:”

A. Myocardial oxygen demand increases TRUE

B. Ratio of systole to diastole increases TRUE

C. Vascular filling is unchanged FALSE

D.Prolonged AP FALSE

E.Decrease in diastolic filling ???The diastolic filling TIME certainly decreases, and at high heart rates filling can be compromised, however tachycardia may be associated with increase diastolic filling in exercise

F. Decrease in coronary perfusion FALSE

G. None of the above

Front 14

CV09 [Mar96] In exercising muscle, the major increase in blood flow is due to:

A. Sympathetic vasodilatation

B. Metabolic vasodilatation

C. Muscle pumping

D. ?

Back 14

B

Front 15

CV09 [Mar96] In exercising muscle, the major increase in blood flow is due to:

A. Sympathetic vasodilatation

B. Metabolic vasodilatation

C. Muscle pumping

D. ?

Back 15

CV09 [Mar96] In exercising muscle, the major increase in blood flow is due to:

A. Sympathetic vasodilatation

B. Metabolic vasodilatation TRUE

C. Muscle pumping

D. ?


Best answer - B

A. The blood flow of resting muscle is known to double after sympathectomy, suggesting that some decrease in tonic vasoconstrictor discharge may contribute to any increase in blood flow. Exercising muscle however, can increase its blood flow as much as x30, hence sympathetic vasodilation is unlikely to be the major cause of increase in blood flow.

B. Local mechanisms maintaining a high blood flow in exercising muscle include:

Fall in tissue pO2
Rise in tissue pCO2
Accumulation of K+ and other vasodilator metabolites (?role of lactate)
Rise in temperature
This is the correct answer.

C. When a muscle contracts or "pumps", blood flow actually ceases during the contraction. It is only between contractions that flow is increased and this is maintained by local mechanisms (refer B above).

Front 16

CV10 [Mar96] Which circulation has predominant metabolic control?

A. Renal

B. Liver

C. Lung

D. Splanchnic

Back 16

ANSWER D

A. Renal

B. Liver

C. Lung

D. Splanchnic TRUE

Autoregulation in intestinal circulation is not as well developed as other vascular beds, eg brain and kidney. The principal mechanism for autoregulation is metabolic although a myogenic mechanism probably also participates (Berne and Levy Cardiovascular Physiology p261)

I think the best answer may be D. Splanchic

In Ganong (p623, 22nd edition), it states "The blood flow to the mucosa...responds to chnages in metabolic activity", but it also states "The intestinal circulation is capable of extensive autoregulation"

Metabolic autoregulation: Muscle>Gut>Liver>Skin>rest

Front 17

CV10b [Mar02] [Jul02] [Jul03] Local metabolic control is most important in determining flow to:

A. Skin

B. Lung

C. Skeletal muscle

D. Kidney

E. Liver

Back 17

CV10b [Mar02] [Jul02] [Jul03] Local metabolic control is most important in determining flow to:

A. Skin FALSE : regulated by SNS

B. Lung : FALSE regulated by alveolar hypoxia,

C. Skeletal muscle TRUE : mainly local metabolic factors but also SNS

D. Kidney FALSE myogenic mechanism and tububuloglomerular feedback

E. Liver FALSE no regulation

Front 18

Which tissues autoregulate blood flow prominently

A. Skin

B. Lung

C. Skeletal muscle

D. Kidney

E. Liver

Back 18

ANSWER C

Front 19

CV11 [Mar96] Myocardial ischaemia in shock is due mainly to:

A. Decreased coronary artery pressure

B. Increased myocardial O2 demand

C. Decreased myocardial O2 supply

D. ?

Back 19

CV11 [Mar96] Myocardial ischaemia in shock is due mainly to:

A. Decreased coronary artery pressure

B. Increased myocardial O2 demand

C. Decreased myocardial O2 supply TRUE

D. ?

Front 20

CV12 [Mar97] [Mar99] [Jul99] [Jul03] The atrial component of ventricular filling

A. 5%

B. 10%

C. 30%

D. 50%

E. 80%

Back 20

CV12 [Mar97] [Mar99] [Jul99] [Jul03] The atrial component of ventricular filling

A. 5%

B. 10%

C. 30% TRUE

D. 50%

E. 80%

Increases with age. One paper (Am J Cardiol. 1987 May 1;59(12):1174-8) suggested that 20yo may be 12% while 80yo with out heart disease may be 45%.

Increases with heart rate. Suggestions of 10% at rest up to 40% at maximum HR

Increases with most forms of heart disease.

Front 21

CV13 [Mar97] Skin perfusion decreases:

A. With standing

B. ?

C. ?

D. ?

Back 21

CV13 [Mar97] Skin perfusion decreases:

A. With standing

B. ?

C. ?

D. ?


Standing causes blood to pool in the legs which results in a sudden decrease in venous return/cardiac output. The baroreceptor reflex (predominantly carotid baroreceptor) causes simultaneous sympathetic activation and vagal inhibition. This causes an increase in the tone of resistance vessels resulting in decreased perfusion to areas such as the skin and will also increase heart rate.

Front 22

CV14 [Mar97] [Jul98] [Mar99] [Feb00] In a 70 kg man 2 metres tall with right atrial pressure of 2 mmHg & aortic root pressure 100 mmHg, the pressure in the dorsum of the foot is:

A. 0 mmHg

B. 2 mmHg

C. 5 mmHg

D. 30 mmHg

E. >50 mmHg

Back 22

CV14 [Mar97] [Jul98] [Mar99] [Feb00] In a 70 kg man 2 metres tall with right atrial pressure of 2 mmHg & aortic root pressure 100 mmHg, the pressure in the dorsum of the foot is:

A. 0 mmHg

B. 2 mmHg

C. 5 mmHg

D. 30 mmHg

E. >50 mmHg


Go for E

My assumption for this question is that the man is standing quietly, and that the question is referring to the pressure in a blood vessel in the dorsum of the foot. They haven't specified artery or vein, but according to Ganong, in either case the answer is (E).

p588 states that in an upright adult human with MAP of 100 mmHg, the pressure in a large artery in the foot is 180 mm Hg.

p595 states that during quiet standing, venous pressure at the ankle is 85-90 mm Hg.

(NB: If the man is contracting his leg muscles, the venous pressure can be reduced to less than 30 mm Hg)

Front 23

CV15 [Mar97] [Apr01] When moving from a supine to an erect position:

A. Mean arterial pressure increases

B. Skin perfusion immediately decreases

C. Decreased renin-angiotensin II

D. Cardiac output increases

E. Decreased ADH secretion

Back 23

ANSWER B

A. Mean arterial pressure increases FALSE

B. Skin perfusion immediately decreases TRUE

C. Decreased renin-angiotensin II FALSE

D. Cardiac output increases FALSE (drops bc decreased venous return)

E. Decreased ADH secretion FALSE Increases

Front 24

CV15b [Mar98] Changes from supine to standing causes:

A. Hypotension

B. Adrenal gland activation

C. ?

D. ?

E.

Back 24

CV15b [Mar98] Changes from supine to standing causes:

A. Hypotension TRUE

B. Adrenal gland activation FALSE (cortex : SNS)

C. ?

D. ?

E.

Front 25

CV16 [Mar97] [Jul99] [Mar03] [Jul03] The lowest intrinsic discharge activity resides in the:

A. SA node

B. AV node

C. Bundle branches

D. Purkinje fibres

E. Ventricular fibres

(see also CV28)

Back 25

CV16 [Mar97] [Jul99] [Mar03] [Jul03] The lowest intrinsic discharge activity resides in the:

A. SA node

B. AV node

C. Bundle branches

D. Purkinje fibres

E. Ventricular fibres TRUE

The myocardial fibres in the ventricle have the lowest intrinsic discharge rate, which is zero. These fibres have a stable phase 4 and are not pacemaker cells

Front 26

March 2003 version:

Slowest conduction (velocity) occurs in:

A. Atrium

B. AV Node

C. Bundle of His

D. Purkinje Fibres

E. Ventricular muscle

Back 26

Answer B



SA node: 0.05 m/s
Atrial pathways: 1 m/s
AV node: 0.05 m/s
Bundle of His 1 m/s
Purkinje system: 4 m/s
Ventricular muscle: 1 m/s

Front 27

CV17 [Mar97] [Jul98] [Apr01] The hepatic artery : portal vein blood flow ratio is:

A. 1 : 10

B. 3 : 1

C. 2 : 1

D. 1 : 6

E. 1 : 3

Back 27

CV17 [Mar97] [Jul98] [Apr01] The hepatic artery : portal vein blood flow ratio is:

