Lecture 6

Question 1

Cardia Cycle

Answer 1

coordinated sequence of mechanical and electrical events that repeats with every heartbeat

Question 2

Heart rate of 75 beats/min, how long do cardiac cycles

Answer 2

0.8 sec

Question 3

Systole

Answer 3

1- Period of contraction and emptying

2- Atrial Systole and ventricular systole

Question 4

Diastole

Answer 4

1- Period of relaxation and filling

2- Atrial diastole and ventricular diastole

Question 5

Stroke Volume

Answer 5

1- Quantity of blood pumped out of either ventricle per beat

2- @ rest - 70 ml/beat; maximum -120 ml/beat

Question 6

Heart Rate

Answer 6

1- # of times the heart beats per minute

2- @ rest - 72 beats/min; maximum - 230 beats/min

Question 7

Cardiac Output

Answer 7

1- quantity of blood pumped by either ventricle per minute
2- @ rest - 5 L/min; maximum - 20-25 L/min
HR x SV = CO

Question 8

Venous Return (VR)

Answer 8

1- Quantity of blood returned to the heart per minute

2- normally, venous return equals CO

Question 9

End Diastolic Volume (EDV)

Answer 9

1- Quantity of blood remaining in either ventricle at the end of ventricular diastole
2- Average value is around 130 ml

Question 10

End Systolic Volume (ESV)

Answer 10

Quantity of blood remaining in either ventricle at the end of ventricular systole

Question 11

End of Isovolumetic ventricular relaxation

Answer 11

1- Left atrial pressure (LAP) exceeds left ventricular pressure (LVP), resulting in opening of the mitral valve
2- Ventricular filling ensues

Question 12

Ventricular Filling (3 Phases)

Answer 12

1- Rapid Passive Filling
2- Slow Passive Filling (Diastasis)
3- Atrial Systole

Question 13

Rapid Passive Filling

Answer 13

1- Blood flows quickly through the mitral valve and into the relaxed ventricle
2- ventricular volume increases
3- No muscle contraction occurs
4- 3rd heart sound produced

Question 14

Slow passive filling

Answer 14

1- Blood flows slowly through the mitral valve and into the relaxed ventricle
2- Venticular volume continues to increase
3- No muscle contraction occurs

Question 15

Atrial Systole

Answer 15

1- Left atrium must first be depolarized (note the location of the P wave just before atrial systole)
2- Atria contract
3- 4th heart sound produced
4- contribution of atrial contraction to ventricular filling is usually SMALL ( approx 10-15% of the total ventricular volume)
5- The left ventricle must first be depolarized ( note the location of the QRS complex just before IVC)
6- Ventricles contract and LVP pressure rises steadily, however no ejection of blood occurs as left ventricular volume remains constant

Question 16

Rapid Ventricular Ejection

Answer 16

1- The Left ventricle develops enough pressure such that LVP exceeds aortic pressure
2- The aortic semilunar valve opens and blood is ejected; Aortic pressure rises
3- Left Ventricular pressure continues to rise also

Question 17

Entering Back into Isovolumetric Relaxation

Answer 17

1- Once blood is ejected, LVP falls below aortic pressure and the aortic semilunar valve shuts
2- Second heart sound produced
3- Aortic pressure falls as blood runs off to arteries
4- T wave produced
5- The volume of blood remaining in the left ventricle after ejection is the ESV

Question 18

Isovolumetric ventricular relaxation

Answer 18

1- All four chambers of the heart are relaxed and all of its valves are closed
2- Ventricular volume is constant
3- Ventricular pressure is decreasing
4- Left atrium is filling with blood that has returned to it via the pulmonary veins
5- Atrial pressure is rising

Question 19

Dichrotic Notch

Answer 19

1- Closure of the aortic valve causes a brief rise in aortic pressure as back flowing blood rebounds off the closed valve cusps
2- The dichroic notch is significant in relation to coronary blood flow