The Cardiac Cycle

Question 1

Diastole

Answer 1

period between ventricular contractions

Question 2

Diastole Parts

Answer 2

1. Isovolumetric Relaxation
2. Ventricular Filling
3. Atrial Contraction

Question 3

Isovolumetric Relaxation

Answer 3

ventricles relaxed

AV and Semilunar Valves are closed

Question 4

Ventricular Filling

Answer 4

AV valves open, passive filling

Atrial Pressure > Ventricular Pressure

Semilunar valves closed

Question 5

Atrial Contraction

Answer 5

gives extra push of blood volume into ventricle

Atrial Systole

Question 6

Systole

Answer 6

period of ventricular contraction

Question 7

Systole Parts

Answer 7

1. Isovolumetric Contraction
2. Ventricular Ejection

Question 8

Isovolumetric Contraction

Answer 8

ventricles contract while valves are closed

Aortic Pressure > Ventricular Pressure

closed valves, tension developed with no shortening

Question 9

Ventricular Ejection

Answer 9

semilunar valves open, AV valves closed

Ventricular Pressure > Aortic Pressure

blood is ejected into aorta and pulmonary artery

Question 10

Cardiac Cycle on a Phonogram

Answer 10

1st = Lub: closing of AV valves
2nd = Dub: closing of the semilunar valves

Question 11

Volume of blood moved by the left ventricle is equal to…

Answer 11

volume of blood moved by the right ventricle

Question 12

End Systolic Volume (ESV)

Answer 12

50 mL

blood left over in the ventricle after ejection

Question 13

End Diastolic Volume (EDV)

Answer 13

120 mL

Question 14

Stroke Volume

Answer 14

End Diastolic Volume (EDV) - End Systolic Volume (ESV)

Question 15

Cardiac Output

Answer 15

Stroke Volume x Heart Rate

Question 16

Atrial Pressure

Answer 16

low pressure (10mmHg>)

increases during atrial systole and atrial filling (when AV valves are closed), can also increase during ventricular contraction

Question 17

Ventricular Pressure

Answer 17

first increase due to atrial systole, big increase during ventricular systole,

increase will continue through the first part of ventricular ejection

low point during AV valve opening,

Question 18

Aortic Pressure

Answer 18

follows peak of Ventricular pressure, blood pressure

includes Windkessel Effect from blood pressing against closed valves

when Aortic Pressure is greater than Ventricular Pressure semilunar valves close

Question 19

Diastolic Filling on the Pressure Volume Curve

Answer 19

starts at A ends at C

Initial pressure decrease due to ventricular relaxation

Question 20

Isovolumetric Contration on the Pressure Volume Curve

Answer 20

C to D

increase in pressure

Aortic Valve opens at D

Question 21

Ejection on the Pressure Volume Curve

Answer 21

D to E

pressure builds then falls

Aortic Valve closes at F

Question 22

Preload

Answer 22

amount of blood in the ventricles prior to contraction

venous return

increases in preload increase stroke volume

Question 23

Afterload

Answer 23

The pressure the heart has to work against to eject blood
| blood pressure

Increase in afterload decreases stroke volume

Question 24

Contractility

Answer 24

efficiency of muscle contraction

increases stroke volume when increased

Question 25

Inotropes

Answer 25

drugs that can effect the force of contraction in the heart muscle