A. 1 : 10

B. 3 : 1

C. 2 : 1

D. 1 : 6

E. 1 : 3 TRUE


FLOW : arterial<venous

Nutrient supply : 50:50

Front 28

CV18 [Mar97] [Mar98] [Jul01] CSF production & absorption:




{Diagram of CSF pressure versus flow with lines}




A. Unit for x-axis is mmCSF

B. A is shifted to A1 when paCO2 is 50mmHg

C. ?

D. B is shifted to B1 with hypothermia to 33°C

E. B is shifted to B1 with metabolic acidosis

Back 28

CV18 [Mar97] [Mar98] [Jul01] CSF production & absorption:




{Diagram of CSF pressure versus flow with lines}




A. Unit for x-axis is mmCSF TRUE

B. A is shifted to A1 when paCO2 is 50mmHg

C. ?

D. B is shifted to B1 with hypothermia to 33°C

E. B is shifted to B1 with metabolic acidosis


Ganong page 613

Front 29

CV19 [Jul97] [Mar03] [Jul03] [Jul04] Which ONE of the following causes vasodilatation

A. TXA2

B. Serotonin (5HT)

C. Endothelin

D. Neuropeptide Y

E. Angiotensin II

F. VIP

Back 29

Answer F

Vasoconstrictors:

TXA2 - promotes platelet aggregation and vasoconstriction
Endothelin - three types produced by endothelial cells, endothelin-1 is one of most potent vasoconstrictors
Angiotensin II - increased with elevated renin secretion when BP falls or ECF volume drops, works to maintain BP
Serotonin - has effects on CNS, GIT and vascular systems
Neuropeptide Y - augments vasoconstrictive effects of noradrenergic neurons, found in brain and autonomic nervous system
Vasodilators:

Prostacyclin - inhibits platelet aggregation and promotes vasodilation
VIP - found in nerves in GIT and circulating blood
ACh, Histamine via H1Rs, Bradykinin, Substance P and VIP act on endothelial system
Adenosin, Histamine via H2Rs produced relation of vascular smooth muscle independent of endothelium
Nitric Oxide

Front 30

CV19b [Feb00] Which of the following is not a vasodilator?

A. cGRP

B. VIP

C. Neuropeptide Y

D. Bradykinin

E. Acetylcholine

Back 30

Answer C

Vasoconstrictors:

TXA2 - promotes platelet aggregation and vasoconstriction
Endothelin - three types produced by endothelial cells, endothelin-1 is one of most potent vasoconstrictors
Angiotensin II - increased with elevated renin secretion when BP falls or ECF volume drops, works to maintain BP
Serotonin - has effects on CNS, GIT and vascular systems
Neuropeptide Y - augments vasoconstrictive effects of noradrenergic neurons, found in brain and autonomic nervous system
Vasodilators:

Prostacyclin - inhibits platelet aggregation and promotes vasodilation
VIP - found in nerves in GIT and circulating blood
ACh, Histamine via H1Rs, Bradykinin, Substance P and VIP act on endothelial system
Adenosin, Histamine via H2Rs produced relation of vascular smooth muscle independent of endothelium
Nitric Oxide

Front 31

CV20 [Jul97] [Feb04] Which ONE of the following causes vasoconstriction:

A. Serotonin

B. Prostacyclin

C. Neuropeptide Y

D. Substance P

E. Alkalaemia

F. cGRP

G. Oxytocin

Back 31

Answer : A and C

Vasoconstrictors:

TXA2 - promotes platelet aggregation and vasoconstriction
Endothelin - three types produced by endothelial cells, endothelin-1 is one of most potent vasoconstrictors
Angiotensin II - increased with elevated renin secretion when BP falls or ECF volume drops, works to maintain BP
Serotonin - has effects on CNS, GIT and vascular systems
Neuropeptide Y - augments vasoconstrictive effects of noradrenergic neurons, found in brain and autonomic nervous system

Vasodilators:

Prostacyclin - inhibits platelet aggregation and promotes vasodilation
VIP - found in nerves in GIT and circulating blood
ACh, Histamine via H1Rs, Bradykinin, Substance P and VIP act on endothelial system
Adenosin, Histamine via H2Rs produced relation of vascular smooth muscle independent of endothelium
Nitric Oxide

Front 32

CV21 [Jul97] [Apr01] [Jul02] In running 100 metres, the increased oxygen requirements of tissues is met by:

A. Increased cardiac output

B. Increased 2,3DPG

C. Increased erythropoietin

D. Rise in CO2 partial pressure, activating peripheral chemoreceptors

E. Increased oxygen tension

F. Increased arterial CO2 partial pressure, leads to vasodilatation

Back 32

CV21 [Jul97] [Apr01] [Jul02] In running 100 metres, the increased oxygen requirements of tissues is met by:

A. Increased cardiac output TRUE

B. Increased 2,3DPG FALSE (only 100m sprint)

C. Increased erythropoietin FALSE

D. Rise in CO2 partial pressure, activating peripheral chemoreceptors FALSE

E. Increased oxygen tension FALSE

F. Increased arterial CO2 partial pressure, leads to vasodilatation FALSE

Front 33

CV20c [Feb00] Each of the following cause vasoconstriction except:

A. Lying down

B. Bradykinin

C. Carotid occlusion

D. Hypovolaemia

E. Valsalva manoeuvre

Back 33

CV20c [Feb00] Each of the following cause vasoconstriction except:

A. Lying down TRUE

B. Bradykinin TRUE

C. Carotid occlusion

D. Hypovolaemia

E. Valsalva manoeuvre

Front 34

CV22 [d] [Jul98] [Mar99] [Jul99] [Jul00] [Apr01] [Feb04] Which one of the following (does/does not) cause (an increased/ a decreased) heart rate?

A. Bainbridge reflex

B. Carotid chemoreflex

C. Bezold-Jarisch reflex

D. Hering-Breuer reflex

E. Cushing reflex

F. Pulmonary chemoreflex

G. Stimulation of atrial stretch receptors

H. Stretching the atrium

I. Stretching the ventricle

Back 34

CV22 [d] [Jul98] [Mar99] [Jul99] [Jul00] [Apr01] [Feb04] Which one of the following (does/does not) cause (an increased/ a decreased) heart rate?

A. Bainbridge reflex INCREASED

B. Carotid chemoreflex DECREASE

C. Bezold-Jarisch reflex DECREASE

D. Hering-Breuer reflex no effect,causes tachycardia

E. Cushing reflex DECREASE

F. Pulmonary chemoreflex DECREASE

G. Stimulation of atrial stretch receptors INCREASE

H. Stretching the atrium INCREASE

I. Stretching the ventricle INCREASE


* Bainbridge reflex: opposite to baroreceptor reflex. Infusion of volume tends to increase heart rate when heart rate is slow/blood volume is high (Ref: Berne+Levy 8th ed p91, "Cardiovascular Physiology", M. N. Levy & A. J. Pappano, 9th ed, Mosby, 2007. page 86). The opposite may occur if initial HR is higher - however, according to Ganong this may be "competition" with the baroreceptor reflex

* Bezold-Jarisch reflex: coronary chemoreflex. Serotonin /capsaicin/veratridine/phenyldiguinide and some other drugs injected into coronary vessels supplying left ventricle stimulates C fibre endings - afferent vagal response casues apneoa, followed by rapid breathing, hypotension and bradycardia. (Ref: Ganong 20th ed p585, 22nd ed - p608).

* Cushing reflex: caused by increased intracranial pressure which compromises blood supply to the vasomotor area causing local hypoxia and hypercapnia which in turn increases its neuronal discharge resulting in an increase in blood pressure. This increased blood pressure stimulates the baroreceptors leading to a decrease in heart rate.

* Pulmonary chemoreflex: similar to the coronary chemoreflex (Bezold-Jarisch reflex-see above) except that the drugs are injected into the pulmonary arteries. Causes a decreased heart rate.

* Stimulation of the atrial stretch receptors: An increase in the rate of discharge of the atrial stretch receptors results in vasodilation and an increase in heart rate.

* Stretching the atrium: This will result in an increase in the rate of discharge of type B atrial stretch receptors, so it will increase the heart rate.

