RESPIRATORY: 601

Question 1

What are the 3 forms by which CO2 is transported from the tissues to the lungs?

Answer 1

1. HCO3
2. Carbaminohemoglobin or HbCO2
3. Dissolved CO2

Question 2

What is the most common form by which CO2 is transported in the body?

Answer 2

HCO3 (90%) in the plasma

The other 2 are 5% each - carbaminohemoglobin and dissolved CO2.

Question 3

What is carbaminohemoglobin?

Answer 3

CO2 bound to Hb at N-terminus of globin (NOT heme)

Question 4

When CO2 is bound to Hb, does this favor the taut or relaxed form?

Answer 4

Taut - remember O2 unloaded in the tissues, taut in the tissues

Question 5

Explain why CO2 is unloaded by hemoglobin in the lungs.

Answer 5

1. Oxygenation of Hb promotes dissociation of H+ from Hb
2. This shifts equilibrium toward CO2 formation
3. CO2 is released from the RBC’s

Question 6

What is the Haldane effect?

Answer 6

Property of hemoglobin - deoxygenation increases its ability to carry CO2

Question 7

What is the Bohr effect?

Answer 7

In peripheral tissue, increased H+ from tissue metabolism shifts curve to the right, unloading O2.

Question 8

What is the equation for the reversible reactions of carbonic anhydrase?

Answer 8

CO2 + H2O H2CO3 H + HCO3

Question 9

In high altitude, what happens to ventilation?

Answer 9

Increase

Question 10

Explain what happens to PaO2 and PaCO2 in response to high altitude.

Answer 10

Decreased atmospheric oxygen –> decreased PaO2 –> increased ventilation –> decreased PaCO2

Question 11

What happens to erythropoietin in response to high altitude?

Answer 11

Increase (leading to increased hematocrit and Hb)

Question 12

Why is 2,3-BPG increased in response to high altitude?

Answer 12

Binds to Hb so that Hb releases more oxygen

Question 13

What cellular change is associated with a response to high altitude?

Answer 13

Increased mitochondria

Question 14

What renal change is associated with a response to high altitude?

Answer 14

Increased renal excretion of bicarbonate to compensate for the respiratory alkalosis

Question 15

What cardiac change can result from chronic exposure to high altitude and why?

Answer 15

Right ventricular hypertrophy due to chronic hypoxic pulmonary vasoconstriction

Question 16

What drug can you use to augment renal excretion of bicarbonate?

Answer 16

Acetazolamide

Question 17

What happens to O2 and CO2 in response to exercise?

Answer 17

Increased O2 consumption and CO2 production

Question 18

What happens to ventilation in response to exercise?

Answer 18

Increases to meet oxygen demand

Question 19

What happens to V/Q ratio in response to exercise?

Answer 19

Becomes more uniform from apex to base

Question 20

What happens to pulmonary blood flow in response to exercise?

Answer 20

Increase due to increase in cardiac output

Question 21

How does exercise affect the body’s pH?

Answer 21

Decreases (secondary to lactic acidosis)

Question 22

What happens to PaO2 and PaCO2 in response to exercise?

Answer 22

No change but increase in venous CO2 content and decrease in venous O2 content