PBL 1- Heart murmur Flashcards
What are the functions of the CV system?
Transport of nutrients, oxygen, waste products around the body
Transfer of heat (generally core to skin)
Buffers body pH
Transport of hormones (e.g. adrenaline from adrenals)
Assists in response to infection
Assists in formation of urine-filtration and circulation
What are the atrioventricular valves?
Tricuspid valve
Bicuspid/ Mitral valve
What are the semilunar valves?
Pulmonary Valve
Aortic Valve
What are the associated structure and function of atrioventricular valves?
Chordae tendinae connect the valves to the papillary muscles.
when relaxed- chordae tendinae are loose
when contracts- chordae tendinae tenses and prevents regurgitation of blood back into the atria.
What are the associated structure and function of semilunar valves?
The semilunar valves prevent the backflow of blood into the right and left ventricles.
They do NOT have Chordae Tendinae.
What is the structure of the Serous Pericardium.
Serous Pericardium is a sac of fluid that has 2 walls:
- Outer Parietal layer: made of connective tissue and holds heart in place.
- Inner Visceral layer- forms the epicardium (outer layer of heart)
Pericardial fluid-fills the space between the 2 layers and allows lubrication of heart/ prevents friction.
What is the structure of the myocardium?
it is the muscular middle layer.
has cardiac myocytes
has coronary vessels
What is the structure of the endocardium?
it is the innermost layer of the heart
- made of endothelium
- lines the heart chambers and valves
Define the cardiac cycle.
The cardiac events that occur from the beginning of one heartbeat to the beginning of the next.
What is an action potential in the heart?
AP is spontaneously generated by the SA node. The AP travels from SA node intro the atria, through the AV valves into the ventricles.
What is the SA node?
Sino atrial node.
Cluster of cells located in the R atrium of the heart.
It is the heart’s natural pacemaker.
Functions to spontaneously generate APs that travels through the heart via the electrical conduction system.
Describe the cardiac cycle.
Ventricular filling (diastole):
- large amounts of blood in the right and left atria because AV valves are closed.
- AV valves open because atrial pressure > ventricular pressure
- Blood flows from atria into ventricles
- -> rapid filling of the ventricles.
Isovolumetric Contraction (systole)
- The ventricular pressure increases abruptly causing the AV valves to close.
- The ventricles begin to contract in this closed chamber.
Ejection (systole)
- ventricular pressure > atrial pressure
- semilunar valves open
- blood is ejected at a high pressure from the ventricles into the arteries
Isovolumteric relaxation (diastole)
- the ventricles relax
- intraventricular pressure drops
- blood flows back against the cusps of the semilunar valves and forces them to close
What is End-Diastolic Volume (EDV)?
The amount of blood remaining in each ventricle at the end of ventricular diastole.
What is End-Systolic Volume (ESV)?
The amount of blood remaining in each ventricle at the end of ventricular systole.
What are Cardiac Myocytes?
Cardiac myocytes are cardiac muscle cells. Each myocardial cell contains myofibrils.
What is the 1st heart sound and how is it produced.
S1 Lubb- closing of the AV valves (mitral & tricuspid)
What is the 2nd heart sound and how is it produced.
S2 Dubb- closing of the semilunar valves (aortic & pulmonary)
What are abnormal sounds and how are they produced.
S3 third sound- can be heard in early diastole and is caused by rapid ventricular filling. common in young people and athletes
S4 fourth sound- occurs just before S1 and is due to forceful atrial contraction against a stiff ventricle. always abnormal and can occur in presence of ventricular hypertrophy.
Where are the heart sounds assessed on a chest examination?
Aortic valve- right 2nd intercostal space
Pulmonary valve- left 2nd intercostal space
Tricuspid valve- inferior left sternal margin
mitral valve- left 5th intercostal space and mid-clavicular line
What are heart murmurs?
Heart murmurs are abnormal sounds during the normal heartbeat cycle such as whooshing or swishing made by turbulent blood in or near the heart.
can be congenital or develop later in life. they are not a a disease but may indicate an underlying heart problem.
Describe Aortic Stenosis.
Obstruction to aortic outflow from the left ventricle into the aorta during systole.
can be caused by rheumatic fever, age related calcification and congenital bicuspid aortic valve
left ventricular hypertrophy
Describe Mitral regurgitation.
the backflow of blood from the left ventricle to the left atrium during systole.
Describe Aortic regurgitation.
incompetent aortic valve that allows blood to leak back from the aorta into the left ventricle during diastole.
results in high stroke volume
Describe Mitral Stenosis.
prevents the free flow of blood from the left atrium into the left ventricle, and slows ventricular filling during diastole
What does stenosis and regurgitation mean.
Stenosis- narrowing
Regurgitation- leakage
What is an innocent murmur?
There is no underlying cardiac pathology.
children- high flow through normal blood vessels
adults- increased cardiac output
What is coronary arterial flow?
Coronary arterial flow is diastolic
Difference between diastole and systole
Systole- heart contracts (atria)
Diastole- heart is relaxed (ventricles)
What are systolic murmurs
Murmurs during systole (between S1 and S2)
Can be due to mitral regurgitation or Aortic stenosis
MR ASS
What are diastolic murmurs
Murmurs during diastole (before S1)
Can be due to mitral stenosis or Aortic regurgitation
MS AR