* L ventricular stretch: Similar to arterial baroreceptor reflex, will cause a decrease in HR

* Carotid Chemoreflex: Primarily involved in regulation of respiration, however, hypoxic stimulation of chemoreceptors causes vasoconstriction and bradycardia - this may be overridden by the hypoxic stimulation of adrenaline secretion which causes tachycardia (Ganong)

* Hering-Breuer Reflex: Primarily regulates lung inflation/deflation, no effect on HR as far as I can see

Front 35

CV23 [d] [Jul98] [Jul01] Pressure difference when lying supine is greatest between:

C. Anterior tibial artery and vein

B. Pulmonary artery and vein

A. Femoral vein and right atrium

D. Renal afferent arteriole & renal vein

E. ?

Back 35

ANSWER A

* Anterior tibial artery (mean BP 90mmHg when supine) and vein (few mmHg) is largest pressure difference

* Pulmonary artery 25mmHg (systolic) - Pulmonary vein 5 mmHg

* Femoral vein 6 mmHg - Right atrium 2 mmHg

* Renal afferent arteriole 60 mmHg - renal vein 4 mmHg

Front 36

CV24 [Jul97] [Mar98] Femoral vein pressure decreased most in standing person by:

A. Taking a step forward

B. Systemic arteriolar constriction

C. Systemic arteriolar vasdilatation

D. Apnoea

E. ?

Back 36

ANSWER A

Taking a step forward would cause the muscular pump to contract and push venous blood up towards the right atrium. The mechanism of the muscle pump is important in decreasing venous pressure from >80 to less than 30mmHg in the lower limbs. The valves in the veins helps to move blood unidirectionally. Useful information (also from Ganong) is that the magnitude of pressure change on standing is 0.77 mmHg/cm at normal blood density, either increasing as you go down or decreasing as you go up.

Front 37

CV25 [Jul97] [Feb00] [Jul01] The highest oxygen extraction is found in the:

A. Carotid body

B. Heart

C. Kidney

D. Brain

(See also CV46)

Back 37

ANSWER B

highest oxygen extraction is in the heart Myocardial oxygen extraction ratio is 55-65%(Kerry Brandis the physiology Viva book) This extraction ratio is much higher than the average oxygen extraction ratio 25% for the body as a whole.

two coronary arteries that supply the myocardium arise from the sinuses of valsalva at the root of aorta,resting coronary blood flow is 225 to 250 mls/min.,or 4 to 5 %of the cardiac output=75 ml/100g/min

resting myocardial oxygen consumption is 8 to 10 mls/100g/min=10%total body oxygen consumption

oxygen consumption of the arrested ,nondistended and normothermic heart is 1ml/100g/min ,compared with 5 ml/100g/min in both the arrested distended and beating but empty heart.

lowering myocardial temperature from 37c to 11c produces only a modest 5%further decrease in myocardial oxygen consumptioncompared with the arrested and nondistended heart

EVEN in normal resting state,oxygen extraction by cardiac cells is nearly maximal (approches 70%)

this means increases in myocardial oxygen consumption must be met by commensurate increases in coronary blood flow,because there is little additional oxygen extraction that can occur.

Front 38

CV25b [Mar03] [Jul03] In order of oxygen extraction from highest to lowest:

A. Heart > Brain > Kidney

B. Kidney > Brain > Heart

C. Kidney > Heart > Brain

D. Brain > Kidney > Heart

E. Heart > Kidney > Brain

Back 38

ANSWER A

Answer E Ganong p570

Front 39

CV25c [Feb06]
In a resting healthy adult, order of A-v oxygen difference from highest to lowest:
A. heart > liver > skeletal muscle > skin > kidney
B. heart > skeletal muscle > liver > kidney > skin
C. heart > liver > skeletal muscle > kidney > skin
D. liver > heart > skeletal muscle.
E. heart > skeletal muscle > liver > skin > kidneys

Back 39

ANSWER E

Heart > Brain >= Muscle > liver > skin > kidneys

Heavy breathing may leave skin (k)lammy.

Front 40

CV26a [Jul97] [Jul00]

In the initial phase of the Valsalva manoeuvre:
A. Heart rate increases
B. Cardiac output increases
C. Venous return increases
D. Blood pressure increases transiently
E. Peripheral vascular resistance increases

Back 40

ANSWER D

The Valsalva manoeuvre - the increase in intrathoracic pressure

As originally described by Valsalva, the manoeuvre was performed by closing off the mouth and nose and raising intrathoracic pressure by contracting the expiratory muscles. When doing this, the glottis is OPEN and the raised pressure is transmitted to the cavities of the mouth, nose (expelling pus from the middle ear via a perforated ear drum)

Phase I: Blood is expelled from the thoracic vessels by the increase in intrathoracic pressure. This causes a transient increase in blood pressure.
Phase 1 is brief
and reflex changes to increase heart rate and SVR have not yet had time to occur.

Phase II: The increase in intrathoracic pressure causes a reduction of venous return, lowering the preload and BP. The baroreceptor reflex is activated, causing vasoconstriction and a tachycardia, raising the BP towards normal.

Phase III: As intrathoracic pressure suddenly drops there is a pooling of blood in the pulmonary vessels, causing a further drop in BP.

Phase IV: With venous return restored there is an overshoot as compensatory mechanisms contineu to operate. The increased BP causes a baroreceptor mediated bradycardia.

Front 41

CV26b [d] [Jul98] [Jul99] [Jul01] [Jul03]

Valsalva manoeuvre during the increased intrathoracic phase:

A. Right ventricular filling increased in diastole

B. Blood pressure initially decreases

C. Vasoconstriction during phase II

D. Heart rate decreased

E. ?

Back 41

ANSWER C

The Valsalva manoeuvre - the increase in intrathoracic pressure

As originally described by Valsalva, the manoeuvre was performed by closing off the mouth and nose and raising intrathoracic pressure by contracting the expiratory muscles. When doing this, the glottis is OPEN and the raised pressure is transmitted to the cavities of the mouth, nose (expelling pus from the middle ear via a perforated ear drum)

Phase I: Blood is expelled from the thoracic vessels by the increase in intrathoracic pressure. This causes a transient increase in blood pressure.
Phase 1 is brief
and reflex changes to increase heart rate and SVR have not yet had time to occur.

Phase II: The increase in intrathoracic pressure causes a reduction of venous return, lowering the preload and BP. The baroreceptor reflex is activated, causing vasoconstriction and a tachycardia, raising the BP towards normal.

Phase III: As intrathoracic pressure suddenly drops there is a pooling of blood in the pulmonary vessels, causing a further drop in BP.

Phase IV: With venous return restored there is an overshoot as compensatory mechanisms contineu to operate. The increased BP causes a baroreceptor mediated bradycardia.

Front 42

July 2001 (Q25) version:

During increased intrathoracic pressure of a Valsalva manoeuvre
A. Diastolic filling of the right ventricle is decreased
B. Arterial baroreceptor activation produces bradycardia
C. Increased venous pressure augments cardiac output
D. Total peripheral resistance is decreased
E. Arterial blood pressure initially decreases

Back 42

ANSWER A

The Valsalva manoeuvre - the increase in intrathoracic pressure

As originally described by Valsalva, the manoeuvre was performed by closing off the mouth and nose and raising intrathoracic pressure by contracting the expiratory muscles. When doing this, the glottis is OPEN and the raised pressure is transmitted to the cavities of the mouth, nose (expelling pus from the middle ear via a perforated ear drum)

Phase I: Blood is expelled from the thoracic vessels by the increase in intrathoracic pressure. This causes a transient increase in blood pressure.
Phase 1 is brief
and reflex changes to increase heart rate and SVR have not yet had time to occur.

Phase II: The increase in intrathoracic pressure causes a reduction of venous return, lowering the preload and BP. The baroreceptor reflex is activated, causing vasoconstriction and a tachycardia, raising the BP towards normal.

Phase III: As intrathoracic pressure suddenly drops there is a pooling of blood in the pulmonary vessels, causing a further drop in BP.

Phase IV: With venous return restored there is an overshoot as compensatory mechanisms contineu to operate. The increased BP causes a baroreceptor mediated bradycardia.

Front 43

CV27 [Jul97] [Feb04]

The LAST part of the heart to depolarise is:
A. Base of the left ventricle
B. Base of the right ventricle
C. The apex of the epicardium
D. The endocardium of the right ventricle
(see also CV40)

Back 43

ANSWER A

Last part to be depolarize is the posterobasal part of the left ventricle

AP travels throgh Bundle of HIs and then down purkinjie fibers in the intraventricular system
Divides two fascicles
: right and left
spreading left to right

however left ventricle is thicker therefore as AP travels from endocardium to epicardium, LV takes longer.

