Properties of Gases

Question 1

What is Boyle’s law?

Answer 1

Pressure of a gas is inversely proportional to its volume

Question 2

How do you calculate total pressure?

Answer 2

Partial pressure of all composite gases added together

Question 3

How do you calculate partial pressure?

Answer 3

Composition % * partial pressure

Question 4

What is atmospheric pressure?

Answer 4

101kPa = 1 atmosphere = 760 mmHg

Question 5

What is saturated vapour pressure?

Answer 5

6.28 kPa at body temp

Question 6

How do you calculate partial pressure of gases in moist air?

Answer 6

(total pressure - 6.28) * composition %

Question 7

How do you calculate amount of gas dissolved?

Answer 7

Partial pressure * solubility constant of gas

Question 8

What is the solubility coefficient solubility of O2 in plasma?

Answer 8

0.01 mmol/L/kPa

Question 9

How much dissolved oxygen is there in plasma?

Answer 9

0.13 mmol/L

Question 10

How do you calculate total content of gas?

Answer 10

Dissolved gas + gas bound to component

Question 11

What is alveolar pO2?

Answer 11

13.3 kPa

Question 12

What is alveolar pCO2?

Answer 12

5.3 kPa

Question 13

What factors affect rate of diffusion of gases?

Answer 13

Partial pressure gradient 
Surface area 
Thickness of diffusion distance 
Solubility of gas
Molecular weight of the gas

Question 14

Does CO2 or O2 diffuse quicker?

Answer 14

CO2

Question 15

Why does CO2 diffuse quicker?

Answer 15

More soluble

Question 16

What makes up the diffusion barrier in the lungs?

Answer 16

Fluid film lining alveolus
Epithelial cell of alveolus
Interstitial space
Endothelial cell of capillary 
Plasma 
Red cell membrane