CVS 2 The Heart As A Pump Flashcards
Name the valves on the left side of the heart
Mitral
Aortic
Name the valves on the right side of the heart
Tricuspid
Pulmonary
How to valves prevent back flow?
Valve cusps are pushed open (due to differential pressure) to allow blood flow and close to seal
What prevent inversion of tricuspid and mitral valves?
Papillary muscles via chordae tendineae
What valve has two leaflets?
Mitral
Stroke volume definition
Amount of blood pumped out per beat
Systole meaning
Contraction and ejection of blood from ventricles
Disastole meaning
Relaxation and filling of ventricles
What type of pressure is systemic circulation under?
High
What type of circulation is under high pressure?
Systemic
What type of pressure is pulmonary circulation under?
Low
What type of circulation is under low pressure?
Pulmonary
What do the papillary muscles and chordae tendineae do?
Attach to the mitral and tricuspid valve to prevent inversion in systole
Explain the process of conduction
1- pacemaker cells in the SAN generate action potential
2- atrial systole
3- AP reaches AVN along the bundle of His
4- AP delayed (~120 ms) to ensure atria have finished contracting
5- AP spreads down septum
6- spreads through ventricular myocardium from inner (endocardial) surface to outer (epicardial) surface
7- purkinje fibres causes ventricles to contract from apex up - ventricular systole
What are the 7 stages in the cardiac cycle?
1- atrial contraction
2- isovolumetric contraction
3- rapid ejection
4- reduced ejection
5- isovolumetric relaxation
6- rapid filling
7- reduced filling
What letters are used for ECG wave?
PQRST
What causes the P wave?
Atrial depolarisation
What causes the QRS wave?
Ventricular depolarisation
What causes the T wave?
Ventricular repolarization
What causes the first heart sound?
Closure of mitral and tricuspid valve
What causes the second heart sound?
Closure of aortic and pulmonary valves
What is ventricular filling making a sound a sign of?
Pathology in adults
Normal in children
Types of abnormal valve function
Stenosis
Regurgitation
What is valve stenosis?
Valve doesn’t open enough
Causes obstruction of blood when valves open
Causes of stenosis
Degenerative - calcification or fibrosis
Congenital - bicuspid form of valve
Chronic rheumatic fever > inflammation
Degenerative meaning
Progressive loss of function
Congenital meaning
From birth
Effects of aortic valve stenosis
Less blood can get through valve
- Increased LV pressure > LV hypertrophy
- Left sided heart failure > angina and syncope
- Shear stress > microangiopathic haemolytic anaemia
Syncope meaning
Fainting
What is the main cause of mitral valve stenosis?
Rheumatic fever
Effects of mitral valve stenosis
- increased LA pressure
- pulmonary oedema, dyspnea and pulmonary hypertension leading to RV hypertrophy
- LA dilation > atrial fibrillation > thrombus formation
- LA dilation > oesophagus compression > dysphagia
Dyspnea meaning
Laboured breathing
Dysphagia meaning
Difficulty swallowing
What is a pulmonary oedema?
Fluid accumulation in the air spaces and parenchyma (tissue) of the lungs
What is valve regurgitation?
Valve doesn’t close all the way
Causes back leakage
Causes of aortic valve regurgitation
- aortic root dilation - leaflets pulled apart
- valvular damage
Effects of aortic valve regurgitation
- blood flows back into LV in systole
- increased stroke volume
- increased systolic pressure
- decreased diastolic pressure
- bounding pulse > Quinke’s sign
- LV hypertrophy
What is Quinke’s sign?
Capillary pulsations upon light compression to tip of fingernail
Causes of mitral valve regurgitation
- myxomatous degeneration > weakens tissue > prolapses of mitral valve
- damaged papillary muscles due to heart attack
- left heart failure > LV dilation > stretched valve
- rheumatic fever > leaflet fibrosis > disrupts seal formation
Myoxmatous degeneration meaning
Deterioration of connective tissue
Effects of mitral valve regurgitation
Blood leaks back > increased pre load > LV hypertrophy
Describe the pathway blood takes from the vena cava to the aorta
1- deoxygenated blood enters right atrium through superior and inferior vena cava
2- tricuspid valve opens
3- blood fills right ventricle
4- pulmonary valve opens
5- blood leaves via pulmonary artery to lungs
6- oxygenated blood enters left atrium through pulmonary vein
7- mitral valve opens
8- blood fills right ventricle
9- aortic valve opens
10- oxygenated blood leaves through aorta to the body
What causes the dicrotic notch?
Aortic valve closes
Short period of increased pressure
What is the approximate stroke volume?
70 ml blood per beat
Valve positions of atrial contraction
MT open
AP closed
Valve positions of isovolumetric contraction
MT closed
AP closed
Valve positions of rapid ejection
MT closed
AP open
Valve positions of reduced ejection
MT closed
AP open
Valve positions of isovolumetric relaxation
MT closed
AP closed
Valve position of rapid filling
MT open
AP closed
Valve positions of reduced filling
MT open
AP closed
How long does systole occur for?
~0.35 s
How long does diastole occur for?
~ 0.55 s
What is the dicrotic notch a marker of?
End of systole
Start of diastole
In arteries
Main cause of mitral valve stenosis
Rheumatic fever
How is electrical activity in the heart initiated?
Spontaneous depolarisation
What is heard with an aortic valve stenosis?
Crescendo descrescendo murmur
What is heard in aortic valve regurgitation?
Early decrescendo diastolic murmur
What is heard in mitral valve regurgitation?
Holosystolic murmur
What is heard in mitral valve stenosis?
Snap as valve opens
Diastolic rumble
What chamber of the heart can cause dysphagia and how?
Left atrium
Can compress the oesophagus can dilated
Auscultations of the heart valves
Apt. M #2245
- Aortic - right side 2nd intercostal space on sternal edge
- Pulmonary - left side 2nd intercostal space on sternal edge
- Tricupsid - left side 4th intercostal space on lower sternal border
- Mitral - left side 5th intercostal space in midcalvicular line
What sided heart murmurs are louder in inspiration?
RILE
Right - Inspiration
What sided heart murmurs are louder in expiration?
RILE
Left - Expiration
Where can the aortic valve be auscultated?
Apt. M #2245
Right side
2nd intercostal space on sternal edge
Where can the pulmonary valve be auscultated?
Apt. M #2245
Left side
2nd intercostal space on sternal edge
Where can the tricupsid valve be auscultated?
Apt. M #2245
Left side
4th intercostal space
On lower left sternal border
Where can the mitral valve be auscultated?
Apt. M #2245
Left side
5th intercostal space
In midclavicular line