Front 44

CV28 [d] [Mar98] [Jul98] [Jul99] [Feb00] [Jul00] [Jul01] [Mar02] [Jul02] [Jul04] [Feb06] The fastest conduction velocity is found in:

A. SA node

B. Atrial muscle

C. AV-node

D. Bundle of His

E. Ventricular conduction system/Purkinje system

F. Ventricular muscle

G. Left bundle branches

H. Right bundle branches

(see also CV16)

Back 44

Answer E

All the textbooks agree that the fastest conduction is in the Purkinje system, but there is some variation in the actual figures given (which is probably why the questions don't mention numbers, just which is fastest).

Front 45

Mar 02 version: Which part of heart has fastest conduction?

A. AV node

B. His bundle

C. Purkinje fibres

D. SA node

E. Epicardium

Back 45

ANSWER C

Front 46

CV30 [d] [Jul98] [Jul00] [Apr01] [Jul01] [Feb04] Isovolumetric contraction is closest to:

A. c wave

B. a wave

C. v wave

D. x descent

E. y descent

(see also CV51)

Back 46

ANSWER A

Isovol contractration occurs during early part of systole
Rapid increase in pressure
Buldging of tricuspid valve
c-wave of JVP

a-wave : atrial kick
c-wave : isovol contraction
v- wave : atrial filling

Front 47

CV31 [Jul97] [Feb00] The Fick principle states that:

A. Oxygen uptake as gas is equal to the arterio-venous oxygen difference in flow through the lungs

B. Arterio-venous oxygen difference in the brain multiplied by flow equals oxygen uptake

C. ?

D. ?

E. None of the above

Back 47

Answer - B

Fick Principle: uptake or output of a substance by a tissue must be equal to the difference between the amount entering (flow x arterial concentration) and the amount leaving the tissue (flow x venous concentration).

This is true because of the conservation of mass.

Using the Fick Principle, we can determine cardiac output from a sample of mixed venous blood, arterial blood and a measurement of O2 uptake.

Cardiac Output = O2 uptake/ (arterial O2 content - mixed venous O2 content

For example, substituting some typical values:

* O2 uptake = 250 mls O2/min
* arterial O2 content = 200mlsO2/l of blood
* mixed venous O2 content: 150mlsO2/l of blood

thus: CO = 250/(200-150) = 5 l/min.

If you use O2 content in units of mlsO2/dl then the answer will be in decilitres.

Though often overlooked, this use of the Fick equation for measuring cardiac output includes the assumption that O2 consumption of the lung from the ventilated gas is negligible. If this was not true, the measured O2 consumption would be higher and the calculated CO higher.

Therefore B is true.

Front 48

CV32 [Jul97] With a mixed venous oxygen content of 110ml/l and an arterial oxygen content of

150ml/l and oxygen uptake of 280ml/min cardiac output is

A. 5 litres/min

B. 6 litres/min

C. 7 litres/min

D. 8 litres/min

E. 9 litres/min

Back 48

ANSWER C

Front 49

CV33b [] [Mar98] [Jul98] [Jul00] [Jul01] [Mar03] [Jul03] [Feb04] Blood flow at rest is most for:

A. Brain

B. Liver

C. Kidney

D. Heart

E. Skin

Back 49

ANSWER B

* The organ with the greatest whole organ blood flow at rest is the liver: 1500 mL/min

* The organ with the greatest blood flow per 100g mass is the kidney: 420 mL/100g/min

Front 50

CV34 [Mar98] [Mar03] [Jul03] [Feb04] Oxygen consumption (in mls/100g/min) is highest for

A. Muscle

B. Brain

C. Kidney

D. Liver

E. Heart

Back 50

ANSWER E

Heart 9.7 mls/100g/min
Kidney 6.0
Brain 3.0
Liver 2.0
Skin 0.2
Muscle 0.2

Front 51

CV34b [Apr01] Oxygen consumption at rest is most for:

A. Brain

B. Heart

C. Liver

D. Kidney

E. Skeletal muscle

F. Skin

Back 51

Depends on question

If whole tissue : C

If per 100g : B

Oxygen consumption in mL/100g/min:

Heart 9.7
Kidneys 6.0
Brain 3.3
Liver 2.0
Skin 0.3
Skeletal Muscle 0.2

Oxgen consumption for whole organs (ml/min):

Liver 51.0
Skeletal Muscle 50.0
Brain 46.0
Heart 29.0
Kidneys 12.

Front 52

CV34c [Apr01] During strong (?severe) exercise, oxygen consumption is greatest in:

A. Brain

B. Heart

C. Skeletal muscle

D. Liver

E. Kidney

F. Skin

Back 52

Again this depends if the question is asking total organ metabolic O2 requirements or per 100g

Oxygen consumption of the heart (mL/100g/min):
* Resting: 8
* Heavy Exercise: 70

Oxygen consumption of skeletal muscle (mL/100g/min):
* Resting muscle: 1
* Contracting muscle: 50

Hence:

* B correct for O2 consuption per 100g
* C correct for whole organ O2 consumption

Front 53

CV35 [] [Mar98] [Jul98] [Jul99] [Mar02] [Jul02] The effects on plasma volume of 500 ml blood loss are neutralized within:

A. 1-2 hours

B. 8-10 hours

C. 24 hours

D. 1 week

E. 1 month

Back 53

Answer C

Plasma volume should return to normal in:
Brandis page 58: 12-72 hrs.
Power and Kam pg 156: 12-24.
Ganong 22nd ed pg 638: 12-72 hrs.

Front 54

Mar 02: Following a 500ml loss of plasma, the volume is compensated by:

A. 8 - 12 hours

B. 24 – 48 hours

C. 3 weeks

D. ?

E. ?

Back 54

Answer B

Plasma volume should return to normal in:
Brandis page 58: 12-72 hrs.
Power and Kam pg 156: 12-24.
Ganong 22nd ed pg 638: 12-72 hrs.

Front 55

CV36 [Mar98] Venoconstriction occurs EXCEPT during:

A. Lying down

B. Valsalva manoeuvre

C. Carotid sinus compression

D. ?

E. ?

Back 55

Answer A and C

A.

Lying down → return of venous blood pooled in legs → ↑ venous retrun to RA → ↑ cardiac output → ↑ BP → ↑ carotid sinus stimulation → venodilation.

B.

Valsalva → ↓ venous retrun to RA → ↓ cardiac output → ↓ BP → ↓ carotid sinus stimulation → venoconstriction.

C.

Carotid sinus compression → ↑ carotid sinus stimulation → venodilation.

Front 56

CV37 [Jul98] [Mar99] [Jul99] [Jul01] Coronary blood flow is:

A. Dominant in left coronary artery in 60% of people

B. Better supply to subendocardium in systole

C. Better supply to subendocardium in diastole

D. Better supply to left ventricle in systole

E. Left > right during systole

F. Supply to subepicardium > in LV than RV during systole

Back 56

C is true, especially in LV diastole.

* A: wrong - Right in 50%, equal in 30%
* B: wrong - diastole
* C: correct - greater blood flow to endocardium during diastole
* D: wrong - diastole
* E: wrong - R>L because of lower pressure developed
* F: wrong

Front 57

Also remembered as: Blood flow in the left (?ventricle/?coronary artery) during systole

A. In less in subendocardium

B. Is less in the middle muscle layers (or: middle layer of ventricular wall)

C. Greater in right ventricle than left ventricle

D. ?

E. ?

Back 57

Answer A

Front 58

Compensatory mechanisms in a patient with coarctation of the (descending) thoracic aorta:
A. Lower sympathetic tone in the lower half of the body
B. Decreased total peripheral resistance
C. Increased BP in upper body
D. Reduced function of the baroreceptors
E. BP in lower limb is normal

Back 58

Answer C

When a constrictor is placed on the aorta above the renal arteries, the blood pressure in both kidneys falls, renin secreted, angiotensin formed causing vasoconstriction. Within a few days, salt and H2O retention occurs so that the arterial pressure in the lower body at the level of the kidneys rises approx. to normal wheras high pressure persists in the upper body. Now the kidneys are no longer ischaemic so secretion of renin will decrease.

Arterial pressure in the lower body is usually almost normal whereas the pressure in the upper body is far higher than normal (55% higher).

Blood flow in arms is normal (despite higher BP) because of compenstation to elevated pressure by local autoregulation.

Blood flow in legs where the pressure is not elevated is almost exactly normal.

