PPT 4

Question 1

What is PCG?

Answer 1

phonocardiogram

• stethoscope is a simple one
• measures contractile activity of cardiohemic system (heart and blood together)
• recorded w microphones, pressure transducers or accelerometers

Question 2

Where does a heart sound originate from?

Answer 2

vibrations of the whole CV system, not valve leaflet movements

Question 3

What are the 2 main heart sounds

Answer 3

S1 - onset of ventricular contraction (systole)

S2 - closure of semilunar valves (diastole)

Question 4

What are the components of S1?

Answer 4

1. ventricles contract, sealing AV valves
2. abrupt tension of closed AV valves
3. semilunar valves open + blood oscillates btwn aorta/ventricle walls
4. turbulence of ejected blood in aorta/pulm. arts.

Question 5

What are the components of S2?

Answer 5

1. closure of aortic valve
2. close of pulmonary valve