cardiac cycle

Question 1

what is a phonocardiogram

Answer 1

chart of heart sounds

Question 2

what causes the S1 sound

Answer 2

AV valve closing (LUB sound)

Question 3

what causes S2 sound

Answer 3

closure of aortic and pulmonic valves (DUB)

Question 4

what causes S3 sound

Answer 4

rush of blood from the atrium into the ventricle as it starts relaxing (also mitral regurg

Question 5

what causes S4 SOUND

Answer 5

atrial contraction

Question 6

what happens in an A wave

Answer 6

atrial contraction (atrial systole)

Question 7

what happens in a C wave

Answer 7

atrial pressure decreases, atrial diastole

Question 8

what happens in an X descent

Answer 8

atrial diastole - atrium relaxes and tricuspid valve moves downward

Question 9

what happens in a V wave

Answer 9

back flow of blood after it hits closed AV valve

Question 10

what happens in Y descent

Answer 10

filling of the ventricle after tricuspid opening

Question 11

list the phases of the cardiac cycle

Answer 11

1. atrial contraction/systole
2. isovolumetric contration
3. rapid ejection
4. reduced ejection
5. isovolumetric relaxation
6. rapid ventricular filling
7. diastole

Question 12

in the normal dog, you only hear S1 and S2 heart sounds. what animal is different

Answer 12

horses - you hear all 4

Question 13

generalize what happens within the 5 phases of cardia cycle

Answer 13

1. atria fill
2. atria contract
3. ventricles fill
4. ventricles contract
5. arteries (pulmonary and aorta) fill

Question 14

describe this diagram of the cariac cycle. why does the atrial pressure increase in phase 3

Answer 14

because the atria are always filling, the ventricles being full put pressure on the atria until the arterial valves open.