Front 59

Jul99 version:
Coarctation of the aorta:
A. Cardiac output is 1.5 times normal
B. Systemic vascular resistance is higher in the lower limbs as
compared to the upper limbs
C. Blood flow in all tissues will be normal
D. Arterial baroreceptors are inactive
E. Blood pressure the same at arm and leg

Back 59

Answer C

When a constrictor is placed on the aorta above the renal arteries, the blood pressure in both kidneys falls, renin secreted, angiotensin formed causing vasoconstriction. Within a few days, salt and H2O retention occurs so that the arterial pressure in the lower body at the level of the kidneys rises approx. to normal wheras high pressure persists in the upper body. Now the kidneys are no longer ischaemic so secretion of renin will decrease.

Arterial pressure in the lower body is usually almost normal whereas the pressure in the upper body is far higher than normal (55% higher).

Blood flow in arms is normal (despite higher BP) because of compenstation to elevated pressure by local autoregulation.

Blood flow in legs where the pressure is not elevated is almost exactly normal.

Wrong, distinguishing features of coarctation is decreased blow flow to lower legs, higher systolic BP arms compared with legs, and increase RAS activity, thus B.CO decreases due to outflow obstruction.

Front 60

CV40 [Mar99] During a cardiac cycle, the first part of the ventricles to contract is:

A. Apex of left ventricle

B. Base of left ventricle

C. Septum

D. Epicardium at base of left ventricle

E. Right ventricle

Back 60

Answer C

The first portions of the ventricles to be excited are the interventricular septum (except at its basal portion) and the papillary muscles.

The last part of the heart to be depolarised is the posterobasal portion of the LV, the pulmonary conus and uppermost (basal) portion of the septum.

Front 61

CV42 [Mar99] [Jul00] [Apr01] [Jul04] When the aortic valve closes, the pressure in the right ventricle is:

A. 0 mmHg

B. 15 mmHg

C. 30 mmHg

D. 50 mmHg

E. 120 mmHg

Back 61

Answer B

Events of cardiac cycle

Front 62

CV43 [Jul98] [Apr01] The velocity of blood flow is greatest in:

A. Capillaries

B. Pulmonary vein during diastole

C. Small arteries

D. Inferior vena cava

Back 62

Answer B

But magic disk says it is C

Its C, aorta and arteries velocity is highest and equal, see well known picture.

Front 63

CV44 [Jul98] [Feb00] [Jul02] [Mar03] [Jul03] [Feb04] In a 70kg trained athlete at rest:

A. Cardiac output is 7 litres per minute

B. Left ventricular end-systolic volume is 60mls

C. Stroke volume is 70mls

D. Oxygen consumption is 350mls/min

E. A-v O2 extraction is 5mlsO2/100mls blood

Back 63

Answer E (O2 extraction normal at rest, all other values are consistent with normal 70kg man.)

A. Cardiac output is 7 litres per minute

In a resting supine man of average size, cardiac output averages out at 5.0 L/min (72bpm x 70ml) In a trained athlete, SV increases and HR decreases, but CO at rest is similar

B. Left ventricular end-systolic volume is 60mls (?? OR: end-diastolic volume is ?60mls ?100mls)

In an average person, the end-diastolic ventricular volume is about 130ml. Stroke volume is about 70-90mls, leaving an end-systolic volume of about 50mls.

In a trained athlete, HR is decreased, increasing the time for diastolic filling. Thus the end diastolic volume will be greater and stroke volume increases through the Frank-Starling mechanism. The end-systolic volume will be unchanged at about 50 mls.

C. Stroke volume is 70mls

70mls is the stroke volume of an average 70kg male at rest in the supine position. A trained athlete has a larger stroke volume and proportionately lower HR.

D. Oxygen consumption is 350mls/min

Oxygen consumption at rest is normally 250mls/minute

E. A-v O2 extraction is 5mlsO2/100mls blood

Physical conditioning is associated with a greater extraction of O2 from the blood. With long term training, capillary density and the numbers of mitochondria imcrease, as does the activity of the oxidative enzymes in the mitochondria. Table 29-4 in Ganong shows A-V O2 difference as 4.3 ml/100mls blood at rest.

Front 64

CV45 [Mar99] Physiological consequences of aortic cross-clamping:

A. ?

B-E. ?

Back 64

Aortic cross-clamping:

* Increase afterload
* decrease organ perfusion
* increase MAP prox to clamp
* LVF, AV regurg
* increase baroreceptor firing -> decrease symp activity -> decr PVR, decr HR

Front 65

CV46 [Mar99] During exercise, oxygen extraction is greatest in:

A. Brain

B. Heart

C. Skeletal muscle

D. ? (see also CV25)

Back 65

Answer B or C

depending on if it is asking about total organ or per 100g

Front 66

CV47 [Mar99] [Mar03] [Jul03] If CO constant & ODC unchanged& O2 consumption constant, mixed venous oxygen tension decreased with:

A. Cyanide toxicity

B. Anaemia

C. Decreased temperature

D. Increased CO2

E. ?Hypocarbia

(See also RE10 which is very similar)

Back 66

Answer B

Front 67

CV48 [Jul99] [Jul01] Afferents from the Carotid ?sinus ?body:

A. Use glycine as a neurotransmitter

B. Synapse in the C1 area of the brainstem

C. Travel via sympathetic nerves

D. ?

E. ?

Back 67

Answer ?B

Baroreceptors in carotid sinus and aortic arch - afferent fibers pass via glosopharyngeal and vagus nerves to medulla.

Most end in Nucleus Tractus Solitarius (?C1 area)

Probably secrete glutamate as excitatory transmitter (B false)

Front 68

July 2001 version (Q24 on this paper): Arterial baroreceptor afferents

A. Reach spinal cord via sympathetic nerves

B. Utilise glycine as a neurotransmitter

C. Primary synapse in C1 area of the medulla

D. Activate GABA inhibitory interneurons

E. Excite autonomic efferents in the anterolateral horn

Back 68

Answer D

Baroreceptors in carotid sinus and aortic arch - afferent fibers pass via glosopharyngeal and vagus nerves to medulla. (A false) Most end in Nucleus Tractus Solitarius (?C1 area) Probably secrete glutamate as excitatory transmitter (B false) Excitatory (glutaminergic) projections to ventrolateral medulla (E false) then stimulate GABA-secreting inhibitory neurons (D true) and so inhibits vasomotor centre outflow

Front 69

CV49 [jq] [Jul01] [Jul04] Which ONE of the following is true:

A. Right atrial systole and left atrial systole occur at same time

B. Pulmonary valve closes before aortic in inspiration

C. c wave of atrial pressure trace occurs at time of peak aortic pressure

D. RV ejection precedes LV ejection

E. ?

Back 69

Answer C

Back 70

All pretty true except A

If the head is say 30cm above the heart, the gravity induced decrease in pressure (Ganong says 0.77mmHg for each cmH2O above heart, but I read somewhere else it should be around 0.73 (? depends on temperature), but really around 0.77 x 30 = 23mmHg below aortic MAP; hence, Ganong 22th ed p. 630 says head MAP is about 60~70mmHg BUT that is for normal MAP say 93 (120/80), so someone with MAP 100 should really have head arterial pressure of 80mmHg (100- (0.77 x 30) = 76.9). So I wouldnt go for option B; Option C would be correct if it is ~95~100mmHg, but not 70mmHg, and option D looks about right: ie. 100mmHg - 23mmHg - normal ICP (10mmHg) = 67mmHg which roughly equals to D.

In an average, healthy 70kg male with standing erect with mean arterial BP of 100mmHg:
A: Cerebral venous pressure is approximately 10mmHg
B: Mean arterial pressure at head level is 70mmHg
C: Venous pressure in foot is approximately ?70/?100mmHg
D. Cerebral perfusion pressure 70mmHg
(See also CV14)

Edit: A-wrong, standing CVP is 4,6mmHg, B is wrong, 80mmHg is correct (3/4 x 30cmH2O = 21mmHg, thus 100-21=79mmHg), C is correct, can be lowered to 30mmHg with calve muscle pump, D is incorrect, 70 is lower border of normal en significant duration as this level can cause ischemic damage to brain.

