Primary FRCA Course CVS Physiology Exam Prep Questions Flashcards
Coronary blood flow:
A. Is approximately 500 mL/min at rest
False. Resting coronary BF is around 250 mL/min
Coronary blood flow:
Supplies muscle that extracts 40 mL/L of oxygen per minute at rest
False. Coronary O2 extraction is about 110 mL/L/min (55-65% of the available content)
Coronary blood flow:
Is altered directly by vagal activity
False. There is no direct parasympathetic innervation to the coronary vessels
Coronary blood flow:
Ceases in systole
False. Left sided coronary flow is reduced during systole, but does not cease
Coronary blood flow:
Undergoes autoregulation
True. It autoregulates between a MAP range of 50-120 mmHg
In the cardiac cycle:
Left ventricular volume is maximal at the end of atrial systole
True. Atrial contraction contributes to final part of ventricular filling
In the cardiac cycle:
The mitral valve closes by contraction of the papillary muscles
False. The papillary muscles maintain the correct tension in the chordae tendineae and so prevent mitral valve prolapse
In the cardiac cycle:
The left ventricular pressure is maximal just before the aortic valve opens
False. LV pressure continues to rise after aortic valve opening
In the cardiac cycle:
The ejection fraction is normally about 85%
False. Normal ejection fraction is around 70%
In the cardiac cycle:
The dicrotic notch is due to rebound of the aortic valve
False. The elastic aortic wall is stretched during peak ejection and then rebounds after aortic valve closure to produce a slight rise in arterial pressure, creating the dicrotic notch
In a healthy adult human heart the:
Left ventricular end systolic volume is approximately 30 mL
True. Normal LVESV is 30 mL
In a healthy adult human heart the:
First heart sound coincides with the onset of ventricular systole
True. The start of systole is defined by the closure of the mitral and tricuspid valves, which generate the first heart sound
In a healthy adult human heart the:
Stroke volume is approximately 70 mL
True. Normal SV is 70 mL
In a healthy adult human heart the:
Left ventricular end-diastolic pressure is about 50 mmHg
False. Normal LVEDP is 10 mmHg
In a healthy adult human heart the:
Second heart sound is caused by closure of the aortic and pulmonary valves
True. Aortic and pulmonary valve closure generate the second heart sound
Pulmonary vascular resistance:
Is increased in chronic hypoxia
True. Hypoxia produces pulmonary vasoconstriction, increasing PVR
Pulmonary vascular resistance:
Has a value appoximately one-sixth that of the systemic circulation
True. Mean PAP is 15 mmHg (around one sixth of systemic MAP), with both circulations having the same flow
Pulmonary vascular resistance:
Can be measured using a flow-directed balloon catheter with a thermistor tip
True. A Swan-Ganz catheter can measure cardiac output and PA pressure, enabling the PVR to be calculated
Pulmonary vascular resistance:
Is increased by isoprenaline
False. The role of adrenoreceptors in the pulmonary circulation is minor and still remains uncertain, but beta-2 agonism probably leads to modest pulmonary vasodilatation
Pulmonary vascular resistance:
Is decreased by 5-hydroxytryptamine (5-HT)
False. 5-HT produces pulmonary vasoconstriction, raising PAP
In the normal adult heart:
Mitral valve closure occurs before tricuspid valve closure
True. The mitral valve closes fractionally before the tricuspid, although it may well be heard as a single sound
In the normal adult heart:
Pulmonary valve closure occurs before aortic valve closure
False. The pulmonary valve closes fractionally after the aortic valve; this delay is slightly greater during inspiration
In the normal adult heart:
Atrial contraction is of more importance to ventricular filling if the heart rate increases
True. Total diastolic time falls as the HR increases, increasing the importance of active filling by atrial contraction
In the normal adult heart:
There is isometric contraction of the left ventricle after the aortic valve opens
False. Isovolumetric contraction occurs before aortic valve opening
In the normal adult heart:
The aortic valve cusps are immobile during ventricular filling
True. The aortic valve should be closed during ventricular filling
The Pressure:
Drop across major veins is simular to that across the major arteries
True. The largest pressure drop occurs across the arterioles; the drop across the major arteries and major veins are both small
The Pressure:
Drop across the hepatic portal bed is similar to that across the splenic vascular bed
False. The hepatic portal bed is a very low pressure/low resistance one
The Pressure:
In the hepatic portal vein is approximately 3 times higher than that in the inferior vena cava
False. Normal hepatic portal vein pressure is 5-10 mmHg, little different from that in the IVC
The Pressure:
Drop across the vascular bed in the foot is greater when standing than when lying down
False. When standing both the arterial and venous pressures in the foot increase to the same extent, leaving the pressure drop unchanged
The Pressure:
Drop across the pulmonary circulation is the same as across the systemic circulation
False. The drop across the pulmonary circulation is only about a sixth of that in the systemic circulation
In the central venous pressure waveform:
The c wave occurs after ventricular systole
False. The c wave occurs during early ventricular contraction (systole), as the closed tricuspid valve bulges back into the right atrium
In the central venous pressure waveform:
The v wave is caused by atrial contraction
False. The v wave represents atrial filling whilst the tricuspid valve is still closed
In the central venous pressure waveform:
The a wave is absent in atrial fibrillation
True. The a wave results from atrial contraction, so is absent in AF
In the central venous pressure waveform:
The a wave corresponds with the closure of the aortic valve
False. The a wave occurs in late diastole, long after aortic valve closure
In the central venous pressure waveform:
The v wave occurs during diastole
True. The v wave occurs during ventricular relaxation (diastole) but before the tricuspid valve opens - this is according to e-LfH but is debatable. Most time-pressure graphs would have the peak of the v-wave occurring on the cusp of systole and diastole.
With reference to the mechanical events in the cardiac cycle in a normal adult human:
The left ventricle ejects more blood per beat than the right ventricle
False. The ventricles must eject equal volumes of blood
With reference to the mechanical events in the cardiac cycle in a normal adult human:
The mitral valve opens when the left atrial pressure exceeds the left ventricular pressure
True. This is what opens the mitral valve
With reference to the mechanical events in the cardiac cycle in a normal adult human:
During strenuous work, the left ventricular end-diastolic volume may be double than at rest
False. It increases by about 10%. Left-ventricular end systolic volume decreases by about 10% due to increased ejection fraction.
With reference to the mechanical events in the cardiac cycle in a normal adult human:
The pulmonary valve opens when the right ventricular pressure reaches 20-25 mmHg
False. The pulmonary valve opens at a pressure of around 10-12 mmHg
With reference to the mechanical events in the cardiac cycle in a normal adult human:
During diastole, the left ventricular pressure is about 70 mmHg
False. LV pressure during diastole falls to around 5 mmHg