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34 Cards in this Set
- Front
- Back
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What does excitation of the myocardial cells actually cause? What about repolarization?
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Excitation --> Contraction
Repolarization --> Relaxation |
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Is diastole relaxing, or contracting?
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Relaxing
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Is systole relaxing, or contracting?
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Contraction
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How long after atrial systole is ventricular systole?
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0.1-0.2s
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The volume filling a ventricle just before it contracts is known as the...
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End-diastolic volume
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What is the end-diastolic volume?
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The volume in a ventricle just before it contracts
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How much blood, as a fraction of its total, does ventricle pump out after it contracts? What is this volume called?
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2/3rds of the blood inside a ventricle is pumped out. Called the *stroke volume*
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What is the stroke volume?
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The amount of blood that is pumped out of a ventricle in one contraction
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A ventricle only pumps out about 2/3rds of the blood in it during a contraction. What is the name for the volume left in the ventricle after a contraction?
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The residual/end-systolic volume
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The proportion of blood ejected during systole is called the...
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ejection fraction
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What is the 'ejection fraction'?
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The proportion of blood ejected during systole
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What are the normal values for an adult human at rest for:
Stroke volume Residual Volume Ejection fraction |
Stroke volume 75 ml
Residual volume 50 ml Ejection fraction ~0.6 |
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What drives the opening and closing of heart valves?
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Pressure differences
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The chordae tendinae connect what to what?
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Cusps of valves to papillary muscles
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These connect cusps of valves to papillary muscles
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Chordae tendinae
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How long does a cardiac cycle last for in a normal individual? What's the break down for systole and diastole?
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~0.8s
~0.3 systole ~0.5 diastole |
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What is a phonocardiogram?
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A recording of the heart sounds
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What is the name for the device used to record heard sounds?
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A phonocardiogram
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As a percentage, how much of the blood in the right atrium goes into the right ventricle during systole?
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~20% of the volume in the atria
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What is isovolumetric contraction?
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For a short time, the semilunar valves at the entrance to the pulmonary artery and the aorta are shut along with the AV valves. That is, the intraventricular pressure rises but the volume does not change - this is isovolumetric contraction
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As blood is forced from the left ventricle to the aorta, it causes the walls of the aorta to stretch, thereby increasing the pressure within the aorta to around...
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16 kPa (120 mmHg) (systolic pressure)
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When the aortic valve closes, there is a brief surge in aortic pressure. This gives rise to the...
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Incisura or 'dichorotic notch'
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What is the 'incisura' or 'dichorotic notch'?
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When the aortic valve closes, there is a brief surge in aortic pressure. This gives rise to the incisura or 'dichorotic notch'
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What is diastolic pressure of the aorta?
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10.6 kPa (80 mmHg)
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How many valves are there between the RA and the internal jugular vein? What's the relevance of this?
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No valves
Pressure changes of the RA are reflected in the jugular pulse. Juggular pulsation can be seen only during heart failure, when the body is at 45* and the head tilted slightly to the left |
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How do you calculate the 'work done' of the heart?
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Change in pressure * change in volume
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Change in pressure * change in volume = (wrt heart)
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'Work done' of the heart
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The work performed by the heart each time it beats is given by the area of the pressure-volume curve for ventricular contraction. This is known as...
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'Stroke work'
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The right and left ventricles pump the same volume of blood in systole. Why is it that the LV has to put in much more work to achieve this?
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The LV has to eject blood against a higher aterial pressure
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What is a heart *murmur*?
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Abnormal heart sounds are usually (not not invariably) of pathological origin, and are called murmurs
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The output of the RV is equal to that of the LV T/F
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T
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Approximately, how many litres of blood pass through the pulmonary vessels each minute?
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5 litres
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In the lungs, blood in the pulmonary capilaries is diverted from areas of a low PO2 or high PCO2 to an area of high PO2 or low PCO2
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This is the opposite of what happens in most other areas of the body (blood is normally directed to areas of low PO2/high PCO2 etc.)
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Blood flow throu ght eupright lung is greatest at the apex/base and least at the apex/base
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Greatest at base, least at apex
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