Answer C

Front 71

CV50b [Jul04]

Which is true in the erect 70kg human (Similar to CV 50 but different values)
A. venous pressure in foot 70mmHg
B. Central venous pressure 10mmHg
C. MAP head 100 mmHg

Back 71

Answer A

Answer to CV50b is A: Venous pressure in foot 70mmHg

B. False: Normal CVP = 4.6mmHg [WG21:p597]

C. False. Need to account for hydrostatic pressure

Front 72

CV51 [Jul00] [Jul01] [Feb04] During isovolumetric contraction of the ventricles:

A. Aortic blood flow is reversed

B. Coronary blood flow increases

C. The pulmonary valve is not yet shut

D. Aortic pressure is falling

E. When both ventricles reach the same pressure their respective outflow valves open

(Q13 on Jul 01)

Back 72

Answer D

Front 73

CV51b [Mar02]

Isovolumetric contraction is associated with:

A. Immediate increase in heart rate due to cardiac sympathetics

B. Cardiac output increased/unchanged

C. Increased systolic BP and decreased diastolic BP

D. Does no work

E. Decrease stroke volume

Back 73

Answer D

Work=Forces x distance

No movement of blood, therefore no work

Front 74

CV52 [Apr01] [Jul03] [Feb04] Cerebral blood flow is increased by:

A. Decrease in CSF pressure of 5 mmHg

B An increase in MAP of …

C. Significantly increased by an increase of pCO2 of 5mmHg

D. Plasma glucose > 10 mmol/l

E. Increased regional (?OR global) neural activity (OR: Increased metabolic requirements)

(Alt version: A significant increase in global cerebral blood flow is most likely to be caused by: )

Back 74

ANSWER C

An increase in pCO2 of 1mmHg increases CBF by 4%. Therefore a 5mmHg increase would increase CBF by 20%. This relationship is linear between the pCO2 range of 20-80mmHg.

Local metabolic requirements do change flow, however total cerebral flow remains constant

Front 75

CV53 [Apr01] Baroreceptors located in all EXCEPT:

A. Carotid sinus

B. Carotid body

C. Right atrium

D. Aortic arch

E. Large veins

Back 75

Answer B

Front 76

CV54 [Apr01] [Jul01] The volume of blood is greatest in:

A. Systemic Capillaries

B. Large veins

C. Small arteries

D. The liver

E. ?The lung

Back 76

Answer B

BLOOD VOLUME

* 4% Aorta + arteries + arterioles
* 5% capilaries
* 67% venous system
* 12% pulmonary
* 5% heart

Front 77

CV55 [Apr01] Hydrostatic pressure increases in:

A. Arteriolar constriction

B. Venous constriction

C. Capillary dilatation

D. ?

Back 77

Answer B

Hydrostatic pressure relates to fluid pressure. Therefore hydrostatic pressure in your legs is higher than in your head. When considering hydrostatic pressures in the capillaries, it is affected by arterial and venous pressures and precapillary and postcapillary resistances. Hydrostatic capillary pressures at the arterial end are 32mmHg and venous end 15mmHg.

Given Poiseulles Law for laminar flow Q= TT(P1-P2)r4/8nl where Q =volume flow rate, (P1-P2)= driving pressure, r = radius, n = viscosity, l = tube length and 8/TT is the constant of proportionality then resistance R = driving pressure (P1-P2)/Flow (Q)=8nl/TTr4 then resistance is inversely proportional to radius4

* A. Arteriolar Constriction : Will lead to decreased radius which will increase the precapillary resistance. The volume of fluid flowing into the capillaries will be reduced. As pressures is inversely proportional to volume then capillary hydrostatic pressures will be reduced. A is incorrect.
* B. Venous Constriciton: Will lead to decreased radius which will increase postcapillary resistance. Less volume of fluid flowing out of capillaries means more volume remains therefore capillary hydrostatic pressure will be increased. B is correct.
* C. Capillary dilatation: Will lead to increased radius of the capillaries which will decrease capillary resistance. This may decrease driving pressure across the capillaries from artery to veins and if venous pressure stays the same P2 then capillary hydrostatic pressuresP1 must decrease.(Note: capillary diameter changes are passive and are caused by alterations in pre and post capillary resistance as capillaries have no smooth muscle and therefore cannot actively vasoconstrict. Their endothelial cells do have actin and myosin so can change shape in response to chemical stimuli.) C likely incorrect.

Also note that Increases in arterial or venous pressures increase capillary hydrostatic pressures as it can be thought of as being the same column of fluid.Venous pressure increases and venous resistance increases have greater effect than arterial changes on capillary hydrostatic pressures.

Front 78

CV56 [Jul01] Configuration of an ECG recording:

A. 25 mm / sec, 0.5 mV /cm

B. 25 mm/sec, 1mV /cm

C. 50mm/sec 0.5 mV /cm

D. 50mm/sec 1mv / cm

E. none

Back 78

Answer B

Standard ECG recording is at 25mm/s, and 1cm =1mV.

Front 79

Alt version: On a standard ECG
A. Speed 50mm/s 50mm/mv
B. Speed 50mm/s 25mm/mv
C. Speed 25mm/s 25mm/mv
D. Speed 25mm/s 50mm/mv
E. None of the above

Back 79

Answer E

Standard ECG recording is at 25mm/s, and 1cm =1mV.

Front 80

CV58 [Mar02] Long term control of tissue blood flow includes:

A. Adenosine

B. Nitric oxide

C. Change in tissue vascularity

D. Oxygen tension at the precapillary sphincter

E. “something else also short term”

Back 80

ANSWER C

Front 81

CV59 [Mar03] [Jul03] Peak left ventricular (LV) volume corresponds with (or correlates best with):

A. a wave

B. v wave

C. c wave

D. x descent

E. y descent

Back 81

Answer is C

c wave corresponds to isovolumetric ventricular contraction, a phase that follows completion of ventricular filling but precedes ventricular ejection (Ganong 22nd 569)

Front 82

CV60 [Mar03] Cardiac muscle is different from skeletal muscle because:

A. Fast Na Channels

B. Slow Ca Channels

C. Presence of actin and myosin

D. Lower RMP

E. ?

Back 82

ANSWER B


Cardiac muscle - initial depolarisation due to opening of voltage gated sodium channels similar to that occuring in skeletal muscle, initial rapid repolarisation is due to closure of sodium channels, subsequent prolonged plateau phase is due to slower but prolonged opening of voltage gated calcium channels.

Front 83

Widened pulse pressure in all except:
A. More rapid ventricular ejection
B. Increased aortic compliance
C. Increased diastolic pressure
D. ?

Back 83

ANSWER B

Pulse pressure widened by

* increased SV
* increased contractility (which for a given preload/afterload, will increase SV)
* decreased aortic compliance

Front 84

Alt version: All increase pulse pressure EXCEPT:
A. Increased LV dP/dT
B. Increased Stroke Volume
C. Increased Diastolic pressure
D. Increased TPR
E. Increased aortic compliance

Back 84

ANSWER C, D, E, no E only is right!

Systolic pressure is related to SV and aortic compliance, while diastolic pressure is related to the TPR, the SV, the compliance

Front 85

Alt version: Pulse pressure does NOT increase with:
A. Increased contractility
B. Increased stroke volume
C. Decreased diastolic BP
D. ?
E. Increased aortic compliance

Back 85

Answer E

Front 86

Adrenaline in VF arrest
A. Increases contractility
B. 'Coarsens' fine VF
C. ?
D. ?
E. ?

Back 86

Answer is none of these


Adrenaline is given IV in ventricular fibrillation but only after CPR has commenced and cardioversion has been attempted twice.

The role of adrenaline is to contract the peripheral circulation and increase the central aortic pressure to improve coronary perfusion.

"Successful defibrillation largely depends on the following 2 key factors:

* duration between onset of VF and defibrillation, and
* metabolic condition of the myocardium."

"VF waveform usually begins with a relatively high amplitude and frequency, and, then, it degenerates to smaller and smaller amplitude until asystole after approximately 15 minutes, possibly from depletion of the heart's energy reserves. Consequently, early defibrillation is vital; emergency response teams can perform defibrillation before arrival at the ED."

"Defibrillation success rates decrease 5-10% for each minute after onset of VF. In strictly monitored settings where defibrillation was most rapid, 85% success rates have been reported." -

Front 87

CV63 [Jul03] In a young woman who loses 20% of her blood volume:

A. Decreased diastolic BP

B. Increased serum ADH

C. Increased pulmonary vascular resistance

D. Decreased cerebral blood flow

E. Increased urinary sodium concentration

Back 87

ANSWER B

A. Decreased diastolic BP

Systolic, diastolic and pulse pressures all diminish in severe haemorrhage. However in moderate haemorrhage, pulse pressure is reduced but mean arterial pressure may be normal.

B. Increased serum ADH

Correct. Vasopressin (ADH) is actively secreted by the posterior pituitary gland in response to haemorrhage. The plasma concentration increases as the arterial blood pressure diminishes.

