4. Control Of Cardiac Output

Question 1

What is the average cardiac output?

Answer 1

5L/min

Question 2

What is the average stroke volume?

Answer 2

70ml

Question 3

What is the formula for cardiac output?

Answer 3

CO = SV x HR

Question 4

What is the formula for stroke volume?

Answer 4

SV = EDV - ESV

Question 5

Approx what percentage of the EDV is the stroke volume/is pumped out with each heart beat ?

Answer 5

67%

Question 6

How can you increase stroke volume in relation to EDV and ESV ?

Answer 6

• increase EDV

- Decrease ESV

Question 7

If total peripheral resistance decreases what happens to arterial and venous pressure ?

Answer 7

• arterial pressure decreases

- venous pressure increases

Question 8

If total peripheral resistance increases what happens to arterial and venous pressure ?

Answer 8

Arterial pressure - increases

Venous pressure - decreases

Question 9

If cardiac output decreases what happens to arterial and venous pressure ?

Answer 9

Arterial pressure - decrease

Venous pressure - increases

Question 10

If cardiac output increases what happens to arterial and venous pressure ?

Answer 10

Arterial pressure - increases

Venous pressure - decreases

Question 11

What is the typical end diastolic volume of the left ventricle ?

Answer 11

120ml

Question 12

What is the typical end diastolic pressure of the left ventricle ?

Answer 12

Approx 10mmHg

Question 13

What happens to the ventricle wall if they are less compliant?

What happens to the pressure in the ventricles if compliance is decreased?

Answer 13

More stiff = hypertrophy = difficult to Stretch

Pressure increases

Question 14

What is the normal sarcomere length ?

Answer 14

1.9 micro meters

Question 15

What is the optimum sarcomere length ?

Answer 15

2.2 micro meters

Question 16

What is afterload ?

Answer 16

Pressure/aortic impedance the heart has to pump against

Question 17

What is aortic impedance roughly similar to?

Answer 17

Arterial pressure

Question 18

What happens to the total peripheral resistance during exercise/increased metabolism ?

Answer 18

TPR REDUCES

Question 19

What is the typical pressure of the left atrium ?

Answer 19

8-10 mmHg

Question 20

What are the typical pressures of left ventricle during systole and diastole ?

Answer 20

Systole - 120mmHg

Diastole - 10mmHg

Question 21

What is the typical pressure of the right atrium ?

Answer 21

0-4mmHg

Question 22

What is the typical pressure of the right ventricle during diastole and systole?

Answer 22

Diastole - 4mmHg

Systole - 25mmHg

Question 23

What is average weight of typical heart?

Answer 23

350g

Question 24

What is the typical duration of a cardiac action potential?

In secs?
In ms?

Answer 24

0.28 secs

280ms

Question 25

What is the duration of a single contraction of the heart?

Answer 25

280ms

Question 26

Which valve in the heart has 2 cusps?

Answer 26

Mitral

Question 27

What can cause a s3 sound?

Answer 27

Ventricular filling

Question 28

What do the papillary muscles do?

Answer 28

Prevent valves from inverting during systole

Question 29

Which organ removes damaged erythrocytes ?

Answer 29

Spleen

Question 30

Which type of anaemia can result from aortic valve stenosis ?

Answer 30

Microangiopathic haemolytic anaemia

Question 31

Which organism results in rheumatic fever?

Answer 31

Streptococcal

Question 32

In >99% of cases rheumatic fever will result in which murmur ?

Answer 32

Mitral valve stenosis

Question 33

What is dysphagia ?

Answer 33

Difficultly swallowing

Question 34

What is dystonia?

Answer 34

Sustained/repetitive muscle contractions resulting in twisting & repetitive movements/abnormal fixed postures

Question 35

What is polydipsia?

Answer 35

Excessive thirst

Question 36

How can mitral valve stenosis result is dysphagia ?

Answer 36

= left atrium dilation = pressing on oesophagus = dysphagia