Respiratory Physiology- Gas Transport in the Blood

Question 1

Henry’s Law

Answer 1

The amount of gas dissolved in a type and volume of liquid at a constant temperature is proportional to the partial pressure of the gas in equilibrium with the liquid

Question 2

How is O2 transported in blood?

Answer 2

It binds to Hb in blood
Hb+O2 form a reversible combination
- Each Hb has four haem groups, each of which binds to an oxygen molecule

Question 3

Oxygen Delivery index

Answer 3

DO2I (ml/min/m^2)=CaO2(ml/L) x CI (L/min/m^2)

CaO2= oxygen content of arterial blood
CI= cardiac index (relates CO to SA of body)

Question 4

Oxygen content of arterial blood

Answer 4

CaO2= 1.34 x [Hb] x SaO2

Question 5

Factors which impair oxygen delivery to tissue

Answer 5

Resp disease
- decreased PaO2-> decreased [Hb]-> decreased O2 content
Anemia
- decreased [Hb]-> decreased O2 content
Heart failure
- decreased CO

Question 6

How does foetal Hb differ from adult Hb?

Answer 6

• HbF has 2 gamma and 2 alpha subunits; HbA has 2 beta and 2 alpha subunits
• HbF has greater affinity for O2 as it interacts less with BPG in RBC

Question 7

Where is myoglobin present?

Answer 7

Skeletal and cardiac muscle

Question 8

Function of Mb

Answer 8

Short term O2 storage in anaerobic conditions

Indicates muscle damage if present in blood

Question 9

How is CO2 transported in the blood?

Answer 9

In solution- 10%
As bicarbonate- 60%
As carbamino compunds- 30%

Question 10

Haldane effect

Answer 10

Removing O2 from Hb increases Hb’s ability to pick up CO2 and CO2 generated H+

Question 11

Bohr effect

Answer 11

Hb’s O2 binding affinity is inversely related both to acidity and to the concentration of CO2

Question 12

What does the Bohr and Haldane effect work together to facilitate?

Answer 12

Freeing O2

CO2 and CO2 generated H+ uptake in tissues