C. Increased pulmonary vascular resistance

Baroreceptor stimulation (from decreased cardiac output) can dilate pulmonary vessels reflexly.

D. Decreased cerebral blood flow

Cerebral blood flow is preserved during mild to moderate haemorrhage. Cerebral vascular resistance may actually diminish in contrast to general peripheral vasoconstriction.

E. Increased urinary sodium concentration

Decreased renal blood flow raises the blood levels of angiotensin II. This accelerates the release of aldosterone which stimulates sodium reabsorption by the renal tubules. Therefore, urinary sodium concentration is decreased.

Front 88

CV64 [Feb04] In chronic anaemia:

A. Increased arterial-venous oxygen content difference

B. Increased venous pO2

C. Increased oxygen consumption

D. Decreased heart rate

E. Increase oxygen tension in mixed venous blood

Back 88

ANSWER E

2,3 DPG increases

Front 89

V65 [Jul04] The QT interval is measured from

A. The start of the q wave to the start of the t wave

B. The peak deflection to the t wave

C. ?

Back 89

ANSWER NONE

QT interval is measured form the start of the q wave to the end of the t wave. Therefore neither of the answers above is correct. The QT interval is inversely related to the heart rate. Normal QTcorrected < 440ms.

Front 90

Pulmonary capillary wedge pressure wave form has:
A. a wave but no c or v waves
B. a and c waves but no v wave
C. a and v waves but no c wave
D. a, c and v waves
E. None of the above

Back 90

ANSWER C

A normal PAOP tracing is shown in Figure 6. Note that, like a central venous pressure trace, 'A' and 'V' waves are present, but that a 'C' wave is usually not present. (Answer C)

Front 91

CV67 [Mar 05]
A decrease in stroke work is due to an increase in:

A. Contractility

B. Ejection fraction

C. Preload

D. Aortic compliance

E. Venous return

Back 91

ANSWER D

Left ventricular work per beat (stroke work) is generally considered to be equal to the product of stroke volume and the mean aortic pressure (afterload) against which the ventricle ejects blood. Increased preload (C), venous return (E) or ejection fraction (B) will all increase stroke volume and therefore stroke work. Increased contractility (A) also leads to increased myocardial oxygen consumption. Conversely increased aortic compliance (D) reduces mean aortic pressure or afterload and thereby stroke work is decreased.

Front 92

CV68 [Mar 05]

Total peripheral resistance:

A. Is 17 times greater than pulmonary vascular resistance

B. Is mainly due to capillary beds

C. Can be determined from the arterial pulse pressure

D. Has units of dynes x sec x cm^-5

E. Can be calculated from MABP, CO and PAOP (alt version: PCWP)

Back 92

ANSWER D

PulVR is 1/7th SystVR
The arterioles are the major resistance vessels of the arterial circuit
The unit used to express resistance is dyne.seconds/centimeters^5

CO = MAP / TPR=MAP-RAP/TPR
answer E uses PAOP therefore incorrect

Front 93

CV69 [Jul06] ECG vs cardiac cycle

A. Isovolumetric contraction starts after QRS complex completed

B. T-wave starts with isovolumetric relaxation

C. QT interval from end of isovolumetric contraction to ???

D. ST segment begins at isovolumetric relaxation

E. P wave immediately before mitral valve opening

F. Peak of left atrial V wave corresponds to start of isovolumetric relaxation

Back 93

ANSWER ???

A : isovolumetric contraction starts in the middle of the QRS

B is incorrect, as T waves start before closure of the aortic valve (during ejection). heart is repolarizing, but still contracting

C: incorrect : QT interval from start of Q to end of T, isovolumetric contraction starts in the middle of QRS

D is incorrect as the ST segment begins at the completion of isovolumetric contraction.

E is incorrect as P waves occur when the mitral valve is already open in diastasis.

F is incorrect as the left atrial V wave peak (LA filling while MV closed) corresponds to just prior to AV opening at the END of isovolumetric relaxation.

Front 94

CV70 [Jul06]

The radial pressure wave differs form the aortic because
A. Systolic pressure lower
B. Diastolic pressure greater
C. Aortic mean pressure greater
D. Dicrotic notch more pronounced
E. Radial systolic pressure peaks earlier

Back 94

ANSWER E

* Radial artery peak and pulse pressures greater than aortic trace so A is wrong
* Radial artery systolic and diastolic pressures greater than aortic
* Radial artery trace delayed onset of upstroke, steeper upstroke and shorter duration versus aortic trace
* Radial artery trace does NOT have a dicrotic notch so D is wrong

Davis and Kenny page 192 - radial artery has lower DBP and higher SBP

MAP is the same, so if systolic is greater, a constant MAP MUST mean that the diastolic is lower.

Front 95

CV72 [Jul06] In the cardiac action potential, the (plateau?) is due to

A.

B.

C. due to slow Ca channel?

D. due to K+ channel ?.....

E.

Back 95

ANSWER C

Front 96

CV73 [Feb06] Effect of ageing (normally):

A. pulse pressure widens

B. diastolic increases

C. increased aortic compliance

D. increased rate of ventricular filling in diastole

E. heart rate increases

Back 96

ANSWER A

* A -True (systolic pressure increases,diastolic pressure stays the same or decreases
* B -False (Diastolic pressure remains the same or decreases (initially rises then falls in middle age due to increased stiffness of the arteries)
* C-False (compliance decreases)
* D-False (LV wall thickens at the expense of the LV Cavity )
* E- False (Heart rate decreases due to increased vagal tone and decreased sensitivity to andrenergic receptors ,heart rate decreases by one beat/min/year over age 50)

Front 97

CV74 [Feb06] The organ most UNLIKELY to demonstrate an increase in blood flow in response to decreased capillary partial pressure of oxygen?

A. Liver

B. Skeletal muscle

C. Heart

D. Kidneys

E. Lung

Back 97

Answer D

A. Liver (hypoxia in port vien, increases hepatic artery flow : semi-reciprical relationship)

B. Skeletal muscle (metabolic autoregulation)

C. Heart (metabolic autoregulation)

D. Kidneys (no metabolic autoregulation, flow is in excess of metaboic needs, flow is regulated to GFR)

E. Lung (HPV) Why not E? HPV will make it extremely unlikely to dilate.

Front 98

CV75 [Feb06] Which of the following are not produced by vascular endothelium?

A. thromboxane

B. Endothelin

C. prostacyclin

D. NO

E. something else that i think was produced by endothelium

Back 98

ANSWER A

A-True (produced by platelets)

B -FALSE

C-False

D -False

Front 99

CV76 [Feb06]

Regarding blood flow in capillaries:
A. increases as diameter decreases
B. is a newtonian fluid
C. increases as viscosity decreases
D. ?
E. ?

Back 99

ANSWER C

A. false
B. false : non newtonian fluid
C. true eg anaemia

Front 100

[Feb06] version

Regarding pressure volume loop of heart:

A. ventricular diastolic elastance curve is change in pressure / change in volume in diastole

B. end systolic pressure volume relationship gives guide of afterload

C. contractility is demonstrated by end systolic point

D. afterload is determined by end diastolic volume

E. aortic valve closes at diastolic blood pressure

Back 100

Answer A

Front 101

CV78 [Feb06] Effect of exercise:

A. systolic BP decreases

B. pulse pressure (?widens/?narrows)

C diastolic BP decreases

D. diastolic pressure increases

E. ?

Back 101

ANSWER A,B,C

Answer B (widens) and C, Exercise increases systolic BP but diastolic remains the same or decrease, depending on fitness levels, e.g. pulse pressure widens. Increasing diastolic BP is a poor prognostic sign.

Initial increase in Cardiac Output

* Increased venous return due to muscle pump
* Increased venous return due to venoconstriction
* Increased demand due to vasodilation
* Increased myocardial contractility and heart rate due to increased SNS outflow.
* Sustained by the associated decrease TPR. (as below)

[edit]
Changes in regional circulation

* Increased muscle blood flow due to neurally mediated relaxation of precapillary sphincters, and further arteriolar vasodilation due to local metabolites and neural factors (β1).
* Associated decrease in TPR.
* Vasoconstriction of splanchnic and renal circulations.
* Increased skin blood flow to dissipate heat.
* Increased Coronary Blood flow mediated by metabolic autoregulation, and β2 stimulation.
* No change in global Cerebral Blood Flow, but may be regional variations.

