Cardiac cycle

Question 1

Cardiac cycle

Answer 1

Period from the beginning of one heart beat to the beginning of the next
Divided into systole and diastole

Question 2

Diastole

Answer 2

Ventricles fill with blood entering via the atria and venous system
To fill, ventricular pressure must be low - equivalent to that in venous system

Question 3

Systole

Answer 3

Ventricles eject blood into arterial system

To empty, ventricular pressure must be high, equivalent to that in arterial system

Question 4

Cardiac cycle is initiated by:

Answer 4

SA node

Question 5

Central venous pressure

Answer 5

Low (1-5 mm Hg)

Question 6

Arterial pressure

Answer 6

High (100 mm Hg)

Question 7

Cardiac cycle

Answer 7

Atria contract to eject blood to ventricles
Bicuspid valve open 
Ventricles relaxed and full with blood 
Pressure on Ventricles low 
Bicuspid valve closes 
Ventricle contracts 
Pressure rises, 1st heart sound
Pressure greater in ventricle 
Aortic valve opens 
Blood enters aorta 
Ventricle relaxes 
Aortic valve closes
Pressure falls in ventricle 
2nd heart sound

Question 8

2 heart sounds heard with stethoscope

Answer 8

1st "lub sound" 
longest and loudest 
Occurs at beginning of systole 
2nd "dub" sound 
occurs at end of systole 
caused by closure of aortic and pulmonary valves

Question 9

Normal heart rate

Answer 9

75 bpm

Question 10

Cardiac cycle lasts

Answer 10

0.8 seconds