Gas Transport

Question 1

What are the two forms of O2 in the blood?

Answer 1

dissolved and associated with hemoglobin

Question 2

The amtoun of dissolved O2 in the blood is proportional to what?

Answer 2

the partial pressure of O2

0.0003 ml/mmHg/dL

Question 3

What will be the amount of O2 associated with hemoglobin at the 40 mmHg O2 of venous blood?

Answer 3

about 15 ml/dl

Question 4

What is maximal O2 binding to hemoglobin?

Answer 4

1.39 ml/g

Question 5

What is O2 saturation?

Answer 5

the amount of O2 combined with hemogllbin divided by the maximal O2 capacity of hemoglobin

Question 6

Normal O2 sat is over what for arterial blood? venous vlood?

Answer 6

over 95% for arterial blood and over 75% for venous blood

Question 7

What will shift the O2 dissociation curve to the RIGHT?

Answer 7

Anything that makes you need a higher pO2 for binding - it means there’s less affinity for O2

• decreased pH
• increased CO2
• increased temperature
• increased diphosphoglycerate
  (anything that happens during exercise)

Question 8

Does carbon monozide have a greater or lower affinity for hemoglobin than O2?

Answer 8

greater - 240 times greater

Question 9

How do you treat carbon monoxide poisoning?

Answer 9

1

Question 10

What are the three forms that CO2 is carried in the blood?

Answer 10

1. dissolved CO2
2. Bicarbonate
3. carbamino compounds

Question 11

How much CO2 is carried in dissolved form?

Answer 11

10%

Question 12

What’s the predominant way CO2 is carried?

Answer 12

bicarb

Question 13

How does bicarb move in regards to the RBC? What ion is affected?

Answer 13

bicarb can diffuse out of the RBC (unlike H+) and it’s exchanged for chloride (chloride shift)

Question 14

Why is deoxygenated hemoglobin a better carrier for CO2?

Answer 14

deoxygenated hemoglobin has more H+ in it = more acidic

Question 15

What percentage of CO2 is carried bound to Hb?

Answer 15

only 5% (more if O2 is low)

Question 16

What shape is the O2 dissociation curve and what shape is the CO2 dissociation curve?

Answer 16

THe O2 dissociation curve is sigmoidal while the CO2 dissociation curve is more linear

Question 17

Since the CO2 dissociation curve is much mor elinear and steeper than that of O2, what does this mean for the amount of CO2 that can be carried in the blood?

Answer 17

the blood can carry more CO2 than O2

Question 18

Bicarb concentration is largely controlled by what organ?

Answer 18

kidneys

Question 19

pCO2 is largely controlled by what organ?

Answer 19

lungs

Question 20

Respiratory acidosis is caused by what in general?

Answer 20

CO2 retention from ypoventilation or ventilation-perfusion mismatch

Question 21

Respiratory alkalosis is caused by what in general?

Answer 21

excessive exhalation of CO2 in hyperventilation or exposure to high altitude

Question 22

Once the hemoglobin gets to the capillaries in skeletal muscle, why does the O2 move into the tissue?

Answer 22

because the pO2 in muscle is very low - like 1-3 mmHg

Question 23

What molecule helps to keep the pO2 int he muscle uniform?

Answer 23

myoglobin

Question 24

In summary, how much O2 is transported in dissolved form in 1 dL the blood

Answer 24

.3 ml/Dl

Question 25

How much oxygen is carried on hemoblobin per dL of blood?

Answer 25

20 ml/dL

Question 26

What does anemia affect: maximum carrying capacity? pO2? O2 saturation?

Answer 26

reduces max carrying capacity, but doesn’t affect pO2 or O2 saturation

Question 27

How do you calculate acid base pH using the concentrations of HCO2 and pCO2?

Answer 27

pH = 6.1 + log [HCO3/(.03 x PCO2)]