[edit]
Changes in Cardiac indices

* Heart rate increases linearly.
* Systolic Blood Pressure increases nonlinearly with increasing intensity of exercise.
* Diastolic Blood Pressure may show a small increase initially or at low levels of exercise but with increasing duration or intensity it will show a decrease.
* There is a nonlinear increase in Stroke Volume due to increased venous return and as such most of the increase occurs during light or moderate exercise (presumably most of this is due to effect of muscle and thoracic pumps).

Front 102

CV79 [Jul06] Blood flow in exercise

A. Decreased blood flow to splanchnic system

B. Increases to all skeletal muscle (it did say skeletal)

C. Increased systemic vascular resistance

D. Skin blood flow does not change.

E. Increased cerebral blood flow

Back 102

ANSWER A

Front 103

PH07 [1986] [Apr96]
Which of the following is NOT a normal pressure measurement?

A. Pulmonary artery: 25/10 mmHg

B. Aortic root: 120/0 mmHg

C. Right ventricle 25/8 mmHg

D. Right atrium: 5 mmHg

E. Left atrium: 3 mmHg

Back 103

ANSWER B

Front 104

PH08 [1986] [Mar93]
The cardiovascular response to rise in intrathoracic pressure to 40 mmHg include:
1. Reduced venous return
2. Increased peripheral vascular resistance (vasoconstriction)
3. Arterial hypotension
4. Bradycardia

Back 104

ANSWER 1 or 2

This is obviously a question about the Valsalva manoeuvre. It does not specify the acuity of the change. Taken directly from the Physiology Viva book: There are 4 phases:

1. pulse rate steady. Small increase in blood pressure (augmented VR).
2. increased HR. Vasoconstriction. Slight decrease in BP (diminished VR).
3. Steady HR. Drop in BP.
4. Increase in BP, with compensatory bradycardia.

Edit TDV: can't be phase 3 or 4 since this is after release of pressure, thus must be referring to phase 2 e.g. induced arterial hypotension secondary to 40mmHg pressure, followed by CVS RESPONSE which are tachycardia and peripheral vasoconstriction. Thus answer is 2.

Front 105

PH09 [1988]
Carboxyhaemoglobin:
A. Due to CO2 combining with Hb
B. Can be 2% in non-smokers
C. Can be up to 15% in smokers
D.

Back 105

ANSWER B

Front 106

PH10 [1988]
Time constant of lung is:
A. Resistance x compliance
B. Resistance / compliance
C. ?
D. ?

Back 106

ANSWER A

Front 107

PH29 [1987] [Mar92] [Mar93] [Aug93]
Mixed venous blood oxygen saturation:
A. Is measured from blood sampled from the right atrium
B. Is accurately calculated from mixed venous pO2 measurements
C. Is used in the calculation of cardiac output
C. Assesses peripheral circulation
D. Has no effect on the A-a oxygen gradient
E. Is normally in the range of 40%

Back 107

ANSWER C

Front 108

PH40 [Apr96] [Aug96] [Jul98] [Apr99]
With regard to CVP trace:
A. The a wave is caused by atrial contraction & occurs at the same time as the p wave on the ECG
B. The c wave is caused by isovolumetric contraction & occurs after QRS
C. The x descent is caused by relaxation of the ventricle
D. The v wave relates to venous filling & peaks after T wave
E. The y descent corresponds with isovolumetric relaxation

Back 108

ANSWER B and D (not D, corresponds with ventricle filling, not venous filling!)

Front 109

PH49 [Jul00]
Most sensitive haemodynamic parameter indicating hypovolaemia:
A. Systolic pressure variability/swing
B. PAOP
C. CVP
D. Hypotension
E. Tachycardia

Back 109

ANSWER A

B and C poor sensitity

D late sign

E variable

Front 110

PH49b ANZCA version [2003-Apr] Q54

In a mechanically ventilated patient the haemodynamic parameter that correlates most closely with hypovolaemia is
A. systolic pressure variation
B. central venous pressure
C. pulmonary artery occlusion pressure
D. pulse pressure
E. cardiac output

Back 110

ANSWER A

Front 111

PH53 ANZCA version [2001-Aug] Q59

In assessing the adequacy of oxygen delivery to meet the body's oxygen demands the best indicator is
A. arterial PO2
B. arteriovenous oxygen content difference
C. oxygen flux calculation
D. mixed venous PO2
E. cardiac output

Back 111

ANSWER D

Front 112

Can04-18 A patient with known coronary artery disease shows the following ECG changes with elevation in I, V2, V3, V4. Which is the most likely vessel occluded?

A. Proximal LAD

B. Proximal Circumflex

C. RCA

D. Distal Circumflex

E. Marginal branches of circumflex

Back 112

ANSWER C


Anterior:
ST elevation in V1, V2, V3, V4

ST depression in II, III, aVF

Inferior: ST elevation in II, III, aVF

ST depression in V1, V2, V3, or I, aVL

Lateral: ST elevation in I, aVL, V5, V6

ST depression in II, II, aVF

Septal wall: ST elevation in I, aVL, V1, V2
Posterior: tall and wide R waves and ST depression in V1, V2
Right Ventricular: ST elevations in V4R, V5R, V6R

Front 113

A patient in an intensive care unit has the following haemodynamic measurements made:

Mean Systemic Arterial Pressure (MAP) 80 mm Hg.
Mean Central Venous Pressure (CVP) 10 mm Hg.
Cardiac Output (CO) 5.0 l/min.
Mean Pulmonary Arterial Pressure (MPAP) 35 mm Hg.
Pulmonary Artery Occlusion Pressure (PAOP) 20 mm Hg.

The pulmonary vascular resistance (PVR) is:

A. 14 dynes.sec.cm-5.
B. 120 dynes.sec.cm-5.
C. 240 dynes.sec.cm-5.
D. 400 dynes.sec.cm-5.
E. 1120 dynes.sec.cm-5.

Back 113

ANSWER C

CO=MAP-RAP/PVR
CO=MPAP-PAOP/PulmVR (35-20)/5 x80
PVR=3 mmHg/L.min

Convert to dynes.sec.cm-5 x 80

=240 dynes.sec.cm-5

Front 114

Which of the following typically result from the application of an aortic cross clamp?

1. Stroke volume decreases.
2. Systemic blood pressure increases.
3. Myocardial contractility decreases.
4. Venous return decreases.

A: 1,2,3 Correct
B: 1,3 Correct
C: 2,4 Correct
D: 4 Correct
E: All Correct

Back 114

ANSWER E

Front 115

The carotid body chemoreceptors are:

1. Stimulated by a decrease in pO2 of arterial blood
2. Stimulated in an hypotensive subject at rest
3. Subject to a blood flow of over 50ml/100g per minute
4. Inhibited by a decrease in pH of arterial blood

A: 1,2,3 Correct
B: 1,3 Correct
C: 2,4 Correct
D: 4 Correct
E: All Correct

Back 115

ANSWER B

Answer A: low BP increase breathing via carotid chemo receptors

Front 116

Concerning the membrane potential of cardiac muscle:

1. Phase 2 is associated with efflux of calcium ions
2. Phase 3 is produced by an efflux of potassium ions
3. Slowing of phase 3 decreases the QT interval
4. Verapamil blocks slow calcium currents

A: 1,2,3 Correct
B: 1,3 Correct
C: 2,4 Correct
D: 4 Correct
E: All Correct

Back 116

ANSWER C

Front 117

The cardiovascular response to cooling to 31 degrees centigrade in a healthy 20 year old is likely to include:

1. Bradycardia.
2. Prolongation of the PR interval.
3. Prolongation of the QT interval.
4. Ventricular fibrillation.


A: 1,2,3 Correct
B: 1,3 Correct
C: 2,4 Correct
D: 4 Correct
E: All Correct

Back 117

ANSWER A

Front 118

The component of the pulmonary artery wedged pressure (PAWP) trace which most accurately reflects the left ventricular end-diastolic pressure is:

A. The peak of the 'V' wave.
B. The trough of the 'X' descent.
C. The peak of the 'A' wave.
D. The trough of the 'Y' descent.
E. The mean value of the PAWP.

Back 118

ANSWER C

Front 119

A volunteer sits with his left arm in a water bath maintained at 42 centigrade and his right arm in a bath at 4 centigrade.

1. The arterial PO2 is higher in his left arm than in his right.
2. The arterial PO2 is lower in his right arm than in his aortic root.
3. The arterial O2 content is the same in both arms.
4. The arterial PO2 will be the same in both arms if temperature corrections are not applied to the measurements.

A 1,2,3 Correct
B: 1,3 Correct
C: 2,4 Correct
D: 4 Correct
E: All Correct

Back 119

ANSWER E