Gas Exchange (3)

Question 1

What is pulmonary ventilation?

Answer 1

The volume of air breathed in and out per minute

Question 2

What is alveolar ventilation?

Answer 2

The volume of air exchanged between atmosphere and alveoli per minute (represents new air available for gas exchange with blood)

Question 3

What is anatomical dead space?

Answer 3

Inspired air that remains in the airways where it is not available for gas exchange

Question 4

What increases pulmonary ventilation and what is more advantageous?

Answer 4

Increase depth (tidal) and rate . Due to dead space , deep breathing is more advantageous.

Question 5

What 2 things does the transfer of gases between the body and atmosphere depend on and explain them?

Answer 5

Ventilation- the rate at which gas is passing through the lugs
Perfusion-the rate at which blood is passing through the lugs

Question 6

What is alveolar dead space?

Answer 6

Ventilated alveoli which are not adequately perfused with blood

Question 7

What is physiological dead space?

Answer 7

Anatomical dead space and the alveolar dead space

Question 8

What matches airflow to blood flow?

Answer 8

Local controls act on smooth muscles of airways and arterioles

Question 9

What 4 factors influence the rate of gas exchange across the alveolar membrane?

Answer 9

1) Partial pressure gradient of O2 and CO2
2) Diffusion coefficient for O2 and CO2
3) Surface area of alveolar membrane
4) Thickness of alveolar membrane

Question 10

What is Daltons law of partial pressure?

Answer 10

The total pressure exerted by a gaseous mixture = sum of the partial pressures of each individual component in the gas mixture

Question 11

What determines the pressure gradient for a gas?

Answer 11

Partial pressure of that gas

Question 12

What is the pressure of inspired air?

Answer 12

atmospheric pressure - water pressure

Question 13

What is the diffusion coefficient?

Answer 13

The solubility of gas in the membrane

Question 14

Which gas has a higher diffusion coefficient?

Answer 14

The diffusion coefficient for CO2 is 20 times that of O2

Question 15

What is Fick’s law of diffusion?

Answer 15

The amount of gas that moves across a sheet of tissue in unit of time is proportional to the area of the sheet but inversely proportional to its thickness

Question 16

How does surface area and a thin membrane affect gas exchange ?

Answer 16

Lungs provide a very large surface area with thin membranes to facilitate effective gas exchange. Airways divides repeatedly and small airways form out pockets to increase surface area

Question 17

What are the non-respiratory functions of respiratory system?

Answer 17

1) route for water loss and heat elimination
2) Enhances venous return
3) help maintain normal acid-base balance
4) Enables speech, singing
5) Defends against inhaled foreign matter
6) Removes,modifies,activates/inactivates various materials passing through the pulmonary circulation
7) nose serves as the organ of smell

Question 18

What is partial pressure?

Answer 18

The pressure that gas that would exert if it occupied the total volume for the mixture in the absence of other components

Question 19

What Is alveolar gas equation?

Answer 19

PAO2= PIO2 - (PaCO2/0.8)
PAO2- partial pressure of alveolar air
PiO2- partial pressure of O2 in inspired air
PaCO2- partial pressure of CO2 in arterial blood