Lecture 2 PPT

Question 1

What does cardiac index measure?

Answer 1

CO while taking into consideration body surface area (BSA)

Question 2

What is a normal BSA?

Answer 2

1.7m^2

Question 3

What is a normal CI?

Answer 3

3L/ min/ m^2

Question 4

When is a female’s CI higher than a male’s?

Answer 4

Late term pregnancy (otherwise M> Fe)

Question 5

At what age does CI hit its peak, and how much is it?

Answer 5

10yo
4L/ min/ m^2

Question 6

Why does CI decline over time?

Answer 6

Declining metabolic demand (organ removed, muscle mass loss, less active, etc)

Question 7

What are some low metabolic states that will decrease CO?

Answer 7

Hypothyroidism, removal of organs/ limbs

Question 8

What does removal of body parts do to vascular resistance?

Answer 8

Increases because you are taking away a pathway option for the blood in a parallel circuit

Question 9

What are some high metabolic states that will increase CO?

Answer 9

Hyperthyroidism, BeriBeri, AV shunt

Question 10

How does an AV shunt increase CO?

Answer 10

By lowering vascular resistance/ adding additional pathway for blood to take

Question 11

What is BeriBeri?

Answer 11

Vitamin B1 deficiency, makes cells less use of energy less efficient

Question 12

What percentage of CO does the heart receive?

Answer 12

4%

Question 13

What percentage of CO does the brain receive?

Answer 13

14%

Question 14

What is the name of the drug that increases metabolic rate of tissues and was used for weight loss before pulled from the market?

Answer 14

Dinitrophenol

Question 15

What is the difference between mean circulatory filling pressure and mean systemic filling pressure?

Answer 15

Mean circulatory filling pressure takes into consideration pulmonary circulation (they are approximately the same value 7mmHg)

Question 16

What is normal intrapleural pressure?

Answer 16

-4 mmHg or -5 cmH2O

Question 17

At what point in the respiratory cycle does intrapleural pressure drop?

Answer 17

Inhalation

Question 18

How does inhalation affect cardiac filling?

Answer 18

Increases VR by lowering intrathoracic pressure

Question 19

What does opening the thorax or sustaining forced exhalation do to CO?

Answer 19

Decreases CO by increasing intrapleural pressure

Question 20

How much does forced exhalation raise intrapleural pressure?

Answer 20

+2mmHg

Question 21

What happens to Psf when RVR is increased?

Answer 21

It’s unchanged (same with decreased RVR)

Question 22

What percentage of cardiac output does the left kidney receive?

Answer 22

11% (together they receive 22%)

Question 23

What will happen to CO if arteries increase pressure, but veins make no change?

Answer 23

Decreased CO

Question 24

How does arterial specific vasodilator affect the venous return and CO curves? What would be an example of this? What does this do to RAP?

Answer 24

CO curve remains the same, venous return slope is shifted up to reflect decreased RVR–> Overall effect is increased CO s/t increased VR

ACE inhibitors

RAP increases

Question 25

How does a venous specific vasodilator lower the venous return curve? What would be an example of this?

Answer 25

Decreases delta P which decreases Psf and VR

NTG

Question 26

If a mixed vasodilator is given that dilates arteries and veins, what would be the over all resulting CO?

Answer 26

Decreased- the lowered VR from relaxed veins would outweigh the decrease in RVR that dilated arteries provides

Question 27

How does venous compliance affect VR?

Answer 27

The more compliant the veins are, the lower the Psf which will yield decreased CO

The less compliant the veins are, the higher the Psf which will yield higher CO

Question 28

In respect to their effect on CO, compare compliance and volume

Answer 28

Compliance is inversely related, while volume is directly related

Question 29

If only SVR is increased with no change in venous compliance, what effect will that have on CO?

Answer 29

Decreased (higher RVR)

Question 30

Describe the compensations that happen in heart failure to maintain CO

Answer 30

Initially, sympathetic output increases to increase tone on veins and increase VR. After days of this, sympathetic output will back off and the kidneys will have had time to retain water and Na+ to increase total volume, increasing RAP drastically